Preoperative parameters that predict postoperative patient-reported outcome measures and range of motion with anatomic and reverse total shoulder arthroplasty

The impact of mental health conditions on clinical and functional outcomes after shoulder arthroplasty: a systematic review

Background

Shoulder arthroplasty (SA) has been shown to improve quality of life, though outcomes may vary between individuals. Multiple factors may affect outcomes, including preoperative mental health conditions (MHCs). The goal of this systematic review was to evaluate the clinical and functional outcomes after SA in patients with MHC compared to patients without MHC.

Methods

This systematic review was performed in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines outlined by Cochrane Collaboration. A search of PubMed, the Medline Library, and EMBASE was conducted from inception until September 2023 to obtain studies reporting outcomes after total shoulder arthroplasty and reverse total shoulder arthroplasty in patients with and without MHC. Study characteristics and information on clinical and functional outcomes were collected. All included studies were case-control studies. The methodological quality of the included primary studies was appraised using the methodological index for nonrandomized studies scoring.

Results

Eleven articles published between 2016 and 2023 met inclusion criteria. In total, 49,187 patients, 49,289 shoulders, and five different MHC were included. 8134 patients in the cohort had a diagnosed MHC. The mean patient age was 67.8 years (range, 63.5-71.6 years), and 52.6% of the patients were female. The mean follow-up time was 35.5 months (range, 16.2-58.3 months). Reverse total shoulder arthroplasty was the most common type of procedure (25,543 shoulders, 51.8%). Depression and anxiety were the most reported psychiatric diagnoses (7990 patients, 98.2%). Patients with versus without MHC reported mean improvements of 38 and 42 in American Shoulder and Elbow Surgeons shoulder score and mean Visual Analog Scale pain improvements of 4.7 and 4.9, respectively. Mean complication rates of 31.4% and 14.2% were observed in patients with versus without MHC, respectively. The most prevalent surgical complication in patients with MHC was infection (1.8%), followed by prosthetic complication (1.7%), and adhesive capsulitis (1.6%).

Conclusions

Patients with MHC may have lower preoperative range of motion, worse postoperative shoulder function, and higher postoperative pain levels than patients without MHC. Patients with MHC demonstrated improvements in range of motion and functional outcomes after SA but had higher reported complication and revision rates when compared to patients without MHC. Depression and anxiety were the leading conditions correlated with lower outcomes in patients with MHC after SA. Preoperative physical therapy, mental health counseling, and expectation setting may help these patients reach the maximal achievable benefit from SA.

A machine learning analysis of patient and imaging factors associated with achieving clinically substantial outcome improvements following total shoulder arthroplasty: Implications for selecting anatomic or reverse prostheses

Background

Indications for reverse total shoulder arthroplasty(rTSA) continue to expand making it challenging to predict whether patients will benefit more from anatomic TSA(aTSA) or rTSA. The purpose of this study was to determine which factors differ between aTSA and rTSA patients that achieve meaningful outcomes and may influence surgical indication.

Methods

Random Forest dimensionality reduction was applied to reduce 23 features into a model optimizing substantial clinical benefit (SCB) prediction of the American Shoulder and Elbow Surgeon score using 1117 consecutive patients with 2-year follow up. Features were compared between aTSA patients stratified by SCB achievement and subsequently with rTSA SCB achievers.

Results

Eight combined features optimized prediction (accuracy = 87.1%, kappa = 0.73): (1) age, (2) body mass index (BMI), (3) sex, (4) history of rheumatic disease, (5) humeral head subluxation (HH) on computed tomography (CT), (6) HH-acromion distance on X-ray, (7) glenoid retroversion on CT, and (8) Walch classification on CT. A higher proportion of males (65.6% vs. 54.9%, p = 0.022), Walch B-C glenoid morphologies (49.5% vs. 37.9%, p < 0.001), and greater BMI (30.1 vs. 26.5 kg/m2, p = 0.038) were observed in aTSA nonachievers compared with aTSA achievers, while aTSA nonachievers were statistically similar to rTSA achievers.

Discussion

Patients with glenohumeral osteoarthritis and intact rotator cuffs that have a BMI > 30 kg/m2 and exhibit Walch B-C glenoids may be less likely to achieve the SCB following aTSA and should be considered for rTSA.

The impact of scapular posture and sagittal spine alignment on motion and functional outcomes following reverse total shoulder arthroplasty: a scoping review

Background

Reverse total shoulder arthroplasty (RTSA) has evolved beyond its initial indication for elderly patients with rotator cuff arthropathy and is now performed in younger patients for various shoulder pathologies. This surgical procedure has recently gained popularity and has been shown to result in similar functional improvements and complication rates compared to anatomical total shoulder arthroplasty. Scapular posture and sagittal spine alignment (SSPA) have recently emerged as factors potentially influencing RTSA outcomes. This scoping review aimed to assess the existing body of evidence on this topic.

Methods

A systematic search was conducted on MEDLINE, Embase, and CENTRAL databases to evaluate the impact of scapular posture and SSPA on RTSA outcomes.

Results

A total of 6 studies (616 shoulders) were included in this review. Scapular posture was found to influence RTSA outcomes, with studies reporting correlations between scapular posture with postoperative range of motion and functional scores. Suboptimal scapular posture, particularly type C (kyphotic posture with protracted scapulae), appeared to be associated with reduced external rotation. However, findings among the included studies regarding SSPA were varied. Some studies suggested that SSPA, notably thoracic kyphosis, might impact RTSA outcomes by influencing scapular posture, while others did not find a clear relationship.

Conclusion

Scapular posture was implicated as a potential factor affecting RTSA outcomes; however, the role of SSPA remains inconclusive. There is currently a lack of high-quality evidence in the literature to draw definitive conclusions regarding the impact of scapular posture and SSPA on RTSA outcomes. More research is warranted to investigate these relationships more comprehensively.

Predictive factors for postoperative outcomes after reverse shoulder arthroplasty: a systematic review

BACKGROUND

The use of reverse total shoulder arthroplasty (RTSA) has increased at a greater rate than other shoulder procedures. In general, clinical and functional outcomes after RTSA have been favorable regardless of indication. However, little evidence exists regarding patient specific factors associated with clinical improvement after RTSA. Predicting postoperative outcomes after RTSA may support patients and physicians to establish more accurate patient expectations and contribute in treatment decisions. The aim of this study was to determine predictive factors for postoperative outcomes after RTSA for patients with degenerative shoulder disorders.

METHODS

EMBASE, PubMed, Cochrane Library and PEDro were searched to identify cohort studies reporting on predictive factors for postoperative outcomes after RTSA. Authors independently screened publications on eligibility. Risk of bias for each publication was assessed using the QUIPS tool. A qualitative description of the results was given. The GRADE framework was used to establish the quality of evidence.

RESULTS

A total of 1986 references were found of which 11 relevant articles were included in the analysis. Risk of bias was assessed as low (N = 7, 63.6%) or moderate (N = 4, 36.4%). According to the evidence synthesis there was moderate-quality evidence indicating that greater height predicts better postoperative shoulder function, and greater preoperative range of motion (ROM) predicts increased postoperative ROM following.

CONCLUSION

Preoperative predictive factors that may predict postoperative outcomes are: patient height and preoperative range of motion. These factors should be considered in the preoperative decision making for a RTSA, and can potentially be used to aid in preoperative decision making.

LEVEL OF EVIDENCE

Level I; Systematic review.

Disease diagnosis and arthroplasty type are strongly associated with short-term postoperative patient-reported outcomes in patients undergoing primary total shoulder arthroplasty

BACKGROUND

Prognostic factors for total shoulder arthroplasty (TSA) clinical outcomes are incompletely understood. This study investigates the associations of preoperative patient, disease-specific, and surgical factors with 1-year postoperative PENN Shoulder Score (PSS) in patients undergoing primary TSA.

METHODS

Cleveland Clinic patients undergoing primary anatomic TSA (aTSA) or reverse TSA (rTSA) for glenohumeral osteoarthritis (GHOA) or rotator cuff tear arthropathy (CTA) between February 2015 and August 2019, and having complete preoperative and 1-year postoperative patient-reported outcome measures (PROMs), were included. Twenty preselected preoperative patient, disease-specific, and surgical factors were used to fit multivariable models for 1-year PSS and its subscores.

RESULTS

Of 1427 eligible primary TSAs, 1174 had 1-year follow-up by PROMs (82%), with 1042 analyzed after additional exclusions, including 30% rTSAs for CTA (n = 308), 26% rTSAs for GHOA (n = 275), and 44% aTSAs for GHOA (n = 459). All PROMs showed statistically significant improvements postoperatively, with 89% of patients reaching an acceptable symptom state. Lower 1-year PSS was associated with younger age, female sex, current smoking, chronic pain diagnosis, history of prior surgery, worker's compensation claim, lower preoperative mental health, lower baseline PSS, absence of glenoid bone loss, and diagnosis-arthroplasty type (CTA-rTSA < GHOA-rTSA < GHOA-aTSA). The most important prognostic factors associated with 1-year PSS were diagnosis-arthroplasty type, baseline mental health status, and insurance status.

CONCLUSIONS

Disease diagnosis, arthroplasty type, and several other baseline factors are strongly and individually associated with PROMs following primary TSA, with patients undergoing aTSA for GHOA demonstrating the highest PROM scores at 1-year follow-up. Patient, disease-specific, and surgical factors can be used to guide postoperative prognosis following primary TSA for improved preoperative patient counseling regarding expected outcomes of these procedures.

Reverse total shoulder arthroplasty for primary osteoarthritis with restricted preoperative forward elevation demonstrates similar outcomes but faster range of motion recovery compared to anatomic total shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty (RSA) has been increasingly utilized for a variety of shoulder pathologies that are difficult to treat with anatomical total shoulder arthroplasty (TSA). Few studies have compared the outcomes of TSA vs. RSA in patients with cuff intact glenohumeral osteoarthritis and poor preoperative forward elevation. This study aimed to determine whether there is a difference in functional outcomes and postoperative range of motion (ROM) between TSA and RSA in these patients.

METHODS

This retrospective cohort study included 116 patients who underwent RSA or TSA between 2013 and 2022 for the treatment of rotator cuff intact primary osteoarthritis with restricted preoperative forward flexion (FF) and a minimum 1-year follow-up. Each arthroplasty group was divided into 2 subgroups: patients with preoperative FF between 91° and 120° or FF lower than or equal to 90°. Patients' clinical outcomes, including active ROM, American Shoulder and Elbow Surgeons score, visual analog scale for pain, and subjective shoulder value were collected. Clinical and radiographic complications were evaluated.

RESULTS

There was no significant difference between RSA and TSA in terms of sex (58.3% male vs. 62.2% male, P = .692), or follow-up duration (20.1 months vs. 17.7 months, P = .230). However, the RSA cohort was significantly older (72.0 ± 8.2 vs. 65.4 ± 10.6, P = .012) and weaker in FF and (ER) before surgery (P < .001). There was no difference between RSA (57 patients) and TSA (59 patients) in visual analog scale pain score (1.2 ± 2.3 vs. 1.3 ± 2.3, P = .925), subjective shoulder value score (90 ± 15 vs. 90 ± 15, P = .859), or American Shoulder and Elbow Surgeons score (78.4 ± 20.5 vs. 82.1 ± 23.2, P = .476). Postoperative active ROM was statistically similar between RSA and TSA cohorts in FF (145 ± 26 vs. 146 ± 23, P = .728) and ER (39 ± 15 vs. 41 ± 15, P = .584). However, internal rotation was lower in the RSA cohort (P < .001). This was also true in each subgroup. RSA led to faster postoperative FF and ER achievement at 3 months (P < .001). There was no statistically significant difference in complication rates between cohorts.

CONCLUSION

This study demonstrates that patients with glenohumeral osteoarthritis who have a structurally intact rotator cuff but limited preoperative forward elevation can achieve predictable clinical improvement in pain, ROM, and function after either TSA or RSA. Reverse arthroplasty may be a reliable treatment option in patients at risk for developing rotator cuff failure.

Machine learning can predict anterior elevation after reverse total shoulder arthroplasty: A new tool for daily outpatient clinic?

The aim of the present study was to individuate and compare specific machine learning algorithms that could predict postoperative anterior elevation score after reverse shoulder arthroplasty surgery at different time points. Data from 105 patients who underwent reverse shoulder arthroplasty at the same institute have been collected with the purpose of generating algorithms which could predict the target. Twenty-eight features were extracted and applied to two different machine learning techniques: Linear regression and support vector regression (SVR). These two techniques were also compared in order to define to most faithfully predictive. Using the extracted features, the SVR algorithm resulted in a mean absolute error (MAE) of 11.6° and a classification accuracy (PCC) of 0.88 on the test-set. Linear regression, instead, resulted in a MAE of 13.0° and a PCC of 0.85 on the test-set. Our machine learning study demonstrates that machine learning could provide high predictive algorithms for anterior elevation after reverse shoulder arthroplasty. The differential analysis between the utilized techniques showed higher accuracy in prediction for the support vector regression. Level of Evidence III: Retrospective cohort comparison; Computer Modeling.

Anatomic Total Shoulder: Predictors of Excellent Outcomes at Five Years after Arthroplasty

PURPOSE

The objectives of this study were to: report minimum 5-year outcomes in patients undergoing TSA and determine characteristics predictive of patients achieving an excellent functional outcome.

METHODS

Pre-operative demographic variables and Simple Shoulder Test (SST) scores were obtained pre-operatively and at a minimum of five years after surgery. A final SST ≥ 10 and percentage of maximal possible improvement (% MPI) of ≥ 66.7% were determined to be the thresholds for excellent outcomes. Univariate and multivariate analysis were performed to identify factors associated with excellent five year clinical outcomes.

RESULTS

Of 233 eligible patients, 188 (81%) had adequate follow-up for inclusion in this study. Mean SST scores improved from 3.4 ± 2.4 to 9.7 ± 2.2 (p < 0.001). Male sex was an independent predictor of both SST ≥ 10 (OR 3.46, 95% CI 1.70-7.31; p < 0.001) and %MPI ≥ 66.7 (OR 2.27, 95% CI 1.11-4.81, p = 0.027). Workers' Compensation insurance was predictive of not obtaining SST ≥ 10 (OR 0.12, 95% 0.02-0.60; p = 0.016) or %MPI ≥ 66.7 (OR 0.16, 95% CI 0.03-0.77, p = 0.025). MCID was passed by the vast majority (95%) of patients undergoing TSA and did not necessarily indicate an excellent, satisfactory outcome.

CONCLUSION

Male sex and commercial insurance coverage were significantly associated with these excellent outcomes, while Workers' Compensation insurance was associated with failure to achieve this result. Thresholds for excellent outcomes, such as final SST ≥ 10 and %MPI ≥ 66.7, may be useful in identifying the characteristics of patients who benefit most from TSA.

Effect of patient-reported allergies on reverse total shoulder arthroplasty outcomes at over two years follow-up

Background/aims

Understanding the factors that lead to poor outcomes after reverse total shoulder arthroplasty (rTSA) is important to appropriate patient counseling. While patient-reported allergies (PRAs) have been shown to be associated with poorer outcomes after both TKA and THA, their effect on rTSA outcomes remains unclear. This study investigated the effect of zero, one, and two or more preoperative PRAs on clinical outcomes after rTSA at over two years follow-up in a cohort of fifty-two patients from our institution.

Methods

Patients who underwent rTSA and had a minimum follow-up time of two years were identified from an institutional database. Patients were split into cohorts of zero, one, and two or more PRAs. Range of motion (ROM) was assessed by degrees of forward elevation, external rotation, and internal rotation. Patient-reported outcomes (PROs) were assessed by the Visual Analog Scale (VAS), American Shoulder and Elbow Surgeon (ASES) score, and Simple Shoulder Test (SST) score.

Results

Fifty-two patients, 10 of whom reported one allergy and 11 of whom reported two or more allergies, were included in our analysis. Mean ROM and PROs improved after rTSA in each cohort. Differences in ROM and PROs between cohorts did not reach statistical significance; however, patients with PRAs tended to have worse preoperative forward elevation, VAS score, and ASES score. Two patients in the zero-allergy cohort required revision (6 %).

Conclusion

This study found no statistically significant difference in clinical outcomes among cohorts of patients with zero, one, or two or more preoperative PRAs after rTSA at over two years follow-up. However, patients with PRAs tended to have lower preoperative functional scores. We postulate that this may be the result of psychosomatic factors at play in these patients. PRAs should not dissuade patients or clinicians from pursuing rTSA.

Treatment of 2-part, 3-part, and 4-part proximal humerus fractures from 2016 to 2020: A nationally-representative database

Introduction

Complex proximal humerus fractures pose challenges in elderly patients, as this common scenario can lead to unpredictable outcomes, regardless of treatment method. Given the evolving nature of the treatment for 3-and-4-part proximal humerus fractures, an epidemiological analysis offers a way to minimize the gap between appropriate understanding and effective intervention. As such, we aimed to i) evaluate the trends of nonoperative and operative management; and ii) compare the complication rates of ORIF to conversion ORIF (to RTSA).

Methods

We utilized a national, all-payer database to include patients who underwent open reduction and internal fixation for 2-part (n = 2783), 3-part (n = 2170), 4-part (n = 1087) proximal humerus fractures between April 2016 to December 2022. Patients who failed ORIF to RTSA included n = 108 for 2-part fractures, n = 123 for 3-part fractures, and n = 128 for 4-part fractures. We collected demographic and postoperative medical and surgical complications at 90-days, in addition to time-interval between ORIF and RTSA.

Results

The malunion and nonunion rates for ORIF between different types of proximal humerus fractures were similar (2-part fractures: 1.8 %, 4.7 %; 3-part fractures: 1.8 %, 3.5 %; 4-part fractures: 2.4 %, 3.7 %). The conversion rates of failed ORIF to RTSA were 1.9 %, 2.8 %, and 5.9 % for 2-part, 3-part, and 4-part fractures, respectively. The time interval from failed ORIF to RTSA was 190 days for 2-part fractures, 169 days for 3-part fractures, and 129 for 4-part fractures.

Conclusion

An epidemiological analysis of proximal humerus fractures by fracture type demonstrated an increase in RTSA for 2-part, 3-part, and 4-part fractures while nonoperative treatment showed no change from 2016 to 2020. Additional research is needed to determine which fractures are best treated operatively while maximizing outcomes. In the setting of complex proximal humerus fractures, several options seem feasible depending on patient demographic characteristics.

Does achieving clinically important thresholds after first shoulder arthroplasty predict similar outcomes of the contralateral shoulder?

BACKGROUND

Patients are increasingly undergoing bilateral total shoulder arthroplasty (TSA). At present, it is unknown whether success after the first TSA is predictive of success after contralateral TSA. We aimed to determine whether exceeding clinically important thresholds of success after primary TSA predicts similar outcomes for subsequent contralateral TSA.

METHODS

We performed a retrospective review of a prospectively collected shoulder arthroplasty database for patients undergoing bilateral primary anatomic (aTSA) or reverse (rTSA) total shoulder arthroplasty since January 2000 with preoperative and 2- or 3-year clinical follow-up. Our primary outcome was whether exceeding clinically important thresholds in the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score for the first TSA was predictive of similar success of the contralateral TSA; thresholds for the ASES score were adopted from prior literature and included the minimal clinically important difference (MCID), the substantial clinical benefit (SCB), 30% of maximal possible improvement (MPI), and the patient acceptable symptomatic state (PASS). The PASS is defined as the highest level of symptom beyond which patients consider themselves well, which may be a better indicator of a patient's quality of life. To determine whether exceeding clinically important thresholds was independently predictive of similar success after second contralateral TSA, we performed multivariable logistic regression adjusted for age at second surgery, sex, BMI, and type of first and second TSA.

RESULTS

Of the 134 patients identified that underwent bilateral shoulder arthroplasty, 65 (49%) had bilateral rTSAs, 45 (34%) had bilateral aTSAs, 21 (16%) underwent aTSA/rTSA, and 3 (2%) underwent rTSA/aTSA. On multivariable logistic regression, exceeding clinically important thresholds after first TSA was not associated with greater odds of achieving thresholds after second TSA when success was evaluated by the MCID, SCB, and 30% MPI. In contrast, exceeding the PASS after first TSA was associated with 5.9 times greater odds (95% confidence interval 2.5-14.4, P < .001) of exceeding the PASS after second TSA. Overall, patients who exceeded the PASS after first TSA exceeded the PASS after second TSA at a higher rate (71% vs. 29%, P < .001); this difference persisted when stratified by type of prosthesis for first and second TSA.

CONCLUSIONS

Patients who achieve the ASES score PASS after first TSA have greater odds of achieving the PASS for the contralateral shoulder regardless of prostheses type.

Initial clinical experience with a predictive clinical decision support tool for anatomic and reverse total shoulder arthroplasty

PURPOSE

Clinical decision support tools (CDSTs) are software that generate patient-specific assessments that can be used to better inform healthcare provider decision making. Machine learning (ML)-based CDSTs have recently been developed for anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty to facilitate more data-driven, evidence-based decision making. Using this shoulder CDST as an example, this external validation study provides an overview of how ML-based algorithms are developed and discusses the limitations of these tools.

METHODS

An external validation for a novel CDST was conducted on 243 patients (120F/123M) who received a personalized prediction prior to surgery and had short-term clinical follow-up from 3 months to 2 years after primary aTSA (n = 43) or rTSA (n = 200). The outcome score and active range of motion predictions were compared to each patient's actual result at each timepoint, with the accuracy quantified by the mean absolute error (MAE).

RESULTS

The results of this external validation demonstrate the CDST accuracy to be similar (within 10%) or better than the MAEs from the published internal validation. A few predictive models were observed to have substantially lower MAEs than the internal validation, specifically, Constant (31.6% better), active abduction (22.5% better), global shoulder function (20.0% better), active external rotation (19.0% better), and active forward elevation (16.2% better), which is encouraging; however, the sample size was small.

CONCLUSION

A greater understanding of the limitations of ML-based CDSTs will facilitate more responsible use and build trust and confidence, potentially leading to greater adoption. As CDSTs evolve, we anticipate greater shared decision making between the patient and surgeon with the aim of achieving even better outcomes and greater levels of patient satisfaction.

Influence of acromioclavicular joint arthritis on outcomes after reverse total shoulder

Background

Although substantial motion at the acromioclavicular joint (ACJ) occurs during overhead shoulder motion, the influence of ACJ arthritis on postoperative outcomes of patients undergoing reverse total shoulder arthroplasty (rTSA) is unclear. We assessed the influence of ACJ arthritis, defined by degenerative radiographic changes, and its severity on clinical outcomes after primary rTSA.

Methods

We conducted a retrospective review of a prospectively collected shoulder arthroplasty database of patients that underwent primary rTSA with a minimum 2-year clinical follow-up. Imaging studies of included patients were evaluated to assess ACJ arthritis classified by radiographic degenerative changes of the ACJ; severity was based upon size and location of osteophytes. Both the Petersson classification and the King classification (a modified Petersson classification addressing superior osteophytes and size of the largest osteophyte) were used to evaluate the severity of degenerative ACJ radiographic changes. Severe ACJ arthritis was characterized by large osteophytes (≥2 mm). Active range of motion (ROM) in abduction, forward elevation, and external and internal rotation as well as clinical outcome scores (American Shoulder and Elbow Surgeons Shoulder, Constant, Shoulder Pain and Disability Index, simple shoulder test, University of California, Los Angeles scores) were assessed both preoperatively and at the latest follow-up; outcomes were compared based on severity of ACJ arthritis. Multivariable linear regression models were used to determine whether increasing severity of ACJ arthritis was associated with poorer outcomes.

Results

A total of 341 patients were included with a mean age of 71 ± 8 years and 55% were female. The mean follow-up was 5.1 ± 2.4 years. Preoperatively, there were no differences in outcomes based on the severity of ACJ pathology. Postoperatively, there were no differences in outcomes based upon the severity of ACJ arthritis except for greater preoperative to postoperative improvement in active internal rotation in patients with normal or grade 1 ACJ arthritis vs. grade 2 and 3 (3 ± 2 vs. 1 ± 2 and 1 ± 3, P = .029). Patients with ACJ arthritis and osteophytes ≥2 mm had less favorable Shoulder Pain and Disability Index scores, corresponding to greater pain (-49.3 ± 21.5 vs. -41.3 ± 26.8, P = .015). On multivariable linear regression, increased severity of ACJ arthritis was not independently associated with poorer postoperative ROM or outcome scores.

Conclusion

Overall, our results demonstrate that greater ACJ arthritis severity score is not associated with poorer outcome scores and has minimal effect on ROM. However, patients with the largest osteophytes (≥2 mm) did have slightly worse pain postoperatively. Radiographic presence of high-stage ACJ arthritis should not alter the decision to undergo rTSA.

Total Shoulder Arthroplasty is associated With Less Pain and Better Functional Outcomes, but Humeral Head Resurfacing may be Preferred in Younger, Higher Demand Patients: A Short-Term Outcomes Study in Patients with Glenohumeral Osteoarthritis

Objectives

This study aimed to compare short-term outcomes following Total Shoulder Arthroplasty (TSA) and Humeral Head Resurfacing (HHR) in patients with glenohumeral osteoarthritis (GHOA).

Methods

A retrospective analysis included patients who had undergone either TSA or HHR for GHOA at a single institution. Baseline demographics, complications, range of motion (active forward flexion, FF and active external rotation, ER), visual analog scores (VAS), and Subjective Shoulder Values (SSV) were collected.

Results

A total of 69 TSA and 56 HHR patients were analyzed. More HHR patients were laborers (44% versus 21%, P=0.01). There were more smokers in the TSA group (25% versus 11%, P=0.04) and more cardiovascular disease in the HHR cohort (64% versus. 6%, p<0.0001). Postoperative FF was similar, but ER was greater in the HHR (47° ± 15°) vs. TSA group (40° ± 12°, P = 0.01). VAS was lower after TSA vs. HHR (median 0, IQR 1 versus median 3.7, IQR 6.9, p<0.0001), and SSV was higher after TSA (89% ± 13% vs. 75% ± 20% after HHR; p<0.0001). Post-operative impingement was more common after HHR (32% vs. 3% for TSA, p<0.0001). All other complications were equivalent.

Conclusion

While younger patients and heavy laborers had improved ER following HHR, their pain relief was greater after TSA. Decisions on surgical technique should be based on patient-specific demographic and anatomic factors.

Clinical outcomes of anatomical versus reverse total shoulder arthroplasty in patients with primary osteoarthritis, an intact rotator cuff, and limited forward elevation

Aims

Both anatomical and reverse total shoulder arthroplasty (aTSA and rTSA) provide functional improvements. A reported benefit of aTSA is better range of motion (ROM). However, it is not clear which procedure provides better outcomes in patients with limited foward elevation (FE). The aim of this study was to compare the outcome of aTSA and rTSA in patients with glenohumeral osteoarthritis (OA), an intact rotator cuff, and limited FE.

Methods

This was a retrospective review of a single institution's prospectively collected shoulder arthroplasty database for TSAs undertaken between 2007 and 2020. A total of 344 aTSAs and 163 rTSAs, which were performed in patients with OA and an intact rotator cuff with a minimum follow-up of two years, were included. Using the definition of preoperative stiffness as passive FE ≤ 105°, three cohorts were matched 1:1 by age, sex, and follow-up: stiff aTSAs (85) to non-stiff aTSAs (85); stiff rTSAs (74) to non-stiff rTSAs (74); and stiff rTSAs (64) to stiff aTSAs (64). We the compared ROMs, outcome scores, and complication and revision rates.

Results

Compared with non-stiff aTSAs, stiff aTSAs had poorer passive FE and active external rotation (ER), whereas there were no significant postoperative differences between stiff rTSAs and non-stiff rTSAs. There were no significant differences in preoperative function when comparing stiff aTSAs with stiff rTSAs. However, stiff rTSAs had significantly greater postoperative active and passive FE (p = 0.001 and 0.004, respectively), and active abduction (p = 0.001) compared with stiff aTSAs. The outcome scores were significantly more favourable in stiff rTSAs for the Shoulder Pain and Disability Index, Simple Shoulder Test, American Shoulder and Elbow Surgeons score, University of California, Los Angeles score, and the Constant score, compared with stiff aTSAs. When comparing the proportion of stiff aTSAs versus stiff rTSAs that exceeded the minimal clinically important difference and substantial clinical benefit, stiff rTSAs achieved both at greater rates for all measurements except active ER. The complication rate did not significantly differ between stiff aTSAs and stiff rTSAs, but there was a significantly higher rate of revision surgery in stiff aTSAs (p = 0.007).

Conclusion

Postoperative overhead ROM, outcome scores, and rates of revision surgery favour the use of a rTSA rather than aTSA in patients with glenohumeral OA, an intact rotator cuff and limited FE, with similar rotational ROM in these two groups.

Patients with poor early clinical outcomes after anatomic total shoulder arthroplasty have sustained poor performance at 2 years from surgery

PURPOSE

We sought to define the risk of persistent shoulder dysfunction after anatomic total shoulder arthroplasty (aTSA) beyond the early postoperative period and identify risk factors for persistent poor performance.

METHODS

We retrospectively identified 144 primary aTSAs performed for primary osteoarthritis with early poor performance and 2-year minimum follow-up. Early poor performance was defined as a postoperative ASES score below the 20th percentile at 3- or 6-months (62 and 72 points, respectively). Persistent poor performance at 2 years was defined as failing to achieve the patient acceptable symptomatic state (PASS) [ASES = 81.7 points].

RESULTS

At 2-year follow-up, 51% (n = 74) of patients with early poor performance at either 3- or 6-month follow-up had persistent poor performance. There was no difference in the rate of persistent poor performance if patients were poor performers at the 3-, 6-month follow-up, or both (50% vs. 49% vs. 56%, P = .795). Of aTSAs achieving the PASS at 2-year follow-up, a greater proportion exceeded the minimal clinically important differences (MCID) [Forward elevation, external rotation, and all outcome scores] and substantial clinical benefit (SCB) [external rotation and all outcome scores] compared to persistent poor performers. However, over half of persistent poor performers still exceeded the MCID for all outcome measures (56-85%). Independent predictors of persistent poor performance were hypertension (2.61 [1.01-6.72], P = .044) and diabetes (5.14 [1.00-26.4], P = .039).

CONCLUSION

Over half of aTSAs with an ASES score < 20th percentile at early follow-up had continued poor shoulder function at 2-years postoperatively. Persistent poor performance was best projected by preoperative hypertension and diabetes.

LEVEL OF EVIDENCE

Level III; Retrospective Cohort Comparison using Large Database; Treatment Study.

Sex-related differences in PROMs prior to the outcome: comparison of preoperative PROMIS physical function scores in female vs. male patients undergoing shoulder arthroplasty

Background

Patient-reported outcome measures (PROMs) are increasingly used to evaluate outcomes in patients undergoing shoulder arthroplasty. The Patient-Reported Outcome Measures Information System (PROMIS) is popular due to low cost and question burden. Females have been reported to have lower postoperative PROMIS scores after shoulder surgery, but studies have not focused on a dedicated cohort of shoulder arthroplasty patients or examined upstream differences in preoperative scores. This study aimed to characterize sex differences in baseline PROMIS scores among anatomic total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (rTSA) patients.

Methods

Data were collected over a 9-month period. Demographics, Charlson Comorbidity Index (CCI), smoking status, BMI, American Shoulder and Elbow Surgeons (ASES) scores, PROMIS Pain, Physical Function (PF), Upper Extremity, Depression, and Anxiety scores, as well as Single Assessment Numeric Evaluation (SANE) scores were collected. Student t-tests were performed to determine correlation with baseline PROMs. A minimal clinically important difference (MCID) of 4 was used to determine if a PROMIS score difference between groups was clinically important. Significance was set as P < .05.

Results

A total of 88 females (34 TSAs 54 rTSA) and 99 males (35 TSA, 64 rTSA) were enrolled. Only sex showed a correlation with preoperative PROMIS score. In rTSA patients, females had significantly lower preoperative PROMIS PF scores (P < .05). Among females undergoing TSA vs. rTSA, lower preoperative PROMIS PF scores were found in rTSA (P < .05). These differences exceeded the MCID of 4. The same difference was not found in men undergoing TSA vs. rTSA.

Conclusion

Preoperative sex-based differences in PROMIS scores are underappreciated in the shoulder arthroplasty literature. This is the largest study to date focusing on sex-based differences among a dedicated cohort of TSA and rTSA patients, showing a difference in baseline PROMIS scores between males and females above the MCID. These findings suggest that PROMIS scores are affected by sex-based baseline differences in rTSA patients. Further study should investigate sex-based differences in baseline scores to determine their effects on ultimate outcome.

Discordance between patient-reported and objectively measured internal rotation after reverse shoulder arthroplasty

BACKGROUND

Patient satisfaction after reverse shoulder arthroplasty (RSA) partly relies on restoring functional internal rotation (IR). Although postoperative assessment of IR includes objective appraisal by the surgeon and subjective report from the patient, these evaluations may not vary together uniformly. We assessed the relationship between objective, surgeon-reported assessments of IR and subjective, patient-reported ability to perform IR-related activities of daily living (IRADLs).

METHODS

Our institutional shoulder arthroplasty database was queried for patients undergoing primary RSA with a medialized-glenoid lateralized-humerus design between 2007-2019 and minimum 2-year follow-up. Patients who were wheelchair bound or had a preoperative diagnosis of infection, fracture, and tumor were excluded. Objective IR was measured to the highest vertebral level reached with the thumb. Subjective IR was reported based on patients' rating (normal, slightly difficult, very difficult, or unable) of their ability to perform 4 IRADLs (tuck in shirt with hand behind back, wash back or fasten bra, personal hygiene, and remove object from back pocket). Objective IR was assessed preoperatively and at latest follow-up and reported as median and interquartile ranges.

RESULTS

A total of 443 patients were included (52% female) at a mean follow-up of 4.4 ± 2.3 years. Objective IR improved pre- to postoperatively from L4-L5 (buttocks to L1-L3) to L1-L3 (L4-L5 to T8-T12) (P < .001). Preoperatively reported IRADLs of "very difficult" or "unable" significantly decreased postoperatively for all IRADLs (P ≤ .004) except those unable to perform personal hygiene (3.2% vs. 1.8%, P > .99). The proportions of patients who improved, maintained, and lost objective and subjective IR was similar between IRADLs; 14%-20% improved objective IR but lost or maintained subjective IR and 19%-21% lost or maintained the same objective IR but improved subjective IR depending on the specific IRADL assessed. When ability to perform IRADLs improved postoperatively, objective IR also increased (P < .001). In contrast, when subjective IRADLs worsened postoperatively, objective IR did not significantly worsen for 2 of 4 IRADLs assessed. When examining patients who reported no change in ability to perform IRADLs pre- vs. postoperatively, statistically significant increases in objective IR were found for 3 of 4 IRADLs assessed.

CONCLUSIONS

Objective improvement in IR parallels improvements in subjective functional gains uniformly. However, in patients with worse or equivalent IR, the ability to perform IRADLs postoperatively does not uniformly correlate with objective IR. When attempting to elucidate how surgeons can ensure patients will have sufficient IR after RSA, future investigations may need to use patient-reported ability to perform IRADLs as the primary outcome measure rather than objective measures of IR.

Smoking cessation prior to total shoulder arthroplasty: A systematic review of outcomes and complications

Background

We conducted a review of current literature to examine the effects of smoking and smoking cessation on shoulder arthroplasty surgery.

Methods

A literature search was performed using the search terms "shoulder arthroplasty AND [smoke OR smoking OR tobacco OR nicotine]." Studies included English-language clinical outcomes studies on anatomic total shoulder arthroplasty (TSA), reverse TSA, and partial shoulder arthroplasty with evidence levels 1 through 4. Descriptive statistics calculated in the included studies were used during the analysis. Categorical variables were reported as proportions, while continuous variables were reported as means with minimum to maximum absolute ranges.

Results

Twenty-four studies were included and analyzed. Following TSA, patients who quit smoking at least 1 month preoperatively had improved outcomes compared to current smokers. Current smokers had statistically significant higher pain scores or opioid use. Five studies found increased rates of revision surgery in smokers. Smokers were significantly (p < 0.05) more likely to have increased rates of surgical, wound, superficial, and deep surgical site complications.

Discussion

Former smokers had lower complication rates and visual analog scale scores when compared to current users. A period of four weeks or more of preoperative smoking cessation is recommended.

Level of Evidence

Level III, Systematic Review.

Quantifying success after anatomic total shoulder arthroplasty: the minimal clinically important percentage of maximal possible improvement

INTRODUCTION

Changes in pre- to postoperative outcome scores are often used to quantify success after anatomic total shoulder arthroplasty (aTSA). However, ceiling effects associated with many outcome scores limit the ability to differentiate success among high-functioning patients. The percentage maximal possible improvement (%MPI) was introduced to better stratify patient success; however, it is unclear if the 30% threshold first proposed correlates with perceived patient success across all outcome scores. The purpose of this study was to compare the proportion of patients that achieved the minimal clinically important difference (MCID) and %MPI for different outcome scores and to define the %MPI thresholds associated with patient satisfaction following primary aTSA.

METHODS

A retrospective review was performed of an international shoulder arthroplasty database between 2003 and 2020. All primary aTSAs performed using a single implant system with minimum 2-year follow-up were reviewed. Pre- and postoperative outcome scores were evaluated for all patients to calculate improvement. The proportion of patients achieving the MCID and 30% MPI were determined for each outcome score. Thresholds for the minimal clinically important %MPI (MCI-%MPI) were calculated using an anchor-based method for each outcome score and stratified by age and sex.

RESULTS

1593 shoulders with a mean follow-up of 59.3 months were included. Outcome scores with known ceiling effects (Simple Shoulder Test [SST], American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], University of California-Los Angeles shoulder score [UCLA]) had higher rates of patients achieving the 30% MPI but not the previously reported MCID. Inversely, outcome scores without significant ceiling effects (Constant and Shoulder Arthroplasty Smart [SAS] scores) had higher rates of patients achieving the MCID but not the 30% MPI. The MCI-%MPI differed among outcome scores, and mean values were as follows: 33% for the SST, 24% for the Constant score, 32% for the ASES score, 38% for the UCLA score, 30% for the Shoulder Pain and Disability Index score, and 33% for the SAS score. The MCI-%MPI increased with greater age (P < .003) and females had thresholds greater than or equal to males for all scores assessed, meaning that patients with higher thresholds required a greater fraction of the possible improvement for a given score to be satisfied.

CONCLUSION

The %MPI offers a simple method to quickly assess improvements across patient outcome scores. However, the %MPI that represents patient improvement after surgery is not uniformly the previously established 30% threshold. Surgeons should use score-specific estimates of the MCI-%MPI to gauge success when evaluating patients undergoing primary aTSA.

Reverse shoulder arthroplasty in upper extremity ambulators: a matched-cohort analysis

BACKGROUND

Upper extremity ambulators (UEAs) who require prolonged use of assistive devices for mobility have a high incidence of shoulder pathology secondary to increased stress across the shoulder joint with upper extremity weight-bearing. Reverse shoulder arthroplasty (RSA) for rotator cuff arthropathy has historically been associated with increased complications in UEA, but more recent studies have shown more promising outcomes. The objective of this study is to evaluate clinical outcomes and complication rates between these 2 groups to define the relative risk of RSA in the UEA population and identify opportunities to improve treatment outcomes.

METHODS

An institutional review board-approved retrospective chart review was performed in patients who underwent RSA at our institution by the senior author from 2004 to 2019. UEAs were defined as patients who used regular upper extremity assistive devices for community ambulation before initial consultation for the surgical extremity. Pre- and postoperative range of motion, visual analog scale scores, American Shoulder and Elbow Surgeons scores, Constant-Murley scores, and Simple Shoulder Test scores were measured at defined intervals. Complications including infection, instability, and need for revision surgery were also compared. All patients were followed for a minimum of 2 years postoperatively.

RESULTS

A total of 159 RSA procedures (70 UEAs, 89 controls) were performed during the study period. On average, UEA patients had more preoperative pain and less shoulder function than controls, with statistically significant differences in visual analog scores (6.897 vs. 5.532, P = .0010) and American Shoulder and Elbow Surgeons scores (33.50 vs. 40.20, P = .0290), respectively. Despite the lower baseline values, UEA patients experienced excellent postoperative improvement, leading to similar postoperative pain and shoulder function except for a lower average forward flexion in the UEA group (127° vs. 135°, P = .0354). Notching and complication rates were also similar between the 2 groups, with notching rates of 59% and 50% and complication rates of 14.3% and 13.5% in the UEA and control groups, respectively.

CONCLUSIONS

RSA in the UEA population can achieve similar pain and functional outcomes as compared with age-matched controls without a significant increase in complication rates; however, further studies are required to assess long-term comparative outcomes in this challenging patient population.

Comparison of clinical outcomes of revision reverse total shoulder arthroplasty for failed primary anatomic vs. reverse shoulder arthroplasty

Background

Both anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (RTSA) are being increasingly performed. In the event of a complication necessitating revision, RTSA is more commonly performed in both scenarios. The purpose of this study was to compare clinical outcomes between patients undergoing revision RTSA for failed primary anatomic versus reverse total shoulder arthroplasty.

Methods

We performed a retrospective review of a prospective single-institution shoulder arthroplasty database. All revision RTSAs performed between 2007 and 2019 with a minimum 2-year clinical follow-up were initially included. After excluding patients with a preoperative diagnosis of infection, an oncologic indication, or incomplete outcomes assessment, we included 45 revision RTSAs performed for failed primary aTSA and 15 for failed primary RTSA. Demographics, surgical characteristics, active range of motion (external rotation [ER], internal rotation, forward elevation [FE], abduction), outcome scores (American Shoulder and Elbow Surgeons score, Constant Score, Shoulder Pain and Disability Index, Simple Shoulder Test, and University of California, Los Angeles score), and the incidence of postoperative complications was compared between groups.

Results

Primary aTSA was most often indicated for degenerative joint disease (82%), whereas primary RTSA was more often indicated for rotator cuff arthropathy (60%). On bivariate analysis, no statistically significant differences in any range of motion or clinical outcome measure were found between revision RTSA performed for failed aTSA vs. RTSA. On multivariate linear regression analysis, revision RTSA performed for failed aTSA vs. RTSA was not found to significantly influence any outcome measure. Humeral loosening as an indication for revision surgery was associated with more favorable outcomes for all four range of motion measures and all five outcome scores assessed. In contrast, an indication for revision of peri-prosthetic fracture was associated with poorer outcomes for three of four range of motion measures (ER, FE, abduction) and four of five outcome scores (Constant, Shoulder Pain and Disability Index, Simple Shoulder Test, University of California, Los Angeles). A preoperative diagnosis of fracture was associated with a poorer postoperative range of motion in ER, FE, and abduction, but was not found to significantly influence any outcome score. However, only two patients in our cohort had this indication. Complication and re-revision rates after revision RTSA for failed primary aTSA and RTSA were 27% and 9% vs. 20% and 14% (P = .487 and P = .515), respectively.

Conclusion

Clinical outcomes of patients undergoing revision RTSA for failed primary shoulder arthroplasty did not significantly differ based on whether aTSA or RTSA was initially performed. However, larger studies are needed to definitively ascertain the influence of the primary construct on the outcomes of revision RTSA.

The impact of tobacco use on clinical outcomes and long-term survivorship after anatomic total shoulder arthroplasty

Introduction

Postoperative outcomes following total shoulder arthroplasty can be affected by preoperative health factors such as tobacco usage.

Methods

The charts of patients who underwent anatomic total shoulder arthroplasty were retrospectively analyzed and stratified based on smoking status. The primary data included range of motion and patient reported outcomes. Additionally, demographic, radiographic, and survivorship analyses were conducted. All data were analyzed using statistical inference.

Results

There were 78, 49, and 16 non-smoker, former smoker, and current smoker shoulders respectively with no significant differences in sex, American Society of Anesthesiologists status, body mass index, or mean follow-up time (average: 10.7 yrs). Smokers (51.5 ± 10.4 years) were younger than both non-smokers (64.9 ± 8.1 years; p < 0.01) and former smokers (65.1 ± 9.1years; p < 0.01) at the time of surgery. For non-smokers and former smokers, all range of motion and patient reported outcome scores significantly improved. Smokers reported significant improvements in all patient reported outcomes and external and internal rotation. Visual Analog Scale, American Shoulder and Elbow, and Simple Shoulder Test scores were lower for smokers comparatively, but these differences did not reach significance. Forward elevation was higher postoperatively for non-smokers (149.7o ± 17.2o) and former smokers (147.1o ± 26.0o) compared to current smokers (130.9o ± 41.2o; p = 0.017). No differences between the cohorts were found in the radiographic analysis. Revision rates were lower in the non-smoking cohort (7.7%) compared to both former (20.4%; p = 0.036) and current smokers (37.5%; p < 0.01). Survival curves showed that non-smoker implants lasted longer than those of current smokers.

Conclusion

After a decade, patients generally had improved shoulder range of motion, functionality, and pain regardless of smoking status. However, current smokers required shoulder replacements sooner and revision surgery more frequently.

Postoperative Rehabilitation After Shoulder Arthroplasty

Total shoulder arthroplasty (TSA), including anatomic TSA (aTSA) and reverse TSA (rTSA), has increased in popularity due to reliably good patient outcomes. Postoperative physical therapy (PT) is considered essential to the success of this operation and has become standard practice. The authors present general rehabilitation principles as well as preferred postoperative PT protocols for aTSA and rTSA, which are based on evidence-based literature and the different early postoperative concerns for each of these procedures.

Comparison of Reverse and Anatomic Total Shoulder Arthroplasty in Patients With an Intact Rotator Cuff and No Previous Surgery

INTRODUCTION

This study's purpose is to compare clinical and radiographic outcomes of primary anatomic total shoulder arthroplasty (aTSA) and primary reverse total shoulder arthroplasty (rTSA) patients with osteoarthritis (OA) and an intact rotator cuff with no previous history of shoulder surgery using a single platform TSA system at a minimum follow-up of 2 years.

METHODS

A total of 370 aTSA patients and 370 rTSA patients matched for age, sex, and length of follow-up from an international multi-institutional Western Institutional Review Board approved registry with a minimum 2-year follow-up were reviewed for this study. All patients had a diagnosis of OA, an intact rotator cuff, and no previous shoulder surgery. All patients were evaluated and scored preoperatively and at latest follow-up using six outcome scoring metrics and four active range of motion measurements.

RESULTS

Mean follow-up was 41 months, and the mean age was 73 years. Preoperatively, the rTSA patients had lower outcome metrics and less motion. Postoperatively, aTSA and rTSA patients had similar clinical outcomes, motion, and function, with the only exception being greater external rotation in aTSA exceeding the minimal clinically important difference. Pain relief was excellent, and patient satisfaction was high in both groups. Humeral radiolucent lines were similar in both groups (8%). Complications were significantly higher with aTSA (aTSA = 4.9%; rTSA = 2.2%; P = 0.045), but revisions were similar (aTSA = 3.2%; rTSA = 1.4%; P = 0.086).

CONCLUSION

At a mean of 41 month follow-up, primary aTSA and rTSA patients with OA and an intact rotator cuff with no previous history of shoulder surgery had similar clinical and radiographic outcomes. Greater external rotation was noted in aTSA patients at follow-up. However, aTSA patients had a significantly greater rate of complications compared with rTSA patients. rTSA is a viable treatment option in patients with an intact rotator cuff and no previous shoulder surgery, offering similar clinical outcomes with a lower complication rate.

LEVEL OF EVIDENCE

Level III.

Impact of Age on Shoulder Range of Motion and Strength

Background

Total shoulder arthroplasty (TSA) is a surgical technique commonly used to treat patients with arthritis and rotator cuff deficiency. Its purpose is to reduce pain and improve shoulder function, namely range of motion (ROM) and strength. While shoulder ROM and strength have been studied extensively in patients with various shoulder pathologies, there is a dearth of knowledge with regard to the asymptomatic population.

Methods

A cross-sectional study was conducted in the outpatient orthopaedic clinic following institutional review board approval. Patients 18 years of age and older with at least one asymptomatic and healthy shoulder with no prior history of shoulder surgery, injury, or pain were enrolled in the study. Demographic information, ROM, and strength measurements were collected for 256 shoulders, evenly stratified into groups by age and sex. A goniometer was used to measure forward elevation, abduction, and external rotation, and a handheld dynamometer was utilized for measuring strength. Statistical evaluation was conducted using Pearson correlations, analysis of variance, and Bonferroni and Mann–Whitney post hoc tests, with P < .01 indicating a significant difference.

Results

Abduction strength (P < .001), external rotation strength (P < .001), and internal rotation strength (P < .001) were negatively correlated with age when viewing the data as a whole and after stratification of males and females. Age and shoulder ROM, namely abduction (P < .001) and forward elevation (P < .001), were also significantly negatively correlated, although internal rotation decreased with age as well. When comparing across age groups, abduction (P = .001) and forward elevation (P = .001) were significantly higher in group 1 (18-35) when compared to group 4 (66+), but external rotation was not significantly different between these groups. External rotation (P = .001) was only significantly different between groups 2 (36-50) and 4. Variation in external rotation strength was also found. Group 4 was found to have significantly less strength than all 3 of the other groups.

Conclusion

Shoulder strength significantly decreased with age, with abduction strength and external rotation strength displaying the strongest negative correlations. Decreases in strength were most prominent in patients 66 years of age and above. Shoulder ROM was not as tightly correlated with age, although abduction, forward elevation, and internal rotation were found to generally decrease over time. Differences in external rotation were not clinically significant. These correlations provide useful controls for patients of various ages regarding their clinical outcomes when presenting with shoulder pathology. Variations in current literature allow this study to verify the impact of age on shoulder ROM and strength.

Relationship Between Preoperative and Postoperative Motion After Four-Corner Wrist Fusion for Osteoarthritis: Clustering and Regression Analyses

PURPOSE

Four-corner fusion (4CF) is a surgical option for refractory scapholunate advanced collapse and scaphoid nonunion advanced collapse wrist arthritis. Preoperative range of motion (ROM) predicts outcomes in many orthopedic procedures. This study investigates ROM in a cohort of 4CF patients to examine the relationship between preoperative and postoperative motion and identifies different clinical patterns.

METHODS

We performed a retrospective review of 4CF patients. Patients with a history of inflammatory arthritis and radiographic characteristics of inflammation were excluded. Demographics, prior wrist surgery history, and ROM data were collected at preoperative and postoperative intervals after cast removal at 8 weeks, 3 months, and 8 months. Regression analysis compared the motion before and after 4CF. Subsequent cluster analysis to reduce confounding compared postoperative motion differences in the top 20% to the bottom 20% of patients by preoperative motion.

RESULTS

We included 148 patients; 27 had prior surgery on the ipsilateral wrist. Preoperative arc averaged 86° ± 28° (flexion 46° ± 17°, extension 40° ± 15°); 8-week arc 43° ± 19° (flexion 19° ± 12°, extension 24° ± 12°); 3-month arc 62° ± 17° (flexion 30° ± 12°, extension 32° ± 11°); and 8-month arc 74° ± 17° (flexion 36° ± 11°, extension 37° ± 12°). Preoperative and final arcs were (r = 0.39). Clustering by the preoperative arc, the top 20% (mean 124° ± 15°) achieved a mean final arc of 81° ± 16°, while the bottom 20% (mean 47° ± 16°) achieved a mean final arc of 65° ± 19°. Intercluster differences were statistically significant. The bottom 20% gained motion postoperatively. Most patients in the middle 60% did not differ significantly in postoperative motion.

CONCLUSIONS

Although wrist motion following 4CF correlates positively with preoperative motion, most patients do not differ significantly in postoperative motion. Patients with substantial preoperative motion deficits gain motion after 4CF. This information is important when counseling patients, determining the timing of surgical intervention, and managing expectations related to motion outcomes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Factors associated with improvement or loss of internal rotation after reverse shoulder arthroplasty

BACKGROUND

Internal rotation (IR) with reverse total shoulder arthroplasty (rTSA) can be unpredictable. Identifying the factors associated with loss of or improved IR could aid preoperative patient counseling. This study quantifies the change in IR experienced by rTSA patients with nonfracture indications and identifies the patient, implant, and operative factors associated with IR loss or gain at 2-year minimum follow-up.

METHODS

A total of 1978 primary rTSA patients were analyzed from an international database of a single rTSA prosthesis to quantify IR at 2 years' minimum follow-up. rTSA patients were divided into 2 cohorts based on their preoperative IR score, with group 1 patients having less active IR as defined by a preoperative IR score ≤3 and group 2 patients having greater active IR as defined by a preoperative IR score ≥4 (ie, L5 or higher). For both group 1 and 2 patients, univariate and multivariate analyses were performed to quantify the risk factors associated with IR loss after rTSA.

RESULTS

Overall, 58.9% of rTSA patients experienced IR improvement and 17.0% lost IR after rTSA. The occurrence of IR loss or gain was dependent on preoperative IR score, as 73.2% of group 1 patients improved IR and only 40.1% of group 2 patients improved IR, whereas 31.0% of group 2 patients lost IR and only 6.3% of group 1 patients lost IR after rTSA. Numerous risk factors for IR loss were identified. For group 1 patients, male sex (P = .004, odds ratio [OR] = 2.056), tobacco usage (P = .004, OR = 0.348), larger humeral stem diameter (P = .008, OR = 0.852), and not having subscapularis repaired (P = .002, OR = 2.654) were significant risk factors for IR loss. For group 2 patients, male sex (P = .005, OR = 1.656), higher body mass index (P = .002, OR = 0.946), a diagnosis other than osteoarthritis (P < .001, OR = 2.189), nonaugmented baseplate usage (P < .001, OR = 2.116), and not having subscapularis repaired (P < .001, OR = 3.052) were significant risk factors for IR loss.

CONCLUSION

The majority of patients improve IR after rTSA in the nonfracture setting. rTSA patients with substantial IR prior to surgery had a greater probability for losing IR compared to patients with poor preoperative IR. Numerous risk factors for IR loss were identified; these risk factors are useful for counseling patients considering rTSA, as some patients are more likely to lose IR than others.

Effect of Implant Size, Version and Rotator Cuff Tendon Preservation on the Outcome of Reverse Shoulder Arthroplasty

Introduction: Functional outcomes following reverse geometry shoulder arthroplasty can vary. This study assessed the effects of glenosphere size, humeral stem version, posterior rotator cuff status and subscapularis repair on patient-reported outcome and range of motion. 

Methods: A consecutive series of 132 patients from two orthopaedic centres that use the same onlay system for reverse shoulder arthroplasty were reviewed over a six-year period. Outcome measures consisted of the Oxford Shoulder score (OSS) and range of motion (ROM) at one year following surgery. These were assessed against glenosphere sizes (small (36-38 mm) and large (40-42 mm)), humeral stem retroversion (less or more than 20 degrees), rotator cuff status (posterior rotator cuff present or absent) and subscapularis tendon (repaired or not) at the end of procedure.

Results: Larger glenospheres and less humeral stem retroversion yielded better ROM and OSS but this was not statistically significant. Subscapularis repair had no effect on outcomes. Preservation of posterior rotator cuff tendons improved functional outcomes. The number of tendons present at the end of procedure had a positive effect on outcome (best with two tendons and better with one compared to a completely bald humeral head).

Conclusion: Preservation of posterior rotator cuff tendons during reverse shoulder arthroplasty improves clinical outcomes unlike subscapularis repair which was found to be unnecessary. Implant size and version in reverse geometry arthroplasty have no significant effects on clinical outcome.

Radiological changes in shoulder osteoarthritis and pain sensation correlate with patients’ age

Purpose

Osteoarthritis (OA) is one of the most common musculoskeletal disorders in the aging population. The correlation of radiographic OA severity, disability and pain is variable and inconsistent for the different joints. This study aims to elucidate the relationship between histological and radiological signs of shoulder OA with pain sensation and functional impairment to potentially adapt the recommendation for surgical treatment for primary total shoulder arthroplasty (TSA).

Methods

Forty-four patients with shoulder OA undergoing TSA using an anatomic stemless implant were included in this study. The radiological OA severity was scored pre-operatively on true ap X-rays according to the Kellgren–Lawrence score (KL-Score). Acromial types according to Bigliani were defined by pre-operative radiological images. The histological OA severity was determined according to the OARSI-Score using bone–cartilage sections from loaded areas of the humeral head. Pain was quantified using the visual analog scale (VAS). The functional status was assessed by the items “mobility” and “strength” out of the Constant–Murley score (CS Score). Demographic data including BMI, age, gender, diabetes mellitus and smoking were recorded.

Results

There was no correlation between radiographic and histological severity in shoulder OA. However, a correlation of age and the severity of radiological changes was observed. Further, pain did not correlate with histological or radiological scores, whereas it correlated with age and the presence of diabetes mellitus. The functional shoulder status (mobility, strength) correlated with the severity of radiological changes, but not with the histologic scoring, which correlated with nicotine abuse.

Conclusion

This study shows that increased age is the main determinant of radiological changes in shoulder OA, as well as pain. Therefore, age and pain sensation should be considered as important parameters for the recommendation for TSA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03137-x.

Using machine learning to predict internal rotation after anatomic and reverse total shoulder arthroplasty

BACKGROUND

Improvement in internal rotation (IR) after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty is difficult to predict, with rTSA patients experiencing greater variability and more limited IR improvements than aTSA patients. The purpose of this study is to quantify and compare the IR score for aTSA and rTSA patients and create supervised machine learning that predicts IR after aTSA and rTSA at multiple postoperative time points.

METHODS

Clinical data from 2270 aTSA and 4198 rTSA patients were analyzed using 3 supervised machine learning techniques to create predictive models for internal rotation as measured by the IR score at 6 postoperative time points. Predictions were performed using the full input feature set and 2 minimal input feature sets. The mean absolute error (MAE) quantified the difference between actual and predicted IR scores for each model at each time point. The predictive accuracy of the XGBoost algorithm was also quantified by its ability to distinguish which patients would achieve clinical improvement greater than the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) patient satisfaction thresholds for IR score at 2-3 years after surgery.

RESULTS

rTSA patients had significantly lower mean IR scores and significantly less mean IR score improvement than aTSA patients at each postoperative time point. Both aTSA and rTSA patients experienced significant improvements in their ability to perform activities of daily living (ADLs); however, aTSA patients were significantly more likely to perform these ADLs. Using a minimal feature set of preoperative inputs, our machine learning algorithms had equivalent accuracy when predicting IR score for both aTSA (0.92-1.18 MAE) and rTSA (1.03-1.25 MAE) from 3 months to >5 years after surgery. Furthermore, these predictive algorithms identified with 90% accuracy for aTSA and 85% accuracy for rTSA which patients will achieve MCID IR score improvement and predicted with 85% accuracy for aTSA patients and 77% accuracy for rTSA which patients will achieve SCB IR score improvement at 2-3 years after surgery.

DISCUSSION

Our machine learning study demonstrates that active internal rotation can be accurately predicted after aTSA and rTSA at multiple postoperative time points using a minimal feature set of preoperative inputs. These predictive algorithms accurately identified which patients will, and will not, achieve clinical improvement in IR score that exceeds the MCID and SCB patient satisfaction thresholds.

Association Between Preoperative Shoulder Strength and Clinical Outcomes After Primary Reverse Total Shoulder Arthroplasty

INTRODUCTION

We aimed to determine whether preoperative shoulder strength predicts postoperative values and improvement in strength, range of motion (ROM), and outcome scores after primary reverse total shoulder arthroplasty (rTSA).

METHODS

We retrospectively reviewed 264 shoulders with a minimum of 2-year follow-up after primary rTSA. Preoperative external rotation (ER) strength, supraspinatus strength, and abduction strength were analyzed to establish their correlation with postoperative values and improvement in strength, ROM, and outcome scores (Constant score, American Shoulder and Elbow Surgeons Shoulder score, Shoulder Pain and Disability Index, Simple Shoulder Test, and the University of California, Los Angeles score). Multiple linear regression models were used to identify the preoperative shoulder strength measures that most affected postoperative outcomes and improvement in outcomes.

RESULTS

Preoperative measures of shoulder strength were positively correlated with all measures of postoperative shoulder strength, active abduction and elevation, and all outcome scores studied. On multivariate analysis, greater preoperative ER, supraspinatus, and abduction strength were significantly associated with greater corresponding postoperative values (P = 0.009, P = 0.041, and P = 0.008, respectively); however, they were also associated with less respective improvement (P < 0.001 for all) because the weakest patients tended to see the largest improvements. Notably, preoperative values of ER and supraspinatus strength exceeding 17.5 and 20.5 lbs were associated with a decline in their respective values postoperatively, but no limit was identified for ROM or outcome score measures. On multivariate analysis, reduced preoperative abduction strength was markedly associated with greater improvement in 3 of 4 ROM measures and 4 of 5 outcome scores.

CONCLUSION

Preoperative shoulder strength, especially abduction strength, predicts superior postoperative outcomes and greater improvement in shoulder strength, ROM, and outcome scores after primary rTSA. However, a minority of patients with well-preserved strength may lose strength after surgery, and patients who are weaker preoperatively tend to see larger improvements in postoperative outcomes.

LEVEL OF EVIDENCE

Ⅳ, prognostic study.

Correlação entre posicionamento do implante das artroplastias parciais de recobrimento do ombro e os resultados funcionais

Objective  The present study aimed to correlate functional outcomes and implant positioning in a case series of partial shoulder resurfacing arthroplasties.

Methods  A total of 25 patients were assessed for range of motion, functional outcome per the University of California at Los Angeles (UCLA) score and radiographic findings. Pre- and postoperative data were compared. In addition, patients were grouped according to the cervical-diaphyseal angle (CDA) determined by an anteroposterior radiography and to the retroversion angle (RVA) determined by an axillary radiography. A CDA from 130° to 140° and a RVA from 20° to 40° consisted in ideal positioning (anatomical standard). Data were analyzed using the Wilcoxon signed-rank test, analysis of variance (ANOVA) followed by the Kruskal-Wallis test or the Mann-Whitney test as appropriate.

Results  The mean follow-up time was 48.3 months (12 to 67 months). The postoperative functional score (31.5) was higher than the preoperative score (15.5) ( p  < 0.001). In 6 patients, the implant was in anatomical positioning, while implant positioning was considered “nonstandard” in 19 subjects. Seven patients had a CDA < 130°, and 14 patients had a CDA ranging from 130° to 140°; in addition, the CDA was > 140° in 4 subjects. The RVA was up to 20° in 15 patients and ranged from 20° to 40° in 10 subjects. Using these criteria to group patients, the postoperative clinical-functional parameters were not statistically different from the preoperative findings ( p  > 0.05).

Conclusion  Partial shoulder resurfacing results in significant postoperative functional recovery in patients with degenerative joint diseases. However, implant positioning assessed by CDA and RVA does not correlate with clinical-functional outcomes and, therefore, it is an inaccurate indicator of surgical success.

Level of Evidence IV; Case Series.

Preoperative shoulder strength is associated with postoperative primary anatomic total shoulder arthroplasty outcomes and improvement

BACKGROUND

Although numerous preoperative factors that influence postoperative outcomes after anatomic total shoulder arthroplasty (aTSA) have been identified, preoperative shoulder strength has not been studied. The purpose of this study was to determine whether preoperative shoulder strength is predictive of postoperative outcomes and improvement after primary aTSA.

METHODS

We conducted a retrospective review of prospectively collected data from 160 shoulders with minimum 2-year follow-up after primary aTSA. Preoperative external rotation (ER) strength, supraspinatus strength, and abduction strength score were analyzed to determine their correlation with postoperative outcomes and improvement in shoulder strength, range of motion (ROM), and outcome scores. Multiple linear regression models were subsequently used to adjust for covariates and determine the preoperative measures of shoulder strength that most influenced postoperative outcomes and improvement.

RESULTS

Preoperative ER strength, supraspinatus strength, and abduction strength score were each moderately correlated with their respective postoperative values and improvement (P < .001 for all). A decrease in ER strength, supraspinatus strength, and abduction strength score postoperatively was identified for preoperative strength values > 8.2 kg, > 6.6 kg, and > 4.5 kg, respectively. In contrast, no upper limit of preoperative shoulder strength led to a decrease in ROM or outcome scores postoperatively. On multivariate analysis, the baseline abduction strength score was a statistically significant predictor of postoperative values and improvement for all 3 measures of shoulder strength, raw and normalized Constant scores, and improvement in active abduction and active elevation.

CONCLUSION

Preoperative shoulder strength is moderately associated with postoperative outcomes and improvements in shoulder strength, ROM, and outcome scores after primary aTSA. It is important to note that we identified preoperative strength values that led to a decrease in strength postoperatively but not ROM or outcome scores. The results of our study demonstrate that abduction strength may be a useful indicator of patient outcomes after aTSA. Our findings will provide surgeons with useful prognostic insight to aid in guiding patient expectations.

Effects of obesity on clinical and functional outcomes following anatomic and reverse total shoulder arthroplasty

BACKGROUND

Limited data exist regarding the clinical and functional outcomes following primary total shoulder arthroplasty in obese patients. The purpose of this study is to determine the effects of obesity on the clinical and functional outcomes following primary anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) in a large patient population with mid-term follow-up.

METHODS

Patients in a multi-institutional shoulder registry receiving either primary aTSA (n = 1520) or rTSA (n = 2054) from 2004 to 2018 with a minimum follow-up period of 2 years were studied. All patients received the same single-platform shoulder prosthesis. Study groups were assigned based on implant type (anatomic or reverse), and further stratification was based on patient body mass index (BMI), with obese patients having a BMI ≥ 30 and non-obese patients having a BMI < 30. Patients were evaluated and scored preoperatively and at latest follow-up by use of 5 scoring metrics and range of motion (ROM).

RESULTS

The mean follow-up period was 5 years (range, 2-14 years). Obese patients comprised 41% of the aTSA group and 35% of the rTSA group. Significant postoperative improvements in visual analog scale pain scores, ROM, and all 5 scoring metrics occurred in both obese and non-obese patients (P < .05). Obese patients in both groups reported higher preoperative and postoperative visual analog scale pain scores and less preoperative and postoperative ROM compared with non-obese patients. Compared with non-obese patients, obese patients receiving aTSA reported significantly worse postoperative Simple Shoulder Test, Constant-Murley, American Shoulder and Elbow Surgeons, University of California, Los Angeles, and Shoulder Pain and Disability Index scores compared with non-obese patients, and those receiving rTSA reported significantly worse American Shoulder and Elbow Surgeons and Shoulder Pain and Disability Index scores (all P < .05). However, these differences did not exceed the minimal clinically important difference or substantial clinical benefit criteria. Radiographic analysis showed that in the rTSA group, obese patients had significantly less postoperative scapular notching and a lower scapular notching grade compared with non-obese patients (P < .05).

DISCUSSION

Both non-obese and obese patients can expect clinically significant improvements in pain, motion, and functional outcome scores following both aTSA and rTSA. Obese patients reported significantly more postoperative pain, lower outcome scores, and less ROM compared with non-obese patients after both aTSA and rTSA at a mean follow-up of 5 years. However, statistically significant differences were not found to be clinically significant with respect to established minimal clinically important difference and substantial clinical benefit criteria. Therefore, obese and non-obese patients experience similar clinical outcomes following total shoulder arthroplasty, regardless of BMI. However, obese patients have more comorbidities, greater intraoperative blood loss, and less scapular notching compared with non-obese patients.

Measuring Patient Value after Total Shoulder Arthroplasty

Evaluating the value of health care is of paramount importance to keep improving patients' quality of life and optimizing associated costs. Our objective was to present a calculation method based on Michael Porter's formula and standard references to estimate patient value delivered by total shoulder arthroplasty (TSA). We retrospectively reviewed the records of 116 consecutive TSAs performed between June 2015 and June 2019. Patient value was defined as quality of care divided by direct costs of surgery. Quality metrics included intra- and postoperative complications as well as weighted improvements in three different patient-reported outcome measures at a minimum of one-year follow-up. Direct costs of surgery were retrieved from the management accounting analyses. Substantial clinical benefit (SCB) thresholds and the standard reimbursement system were used as references for quality and cost dimensions. A multivariable linear regression was performed to identify factors associated with patient delivered value. Compared to a reference of 1.0, the quality of care delivered to patients was 1.3 ± 0.3 (range, 0.6-2.0) and the associated direct cost was 1.0 ± 0.2 (range, 0.7-1.6). Ninety patients (78%) had a quality of care ≥1.0 and 61 patients (53%) had direct costs related to surgery ≤1.0. The average value delivered to patients was 1.3 ± 0.4 (range, 0.5-2.5) with 91 patients (78%) ≥ 1.0, was higher for non-smokers (beta, 0.12; p = 0.044), anatomic TSA (beta, 0.53; p < 0.001), increased with higher pre-operative pain (beta, 0.08; p < 0.001) and lower pre-operative Constant score (beta, -0.06; p = 0.001). Our results revealed that almost 80% of TSAs provided substantial patient value. Patient pre-operative pain/function, tobacco use, and procedure type are important factors associated with delivered patient value.

Development and validation of a predictive model for outcomes in shoulder arthroplasty: a multicenter analysis of nearly 2000 patients

BACKGROUND

Guiding expectations following shoulder arthroplasty is important in improving patient satisfaction. The purpose of this study was to develop a predictive model to calculate 2-year American Shoulder and Elbow Surgeons (ASES) scores in shoulder arthroplasty patients from a comprehensive set of preoperative patient factors and types of arthroplasty performed.

METHODS

This retrospective multicenter study included 1947 shoulder arthroplasties performed from 2010 to 2015 at 3 high-volume centers. Twenty-six variables were evaluated for an association with 2-year ASES scores, and variables with P < .20 in our pair-wise analysis were used to develop a predictive model. The prediction root-mean-square error was calculated. External validation was performed using data from 233 patients who underwent shoulder arthroplasty performed by a separate shoulder surgeon at a center not involved with creation of the predictive model.

RESULTS

A total of 1947 patients were analyzed, and their data were used to construct the predictive model. Variables most associated with 2-year ASES scores were patient age, preoperative ASES score, disability, chronic obstructive pulmonary disease, alcohol use, anatomic vs. reverse total shoulder arthroplasty, and primary vs. revision shoulder arthroplasty. By use of cross validation, the prediction error was 20.1, the proportion of variance explained was 25.3%, the mean absolute error was 15.9, and the C statistic for the linear regression model was 0.66. After external validation, the mean difference between predicted and actual 2-year ASES scores was 12.7 points, within the accepted minimal clinically important difference after shoulder arthroplasty.

DISCUSSION

Data from nearly 2000 shoulder arthroplasties allowed the development and validation of a model to predict 2-year ASES scores following shoulder arthroplasty. The model was accurate within the minimal clinically important difference in 85% of patients.

Teres minor muscle hypertrophy is a negative predictor of outcomes after reverse total shoulder arthroplasty: an evaluation of preoperative magnetic resonance imaging and postoperative implant position

BACKGROUND

Predictors of outcomes after reverse total shoulder arthroplasty (rTSA) remain unclear. The purpose of this study was to analyze the impact of preoperative muscle quality and postoperative implant positioning on patient-reported outcomes following rTSA.

METHODS

We evaluated 88 shoulders treated with rTSA in which preoperative magnetic resonance imaging was available. Preoperative muscle quality was evaluated, including fatty infiltration, rotator cuff muscle volume, and total tear size. Postoperative implant position was determined radiographically. The correlation between imaging parameters and the 2-year postoperative American Shoulder and Elbow Surgeons (ASES) score was examined. Multivariate analyses were performed to adjust for confounding factors including patient demographic characteristics and implant position.

RESULTS

Univariate analysis showed that the ASES score was significantly lower in patients with teres minor muscle hypertrophy relative to those with normal muscle (73.3 ± 22.8 vs. 84.2 ± 16.9, P = .02). The functional subscore was significantly lower in patients with grade 2 fatty infiltration of the deltoid muscle relative to those with grade 0 fatty infiltration (26.1 ± 14.6 vs. 34.8 ± 11.6, P = .03). Older age was associated with a higher pain subscore (ρ = 0.32, P = .002). Multivariate analysis demonstrated that teres minor muscle hypertrophy remained a significant independent predictor of the ASES score (β coefficient = 91.3, P = .03).

CONCLUSION

Teres minor muscle hypertrophy is an independent negative predictor of patient-reported outcomes after rTSA.

Influence of Thoracic Kyphosis on Reverse Total Shoulder Arthroplasty Outcomes

INTRODUCTION

Patient dissatisfaction after primary reverse total shoulder arthroplasty (rTSA) has been reported as high as 9%. In patients with excessive thoracic kyphosis, the scapula protracts and tilts anteriorly, which may lead to early impingement with the acromion and loss of forward elevation. The primary purpose of this study was to evaluate the effect of thoracic kyphosis on overhead ROM after rTSA.

METHODS

A prospectively collected shoulder registry was retrospectively reviewed for all patients undergoing primary rTSA with a minimum of 2-year follow-up. Preoperative and latest follow-up ROM (forward elevation, abduction, internal rotation, and external rotation), patient-reported outcome measures (SPADI, SST-12, ASES, UCLA, SF-12, and the visual analog scale), and the Constant score were collected. Postoperative radiographs were evaluated for implant loosening and notching. Patients were separated into three groups according to the thoracic kyphosis angle (<25°, 25 to 45°, and >45°) and also analyzed as a continuous variable. The groups were compared using analysis of variance and chi-square tests as indicated.

RESULTS

Three hundred five shoulders in 279 patients were reviewed at a mean follow-up of 3.9 years (range 2 to 10 years). Female patients and patients with a history of heart disease were statistically more likely to have increased thoracic kyphosis (P < 0.05). After surgery, forward elevation and abduction were similar among all groups (<25: 133°, 25 to 45: 132°, >45: 127°; P = 0.199 and <25: 123°, 25 to 45: 122°, >45: 117°; P = 0.330). All other postoperative ROM measurements and all patient-reported outcome measures were also similar, regardless of measured kyphosis. In addition, no association was observed between the degree of thoracic kyphosis and scapular notching (P = 0.291).

DISCUSSION

Despite thoracic kyphosis being a known risk factor for loss of overhead motion in the native shoulder, shoulders with excessive thoracic kyphosis demonstrated similar overhead ROM at early follow-up after primary rTSA.

LEVEL OF EVIDENCE

III.

Preoperative factors associated with loss of range of motion after reverse shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) is a successful procedure, often allowing patients to achieve better range of motion (ROM) compared with their preoperative baseline. However, there is a subset of patients who either fail to improve or lose ROM postoperatively. These patients are at increased risk of poor satisfaction and patient-reported outcomes. To date, characteristics of this subset of patients have not been well described. The purpose of this study is to determine risk factors associated with loss of ROM after primary RTSA.

METHODS

A retrospective review using a commercial international RTSA database (Exactech Inc., Gainesville, FL, USA) of patients who underwent primary RTSA between 2007 and 2017 was performed. A total of 123 (7.7%) shoulders lost ≥10° of forward elevation (FE) (group 1, P₁) and 183 (11.4%) lost ≥10° of external rotation (ER) (group 2, P₂). Univariate and multivariate analyses were performed comparing these patients with control cohorts to evaluate risk factors for loss of motion.

RESULTS

Better preoperative abduction, FE, ER, and internal rotation were each associated with greater loss of FE (P₁ < .001) and ER (P₂ < .001) postoperatively. Higher preoperative Simple Shoulder Test (P₁ < .001, P₂ < .001), Constant (P₁ < .001, P₂ < .001), Shoulder Pain and Disability Index (P₁ < .001, P₂ < .001), American Shoulder Elbow Surgeons (P₁ < .001), and University of California at Los Angeles (P₁ < .001) scores were also strongly associated with loss of ROM postoperatively. Other factors associated with a higher risk of losing ROM included a diagnosis of irreparable rotator cuff tear (P₁ = .038), rotator cuff arthropathy (P₁ = .017, P₂ ≤ .001), and inflammatory arthropathy (P₁ = .021). After multivariate analysis, higher preoperative FE (P₁ < .001), internal rotation (P₁ = -.018), and weight (P₁ = .008) remained significant predictors of loss of FE. Better preoperative FE (P₂ = .003), ER (P₂ < .001), and University of California at Los Angeles score (P₂ < .001) remained significant predictors of loss of ER. Patients who lost FE or ER were more likely to report lower satisfaction scores than their counterparts who did not lose ROM (P₁ < .001, P₂ < .001).

CONCLUSION

Patients with greater preoperative shoulder ROM or higher patient-reported outcomes are at higher risk of losing ROM after primary RTSA. They are also at higher risk of reporting lower postoperative satisfaction, though the majority were still satisfied. Surgeons should strongly counsel patients with well-preserved preoperative function on the risk of loss of ROM.

Acute versus delayed reverse total shoulder Arthroplasty for the management of Proximal Humerus Fractures

OBJECTIVES

Proximal humerus fractures (PHF) are common, yet their optimal management remains debated. Reverse total shoulder arthroplasty (rTSA) is an increasingly popular option, particularly for non-reconstructible or osteoporotic fractures. Despite this trend, current literature provides limited guidance with regards to surgical timing and patient selection for rTSA. A trial of non-operative management might be beneficial for many patients who are not clearly indicated for surgery, provided this does not have a major negative impact on results for those who ultimately require rTSA. The purpose of this study was to investigate whether delayed reverse shoulder arthroplasty for fracture (>28 days from injury) is associated with any difference in complication rates or functional outcomes relative to acute surgery.

DESIGN

Retrospective cohort study PATIENTS/PARTICIPANTS: 114 consecutive patients who underwent rTSA as the primary management of a PHF at two Level 1 trauma centers and one academic community hospital between 2004 and 2016.

INTERVENTION

rTSA as primary management of proximal humerus fracture MAIN OUTCOME MEASUREMENTS: Complications, range of motion, and patient-reported functional outcomes scores (DASH, PROMIS physical function, and EQ-5D) RESULTS: Eighty-two of 114 patients (72%) underwent early surgery. Complex (4-part, head-split, dislocated) fractures were significantly more common in the acutely treated group. There was no significant difference in complications. Overall complication rate was 11.4%. There was a significant difference in DASH score favoring early surgery, with an average score of 22.4 in acutely treated patients versus 35.1 in delayed patients (p = 0.034). There was a non-statistically significant trend towards better PROMIS physical function scores and ROM in the acutely treated group.

CONCLUSION

Delay in performing primary rTSA for management of PHF does not lead to an increase in complication rates but it may come at the cost of worse functional outcomes in patients who ultimately require rTSA.

Three-dimensional kinematics of reverse shoulder arthroplasty: a comparison between shoulders with good or poor elevation

Background

Various factors may be related to outcomes of reverse shoulder arthroplasty (RSA) including patient and surgical factors. Differences in shoulder kinematics might be associated with poor function after RSA; however, kinematic differences between shoulders with good or poor elevation have not been elucidated. The purpose of this study was to compare RSA kinematics between shoulders with good or poor elevation.

Methods

The study included 28 shoulders with a minimum 6-month follow-up after RSA using Grammont-type prostheses. Subjects comprised 17 men and 11 women with the mean age of 75 years (range, 63-91). Subjects underwent fluoroscopy during active scapular plane abduction. Computed tomography of their shoulders was performed to create 3-dimensional scapular implant models. Using model-image registration techniques, poses of 3-dimensional implant models were iteratively adjusted to match their silhouettes with the silhouettes in the fluoroscopic images, and 3-dimensional kinematics of implants were computed. Kinematics and glenosphere orientation were compared between shoulders with good (>90 degree) or poor (<90 degree) scapular plane abduction.

Results

Nineteen and 9 shoulders were assigned to the good- and poor-elevation groups, respectively. There were no significant differences between the groups in age, sex, height, weight, preoperative range of motion, or Constant score, but body mass index in the poor elevation shoulders was significantly larger than that in the good elevation shoulders. There were no significant differences in glenosphere (upward/downward rotation, anterior/posterior tilt, internal/external rotation) or glenohumeral (internal/external rotation, abduction/adduction) kinematics between the good and poor elevation shoulders. Scapulohumeral rhythm was significantly higher in the good elevation shoulders than the poor elevation shoulders (P = .04). Glenosphere superior tilt was 2.3° ± 4.2° in the good-elevation group and 8.1° ± 8.9° in the poor-elevation group, and the difference was statistically significant (P = .03).

Discussion

Shoulders with good elevation after RSA demonstrated better scapulohumeral rhythm than those with poor elevation, though there were no significant differences in glenosphere and glenohumeral kinematics. It may be important for better elevation to achieve good glenohumeral motion in shoulders with RSA. Glenosphere orientations may affect postoperative shoulder function.

Deltoid fatigue: a longitudinal assessment of reverse shoulder arthroplasty over time

BACKGROUND

Studies evaluating the mid-term performance of reverse shoulder arthroplasty (RSA) have identified a drop in the Constant-Murley score between 6 and 8 years after surgery, which is most affected by a loss of forward elevation and strength. Alterations of the deltoid length and moment arm after RSA lead to nonphysiological stress on the deltoid muscle. Concern has arisen that the long-term implications of increased deltoid work may be causing "deltoid fatigue." The purpose of this study was to evaluate the long-term effects of RSA on overhead range of motion (ROM) and validate the hypothesis of deltoid fatigue.

METHODS

We performed a retrospective review of 165 RSAs over a 5-year period. Diagnoses were limited to cuff tear arthropathy, osteoarthritis with rotator cuff deficiency, and irreparable rotator cuff tear. All procedures were performed using a single implant system. Patients were evaluated longitudinally at multiple time points. They were required to undergo a minimum of 3 follow-up visits, with at least 1 visit at >5 years. ROM and patient-reported outcome measures were evaluated using linear mixed models for repeated measures to evaluate changes in outcome measures over time. A secondary analysis was performed to assess the influence of patient demographic factors on observed changes in ROM and patient-reported outcome measures.

RESULTS

Primary RSA shoulders were observed to lose 0.8° of forward elevation and abduction per year starting at 1 year postoperatively (P = .006), without a significant drop at mid-term follow-up. No significant change in external or internal rotation was observed. Male patients and patients with a diagnosis of osteoarthritis with rotator cuff deficiency showed greater baseline overhead ROM at 1 year postoperatively, but the subsequent rates of functional decline were similar regardless of age, sex, or indication.

DISCUSSION

This study challenges the previous theory of deltoid fatigue resulting in a significant loss of overhead ROM beginning 6-8 years after index arthroplasty. However, a slower progressive decline in overhead ROM in well-functioning RSA shoulders was observed, averaging 0.8° of overhead ROM per year. This progressive deterioration occurs at a slightly greater rate than that observed in the natural shoulder. The observed rate of functional decline was found to be independent of age, sex, and preoperative diagnosis.

Assessing the Value to the Patient of New Technologies in Anatomic Total Shoulder Arthroplasty

BACKGROUND

Publications regarding anatomic total shoulder arthroplasty (TSA) have consistently reported that they provide significant improvement for patients with glenohumeral arthritis. New TSA technologies that have been introduced with the goal of further improving these outcomes include preoperative computed tomography (CT) scans, 3-dimensional preoperative planning, patient-specific instrumentation, stemless and short-stemmed humeral components, as well as metal-backed, hybrid, and augmented glenoid components. The benefit of these new technologies in terms of patient-reported outcomes is unknown.

METHODS

We reviewed 114 articles presenting preoperative and postoperative values for commonly used patient-reported metrics. The results were analyzed to determine whether patient outcomes have improved over the 20 years during which new technologies became available.

RESULTS

The analysis did not identify evidence that the results of TSA were statistically or clinically improved over the 2 decades of study or that any of the individual technologies were associated with significant improvement in patient outcomes.

CONCLUSIONS

Additional research is required to document the clinical value of these new technologies to patients with glenohumeral arthritis.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Using machine learning to predict clinical outcomes after shoulder arthroplasty with a minimal feature set

BACKGROUND

A machine learning analysis was conducted on 5774 shoulder arthroplasty patients to create predictive models for multiple clinical outcome measures after anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA). The goal of this study was to compare the accuracy associated with a full-feature set predictive model (ie, full model, comprising 291 parameters) and a minimal-feature set model (ie, abbreviated model, comprising 19 input parameters) to predict clinical outcomes to assess the efficacy of using a minimal feature set of inputs as a shoulder arthroplasty clinical decision-support tool.

METHODS

Clinical data from 2153 primary aTSA patients and 3621 primary rTSA patients were analyzed using the XGBoost machine learning technique to create and test predictive models for multiple outcome measures at different postoperative time points via the full and abbreviated models. Mean absolute errors (MAEs) quantified the difference between actual and predicted outcomes, and each model also predicted whether a patient would experience clinical improvement greater than the patient satisfaction anchor-based thresholds of the minimal clinically important difference and substantial clinical benefit for each outcome measure at 2-3 years after surgery.

RESULTS

Across all postoperative time points analyzed, the full and abbreviated models had similar MAEs for the American Shoulder and Elbow Surgeons score (±11.7 with full model vs. ±12.0 with abbreviated model), Constant score (±8.9 vs. ±9.8), Global Shoulder Function score (±1.4 vs. ±1.5), visual analog scale pain score (±1.3 vs. ±1.4), active abduction (±20.4° vs. ±21.8°), forward elevation (±17.6° vs. ±19.2°), and external rotation (±12.2° vs. ±12.6°). Marginal improvements in MAEs were observed for each outcome measure prediction when the abbreviated model was supplemented with data on implant size and/or type and measurements of native glenoid anatomy. The full and abbreviated models each effectively risk stratified patients using only preoperative data by accurately identifying patients with improvement greater than the minimal clinically important difference and substantial clinical benefit thresholds.

DISCUSSION

Our study showed that the full and abbreviated machine learning models achieved similar accuracy in predicting clinical outcomes after aTSA and rTSA at multiple postoperative time points. These promising results demonstrate an efficient utilization of machine learning algorithms to predict clinical outcomes. Our findings using a minimal feature set of only 19 preoperative inputs suggest that this tool may be easily used during a surgical consultation to improve decision making related to shoulder arthroplasty.

Influence of humeral stem inclination in reverse shoulder arthroplasty on range of motion: a meta-analysis

Hypothesis

The reverse shoulder arthroplasty, as introduced by Grammont, has had many modifications over time. One of these modifications was reducing the neck-shaft angle (NSA) from 155 degrees to 135 degrees. Biomechanical studies indicated that lowering the NSA increases external rotation and reduces abduction and the incidence of scapular notching. The purpose of this study was to compare range of motion, functional outcome measures, and complications in patients undergoing reverse shoulder arthroplasty, depending on the NSA, through a systematic review and meta-analysis.

Methods

A literature search was conducted (articles published from January 1985 to January 2020) in the PubMed/MEDLINE, Embase, and CINAHL databases and the Cochrane library. All studies reporting outcomes after primary reverse shoulder arthroplasty for osteoarthritis and rotator cuff-related disease were included. Patients were divided into 2 groups: a medialized design (MD) with an NSA of 150-155 degrees and a lateralized design (LD) with an NSA of less than 150 degrees. Pooled effects were calculated in the form of mean differences and 95% confidence intervals (CIs). Risk of bias was assessed using the Risk Of Bias In Non-Randomized Studies - of Interventions tool for non-Randomized Controlled Trials and the Risk Of Bias 2 tool for Randomized Controlled Trials.

Results

A total of 21 studies and 3134 arthroplasties were included: 1366 with an MD and 1678 with an LD. The mean age was 73.0 years (MD 74.0 and LD 72.5). A direct comparative meta-analysis was not feasible, and therefore, all data were compared using the minimal clinically important difference. The MD group demonstrated a larger improvement in abduction (56.76°, 95% CI 37.03-76.49) than the LD group (48.52°, 95% CI 28.27-68.78), however the LD group demonstrated a larger improvement in external rotation with the arm at the side (MD: 7.69°, 95% CI 0.01-15.37; LD: 16.14° 95% CI 7.18-25.09). When looking at the postoperative range of motion, the MD group had more abduction than the LD group (MD: 136.28°, 95% CI 127.36-145.20; LD: 127.77° 95% CI 117.02-138.52). Both designs had a comparable improvement in the Constant Murley score (MD 42.04 points, LD 41.14 points). Lowering the NSA was accompanied by a decrease in dislocation rate (MD: 4.6%; LD: 1.4%; P value .037) and notching rate (MD: 40.3%; LD: 17.3%; P value <.0001).

Conclusion

In our analysis, lowering the NSA decreases the amount of abduction but increases the amount of external rotation. This change in range of motion is accompanied by less scapular notching and dislocations. There is no clear impact on functional outcome measures.

Establishing clinically significant outcome thresholds for the Single Assessment Numeric Evaluation 2 years following total shoulder arthroplasty

BACKGROUND

Single Assessment Numerical Evaluation (SANE) is a simple, time-efficient patient-reported outcome measure (PROM) used to assess postoperative shoulder function. Clinically significant outcome values and ability to correlate with longer legacy PROM scores at 2 years following shoulder arthroplasty are unknown.

METHODS

A retrospective analysis was performed using SANE, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Constant scores that were collected at a minimum 2-year follow-up. A total of 153 patients who underwent anatomic total shoulder arthroplasty (TSA) or reverse total shoulder arthroplasty (RTSA) were included. A distribution-based method was used to determine the minimal clinically important difference (MCID). An anchor-based method was used to determine substantial clinical benefit (SCB). The following anchor question was collected alongside the PROMs and graded on a 15-point Likert-type scale to establish the SCB: "Since your surgery, has there been any change in the pain in your shoulder?" Linear regression was used to assess correlations between PROMs.

RESULTS

SANE showed moderate correlation with ASES (R² = 0.493) and Constant (R² = 0.586) scores (P < .001). The MCID value was 14.9, and the SCB absolute value was 80.4 (area under the curve = 0.663) for SANE. Multivariate logistic regression demonstrated that patients undergoing RTSA were less likely to achieve SCB on all 3 outcome measures (P < .02).

CONCLUSIONS

This study establishes concurrent construct validity for SANE and suggests that it is a valid metric to assess the MCID and SCB at 2 years following anatomic TSA and RTSA. SANE demonstrated moderate correlations with ASES and Constant scores. Patients undergoing RTSA demonstrated a lower propensity to achieve SCB at 2 years postoperatively compared with anatomic TSA.

Reverse total shoulder arthroplasty clinical and patient-reported outcomes and complications stratified by preoperative diagnosis: a systematic review

OBJECTIVE

This systematic review aimed to investigate differences in clinical outcomes, patient-reported outcomes (PROs), and complication types and rates among preoperative diagnoses following reverse total shoulder arthroplasty (RTSA): rotator cuff tear arthropathy, primary osteoarthritis, massive irreparable rotator cuff tear, proximal humeral fracture, rheumatoid arthritis (RA), and revision of anatomic arthroplasty (Rev).

LITERATURE SEARCH

Three electronic databases were searched from inception to January 2020.

STUDY SELECTION CRITERIA

The inclusion criteria were (1) patients with a minimum age of 60 years who underwent RTSA for the stated preoperative diagnoses, (2) a minimum of 2 years' follow-up, and (3) preoperative and postoperative values for clinical outcomes and PROs.

DATA SYNTHESIS

Risk of bias was determined by the Methodological Index for Non-randomized Studies tool and the modified Downs and Black tool. Weighted means for clinical outcomes and PROs were calculated for each preoperative diagnosis.

RESULTS

A total of 53 studies were included, of which 36 (68%) were level IV retrospective case series. According to the Methodological Index for Non-randomized Studies tool, 33 studies (62%) showed a high risk of bias; the 3 randomized controlled trials showed a low risk of bias on the modified Downs and Black tool. RTSA improved clinical outcomes and PROs for all preoperative diagnoses. The Rev group had poorer final outcomes as noted by a lower American Shoulder and Elbow Surgeons score (69) and lower pain score (1.8) compared with the other preoperative diagnoses (78-82 and 0.4-1.4, respectively). The RA group showed the highest complication rate (28%), whereas the osteoarthritis group showed the lowest rate (1.4%).

CONCLUSION

Studies in the RTSA literature predominantly showed a high risk of bias. All preoperative diagnoses showed improvements; Rev patients showed the worse clinical outcomes and PROs, and RA patients showed higher complication rates. The preoperative diagnosis in RTSA patients can impact outcomes and complications.

What Is the Accuracy of Three Different Machine Learning Techniques to Predict Clinical Outcomes After Shoulder Arthroplasty?

BACKGROUND

Machine learning techniques can identify complex relationships in large healthcare datasets and build prediction models that better inform physicians in ways that can assist in patient treatment decision-making. In the domain of shoulder arthroplasty, machine learning appears to have the potential to anticipate patients' results after surgery, but this has not been well explored.

QUESTIONS/PURPOSES

(1) What is the accuracy of machine learning to predict the American Shoulder and Elbow Surgery (ASES), University of California Los Angeles (UCLA), Constant, global shoulder function, and VAS pain scores, as well as active abduction, forward flexion, and external rotation at 1 year, 2 to 3 years, 3 to 5 years, and more than 5 years after anatomic total shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA)? (2) What is the accuracy of machine learning to identify whether a patient will achieve clinical improvement that exceeds the minimum clinically important difference (MCID) threshold for each outcome measure? (3) What is the accuracy of machine learning to identify whether a patient will achieve clinical improvement that exceeds the substantial clinical benefit threshold for each outcome measure?

METHODS

A machine learning analysis was conducted on a database of 7811 patients undergoing shoulder arthroplasty of one prosthesis design to create predictive models for multiple clinical outcome measures. Excluding patients with revisions, fracture indications, and hemiarthroplasty resulted in 6210 eligible primary aTSA and rTSA patients, of whom 4782 patients with 11,198 postoperative follow-up visits had sufficient preoperative, intraoperative, and postoperative data to train and test the predictive models. Preoperative clinical data from 1895 primary aTSA patients and 2887 primary rTSA patients were analyzed using three commercially available supervised machine learning techniques: linear regression, XGBoost, and Wide and Deep, to train and test predictive models for the ASES, UCLA, Constant, global shoulder function, and VAS pain scores, as well as active abduction, forward flexion, and external rotation. Our primary study goal was to quantify the accuracy of three machine learning techniques to predict each outcome measure at multiple postoperative timepoints after aTSA and rTSA using the mean absolute error between the actual and predicted values. Our secondary study goals were to identify whether a patient would experience clinical improvement greater than the MCID and substantial clinical benefit anchor-based thresholds of patient satisfaction for each outcome measure as quantified by the model classification parameters of precision, recall, accuracy, and area under the receiver operating curve.

RESULTS

Each machine learning technique demonstrated similar accuracy to predict each outcome measure at each postoperative point for both aTSA and rTSA, though small differences in prediction accuracy were observed between techniques. Across all postsurgical timepoints, the Wide and Deep technique was associated with the smallest mean absolute error and predicted the postoperative ASES score to ± 10.1 to 11.3 points, the UCLA score to ± 2.5 to 3.4, the Constant score to ± 7.3 to 7.9, the global shoulder function score to ± 1.0 to 1.4, the VAS pain score to ± 1.2 to 1.4, active abduction to ± 18 to 21°, forward elevation to ± 15 to 17°, and external rotation to ± 10 to 12°. These models also accurately identified the patients who did and did not achieve clinical improvement that exceeded the MCID (93% to 99% accuracy for patient-reported outcome measures (PROMs) and 85% to 94% for pain, function, and ROM measures) and substantial clinical benefit (82% to 93% accuracy for PROMs and 78% to 90% for pain, function, and ROM measures) thresholds.

CONCLUSIONS

Machine learning techniques can use preoperative data to accurately predict clinical outcomes at multiple postoperative points after shoulder arthroplasty and accurately risk-stratify patients by preoperatively identifying who may and who may not achieve MCID and substantial clinical benefit improvement thresholds for each outcome measure.

CLINICAL RELEVANCE

Three different commercially available machine learning techniques were used to train and test models that predicted clinical outcomes after aTSA and rTSA; this device-type comparison was performed to demonstrate how predictive modeling techniques can be used in the near future to help answer unsolved clinical questions and augment decision-making to improve outcomes after shoulder arthroplasty.