Indications for reverse total shoulder arthroplasty in rotator cuff disease

Glenosphere Size Does Not Matter in Reverse Total Shoulder Arthroplasty

Objective  There are few studies to date reporting on outcomes following reverse total shoulder arthroplasty with cohorts stratified by glenosphere size. The purpose of this study is to investigate the role that glenosphere size has on postoperative outcomes. Methods  Patients who underwent reverse TSA between 1987 with minimum of 2.0 years of follow-up were included. Patients were stratified into two cohorts based on glenosphere size of 36mm or 40mm. Patients' range of motion, patient-reported outcomes, and radiographic variables (glenoid preoperative morphology, scapular notching, humeral loosening) were evaluated. Results  All measurements of range of motion measurements with the exception of internal rotation saw significant preoperative to postoperative improvements within each cohort. There were no significant differences in postoperative range of motion, ASES, or VAS pain scores across the two cohorts. Overall, forward elevation improved to 134° ± 16° in the 36mm cohort and 133° ± 14° in the 40mm cohort ( p  = 0.47). External rotation improved to 37° ± 13° for 36mm patients and 35° ± 19° for 40mm patients ( p  = 0.58). In the 36mm group, internal rotation increased by 1.3 vertebral levels and 2.3 vertebral levels in the 40mm cohort. At final follow-up, the 36mm cohort had a VAS score of 2 ± 2, ASES score of 66 ± 19, and SST score of 6 ± 3. Similarly, the 40mm cohort had a VAS score of 2 ± 3, ASES score of 77 ± 28, and SST score of 9 ± 3. Conclusions  Reverse TSA provides sustained improvements in range of motion and shoulder function irrespective of glenosphere size. Level of Evidence  III.

Clinical outcomes of anatomic vs. reverse total shoulder arthroplasty in primary osteoarthritis with preoperative external rotation weakness and an intact rotator cuff: a case-control study

BACKGROUND

Anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA) are well-established treatments for patients with primary osteoarthritis and an intact cuff. However, it is unclear whether aTSA or rTSA provides superior outcomes in patients with preoperative external rotation (ER) weakness.

METHODS

A retrospective review of a prospectively collected shoulder arthroplasty database was performed between 2007 and 2020. Patients were excluded for preoperative diagnoses of nerve injury, infection, tumor, or fracture. The analysis included 333 aTSAs and 155 rTSAs performed for primary cuff-intact osteoarthritis with 2-year minimum follow-up. Defining preoperative ER weakness as strength <3.3 kilograms (7.2 pounds), 3 cohorts were created and matched: (1) weak aTSAs (n = 74) vs. normal aTSAs (n = 74), (2) weak rTSAs (n = 38) vs. normal rTSAs (n = 38), and (3) weak rTSAs (n = 60) vs. weak aTSAs (n = 60). We compared range of motion, outcome scores, strength, complications, and revision rates at the latest follow-up.

RESULTS

Despite weak aTSAs having poorer preoperative strength in forward elevation and ER (P < .001), neither of these deficits persisted postoperatively compared with the normal cohort. Likewise, weak rTSAs had poorer preoperative strength in forward elevation and ER, overhead motion, and Constant, Shoulder Pain and Disability Index, and University of California, Los Angeles scores (P < .029). However, no statistically significant differences were found between preoperatively weak and normal rTSAs. When comparing weak aTSA vs. weak rTSA, no differences were found in preoperative and postoperative outcomes, proportion of patients achieving the minimal clinically important difference and substantial clinical benefit, and complication and rate of revision surgery.

CONCLUSIONS

In preoperatively weak patients with cuff-intact primary osteoarthritis, aTSA leads to similar postoperative strength, range of motion, and outcome scores compared with patients with normal preoperative strength, indicating that preoperative weakness does not preclude aTSA use. Furthermore, patients who were preoperatively weak in ER demonstrated improved postoperative rotational motion after undergoing aTSA and rTSA, with both groups achieving the minimal clinically important difference and substantial clinical benefit at similar rates.

Insertion sites of latissimus dorsi tendon transfer performed during reverse shoulder arthroplasty: A systematic review and meta-analysis

BACKGROUND

Reverse shoulder arthroplasty (RSA) with concurrent latissimus dorsi transfer (LDT) is a potential treatment option for restoration of external rotation (ER). Biomechanical studies have emphasized the importance of the insertion site location for achieving optimal outcomes. In this systematic review and meta-analysis, we aimed to describe what insertion sites for LDT are utilized during concomitant RSA and their associated clinical outcomes.

METHODS

A systematic review and meta-analysis were performed per PRISMA guidelines. We queried PubMed/MEDLINE, Embase, Web of Science, and Cochrane databases to identify articles reporting on patients who received RSA with LDT to restore ER and specified the site of tendon transfer insertion on the humerus. We first describe reported insertion sites in the literature. Secondarily, we present preoperative and postoperative range of motion and Constant score for different insertion sites as well as reported complications.

RESULTS

Sixteen studies, analyzed as 19 separate cohorts (by insertion site and tendon-transfer), reporting on 264 RSAs with LDT (weighted mean age 66 years, follow-up 39 months, 61% female) were evaluated. Of these, 143 (54%) included a concomitant teres major transfer (LDT/TMT) and 121 (46%) were LDT-only. Fourteen cohorts (14/19, 74%) reported insertion at the posterolateral aspect of the greater tuberosity, four cohorts (4/19, 21%) reported insertion site at the lateral bicipital groove, and one cohort (1/19, 5%) reported separate LDT and TMT with insertion of the TMT to the posterolateral aspect of the greater tuberosity and LDT to the lateral bicipital groove. Meta-analysis revealed no differences in range of motion or Constant score based on humeral insertion site or whether the LDT was transferred alone or with TMT. Leading complications included dislocation, followed by infection and neuropraxia. No discernible correlation was observed between postoperative outcomes and the strategies employed for tendon transfer, prosthesis design, or subscapularis management.

CONCLUSION

The posterolateral aspect of the greater tuberosity was the most-utilized insertion site for LDT performed with RSA. However, in the current clinical literature, LDT with or without concomitant TMT result in similar postoperative ROM and Constant score regardless of insertion site. Analysis of various proposed transfer sites reinforce the ability of LDT with RSA to restore both FE and ER in patients with preoperative active elevation and external rotation loss. Meta-analysis revealed significant improvements in range of motion and Constant score regardless of humeral insertion site or whether the LDT was transferred alone or with TMT, although future studies are needed to determine whether an ideal tendon transfer technique exists.

LEVEL OF EVIDENCE

IV.

Patient-specific implants in reverse shoulder arthroplasty

Reverse total shoulder arthroplasty (RTSA) is widely popular among shoulder surgeons and patients, and its prevalence has increased dramatically in recent years. With this increased use, the indicated pathologies associated with RTSA are more likely to be encountered, and challenging patient presentations are more likely to be seen. One prominent challenging presentation is RTSA patients with severe glenoid bone loss. Several techniques with varying degrees of invasiveness, including excessive reaming, alternate centerline, bone grafting, and patient-specific implants (PSIs), have been developed to treat patients with this presentation. PSI treatment uses a three-dimensional reconstruction of a computed tomography scan to design a prosthetic implant or component customized to the patient's glenoid morphology, allowing compensation for any significant bone loss. The novelty of this technology implies a paucity of available literature, and although many studies show that PSIs have good potential for solving challenging shoulder problems, some studies have reported questionable and equivocal outcomes. Additional research is needed to explore the indications, outcomes, techniques, and cost-efficiency of this technology to help establish its role in current treatment guidelines and strategies.

Subacromial Balloon Spacer Implantation Is a Promising Alternative for Patients With Massive Irreparable Rotator Cuff Tears: A Systematic Review

PURPOSE

To provide an overview of the existing literature on subacromial balloon spacers for the treatment of massive irreparable rotator cuff tears, in an effort to inform surgeons of the procedure's clinical effectiveness.

METHODS

The PubMed, Scopus, and Ovid EMBASE databases were queried to identify studies evaluating the clinical, radiographic, and patient-reported outcomes of patients indicated for subacromial balloon spacer implantation. The following datapoints were extracted: study demographics, patient baseline characteristics, and postoperative outcomes of interest. Outcomes were evaluated at baseline and at the longest available follow-up period.

RESULTS

A total 766 patients were included among 22 included studies, with an average follow-up of 27.54 months. Improvements were seen for all clinical and patient-reported outcomes: forward elevation (ranging from 9.20 to 90.00° improvement), external rotation (ranging from 2.00 to 22.00°), abduction (ranging from 14.00 to 95.00°), Total Constant Score (ranging from 7.70 to 50.00), American Shoulder and Elbow Surgeons score (ranging from 24.60 to 59.84), Oxford Shoulder Score (ranging from 7.20 to 22.20), and pain score (ranging from 3.57 to 6.50). Minimal differences were seen in acromiohumeral interval (ranging from -2.00 to 1.27). Reoperation and complication rates ranged from 0% to 33% and 0% to 19.64%, respectively.

CONCLUSIONS

The short-term results of subacromial balloon spacers for management of massive rotator cuff tears demonstrate clinically relevant improvements in shoulder range of motion and substantial improvements in patient-reported outcome measures. Of note, minimal change in acromiohumeral interval was seen on postoperative radiography, and wide variations in complication and reoperation rates were reported across studies.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Three-dimensional finite element modeling of glenoid bone loss and baseplate fixation in reverse total shoulder arthroplasty

Background

Posterior glenoid bone loss is frequently observed in patients with osteoarthritis undergoing reverse total shoulder arthroplasty. Glenoid bone loss can reduce the baseplate back support area and the number of screws for fixation. The purpose of this study is to determine how initial baseplate fixation is affected by biomechanical factors introduced by glenoid bone loss such as reduced baseplate back support area and reduced screw number using three-dimensional finite element analysis.

Methods

Computerized tomography images of a healthy shoulder were selected and segmented to obtain the solid geometry. Solid models were generated with 100%, 75%, 67%, 50%, and 25% glenoid baseplate back support. With these geometries, two groups of finite element models were then built. In the bone loss areas, screws were maintained in one group of models but were removed in the other group of models. 750N compressive loading was applied along the direction parallel to the scapula axis. Maximum von Mises stress and maximum micromotion between the bone and implant were recorded and evaluated for each glenoid bone model.

Results

In the group of models where all screws remained in place, the maximum stress and maximum micromotion between the bone and implant exhibited minimal variation. The maximum stresses were 21.10MPa and the maximum micromotions were between 2-3 μm. However, in the group of models removing screws in the bone loss areas, maximum stress increased from 20MPa to 45MPa and maximum micromotion increased from 2 μm to 85 μm as the backside support area decreased from 100% to 25%.

Discussion

In conclusion, this three-dimensional finite element analysis study demonstrates that initial fixation can be achieved with approximately 1/3 posterior glenoid bone deficiency even without screw placement in the area of bone loss. Glenoid bone loss affects baseplate fixation mainly by reducing the screw numbers for fixation. If screws can be placed in the bone loss area, the decreased baseplate back support area will not result in increased stresses or micromotion leading to baseplate failure. This study suggests that surgeons should consider applying screws to the bone loss area if the remaining bone is able to hold the screw.

Level of evidence

Computer Modeling Study.

The 50 most-cited articles in reverse shoulder arthroplasty

Background

Citation analyses have been used to understand the impact that a group of publications has on its field. As the techniques and indications of reverse total shoulder arthroplasty (RTSA) continue to expand, it is important to identify articles that can orient readers to the history, evolution, and current status of the body of RTSA literature. The purpose of this study was to identify and analyze the 50 most-cited articles related to RTSA.

Methods

Various Boolean queries were searched on the Clarivate Analytics Web of Science. Information collected included author name, publication year, country of origin, journal name, article type, total number of citations, and level of evidence.

Results

Top 50 most-cited articles amassed a total of 10,521 citations. The most-cited article was cited a total of 766 times. The most common study designs were case series (28) and cohort studies (9). Authors from the United States (24) contributed the most to included papers, followed by France (19) and Switzerland (8).

Discussion

The most-cited articles on RTSA are expert opinions, case studies, and cohort studies published by American authors. As RTSA continues to grow over the next decade, studies with higher levels-of-evidence may overtake articles included in this analysis.

Reverse shoulder arthroplasty: State-of-the-art

The reverse shoulder arthroplasty conceived by Paul Grammont in 1985 has gradually gained popularity as a treatment for multiple shoulder diseases. Unlike previous reverse shoulder prosthesis characterized by unsatisfactory results and a high glenoid implant failure rate, the Grammont design has immediately shown good clinical outcomes. This semi constrained prosthesis solved the issues of the very first designs by medializing and distalizing the center of rotation with an increased stability of the replacement of the component. The indication was initially limited to cuff tear arthropathy (CTA). It has then been expanded to irreparable massive cuff tears and displaced humeral head fractures. The most frequent problems of this design are a limited postoperative external rotation and scapular notching. Different modifications to the original Grammont design have been proposed with the aim of decreasing the risk of failure and complications and improving the clinical outcomes. Both the position and version/inclination of the glenosphere and the humeral configuration (e.g. neck shaft angle) influence the RSA outcomes. A lateralized glenoid (whether with bone or metal) and a 135° Inlay system configuration leads to a moment arm which is the closest to the native shoulder. Clinical research will focus on implant designs reducing bone adaptations and revision rate, strategies to prevent more effectively infections. Furthermore, there is still room for improvement in terms of better postoperative internal and external rotations and clinical outcomes after RSA implanted for humeral fracture and revision shoulder arthroplasty.

Comparison of Outcomes After Reverse Total Shoulder Arthroplasty in Patients With Proximal Humerus Fractures Versus Rotator Cuff Arthropathy

INTRODUCTION

Indications for reverse total shoulder arthroplasty (rTSA) has expanded to encompass complex proximal humerus fractures (PHFs) in recent years. The purpose of this study was to report and assess whether PHF patients treated with rTSA could achieve similar functional outcomes and short-term survivorship to patients who underwent rTSA for rotator cuff arthropathy (RTCA).

METHODS

All consecutive patients with a preoperative diagnosis of PHF or RTCA, 18 years or older, treated with rTSA at a single academic institution between 2018 and 2020 with a minimum 2-year follow-up were retrospectively reviewed. Primary outcomes were survivorship defined as revision surgery or implant failure analyzed using the Kaplan-Meier survival curve, and functional outcomes, which included Quick Disabilities of the Arm, Shoulder, and Hand, and range of motion (ROM) were compared at multiple follow-up time points up to 2 years. Secondary outcomes were patient demographics, comorbidities, surgical data, length of hospital stay, and discharge disposition.

RESULTS

A total of 48 patients were included: 21 patients (44%) were diagnosed with PHF and 27 patients (56%) had RTCA. The Kaplan-Meier survival rate estimates at 3 years were 90.5% in the PHF group and 85.2% in the RTCA group. No differences in revision surgery rates between the two groups (P = 0.68) or survivorship (P = 0.63) were found. ROM was significantly lower at subsequent follow-up time points in multiple planes (P < 0.05). A greater proportion of patients in the PHF group received cement for humeral implant fixation compared with the RTCA group (48% versus 7%, P = 0.002). The mean length of hospital stay was longer in PHF patients compared with RTCA patients (2.9 ± 3.8 days versus 1.6 ± 1.8 days, P = 0.13), and a significantly lower proportion of PHF patients were discharged home (67% versus 96%, P = 0.015).

CONCLUSION

The rTSA implant survivorship at 3 years for both PHF and RTCA patients show comparable results. At the 2-year follow-up, RTCA patients treated with rTSA were found to have better ROM compared with PHF patients.

The association between humeral lengthening and clinical outcomes after reverse shoulder arthroplasty: a systematic review and meta-analysis

BACKGROUND

The purpose of this study was to evaluate the relationship between humeral lengthening and clinical outcomes after reverse shoulder arthroplasty (RSA) with stratification based on measurement method and implant design.

METHODS

This systematic review was performed using PRISMA-P guidelines. PubMed/Medline, Cochrane Trials, and Embase were queried for articles evaluating the relationship between humeral lengthening and clinical outcomes inclusive of range of motion (ROM), strength, outcome scores, and pertinent complications (acromial and scapular spine fractures, nerve injury) after RSA. The relationship between humeral lengthening and clinical outcomes was reported descriptively overall and stratified by measurement method and implant design (globally medialized vs. lateralized). A positive association was defined as increased humeral lengthening being associated with greater ROM, outcome scores, or a greater incidence of complications, whereas a negative association denoted that increased humeral lengthening was associated with poorer ROM, outcome scores, or a lower incidence of complications. Meta-analysis was performed to compare humeral lengthening between patients with and without fractures of the acromion or scapular spine.

RESULTS

Twenty-two studies were included. Humeral lengthening was assessed as the acromiohumeral distance (AHD), the distance from the acromion to the greater tuberosity (AGT), the acromion to the deltoid tuberosity (ADT), and the acromion to the distal humerus (ADH). Of 11 studies that assessed forward elevation, a positive association with humeral lengthening was found in 6, a negative association was found in 1, and 4 studies reported no association. Of studies assessing internal rotation (n = 9), external rotation (n = 7), and abduction (n = 4), all either identified a positive or lack of association with humeral lengthening. Studies assessing outcome scores (n = 11) found either a positive (n = 5) or no (n = 6) association with humeral lengthening. Of the studies that assessed fractures of the acromion and/or scapular spine (n = 6), 2 identified a positive association with humeral lengthening, 1 identified a negative association, and 3 identified no association. The single study that assessed the incidence of nerve injury identified a positive association with humeral lengthening. Meta-analysis was possible for AGT (n = 2) and AHD (n = 2); greater humeral lengthening was found in patients with fractures for studies using the AGT (mean difference 4.5 mm, 95% CI 0.7-8.3) but not the AHD. Limited study inclusion and heterogeneity prohibited identification of trends based on method of measuring humeral lengthening and implant design.

CONCLUSION

The relationship between humeral lengthening and clinical outcomes after RSA remains unclear and requires future investigation using a standardized assessment method.

Latissimus Dorsi and Teres major tendon transfer increases internal rotation torque following lateralized reverse shoulder arthroplasty with subscapularis insufficiency

INTRODUCTION

Limitation of active Internal Rotation (IR) following Reverse Shoulder Arthroplasty (RSA) in patients with massive Rotator Cuff Tears (mRCTs) with subscapularis insufficiency remains a challenge. Recently, RSA with Latissimus dorsi and Teres major (LDTM) transfer in patients with limited active IR has been demonstrated as a reliable treatment option. The purpose of this study was to biomechanically compare the IR torque following LDTM transfer with RSA in mRCT with subscapularis insufficiency to RSA without tendon transfer.

METHODS

Eight cadaveric shoulders were tested (mean age: 64.5 ± 1.9 years) using a custom shoulder testing system that permits loading conditions of mRCT with subscapularis insufficiency. Two conditions were tested and compared. The first condition was RSA alone and the second condition was RSA with LDTM transfer. RSA with a medialized glenoid and lateralized humerus design was used for all specimens. The specimens were tested at 0°, 20° and 40° abduction at three different muscle loads: baseline, double, and triple, while the Teres minor and deltoid loads were kept constant. IR torque was measured with a torque wrench at 0°, 20°, and 40° abduction and 60° and 45° IR positions. Force required for anterior dislocation was measured at 20° abduction and 10° IR position.

RESULTS

RSA with LDTM transfer had significantly higher IR torque at all abductions and muscle loading compared with RSA without transfer (average at all positions; RSA without transfer: 0.80 ± 0.02 Nm, LDTM transfer for all loads: 1.43 ± 0.10 Nm). RSA with LDTM transfer (91.4 ± 3.9 N) needed higher force for anterior dislocation compared to RSA alone (89.4 ± 4.1 N), but there was no significant difference.

CONCLUSION

LDTM transfer with RSA increases IR torque compared to RSA without tendon transfer in a cadaveric model. LDTM transfer with RSA may be a reliable treatment option for patients with mRCT and subscapularis insufficiency who are expected to have limited active IR following RSA.

Effect of Anterior Acromial Coverage on Functional and Radiological Outcomes After Arthroscopic Repair of Anteroposterior Massive Rotator Cuff Tears

BACKGROUND

Rotator cuff tear size, fatty infiltration, and scapular morphology are correlated with tendon healing and functional outcomes after arthroscopic repair; however, the association between anteroposterior acromial coverage and the clinical outcomes of anteroposterior massive rotator cuff tears (AP-MRCTs; involving all 3 tendons) remains unclear.

PURPOSE

To identify the association between AP acromial coverage and functional and radiological outcomes after arthroscopic repair of AP-MRCTs.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 98 patients who underwent arthroscopic repair of AP-MRCTs between January 2015 and December 2020 were included in the study and classified according to whether anterior acromial coverage (AAC) was anterior (46 patients; positive AAC group) or posterior (52 patients; negative AAC group) to the scapular line on true lateral shoulder radiographs. Demographic characteristics, surgical details, and functional outcomes were prospectively collected. Acromial morphological features, global tear extension (GTE), the global fatty infiltration index (GFII), tendon integrity after repair, proximal humeral migration, and glenohumeral abduction were measured and calculated on radiographs or magnetic resonance imaging scans preoperatively and at 2 years postoperatively. Multivariate logistic regression was performed to identify the independent risk factors of a rotator cuff retear.

RESULTS

The positive AAC group showed larger AAC, posterior acromial tilt, and anterior acromial slope as well as smaller posterior acromial coverage compared with the negative AAC group. Postoperatively, the American Shoulder and Elbow Surgeons score (82.5 ± 8.3 vs 77.2 ± 11.5, respectively; P = .013), active abduction (157.8°± 27.1° vs 142.7°± 39.6°, respectively; P = .048), and glenohumeral abduction (45.6°± 10.4° vs 39.7°± 14.9°, respectively; P = .041) in the positive AAC group were significantly higher than those in the negative AAC group, while the retear rate (23.9% vs 44.2%, respectively; P = .035) and proximal humeral migration (1.7 ± 1.0 vs 2.3 ± 1.2 mm, respectively; P = .006) were significantly lower in the positive AAC group than in the negative AAC group. Smaller AAC (odds ratio [OR], 0.93 [95% CI, 0.87-1.00]; P = .040), larger GTE (OR, 1.03 [95% CI, 1.01-1.06]; P = .017), and a higher GFII (OR, 3.49 [95% CI, 1.09-11.19]; P = .036) were associated with an increased risk of a rotator cuff retear.

CONCLUSION

Increased AAC was associated with a lower retear rate and better functional outcomes after arthroscopic repair of AP-MRCTs. A preliminary risk evaluation integrating GTE, the GFII, and AAC is recommended to consider the necessity of additional procedures for patients in need of arthroscopic rotator cuff repair.

No significant difference in risk of prolonged opioid use following outpatient versus inpatient total shoulder arthroplasty: A propensity matched analysis

Background

The purpose of this investigation was to compare rates of filled opioid prescriptions and prolonged opioid use in opioid naïve patients undergoing total shoulder arthroplasty (TSA) in inpatient versus outpatient settings.

Methods

A retrospective cohort study was conducted using a national insurance claims database. Inpatient and outpatient cohorts were created by identifying continuously enrolled, opioid naïve TSA patients. A greedy nearest-neighbor algorithm was used to match baseline demographic characteristics between cohorts with a 1:1 inpatient to outpatient ratio to compare the primary outcomes of filled opioid prescriptions and prolonged opioid use following surgery between cohorts.

Results

A total of 11,703 opioid naïve patients (mean age 72.5 ± 8.5 years, 54.5% female, 87.6% inpatient) were included for analysis. After propensity score matching (n = 1447 inpatients; n = 1447 outpatients), outpatient TSA patients were significantly more likely to fill an opioid prescription in the perioperative window compared to inpatients (82.9% versus 71.5%, p < 0.001). No significant differences in prolonged opioid use were detected (5.74% inpatient versus 6.77% outpatient; p = 0.25).

Conclusions

Outpatient TSA patients were more likely to fill opioid prescriptions compared to inpatient TSA patients. The quantity of opioids prescribed and rates of prolonged opioid use were similar between the cohorts.

Level of evidence

Therapeutic Level III.

Comparison of Outcomes after Arthroscopic Rotator Cuff Repair between Elderly and Younger Patient Groups: A Systematic Review and Meta-Analysis of Comparative Studies

This study aimed to compare the outcomes of arthroscopic rotator cuff repair (ARCR) surgery between younger and older patients. We performed this systematic review and meta-analysis of cohort studies comparing outcomes between patients older than 65 to 70 years and a younger group following arthroscopic rotator cuff repair surgery. We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and other sources for relevant studies up to 13 September 2022, and then assessed the quality of included studies using the Newcastle-Ottawa Scale (NOS). We used random-effects meta-analysis for data synthesis. The primary outcomes were pain and shoulder functions, while secondary outcomes included re-tear rate, shoulder range of motion (ROM), abduction muscle power, quality of life, and complications. Five non-randomized controlled trials, with 671 participants (197 older and 474 younger patients), were included. The quality of the studies was all fairly good, with NOS scores ≥ 7. The results showed no significant differences between the older and younger groups in terms of Constant score improvement, re-tear rate, or other outcomes such as pain level improvement, muscle power, and shoulder ROM. These findings suggest that ARCR surgery in older patients can achieve a non-inferior healing rate and shoulder function compared to younger patients.

Preoperative Planning for Reverse Shoulder Arthroplasty: Does the Clinical Range of Motion Match the Planned 3D Humeral Displacement?

INTRODUCTION

The functional outcome after reverse shoulder arthroplasty (RSA) is closely linked to how much the humerus shifts because of the implants. While two-dimensional (2D) angle measurements have been used to capture this shift, it can be measured in three dimensions (3D) as the arm change position (ACP). In a previous study, the ACP was measured using 3D preoperative planning software with the passive virtual shoulder range of motion obtained after RSA. The main objective of this study was to evaluate the relationship between the ACP and the actual active shoulder range of motion measured after RSA. The hypothesis was that the ACP and the active clinical range of motion are related such that the ACP is a reliable parameter to guide the preoperative planning of an RSA. The secondary objective was to assess the relationship between 2D and 3D humeral displacement measurements.

MATERIALS AND METHODS

This prospective observational study enrolled 12 patients who underwent RSA and had a minimum follow-up of 2 years. The active range of motion in shoulder flexion, abduction, and internal and external rotation was measured. At the same time, ACP measurements were taken from a reconstructed postoperative CT scan, in addition to the radiographic measurements of humeral lateralization and distalization angles on AP views in neutral rotation.

RESULTS

The mean humeral distalization induced by RSA was 33.3 mm (±3.8 mm). A non-statistically significant increase in shoulder flexion was observed for humeral distalization beyond 38 mm (R² = 0.29, p = 0.07). This "threshold" effect of humeral distalization was also observed for the gains in abduction, as well as internal and external rotations, which seemed better with less than 38 mm or even 35 mm distalization. No statistical correlation was found between the 3D ACP measurements and 2D angle measurements.

CONCLUSION

Excessive humeral distalization seems to be detrimental to joint mobility, especially shoulder flexion. Humeral lateralization and humeral anteriorization measured using the ACP seem to promote better shoulder range of motion, with no threshold effect. These findings could be evidence of tension in the soft tissues around the shoulder joint, which should be taken into consideration during preoperative planning.

Survivorship after reverse total shoulder arthroplasty and predictors of 1-year and overall mortality

BACKGROUND

Patient survivorship and risk factors of mortality after reverse total shoulder arthroplasty (RTSA) are seldom and inadequately studied. The purpose of this study was to evaluate the mortality rates and predictors of 1-year and overall mortality after RTSA.

METHODS

We retrospectively reviewed 1518 consecutive adult patients who underwent RTSA at our institution. The Social Security Death Index and institutional electronic medical records were queried to verify patient living status. Patients were censored at date of death if deceased, the date that living status was verified if alive, or latest follow-up if living status could not be verified. Mortality rates and risk factors of 1-year and overall mortality after RTSA were identified on univariate and multivariate analysis.

RESULTS

Mean follow-up was 5.1 ± 3.8 years. Thirty-day (0.1%), 90-day (0.7%), and 1-year (1.8%) mortality rates were low but increased to 11% at 5 years. Increased odds of 1-year mortality were independently associated with heart disease (odds ratio [OR] 2.64, 95% confidence interval [CI] 1.07-6.50, P = .035) and use of a cemented stem (OR 2.64, 95% CI 1.04-6.69, P = .041). Independent risk factors of overall mortality included older age at surgery (hazard ratio [HR] 1.05, 95% CI 1.03-1.07, P < .001), minority ethnicity (protective risk factor, HR 0.37, 95% CI 0.15-0.91, P = .031), heart disease (HR 1.42, 95% CI 1.00-2.02, P = .048), diabetes mellitus (HR 1.47, 95% CI 1.04-2.08, P = .028), tobacco use (HR 1.79, 95% CI 1.08-2.98, P = .025), post renal transplant (HR 12.69, 95% CI 3.92-41.05, P < .001), chronic liver failure (HR 4.40, 95% CI 1.38-14.09, P = .013), and receiving a cemented stem (HR 1.60, 95% CI 1.13-2.26, P = .008).

CONCLUSIONS

RTSA carries a low risk of short-term mortality postoperatively. When counseling patients preoperatively, surgeons should consider the predictors of mortality after RTSA reported herein to ensure appropriate patient selection and counseling.

Radiographic and anatomic variations on postoperative acromion fractures after inlay and lateralized reverse shoulder arthroplasty

INTRODUCTION

Postoperative fracture of the acromion is a complication uniquely more common after reverse shoulder arthroplasty (RSA) than other forms of shoulder arthroplasty. There is limited knowledge regarding the etiology of these fractures or the anatomic risk factors. The purpose of this study is to identify associations of the acromioclavicular (AC) joint and relative humeral and glenoid positioning on the occurrence of acromial fractures after RSA.

METHODS

A retrospective case-controlled study was performed on primary RSA patients treated by a single surgeon from September 2009 to September 2019. Patients with a postoperative acromion fracture were matched in a 3:1 ratio based on gender, indication, and age to those without a fracture and with a 2-year minimum follow-up. Preoperative and the immediate postoperative radiographs were reviewed by 2 investigators to measure critical shoulder angle, acromion-humeral interval, global lateralization, delta angle, preoperative glenoid height, and the level of inlay or onlay of the humeral stem. The morphology, width, and stigmata of osteoarthritis in the AC joint were assessed using computed tomography scans taken preoperatively.

RESULTS

Of a total of 920 RSAs performed, 47 (5.1%) patients suffered a postoperative acromion fracture. These patients were compared with a control group of 141 patients, with a mean age of 76.4 years and similar distributions of gender and surgical indication. Patients in both groups had similar preoperative glenoid height (P = .953) and postoperative degree of inset or offset of humeral implant relative to the anatomic neck (P = .413). There were no differences in critical shoulder angle, acromion-humeral interval, global lateralization, and delta angle both preoperatively and postoperatively between the fracture and nonfracture groups. Computed tomography analysis also showed no differences in AC joint morphology (P = .760), joint space (P = .124), and stigma of osteoarthritis (P = .161).

CONCLUSION

There was no relation between the features of the AC joint and the anatomic parameters of the humerus relative to the glenoid and acromion on postoperative acromion fractures after RSA.

Best practice in shoulder arthroplasty-a reflective personal review

Introduction

Shoulder arthroplasty is uncommon but increasing in number when compared to hip and knee arthroplasty. The average UK shoulder surgeon performs less than 10 a year and revision surgery is even more rare. The surgeon should be familiar with surgical approaches, implant designs and preferably be fellowship trained to produce good outcomes.

Methods

Narrative review was undertaken and senior author's personal practice was discussed.

Results

The need for a clear understanding of indications and contraindications for both anatomic shoulder arthroplasty and reverse total shoulder arthroplasty, good preoperative planning, protocol-based peri-operative management and good rehabilitation protocol in the post operative period cannot be overemphasized.

Conclusion

We are still learning best practice and prosthesis designs have changed over the past years with extensive choices especially in Reverse arthroplasty. Each of these designs has unique biomechanical properties and require a deep understanding of indications. Good surgical training and the use of multi-disciplinary team meetings for complex cases should improve the safety and quality of surgery for patients and ultimately long-term outcome of shoulder arthroplasty.

Anterosuperior approach versus deltopectoral approach for reverse total shoulder arthroplasty: a systematic review and meta-analysis

BACKGROUND

Surgical approach is an important factor that may affect the outcomes of reverse total shoulder arthroplasty (RTSA). The most common approaches for RTSA are anterosuperior (AS) and deltopectoral (DP). However, controversy exists on which surgical approach is better. This meta-analysis aimed to compare both approaches in terms of radiological and clinical outcomes and complications.

METHODS

We searched PubMed, Embase, and Cochrane Library databases for studies that compared the postoperative outcomes of the AS and DP approaches for RTSA. After screening and quality assessment of the articles, we obtained two randomized controlled trials and four retrospective comparative studies. We analyzed the radiologic outcomes, functional outcomes, and complications between the two approaches. The standardized mean difference and odds ratio were used to analyze the differences in outcomes between the two surgical approaches. Statistical significance was set at P < 0.05.

RESULTS

The incidence rate of glenoid implant loosening was significantly (P = 0.04) lower in the AS group than that in the DP group. In terms of forward flexion after surgery, the DP approach produced significantly (P = 0.03) better outcomes compared with the AS approach. There were no significant differences in radiological outcomes or other complication rates between the two approaches.

CONCLUSION

As a result of this meta-analysis, one of the two approaches did not bring a better result than the other. One has strength for better forward flexion and the other for a lower glenoid loosening rate. With this in mind, it is recommended to use the approach that the surgeon is most familiar with.

Subscapularis repair techniques for reverse total shoulder arthroplasty: A systematic review

IMPORTANCE

Repair of the subscapularis can be effective in the setting of reverse total shoulder arthroplasty (rTSA). However, there has yet to be a consensus on an optimal repair technique.

OBJECTIVES

The purpose of this systematic review is to consolidate current high-quality studies comparing outcomes after rTSA with different subscapularis repair techniques.

EVIDENCE REVIEW

A comprehensive literature review was conducted according to the preferred reporting items for systematic reviews and meta-Analyses using the PubMed, Embase, Scopus and Cochrane databases for original, English-language studies observing outcomes of rTSA after subscapularis repair published between January 1, 2000 and December 31, 2020. Subscapularis management techniques were repair to (1) tendon (tendon-tendon), (2) prosthetic stem, (3) lesser tuberosity (bone tunnels) or (4) a subscapularis-preserving approach (intact). The repair technique was recorded for included studies, and clinical and functional subjective scores were extracted from text, tables and figures. Forest plots were created to allow for qualitative comparison of the outcomes of interest between subscapularis repair techniques.

FINDINGS

Seven comprehensive studies were identified, which included 367 patients. The mean age of patient at the time of surgery was 71.1 ± 2.8 years (range = 47-87 years). Overall, 259 patients underwent tendon-tendon repair, 48 patients underwent repair to prosthetic stem, 40 patients underwent repair with bone tunnels and 20 patients' subscapularis remained intact. Significant improvement was seen in most studies for Single Assessment Numeric Evaluation (range, Δ 42.6-Δ 46.0 out of 3), American Shoulder and Elbow Surgeons (range, Δ44.2-Δ43.6 out of 3) and Visual Analogue Scale pain scores (range Δ 4.2-Δ 6 out of 5). Active forward elevation (range Δ 40.4°-Δ 57.3° out of 4) and active external rotation (range Δ 2.9°-Δ 16.0° out of 4) significantly improved, but forward elevation varied by nearly 17° (Δ16.94°), while external rotation varied by 13° (Δ13.16°) among repair techniques. Complications were reported in only one study, which used a tendon-tendon technique.

CONCLUSIONS AND RELEVANCE

This study summarizes the current evidence regarding subscapularis repair techniques after rTSA including functional and subjective clinical outcome scores. Several different subscapularis repair techniques during rTSA appear to lend to sufficient improvement in clinical and subjective outcomes. This information can help guide future studies in this area and highlights the need for high quality studies comparing different subscapularis repair techniques.

LEVEL OF EVIDENCE

III.

Return to work following shoulder arthroplasty: A systematic review

BACKGROUND

Many patients prioritize the ability to return to work (RTW) after shoulder replacement surgeries such as total shoulder arthroplasty (TSA), reverse TSA (rTSA), and shoulder hemiarthroplasty (HA). Due to satisfactory clinical and functional long-term outcomes, the number of shoulder replacements performed will continue to rise into this next decade. With younger individuals who compose a significant amount of the workforce receiving shoulder replacements, patients will begin to place a higher priority on their ability to RTW following shoulder arthroplasty.

AIM

To summarize RTW outcomes following TSA, rTSA, and HA, and analyze the effects of workers’ compensation status on RTW rates and ability.

METHODS

This systematic review and analysis was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search regarding RTW following shoulder arthroplasty was performed using four databases (PubMed, Scopus, Embase, and Cochrane Library), and the Reference Citation Analysis (https://www.referencecitationanalysis.com/). All studies in English relevant to shoulder arthroplasty and RTW through January 2021 that had a level of evidence I to IV were included. Nonclinical studies, literature reviews, case reports, and those not reporting on RTW after shoulder arthroplasty were excluded.

RESULTS

The majority of patients undergoing TSA, rTSA, or HA were able to RTW between one to four months, depending on work demand stratification. While sedentary or light demand jobs generally have higher rates of RTW, moderate or heavy demand jobs tend to have poorer rates of return. The rates of RTW following TSA (71%-93%) were consistently higher than those reported for HA (69%-82%) and rTSA (56%-65%). Furthermore, workers’ compensation status negatively influenced clinical outcomes following shoulder arthroplasty. Through a pooled means analysis, we proposed guidelines for the average time to RTW after TSA, rTSA, and HA. For TSA, rTSA, and HA, the average time to RTW regardless of work demand stratification was 1.93 ± 3.74 mo, 2.3 ± 2.4 mo, and 2.29 ± 3.66 mo, respectively.

CONCLUSION

The majority of patients are able to RTW following shoulder arthroplasty. Understanding outcomes for rates of RTW following shoulder arthroplasty would assist in managing expectations in clinical practice.

Combined Margin Convergence Repair and Subacromial Balloon Spacer for the Treatment of Massive Rotator Cuff Tears

Background:

Current joint-sparing treatment options for massive, irreparable rotator cuff tears aim to prevent superior migration of the humeral head and maintain the subacromial space. Although options such as superior capsular reconstruction and posterosuperior tendon transfer may appropriately restore function and reduce pain, these procedures harbor significant comorbidity and intense postoperative rehabilitation. Recently, studies have demonstrated excellent results from a subacromial balloon spacer composed of a biocompatible copolymer that degrades over the 12 months following implantation. This spacer enables a more anatomic position of the humeral head to restore normal shoulder biomechanics.

Indications:

The subacromial balloon spacer is primarily indicated in patients with massive, irreparable rotator cuff tears who demonstrate proximal humeral migration. Contraindications include subscapularis or teres minor tendon tears, deltoid dysfunction, and pseudoparalysis.

Technique Description:

Standard arthroscopic portals are established, and a diagnostic arthroscopy is performed to assess the glenohumeral joint space and subscapularis tendon. A subacromial bursectomy is performed without proceeding medial to the superior glenoid rim. The subacromial space is measured utilizing an arthroscopic measurement probe to ensure that the selected spacer will lie slightly medial to the glenoid. The rotator cuff is then reapproximated from the lateral to medial aspect of the tear and repaired via a side-to-side manner with high strength, nonabsorbable tape, and a self-capturing suture device. Following repair, the deployment device is inserted through the lateral portal, placed slightly medial to the glenoid, and inflated with saline.

Results:

Utilization of the described subacromial balloon augmentation provides significant pain relief by restoring glenohumeral biomechanics, improvements in range of motion, and an enhancement in quality of life.

Discussion:

This case report and video review of a technique for utilizing a subacromial balloon spacer demonstrates an effective, simple, and safe treatment for massive, irreparable rotator cuff tears. Positive results rely on appropriate inflation and secure fixation. Recent clinical trial data suggest that functional outcomes for the subacromial balloon spacer are noninferior to that of partial rotator cuff repair. These promising results suggest that the subacromial balloon spacer may prove an essential tool for joint-preserving surgery following massive, irreparable rotator cuff tears.

Total shoulder arthroplasty versus reverse total shoulder arthroplasty: Outcome comparison in osteoarthritis patients with or without concurrent rotator cuff deficiency

Osteoarthritis (OA) is a common shoulder disorder that impacts shoulder functions. Shoulder arthroplasty is often required to restore function and quality of life. Reverse total shoulder arthroplasty (RSA), which was originally designed mainly for irreparable rotator cuff damage, has gained popularity in recent years for the treatment of advanced shoulder OA instead of the clinically standard total shoulder arthroplasty (TSA). However, this RSA has some nonnegligible flaws such as higher complications rate and economic cost, not mention the following problems caused by irreversible physical structural damage. Therefore, the employment of RSA needs to be carefully considered. This study aimed to compare TSA and RSA in OA patients with or without rotator cuff damage to better guide clinical decision making. We believe the radical use of RSA in patients without rotator cuff deficiency may cause more harm than good. We queried the Nationwide Inpatient Sample (NIS) database from 2011 to 2014 to collect information on OA patients who received TSA and RSA. Patients were divided into 2 groups of comparison according to the presence of rotator cuff deficiency and matched with propensity score analysis. A total of 57,156 shoulder arthroplasties were identified. RSA patients in the rotator cuff deficiency group had significant higher transfusion rates and longer hospital stays. RSA patients without rotator cuff deficiency had a statistically significantly higher number of implant-related mechanical complications, acute upper respiratory infections and postoperative pain. Overall, RSA incurred higher costs in both groups. For OA patients with rotator cuff deficiencies, RSA has its benefits as complication rates were comparable to TSA. For those patients without rotator cuff deficiencies, the use of RSA should be reconsidered as there were more complications with higher severity.

Systematic review of prevalence, risk factors, and management of instability following reverse shoulder arthroplasty

Background

Since its approval for use, reverse shoulder arthroplasty (RSA) has become the primary treatment for cuff tear arthropathy, with indications expanding more recently to include revision fracture, osteoarthritis with significant glenoid bone loss, tumor, and chronic instability. Instability is a well-described postoperative complication, occurring in 1to 31% of relatively small cohorts and case series. Given the relative infrequency of instability, there remains a need for a comprehensive review of instability with a focus on risk factors and management. Our goal of this systematic review is to describe the prevalence, risk factors, and management strategies for instability following RSA.

Methods

A systematic review of the PubMed, EMBASE, MEDLINE, Scopus, and Cochrane Library databases was performed according to PRISMA guidelines. Inclusion criteria included primary RSA cohorts ≥ 100 patients, revision RSA cohorts of any size, and minimum 1-year follow-up. The primary outcome of interest was postoperative instability. MINORS criteria were used to assess study bias. Descriptive statistical analysis was performed with data reported as ranges.

Results

Seventeen studies that included 7885 cases of RSA were reviewed. The mean follow-up ranged from 12 to 84 months. Mean age ranged from 64 to 77 years old, and males represented 19 to 39% of cohorts. There were 204 (2.5%) dislocations in 7885 cases, accounting for a rate of instability from 0.4 to 49% across all studies. By intervention, instability rates ranged from 1 to 5% (primary RSA cases), 1 to 49% (revision RSA cases only), and 0.4 to 10% (mixed cohorts). Subscapularis insufficiency and proximal humerus fractures, and fracture sequelae (malunion and nonunion) were identified as risk factors for instability. Closed reduction and casting and revision RSA were reported as successful treatment strategies with acceptable rates of stable prostheses (28-100% and 55-100%, respectively, across studies). Hemiarthroplasty or resection arthroplasty due to recurrent instability was not uncommon after 2 or more episodes of instability.

Conclusion

Instability following RSA occurs infrequently (1-5%) following primary RSA and more commonly following revision RSA (1-49%). RSA for acute proximal humerus fracture and fracture sequelae carries a higher risk of instability. Subscapularis repair appears to be a protective factor. While instability may be successfully treated with closed management or revision RSA, recurrent instability may ultimately require hemiarthroplasty or resection arthroplasty.

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.

Return of Scapulohumeral Rhythm in Patients After Reverse Shoulder Arthroplasty: A Midterm Stereoradiographic Imaging Analysis

BACKGROUND

Reverse shoulder arthroplasty (RSA) is associated with high rates of midterm complications including scapular notching, implant wear, and mechanical impingement. Scapulo-humeral rhythm (SHR), described by Codman in the 1920's, is defined as the ratio of glenohumeral motion to scapulothoracic motion. SHR is used as an indicator of shoulder dysfunction, as alterations in SHR can have profound implications on shoulder biomechanics. The determination of SHR can be hindered by soft-tissue motion artifacts and high radiation burdens associated with traditional surface marker or fluoroscopic analysis. EOS low dose stereoradiographic imaging analysis utilizing 3D model construction from a 2D X-ray series may offer an alternative modality for characterizing SHR following RSA.

METHODS

Patients (n=10) underwent an EOS imaging analysis to determine SHR at six and twelve months post-RSA. Leveraging 3D models of the implants, 2D/3D image registration methods were used to calculate relative glenohumeral and scapulothoracic positioning at 60, 90 and 120° of shoulder elevation. Subject-specific SHR curves were assessed and midterm changes in post-RSA SHR associated with follow-up time and motion phase were evaluated. Pearson correlations assessed associations between patient-specific factors and post-RSA SHR.

RESULTS

Mean post-RSA SHR was 0.81:1 across subjects during the entire midterm postoperative period. As a cohort, post-RSA SHR was more variable for 60-90° of shoulder motion. SHR for 90-120° of motion decreased (0.43:1) at twelve months post-RSA. Post-RSA SHR could be categorized using three relative motion curve patterns, and was not strongly associated with demographic factors such as BMI. 50% of subjects demonstrated a different SHR relative motion curve shape at twelve months post-RSA, and SHR during the 90120° of motion was found to generally decrease at twelve months.

CONCLUSION

Midterm post-RSA SHR was successfully evaluated using EOS technology, revealing lower SHR values (i.e., greater scapulothoracic motion) compared to normal values reported in the literature. SHR continued to change for some subjects during the midterm post-RSA period, with the greatest change during 90-120° of shoulder motion. Study findings suggest that future post RSA rehabilitation efforts to address elevated scapulothoracic motion may benefit from being patient-specific in nature and targeting scapular stabilization during 90-120° of shoulder motion. Level of Evidence: IV.

Restoration of active internal rotation following reverse shoulder arthroplasty: anterior latissimus dorsi and teres major combined transfer

BACKGROUND

Reverse shoulder arthroplasty (RSA) for irreparable massive rotator cuff tear (mRCT) and cuff tear arthropathy (CTA) demonstrates satisfactory clinical outcomes. However, many studies have reported no significant improvements in internal and external rotation. To our knowledge, there have been no studies on new attempts to restore active internal rotation following RSA. The purpose of this study was to compare RSA alone and RSA with anterior latissimus dorsi and teres major (aLDTM) tendon transfer in patients with CTA and mRCT with combined loss of active elevation and internal rotation (CLEIR).

METHODS

This retrospective cohort study included patients who underwent RSA with a lateralized design and had CLEIR between October 2014 and January 2019. Two groups were classified: patients who underwent RSA alone (group R, n = 36) and patients who underwent RSA with aLDTM tendon transfer (group T, n = 24). Clinical outcomes, including the visual analog scale score, Constant score, American Shoulder and Elbow Surgeons score, active range of motion, score for activities of daily living requiring active internal rotation (ADLIR), and ability to perform toileting activity, were compared. Moreover, radiologic outcomes and complications were compared.

RESULTS

The mean follow-up period was 36.8 ± 11.6 months (range, 24-67 months). Both group R and group T showed significant improvements in clinical scores and active range of motion preoperatively and postoperatively. In group T, the Constant score (65.2 ± 7.5 vs. 58.1 ± 12.3, P = .008), ADLIR score (26.1 ± 3.1 vs. 20.3 ± 5.0, P < .001), internal rotation level with the arm behind the back (P < .001), and subscapularis-specific physical examination findings (P < .001) were significantly better than in group R. However, no significant difference in the American Shoulder and Elbow Surgeons score, forward flexion, and external rotation at 0° and 90° of abduction were found at final follow-up. Transient axillary nerve palsy was found in 2 patients in group T. However, there were no significant differences in complication rates between 2 groups.

CONCLUSION

Lateralized RSA with aLDTM tendon transfer for patients with CTA and mRCT with CLEIR restored shoulder function and improved clinical outcomes, especially the ability to perform ADLIR and toileting activity.

Is Advanced Imaging to Assess Rotator Cuff Integrity Before Shoulder Arthroplasty Cost-effective? A Decision Modeling Study

BACKGROUND

Shoulder arthroplasty is increasingly performed for patients with symptoms of glenohumeral arthritis. Advanced imaging may be used to assess the integrity of the rotator cuff preoperatively because a deficient rotator cuff may be an indication for reverse shoulder arthroplasty (RSA) rather than anatomic total shoulder arthroplasty (TSA). However, the cost-effectiveness of advanced imaging in this setting has not been analyzed.

QUESTIONS/PURPOSES

In this cost-effectiveness modeling study of TSA, all patients underwent history and physical examination, radiography, and CT, and we compared (1) no further advanced imaging, (2) selective MRI, (3) MRI for all, (4) selective ultrasound, and (5) ultrasound for all.

METHODS

A simple chain decision model was constructed with a base-case 65-year-old patient with a 7% probability of a large-to-massive rotator cuff tear and a follow-up of 5 years. Strategies were compared using the incremental cost-effectiveness ratio (ICER) with a willingness to pay of both USD 50,000 and 100,000 per quality-adjusted life year (QALY) used, in accordance with the Second Panel on Cost-Effectiveness in Health and Medicine. Diagnostic test sensitivity and specificity were extracted from published systematic reviews and meta-analyses, and patient utilities were obtained using the Cost-Effectiveness Analysis Registry from the Center for the Evaluation of Value and Risk in Health. Final patient states were categorized as either inappropriate or appropriate based on the actual rotator cuff integrity and type of arthroplasty performed. Additionally, to evaluate the real-world impact of intraoperative determination of rotator cuff status, a secondary analysis was performed where all patients indicated for TSA underwent intraoperative rotator cuff examination to determine appropriate implant selection.

RESULTS

Selective MRI (ICER of USD 40,964) and MRI for all (ICER of USD 79,182/QALY) were the most cost-effective advanced imaging strategies at a willingness to pay (WTP) of USD 50,000/QALY gained and 100,000/QALY gained, respectively. Overall, quality-adjusted life years gained by advanced soft tissue imaging were minimal: 0.04 quality-adjusted life years gained for MRI for all. Secondary analysis accounting for the ability of the surgeon to alter the treatment plan based on intraoperative rotator cuff evaluation resulted in the no further advanced imaging strategy as the dominant strategy as it was the least costly (USD 23,038 ± 2259) and achieved the greatest health utility (0.99 ± 0.05). The sensitivity analysis found the original model was the most sensitive to the probability of a rotator cuff tear in the population, with the value of advanced imaging increasing as the prevalence increased (rotator cuff tear prevalence greater than 12% makes MRI for all cost-effective at a WTP of USD 50,000/QALY).

CONCLUSION

In the case of diagnostic ambiguity based on physical exam, radiographs, and CT alone, having both TSA and RSA available in the operating room appears more cost-effective than obtaining advanced soft tissue imaging preoperatively. However, performing selective MRI to assess rotator cuff integrity to indicate RSA or TSA is cost-effective if surgical preparedness, patient expectations, and implant availability preclude the ability to switch implants intraoperatively.

LEVEL OF EVIDENCE

Level III, economic and decision analysis.

Risk Factors for Blood Transfusions in Primary Anatomic and Reverse Total Shoulder Arthroplasty for Osteoarthritis

BACKGROUND

The purpose of this study was to determine risk factors for blood transfusion in primary anatomic and reverse total shoulder arthroplasty (TSA) performed for osteoarthritis.

METHODS

Patients who underwent anatomic or reverse TSA for a diagnosis of primary osteoarthritis were identified in a national surgical database from 2005 to 2018 by utilizing both CPT and ICD-9/ICD-10 codes. Univariate analysis was performed on the two transfused versus non-transfused cohorts to compare for differences in comorbidities and demographics. Independent risk factors for perioperative blood transfusions were identified via multivariate regression models.

RESULTS

305 transfused and 18,124 nontransfused patients were identified. Female sex (p<0.001), age >85 years (p=0.001), insulin-dependent diabetes mellitus (p=0.001), dialysis dependence (p=0.001), acute renal failure (p=0.012), hematologic disorders (p=0.010), disseminated cancer (p<0.001), ASA ≥ 3 (p<0.001), and functional dependence (p=0.001) were shown to be independent risk factors for blood transfusions on multivariate logistic regression analysis.

CONCLUSION

Several independent risk factors for blood transfusion following anatomic/reverse TSA for osteoarthritis were identified. Awareness of these risk factors can help surgeons and perioperative care teams to both identify and optimize high-risk patients to decrease both transfusion requirements and its associated complications in this patient population. Level of Evidence: III.

What is the deviation in 3D preoperative planning software? A systematic review of concordance between plan and actual implant in reverse total shoulder arthroplasty

BACKGROUND

Three-dimensional (3D) preoperative planning software for reverse total shoulder arthroplasty (rTSA) has been implemented in recent years in order to increase accuracy, improve efficiency, and add value to the outcome. A comprehensive literature review is required to determine the utility of preoperative 3D planning software in guiding orthopedic surgeons for implant placement in rTSA. We hypothesize that implementation of 3D preoperative planning software in the setting of rTSA leads to high concordance with minimal deviation from the preoperative plan.

METHODS

A comprehensive and iterative literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using the PubMed, Embase, OVID Medline, Scopus, Cinahl, Web of Science, and Cochrane databases for original English-language studies evaluating the impact of preoperative planning software usage on rTSA outcomes published from January 1, 2000, to present. Blinded reviewers conducted multiple screens. All included studies were graded based on level of evidence, and data concerning patient demographics and postoperative outcomes were extracted.

RESULTS

Nine articles met inclusion criteria (1 level II, 3 level III, and 5 level IV articles), including 415 patients and 422 shoulders. Of the patients who underwent rTSA, 235 were female and 140 were male, although 3 studies (n = 40) did not report sex breakdowns for rTSA patients. The average age was 72.7 years. Four studies (79 shoulders) reported implant final position as mean deviation from planned version and planned inclination. Six studies (n = 236) reported screw angle deviation, fixation, length, and concordance. Concordance with the preoperative plan was measured in 3 studies (n = 178), resulting in complete concordance of 90% (n = 100), arthroplasty type concordance (rTSA vs. TSA) of 100% (n = 100), and glenosphere size concordance between 93% (n = 100) and 88% (n = 76). For screw length concordance, baseplate screw matched by 81% (n = 76) and 100% (n = 2), and upper (n = 35) and lower (n = 35) screw length concordance was observed as 74% and 69%, respectively. The use of preoperative planning (n = 178) was associated with low deviation from preoperative plan, more 2-screw fixations, and longer average screw length in comparison with an unplanned cohort.

CONCLUSION

The use of preoperative planning software in the setting of rTSA results in minimal deviation from preoperative plan. High levels of concordance in screw angle, screw length, and glenosphere size were observed. Further prospective studies should be conducted to further substantiate these results.

Conjoint tendon lengthening for recalcitrant anterior shoulder pain after reverse shoulder arthroplasty: a technique article

The incidence of reverse shoulder arthroplasty (RSA) has increased since the Food and Drug Administration approved its use in the United States in 2004. With the current RSA implants available for surgeon use within the United States of America, each design, regardless of humeral inlay vs. onlay, distalizes the shoulder's center of rotation. This new center of rotation purposely increases tension to the deltoid, which is the main working muscle in RSA, but also retensions the adjacent tendons. Some patients after RSA experience continued anterior shoulder discomfort that limits their active range of motion and overall patient satisfaction. It has been isolated with physical examination that there is tenderness to palpation at the coracoid process and throughout the conjoint tendon. We have completed conjoint tendon lengthening procedures on this subset of patients with excellent clinical results. This article describes the technique for patients who underwent conjoint tendon lengthening after RSA for recalcitrant anterior shoulder pain.

Range of Movement and Patient-Reported Outcomes in Shoulder Arthroplasty in the Elderly: A Comparison of Anatomical Versus Reverse Shoulder Replacements

Introduction Shoulder arthroplasty is in increasing demand in the elderly given the rising prevalence of glenohumeral osteoarthritis (OA) across the population. There is a dearth of evidence in the current literature comparing anatomical total shoulder arthroplasty and reverse total shoulder arthroplasty (RTSA) in the elderly population. This study compares patient-reported outcome measures and range of movement (ROM) between anatomical and reverse total shoulder replacements in matched patient cohorts over the age of 70 years. Materials and methods This retrospective cohort study compares range of movement and patient-reported outcomes between anatomical total shoulder arthroplasty and reverse total shoulder arthroplasty in matched cohorts over the age of 70 years at a single institution between 2011 and 2015. Overall, 75 patients were recruited, including 44 patients with anatomical total shoulder arthroplasty and 31 patients with reverse total shoulder arthroplasty. Cohorts were matched according to age, preoperative Oxford Shoulder Score (OSS), and preoperative range of movement. The minimum clinical follow-up was one year. Results At one year, range of movement metrics in flexion, abduction, and external rotation all demonstrated greater improvements in the anatomical total shoulder arthroplasty cohort in comparison to the reverse total shoulder arthroplasty cohort (p<0.0001). No statistical difference in Oxford Shoulder Score was evident between cohorts. Conclusion Anatomical total shoulder arthroplasty demonstrates a significant improvement in range of movement in comparison to reverse total shoulder arthroplasty in matched elderly patient cohorts. However, there was no statistical difference in functional assessment scores between reverse shoulder replacement and anatomical shoulder replacement.

Development of a Machine Learning Algorithm for Prediction of Complications and Unplanned Readmission Following Reverse Total Shoulder Arthroplasty

Background

Reverse total shoulder arthroplasty (rTSA) offers tremendous promise for the treatment of complex pathologies beyond the scope of anatomic total shoulder arthroplasty but is associated with a higher rate of major postoperative complications. We aimed to design and validate a machine learning (ML) model to predict major postoperative complications or readmission following rTSA.

Methods

We retrospectively reviewed California's Office of Statewide Health Planning and Development database for patients who underwent rTSA between 2015 and 2017. We implemented logistic regression (LR), extreme gradient boosting (XGBoost), gradient boosting machines, adaptive boosting, and random forest classifiers in Python and trained these models using 64 binary, continuous, and discrete variables to predict the occurrence of at least one major postoperative complication or readmission following primary rTSA. Models were validated using the standard metrics of area under the receiver operating characteristic (AUROC) curve, area under the precision–recall curve (AUPRC), and Brier scores. The key factors for the top-performing model were determined.

Results

Of 2799 rTSAs performed during the study period, 152 patients (5%) had at least 1 major postoperative complication or 30-day readmission. XGBoost had the highest AUROC and AUPRC of 0.681 and 0.129, respectively. The key predictive features in this model were patients with a history of implant complications, protein-calorie malnutrition, and a higher number of comorbidities.

Conclusion

Our study reports an ML model for the prediction of major complications or 30-day readmission following rTSA. XGBoost outperformed traditional LR models and also identified key predictive features of complications and readmission.

The biomechanical effectiveness of tendon transfers to restore rotation after reverse shoulder arthroplasty: latissimus versus lower trapezius

BACKGROUND

The purpose of this biomechanical simulator study was primarily to compare latissimus dorsi to lower trapezius tendon transfers for active external rotation and the pectoralis major transfer for internal rotation after reverse shoulder arthroplasty. Secondarily, the role of humeral component lateralization on transfer function was assessed.

METHODS

Eight rotator cuff deficient cadavers underwent reverse shoulder arthroplasty with an adjustable lateralization humeral component. Latissimus dorsi and lower trapezius transfers were compared for active external rotation restoration and pectoralis major transfer for internal rotation restoration. Internal rotation/external rotation torques were measured for each lateralization at varying abduction and internal rotation/external rotation ranges-of-motion.

RESULTS

The lower trapezius transfer generated, on average, 1.6 ± 0.2 nm more torque than the latissimus dorsi transfer (p < 0.001). The internal rotation/external rotation torques of all tendon transfers decreased as abduction increased (p < 0.01). At 0° elevation, reverse shoulder arthroplasty humeral component lateralization had a significant positive effect on tendon transfer torque at 60° internal rotation and external rotation (p < 0.01).

DISCUSSION

Both the lower trapezius and the latissimus dorsi tendon transfers were effective in restoring active external rotation after reverse shoulder arthroplasty; however, the lower trapezius generated significantly more torque. Additionally, the pectoralis major transfer was effective in restoring active internal rotation. All tendon transfers were optimized with greater humeral component lateralization.

Factors Influencing Acromial and Scapular Spine Strain after Reverse Total Shoulder Arthroplasty: A Systematic Review of Biomechanical Studies

BACKGROUND

Acromial and scapular spine fractures after reverse total shoulder arthroplasty (RTSA) can be devastating complications leading to substantial functional impairments. The purpose of this study was to review factors associated with increased acromial and scapular spine strain after RTSA from a biomechanical standpoint.

METHODS

A systematic review of the literature was conducted based on PRISMA guidelines. PubMed, Embase, OVID Medline, and CENTRAL databases were searched and strict inclusion and exclusion criteria were applied. Each article was assessed using the modified Downs and Black checklist to appraise the quality of included studies. Study selection, extraction of data, and assessment of methodological quality were carried out independently by two of the authors. Only biomechanical studies were considered.

RESULTS

Six biomechanical studies evaluated factors associated with increased acromial and scapular spine strain and stress. Significant increases in acromial and scapular spine strain were found with increasing lateralization of the glenosphere in four of the included studies. In two studies, glenosphere inferiorization consistently reduced acromial strain. The results concerning humeral lateralization were variable between four studies. Humeral component neck-shaft angle had no significant effect on acromial strain as analysed in one study. One study showed that scapular spine strain was significantly increased with a more posteriorly oriented acromion (55° vs. 43°; p < 0.001). Another study showed that the transection of the coracoacromial ligament increased scapular spine strain in all abduction angles (p < 0.05).

CONCLUSIONS

Glenoid lateralization was consistently associated with increased acromial and scapular spine strain, whereas inferiorization of the glenosphere reduced strain in the biomechanical studies analysed in this systematic review. Humeral-sided lateralization may increase or decrease acromial or scapular spine strain. Independent of different design parameters, the transection of the coracoacromial ligament resulted in significantly increased strains and scapular spine strains were also increased when the acromion was more posteriorly oriented. The results found in this systematic review of biomechanical in-silico and in-vitro studies may help in the surgical planning of RTSA to mitigate complications associated with acromion and scapular spine fracture.

Gender Influences on Shoulder Arthroplasty

PURPOSE OF REVIEW

As the incidence of shoulder arthroplasty continues to increase, there is growing interest in patient-based factors that may predict outcomes. Based on existing literature demonstrating gender-based disparities following total hip and knee arthroplasty, gender may also influence shoulder arthroplasty. The purpose of this review is to discuss the recent literature on the influence of gender on shoulder arthroplasty, focusing on differences in preoperative parameters, perioperative complications, and postoperative outcomes.

RECENT FINDINGS

While both female and male patients generally benefit from shoulder arthroplasty, several differences may exist in preoperative factors, acute perioperative complications, and postoperative outcomes. Preoperatively, female patients undergo shoulder arthroplasty at an older age compared to their male counterparts. They may also have greater levels of preoperative disability and different preoperative expectations. Perioperatively, female patients may be at increased risk of extended length of stay, postoperative thromboembolic events, and blood transfusion. Postoperatively, female patients may achieve lower postoperative functional scores and decreased range of motion compared to male patients. Differences in postoperative functional scores may be influenced by gender-based differences in activities of daily living. Finally, female patients may be at greater risk for periprosthetic fracture and aseptic loosening while male patients appear to be at greater risk for periprosthetic infection and revision surgery. Current literature on the influence of gender on shoulder arthroplasty is limited and conflicting. Further research is necessary to delineate how gender affects patients at the pre- and postoperative levels to better inform decision-making and outcomes.

Protocol for a multicenter, randomised controlled trial of surgeon-directed home therapy vs. outpatient rehabilitation by physical therapists for reverse total shoulder arthroplasty: the SHORT trial

Background

Reverse total shoulder arthroplasty (RTSA) has emerged as a successful surgery with expanding indications. Outcomes may be influenced by post-operative rehabilitation; however, there is a dearth of research regarding optimal rehabilitation strategy following RTSA. The primary purpose of this study is to compare patient reported and clinical outcomes after RTSA in two groups: in one group rehabilitation is directed by formal, outpatient clinic-based physical therapists (PT group) as compared to a home therapy group, in which patients are instructed in their rehabilitative exercises by surgeons at post-operative appointments (HT group). Secondary aims include comparisons of complications, cost of care and quality of life between the two groups.

Methods

This randomised controlled trial has commenced at seven sites across the United States. Data is being collected on 200 subjects by clinical research assistants pre-operatively and post-operatively at 2, 6, and 12 weeks, 6 months, 1 and 2 year visits. The following variables are being assessed: American Shoulder and Elbow Surgeons (ASES), pain level using the numeric pain scale, the Single Assessment Numeric Evaluation (SANE) score, and shoulder active and passive range of motion for analysis of the primary aim. Chi square and t-tests will be used to measure differences in baseline characteristics of both groups. Repeated measures linear mixed effects modeling for measurement of differences will be used for outcomes associated with ASES and SANE and scores, and range of motion measures. Secondary aims will be analyzed for comparison of complications, cost, and quality of life assessment scores using data obtained from the PROMIS 29 v. 2, questionnaires administered at standard of care post-operative visits, and the electronic health record. Subjects will be allowed to crossover between the PT and HT groups, and analysis will include both intention-to-treat including patients who crossed over, and a second with cross-over patients removed, truncated to the time they crossed over.

Discussion

RTSA is being performed with increasing frequency, and the optimal rehabilitation strategy is unclear. This study will help clarify the role of formal physical therapy with particular consideration to outcomes, cost, and complications. In addition, this study will evaluate a proposed rehabilitation strategy.

Trial registration

This study is registered as NCT03719859 at ClincialTrials.gov.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40945-021-00121-2.

Influence of rotator cuff integrity on loading and kinematics before and after reverse shoulder arthroplasty

Reverse Shoulder Arthroplasty has become a very common procedure for shoulder joint replacement, even for scenarios where an anatomical reconstruction would traditionally be used. Our hypothesis is that implanting a reverse prosthesis with a functional rotator cuff may lead to higher joint reaction force (JRF) and have a negative impact on the prosthesis. Available motion capture data during anterior flexion was input to a finite-element musculoskeletal shoulder model, and muscle activations were computed using inverse dynamics. Simulations were carried out for the intact joint as well as for various types of rotator cuff tears: superior (supraspinatus), superior-anterior (supraspinatus and subscapularis), and superior-posterior (supraspinatus, infraspinatus and teres minor). Each rotator cuff tear condition was repeated after shifting the humerus and the glenohumeral joint center of rotation to represent the effect of a reverse prosthesis. Changes in compressive, shear, and total JRF were analyzed. The model compared favorably to in vivo JRF measurements, and existing clinical and biomechanical knowledge. Implanting a reverse prosthesis with a functional rotator cuff or with an isolated supraspinatus tear led to more than 2 times higher compressive JRF than with massive rotator cuff tears (superior-anterior or superior-posterior), while the shear force remained comparable. The total JRF increased more than 1.5 times. While a lower shear to compressive ratio may reduce the risk of glenosphere loosening, higher JRF might increase the risk for other failure modes such as fracture or polyethylene wear of the reverse prosthesis.

Revision Reverse Total Shoulder Arthroplasty in Patients 65 Years Old and Younger: Outcome Comparison to Older Patients

Background

Reverse total shoulder arthroplasty (RTSA) is a procedure growing in prevalence among younger populations. Consequently, its use in revision arthroplasty is growing in this demographic. However, studies examining the functional outcomes of revision RTSA in younger populations compared with older populations are lacking. The primary purpose of this study is to evaluate the functional outcomes of revision RTSA in patients 65 years old and younger compared with older patients who underwent revision RTSA. We hypothesized that younger patients would have similar outcomes to older patients and both groups would demonstrate improvement in outcomes.

Methods

A retrospective review was conducted on a prospectively collected research database at a single tertiary referral center of all patients who underwent RTSA between 2007 and 2018. Patients 65 years old or younger who underwent a revision RTSA and had minimum 2-year follow-up were evaluated. A control group of patients ≥70 years old who underwent revision RTSA were also evaluated. Demographics, surgical factors, active range of motion (ROM), and patient-reported outcomes (PROMs) were compared. The ROM parameters measured were forward elevation, abduction, external rotation, and level of internal rotation. The PROMs collected included American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, University of California–Los Angeles score, Constant score, normalized Constant, and Shoulder Pain and Disability Index 130. The differences in outcomes were compared against the minimal clinically important difference and substantial clinical benefit reported for primary reverse shoulder arthroplasty.

Results

A total of 81 patients undergoing revision RTSA were evaluated at a mean follow-up of 4.5 years with 42 patients in the study group and 39 patients in the control group. Both groups demonstrated similar demographics and rates of prior surgeries. Preoperative outcome scores were lower in the study group (≤65 years old) than those in the older control group with American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, and Shoulder Pain and Disability Index 130 remaining worse postoperatively. Both groups experienced statistically significant improvements in ROM from before operation to after operation, with slightly higher improvements in overhead motion in the younger cohort. Both the study group and the control group demonstrated statistically significant improvements in all PROMs with improvement above the substantial clinical benefit for the Constant and Simple Shoulder Test scores. Despite lower functional outcomes reported in the study group postoperatively, the improvement from before operation to after operation in all PROMs was similar between groups.

Conclusion

Revision RTSA is a viable option for patients ≤65 years old with a poorly functioning shoulder arthroplasty. ROM and outcome improvements are similar compared with older patients undergoing revision RTSA, but the preoperative and postoperative functional outcomes are worse in the younger patients.

CT versus MRI planning for reverse geometry total shoulder arthroplasty

Introduction

Preoperative planning for Reverse Total Shoulder Arthroplasty (RTSA) using CT or MRI is well described.1, 2, 3, 4, 5, 6, 7 We aimed to compare pre-operative CT versus MRI measurement accuracy for predicting intra-operative glenoid implant sizing.

Methods

All patients with a preoperative CT or MRI undergoing RTSA at our tertiary referral center from October 2017 to February 2020 were included. Data was collected from theatre and implant registers. Glenosphere Width (GW) and Baseplate Central Screw Length (BCSL) were independently predicted from pre-operative CT or MRI imaging by 2 blinded senior authors. A sub-group analysis was also performed between trauma and non-trauma CT cases. SPSS v26 was used for statistical comparison between predicted and actual implants.

Results

71 data sets from 69 patients were included for analysis: 31 CT predictions and 40 MRI predictions. 61.3% of CT measured GW predictions were accurate compared to 82.5% of MRI predictions (p = 0.045). BCSL predictions were 77.4% and 70% accurate for CT and MRI respectively, without significant difference. There was no significant difference in sub-group analysis for trauma vs elective CT accuracy of BCSL or GW measurements.

Conclusion

MRI imaging may be superior to CT for predicting GW and no less accurate than CT for predicting BCSL in the elective setting. No difference in CT measurement accuracy was seen between trauma and elective settings. While simultaneously clearly defining shoulder soft tissue anatomy, MRI may also be the preferred modality for bony measurements during pre-operative planning for elective RTSA.

Reverse total shoulder arthroplasty for oncologic reconstruction of the proximal humerus: a systematic review

BACKGROUND

In recent years, there has been growing interest in the use of reverse total shoulder arthroplasty (rTSA) for reconstruction of the proximal humerus after oncologic resection. However, the indications and outcomes of oncologic rTSA remain unclear.

METHODS

We conducted a systematic review to identify studies that reported outcomes of patients who underwent rTSA for oncologic reconstruction of the proximal humerus. Extracted data included demographic characteristics, indications, operative techniques, outcomes, and complications. Weighted means were calculated according to sample size.

RESULTS

Twelve studies were included, containing 194 patients who underwent rTSA for oncologic reconstruction of the proximal humerus. The mean patient age was 48 years, and 52% of patients were male. Primary malignancies were present in 55% of patients; metastatic disease, 30%; and benign tumors, 9%. The mean humeral resection length was 12 cm. The mean postoperative Musculoskeletal Tumor Society score was 78%; Constant score, 60; and Toronto Extremity Salvage Score, 77%. The mean complication rate was 28%, with shoulder instability accounting for 63% of complications. Revisions were performed in 16% of patients, and the mean implant survival rate was 89% at a mean follow-up across studies of 53 months.

CONCLUSIONS

Although the existing literature is of poor study quality, with a high level of heterogeneity and risk of bias, rTSA appears to be a suitable option in appropriately selected patients undergoing oncologic resection and reconstruction of the proximal humerus. The most common complication is instability. Higher-quality evidence is needed to help guide decision making on appropriate implant utilization for patients undergoing oncologic resection of the proximal humerus.

Influence of subscapularis stiffness with glenosphere lateralization on physiological external rotation limits after reverse shoulder arthroplasty

BACKGROUND

Repair of the subscapularis following reverse shoulder arthroplasty (RSA) remains a controversial topic among surgeons. Poor rotator cuff muscle quality is associated with increased musculotendinous stiffness, and the subsequent effect of compromised tissue repair on RSA functional outcomes remains unclear. The objective was to investigate the influence of subscapularis stiffness together with glenoid component lateralization on pre- and postimpingement joint mechanics during external rotation after RSA.

METHODS

A validated finite element model incorporating the Zimmer Trabecular Metal reverse system was used. The deltoid and subscapularis tendon were tensioned and wrapped around the joint prior to controlled shoulder external rotation. Baseline subscapularis stiffness, determined from cadaveric testing, was varied to 80%, 120% and 140% of baseline, to simulate a range of pliability associated with fatty infiltration and fibrosis. We evaluated the effects of varying subscapularis stiffness and the corresponding variation in joint tension with varying glenosphere lateralization (2, 4, and 10 mm) on the torque required to externally rotate the shoulder and the impingement/subluxation risk.

RESULTS

Prior to any impingement, the torques required to externally rotate the shoulder ranged from 22-47 Nm across the range of parameters studied, with the greatest torques required for the 10-mm glenosphere lateralization. The impact of increasing subscapularis stiffness on torque requirements was most pronounced at the 10-mm lateralization, as well. A 20% increase in subscapularis stiffness necessitated a 7%-14% increase in preimpingement torque, whereas a 40% stiffness increase was associated with a 12%-27% increase in torque. Torque was proportional to lateralization. When lateralization was increased from 2 to 4 mm, the preimpingement torque increased by 10%-13%, whereas a 10-mm lateralization necessitated a 35%-62% torque increase relative to 2 mm of lateralization. Increased subscapularis stiffness did not limit impingement-free range of motion or substantially decrease postimpingement subluxation in this model.

DISCUSSION

Mechanical gains achieved through lateralization may be hindered by increased torque demands, especially when a stiffer subscapularis is repaired. As lateralization increases subscapularis tension, greater torque is required to externally rotate the shoulder. The torque required for external rotation has been reported between 15-50 Nm. Subscapularis repair with the simulated increases in stiffness requires relative increases in torque that the reconstructed shoulder may not be able to physically produce to rotate the glenohumeral joint, particularly at 10-mm lateralization. These results suggest that subscapularis repair may not be indicated in cases where a lateralized glenoid component is used and the subscapularis is compromised.

The in vivo impact of computer navigation on screw number and length in reverse total shoulder arthroplasty

BACKGROUND

Little information exists regarding the benefit of computer navigation in shoulder arthroplasty in the clinical setting. This study aimed to quantify how computer navigation affects the number and length of screws used during in vivo reverse total shoulder arthroplasty (RSA) placement.

METHODS

We performed a retrospective review of a research database to identify patients who underwent primary RSA before and after the use of computer navigation between January 1, 2015, and December 31, 2019. One hundred consecutive RSAs were selected from the computer navigation implantation date; then, 100 consecutive sex-matched RSAs were chosen prior to navigation implantation in reverse chronologic order. Baseplate augmentations were chosen based on surgeon discretion, with the goal of restoring version to within 10° of neutral and inclination to neutral or slightly inferior with removal of the smallest amount of subchondral bone possible. Screws were placed with the goal of ≥3 screws with good purchase and were added as needed, with up to 5 screws used. We compared demographic factors, comorbidities, preoperative diagnosis, number of screws, screw length, number of wasted screws, and number of cases with bone graft used behind the baseplate between the 2 groups. We used the χ² test for bivariate analysis and the Student t test for continuous variables.

RESULTS

A total of 200 RSAs were included, with 100 primary RSAs (mean age, 69.3 years) performed prior to computer navigation compared with 100 primary RSAs (mean age, 69.7 years) performed using computer navigation. The total number of screws used in RSAs without computer navigation was 414; the total used in the computer navigation cases was 344. RSAs placed with computer navigation used significantly fewer screws per case (3.4 screws vs. 4.1 screws, P < .001) and had a significantly greater average screw length (35.0 mm vs. 32.6 mm, P < .001). Three screws were implanted in 61% of computer navigation cases vs. 1% of cases without computer navigation (P < .001). Screws ≥ 30 mm in length were more commonly used in patients undergoing RSA using computer navigation (84.6% vs. 73.7%, P < .001).

CONCLUSION

This study shows that computer navigation in RSA leads to longer and fewer glenoid baseplate screws being implanted. Computer navigation appears to assist with better screw placement, which may have similar clinical benefits of better glenoid fixation. Additionally, using fewer screws can save glenoid bone stock, avoid added glenoid stress risers, and decrease operative time.

Reverse shoulder arthroplasty in complex fractures of the proximal humerus: results after 7 years of follow-up

BACKGROUND

There is still little information about the long-term results of clinical and radiological evolution in patients older than 65 years with complex proximal humerus fractures (CPHF) treated acutely with reverse shoulder arthroplasty (RSA). The aim of this paper was to evaluate function and results 7 years after surgery.

MATERIAL AND METHODS

A prospective cross-sectional cohort study was designed for this purpose. Patients who underwent RSA surgery during 2012 because of a CPHF were included. The surgical approach was randomized (deltopectoral vs anterosuperior). Functional activity, evolution of tuberosities and evidence of scapular notching 7 years after surgery were analyzed.

RESULTS

After evaluating 32 patients, the Constant score improved from 64.83 in the first year to 69.54 at 7 years postoperative. Results were independent of the approach used. Functional outcomes were poorer in patients with scapular notching and when tuberosities were resorbed or displaced.

CONCLUSIONS

At 7 years, function in patients undergoing RSA after CPHF demonstrated improvement in all patients except those who developed scapular notching or when tuberosities did not consolidate in an anatomical position. These results are completely independent of the approach used.

LEVEL OF EVIDENCE

III Controlled cohort study.

Putting Our Shoulder to the Wheel: Current Understanding and Gaps in Nerve Ablation for Chronic Shoulder Pain

Shoulder pain is prevalent, burdensome, and functionally limiting, with diverse pathology and associated treatments. This narrative review provides a summary of relevant neuroanatomy, proposed ablation targets, safety and efficacy concerns for ablation targets, and current research gaps. Radiofrequency ablation (RFA) of peripheral sensory nerves is a well-established treatment for chronic joint and spine pain, but it is relatively nascent for shoulder pain. Cadaveric studies demonstrate the shoulder joint is innervated by articular branches of the suprascapular nerve, axillary nerve, lateral pectoral nerve, and upper and lower subscapular nerves. Shoulder articular branch RFA appears to be a safe and effective treatment for chronic shoulder pain, but there are currently no widely accepted protocols for ablation targets. There are also no randomized controlled trials (RCT) assessing safety and efficacy of proposed targets or the prognostic value of articular blocks. Future research studies should prioritize categorical data, use appropriate functional measures as primary endpoints, and would ideally include a large-scale RCT.

Patient risk factors for acromial stress fractures after reverse shoulder arthroplasty: a multicenter study

BACKGROUND

Despite the growing recognition of acromial stress fractures (ASFs) after reverse total shoulder arthroplasty (RTSA), most of the current data are derived from single-center studies with limited generalizability. This multicenter study investigated the incidence of ASFs after RTSA and identified preoperative patient characteristics associated with their occurrence.

METHODS

Using 2 institutional registries from different regions of the United States, we identified 1479 patients undergoing either primary or revision RTSA between 2013 and 2018 with minimum 3-month follow-up. ASFs were defined as radiographic evidence of an acromial or scapular spine fracture with clinical symptoms (eg, tenderness over the acromion or scapular spine). Multivariable logistic regression was performed to identify preoperative patient factors associated with the development of ASFs.

RESULTS

Overall, 54 (3.7%) patients were diagnosed with an ASF after RTSA. Patient-related factors independently associated with the development of an ASF included female sex (odds ratio [OR], 2.21 reference: male; 95% confidence interval [CI], 1.03-4.74; P < .05), rheumatoid arthritis (OR, 2.30; 95% CI, 1.02-5.16; P < .05), osteoporosis (OR, 2.55; 95% CI, 1.24-5.21; P < .05), a diagnosis of degenerative joint disease with rotator cuff tear (OR, 4.74 reference: degenerative joint disease without rotator cuff tear; 95% CI, 1.84-12.23; P < .05), and fracture malunion/nonunion (OR, 5.21; 95% CI, 1.20-22.76; P < .05).

CONCLUSIONS

The non-negligible percentage of ASFs that occur after RTSA is associated with the diagnoses of rotator cuff dysfunction and chronic fracture sequelae in female patients with suboptimal bone health. This information can be used to counsel patients and set expectations about potential setbacks in recovery.