Problems, complications, reoperations, and revisions in reverse total shoulder arthroplasty: a systematic review

Reverse versus anatomic total shoulder arthroplasty: A large matched cohort analysis

Introduction

The annual utilization of reverse total shoulder arthroplasty (RTSA) and anatomic total shoulder arthroplasty (ATSA) has grown exponentially, in part due to the expanded indications of RTSA. This evolution in shoulder arthroplasty prompts the need to evaluate outcomes between ATSA and RTSA. However, many other studies comparing outcomes between ATSA and RTSA lacked a large nationally-represented sample, a matched cohort analysis, or both. In this study, we compare outcomes between patients undergoing ATSA or RTSA in a large matched-cohort analysis.

Methods

Patients undergoing RTSA or ATSA from the National Inpatient Sample database between 2016 and 2019 were identified. Groups were propensity-matched based on demographics and comorbidities. We compared medical and surgical complications, length of stay, and total hospital charges. T-tests and chi-square tests were performed for continuous and categorical variables, respectively. Odds ratios were calculated as a ratio between RTSA and ATSA groups.

Results

Following matching, there were 38,782 patients in the ATSA group and 35,461 patients in the RTSA group. The RTSA group had higher odds of acute renal failure (OR 1.35), blood loss anemia (OR 1.39), and pneumonia (OR 1.19). There were no differences for myocardial infarction, pulmonary embolism, deep venous thrombosis, mortality, periprosthetic fracture, or dislocation. The RTSA group had higher odds of periprosthetic mechanical complication (OR 1.92), but lower odds of periprosthetic joint infection (OR 0.65). The mean length of stay and total hospital charges were both higher in the RTSA group (p < 0.001).

Discussion

We found patients undergoing RTSA are at higher odds of inpatient medical complications, including acute renal failure and acute blood loss anemia. RTSA is associated with higher odds of short-term periprosthetic mechanical complications.

Implantation of Reverse Shoulder Endoprothesis Using Navigation

The implantation of a reverse shoulder arthroplasty (RSA) is a proven method for pain relief and improvement in shoulder function. Results vary, depending on the patient's age, the severity of the disease, and the experience of the surgeon. Indications for RSA are diverse, ranging from rotator cuff arthropathy to fractures. Recent studies show improved survival rates and reduced complications after primary implantation. Preoperative planning using 3D-CT or MRI is considered to be the gold standard. Patient-specific instruments (PSI) have been introduced, but are associated with costs and waiting times. Navigation with augmented reality (AR) provides a more efficient alternative. The intraoperative transfer of the plan to the patient is carried out via AR glasses, allowing real-time information without having to divert the surgeon's attention from the surgical site. This optimises the workflow and potentially yields more precise implantation results. In summary, the combination of 3D planning, navigation, and AR offers a promising method for precise and efficient RSA-implantations. Nevertheless, long-term results and functional scores are not yet available.

Reliable technique for acromion density assessment on CT

INTRODUCTION

Acromial stress fracture (ASF) is an uncommon but acknowledged complication of reverse total shoulder arthroplasty (RTSA). There is no standardised method to directly measure the bone mineral density of the acromion to allow a detailed analysis of the potential mechanism of ASF. The aim is to establish a reliable and reproducible technique for measurement of acromial density on computer tomography (CT).

METHODS

A retrospective review on CT scans obtained for three groups of patients: those planned for RTSA (n = 26); age and gender-matched non-operative (n = 26); and young non-operative patients (n = 28) were performed. Standardised axial images of 1 mm thickness at 1 mm increments were created following horizontal straightening on the coronal and sagittal views. To assess inter-rater reliability, two senior CT radiographers performed density measurements using standard region of interest (ROI) tool on the CTs with the ROI placed on the mid (ROI 1) and posterior (ROI 2) acromion. ROIs were selected as the most common locations for acromion fracture post RTSA. Measurements were repeated at least 6 weeks apart. Intra-class coefficients (ICC) were used to determine intra- and inter-rater reliability.

RESULTS

ICCs demonstrated good to high intra-rater and inter-rater reliability for both ROI 1 and ROI 2 across all three groups. The lower margin of 95% confidence intervals was more than 0 for all intra-class coefficients.

CONCLUSION

This study demonstrates a reliable method of measuring acromion density on CT. This method can be used to assess bone mineral density in the clinical setting and in future studies investigating ASF following RTSA.

The effect of humeral tray thickness on glenohumeral loads in a reverse shoulder 'smart' implant

PURPOSE

The aim of this study was to observe the effects of changing humeral tray thickness on the resultant of intraoperative glenohumeral joint loads using a load-sensing system (LSS).

METHODS

An rTSA was performed on fresh frozen full-body cadaver shoulders by using an internal proprietary LSS on the humeral side. The glenohumeral loads (Newtons) and the direction of the resultant force applied on the implant were recorded during four standard positions (External rotation, Extension, Abduction, Flexion) and three "complex" positions of Activity Daily Life ("behind back", "overhead reach" and "across chest"). For each position, the thickness was increased from 0 to 6 mm in a continuous fashion using the adjustment feature of the humeral system. Each manoeuvre was repeated three times.

RESULTS

All shoulder positions showed a high repeatability of the glenohumeral load magnitude measured with an intra-class correlation coefficient of over 0.9. For each position, we observed a strong but no linear correlation between humeral tray thickness and joint loads. It was a cubical correlation (rs = 0,91) with a short ascending phase, then a plateau phase, and finally a phase with an exponential growth of the loads on the humeral implant. In addition, an increase in trail-poly thickness led to a recentering of force application at the interface of the two glenohumeral implants.

CONCLUSION

This study provides further insight into the effects of humeral implant thickness on rTSA glenohumeral joint loads during different positions of the arm. Data obtained using this type of device could guide surgeons in finding the proper implant balance during rTSA.

Vancomycin Soaking to Reduce Intraoperative Contamination by Cutibacterium acnes During the Latarjet Procedure

BACKGROUND

Postoperative infection after the Latarjet procedure, ranging from 1% to 6%, can compromise the functional outcome of young athletes. Cutibacterium acnes is a main pathogen as a consequence of an intraoperative contamination.

PURPOSE

To evaluate intraoperative contamination with C. acnes and the effectiveness of the local application of vancomycin during the Latarjet procedure.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This was a single-center study including 75 patients (mean age, 26 years; range, 15-55 years) operated on for anterior shoulder instability with the primary open Latarjet procedure; they underwent the same protocol of skin preparation and preoperative prophylactic antibiotics. Three groups of 25 patients were created and divided sequentially, without the results of each group being known before the end of the study: group A (5 mg/mL of vancomycin), group B (20 mg/mL of vancomycin), and group C (control group with no vancomycin). Swab samples of the coracoid were taken before sectioning the coracoid process (time 1) and after its preparation (time 2). The coracoid was then wrapped in gauze impregnated with different concentrations of vancomycin, except for group C. A final sample (time 3) was taken before screwing the bone block onto the glenoid. All samples were cultured for 21 days, and patients underwent clinical and radiological follow-up for 6 months.

RESULTS

The C. acnes contamination rates at times 1, 2, and 3 were 25%, 44%, and 45%, respectively, without significant difference. There was no significant difference between groups A and B with respect to the number of positive cultures at each time point. Of 9 positive cultures at time 1, all were still positive at time 3 in group A, whereas 3 of 5 were negative in group B (P = .027). The rate of C. acnes at time 3 in the control group was higher than that in the 2 other groups (68% vs 44% for group A and 20% for group B; P = .003). Body mass index was the only prognostic factor for a C. acnes-positive culture (26.05 ± 3.39 vs 23.34 ± 2.33; P = .018). No clinical infection was reported at the 6-month postoperative follow-up.

CONCLUSION

The rate of C. acnes contamination ranged from 25% to 68% during the open Latarjet procedure in young athletes. Vancomycin reduced the bacterial contamination when it was used at high concentrations in a gauze wrap on the coracoid. The type of C. acnes detected and its clinical implications remain to be studied.

Malawer type I/V proximal humerus reconstruction after tumor resection: a systematic review

BACKGROUND

Several reconstruction methods exist for Malawer type I/V proximal humerus reconstruction after bone tumor resection; however, no consensus has been reached regarding the preferred methods.

METHODS

We conducted a literature search on various types of proximal humerus oncologic reconstruction methods. We collected data on postoperative functional outcomes assessed based on Musculoskeletal Tumor Society (MSTS) scores, 5-year reconstruction survival rates, and complications. We calculated each reconstruction's weighted mean based on the sample size and standard errors. Complications were categorized based on the Henderson classification. Based on these integrated data, our primary objective is to propose an optimal strategy for proximal humerus reconstruction after bone tumor resection.

RESULTS

We examined various reconstruction techniques, including modular prosthesis (752 patients in 21 articles), osteoarticular allograft (142 patients in 6 articles), allograft prosthesis composites (APCs) (236 patients in 12 articles), reverse shoulder total arthroplasty (141 patients in 10 articles), composite reverse shoulder total arthroplasty (33 patients in 4 articles), claviculo-pro-humero (CPH) technique (51 patients in 6 articles), and cement spacer (207 patients in 4 articles). Weighted mean MSTS scores were: modular prosthesis (73.8%), osteoarticular allograft (74.4%), APCs (79.2%), reverse shoulder total arthroplasty (77.0%), composite reverse shoulder total arthroplasty (76.1%), CPH technique (75.1%), and cement spacer (69.1%). Weighted 5-year reconstruction survival rates were modular prosthesis (85.4%), osteoarticular allograft (67.6%), APCs (85.2%), reverse shoulder total arthroplasty (84.1%), and cement spacer (88.0%). Reconstruction survival data was unavailable for composite reverse shoulder total arthroplasty and CPH technique. Major complications included shoulder joint instability: modular prosthesis (26.2%), osteoarticular allograft (41.5%), APCs (33.9%), reverse shoulder total arthroplasty (17%), composite reverse shoulder total arthroplasty (6.1%), CPH technique (2.0%), and cement spacer (8.7%). Aseptic loosening of the prosthesis occurred: modular prosthesis (3.9%) and reverse shoulder total arthroplasty (5.7%). Allograft fracture was observed in 54.9% of patients with osteoarticular allograft.

CONCLUSION

The complication profiles differed among reconstruction methods. Weighted mean MSTS scores exceeded 70% in all methods except cement spacer, and the 5-year reconstruction survival rate surpassed 80% for all methods except osteoarticular allograft. Proximal humerus reconstruction after bone tumor resection should consider potential complications and patients' individual factors.

Rheumatoid arthritis is associated with higher 90-day systemic complications compared to osteoarthritis after total shoulder arthroplasty: a cohort study

BACKGROUND

Total shoulder arthroplasty (TSA) in patients with rheumatoid arthritis (RA) can present unique challenges. The aim of this study was to compare both systemic and joint-related postoperative complications in patients undergoing primary TSA with RA versus those with primary osteoarthritis (OA).

METHODS

Using the TriNetX database, Current Procedural Terminology and International Classification of Diseases, 10th edition codes were used to identify patients who underwent primary TSA. Patients were categorized into two cohorts: RA and OA. After 1:1 propensity score matching, postoperative systemic complications within 90 days following primary TSA and joint-related complications within 5 years following anatomic TSA (aTSA) and reverse shoulder arthroplasty (RSA) were compared.

RESULTS

After propensity score matching, the RA and OA cohorts each consisted of 8,523 patients. Within 90 days postoperation, RA patients had a significantly higher risk of total complications, deep surgical site infection, wound dehiscence, pneumonia, myocardial infarction, acute renal failure, urinary tract infection, mortality, and readmission compared to the OA cohort. RA patients had a significantly greater risk of periprosthetic joint infection and prosthetic dislocation within 5 years following aTSA and RSA, and a greater risk of scapular fractures following RSA. Among RA patients, RSA had a significantly higher risk of prosthetic dislocation, scapular fractures, and revision compared to aTSA.

CONCLUSIONS

Following TSA, RA patients should be considered at higher risk of systemic and joint-related complications compared to patients with primary OA. Knowledge of the risk profile of RA patients undergoing TSA is essential for appropriate patient counseling and education. Level of evidence: III.

Influence of design features and brand of reverse shoulder arthroplasties on survivorship and reasons for revision surgery: results of 5,494 arthroplasties with up to 15 years' follow-up reported to the Norwegian Arthroplasty Register 2007-2022

BACKGROUND AND PURPOSE

We aimed to report the survival of different reverse shoulder arthroplasty (RSA) designs and brands, and factors associated with revision. The secondary aim was to evaluate the reasons for revision.

METHODS

We included 4,696 inlay and 798 onlay RSAs reported to the Norwegian Arthroplasty Register (NAR) 2007-2022. Kaplan-Meier estimates of survivorship and Cox models adjusted for age, sex, diagnosis, implant design, humeral fixation, and previous surgery were investigated to assess revision risks. The reasons for revision were compared using competing risk analysis.

RESULTS

Overall, the 10-year survival rate was 94% (confidence interval [CI] 93-95). At 5 years all brands exceeded 90%. Compared with Delta Xtend (n = 3,865), Aequalis Ascend Flex (HR 2.8, CI 1.7-4.6), Aequalis Reversed II (HR 2.2, CI 1.2-4.2), SMR (HR 2.5, CI 1.3-4.7), and Promos (HR 2.2, CI 1.0-4.9) had increased risk of revision. Onlay and inlay RSAs had similar risk of revision (HR 1.2, CI 0.8-1.8). Instability and deep infection were the most frequent revision causes. Male sex (HR 2.3, CI 1.7-3.1), fracture sequelae (HR 3.1, CI 2.1-5.0), and fractures operated on with uncemented humeral stems had increased risk of revision (HR 3.5, CI 1.6-7.3).

CONCLUSION

We found similar risk of revision with inlay and onlay designs. Some prosthesis brands had a higher rate of revision than the most common implant, but numbers were low.

Shoulder balloon spacer for massive irreparable rotator cuff tears results in significant improvements

PURPOSE

The aim of the present study was to assess the effectiveness of balloon implantation in patients with irreparable supraspinatus tears alone or in combination with other rotator cuff (RC) tendon tears and the effect of several covariables, such as age, gender, status of the long head biceps, with or without tendon repair and regardless the number of tendon involved.

METHODS

Patients enrolled from 'San Carlo' Hospital of Potenza (Italy, IT), from January 2012 to September 2014, underwent arthroscopic implantation of shoulder balloon by a single surgeon, and followed for 3 years. The American Shoulder and Elbow Surgeons (ASES) and Constant score (CS) were administered pre-, post-operatively at 12 months, and then annually. Patients were classified on the basis of the number of tendons involved in the tears and treatment performed, considering the reparability of the tendons themselves. Gleno-humeral joint osteoarthrosis (OA) was evaluated through shoulder radiographs and classified according to the Samilson-Prieto classification, at the first examination and at the final follow-up. Statistical improvements were evaluated using a variance model (least-squares means) and a T distribution test for the evaluation between different treatment groups.

RESULTS

A total of 61 procedures were performed, and eight patients were lost during follow-up. The mean baseline CS was 30.2 ± 15.4 with statistically significant improvement, respectively, at 1-, 2- and 3-year follow-up to 69.3 ± 4.2, 74.6 ± 3.6 and 69.7 ± 5.1 respectively. ASES score at baseline was 22.5 ± 10.9, with a statistically significant improvement to 69.7 ± 9.2, 68 ± 17.8 and 71.2 ± 16.6 at 1-, 2- and 3-year follow-up, respectively. Tenotomy or absence of long head biceps at presentation did not influence results (n.s.), with no difference according to gender and age. At final follow-up, 24 patients (43.9%) showed progression of glenohumeral OA. One patient required secondary surgery for shoulder replacement after 18 months for persistent pain and one patient required implant removal following post-operative laser treatment.

CONCLUSION

Arthroscopic rotator cuff tears repair with subacromial spacer balloon implantation showed statistically significant clinical and functional improvement at 3-year follow-up. Patients treated with combined partial repair and subacromial spacer balloon implantation experienced good results independent of gender, age, type of tear and long-head biceps tendon status. The risks related to this procedure appear to be minimal.

LEVEL OF EVIDENCE

Level IV.

Locked Stem Reverse Total Shoulder Arthroplasty for Complex Proximal Humerus Fracture in the Elderly: Clinical and Radiological Short-Term Results

Purpose

To evaluate both the short-term clinical and radiological results of reverse shoulder arthroplasty (RSA) with uncemented locked stem in the management of a proximal humerus fracture (PHFs) in the elderly.

Methods

Retrospective study including 40 consecutive 3-4 part proximal humerus fractures treated with reverse shoulder arthroplasty with a minimum of 24 months follow-up. In all the cases, the greater tuberosity (GT) was reattached with a standardized suture technique and a local horseshoe bone graft. All the patients were assessed at the 24-month follow-up with Constant-Murley Score (CMS) and Visual Analog Score (VAS). Radiographic healing of the greater tuberosity was noted in addition to stem locking screws radiographic changes. Complications and revision rates were reported.

Results

Mean final CMS for this cohort was 80 points. The greater tuberosity healed in the anatomic position in 90% of the cases (N = 36), obtaining an average CMS of 80 in these patients. Healing of the greater tuberosity did not occur in 10% of the cases (N = 4), obtaining an average CMS of 60. All patients scored above 100° in forward elevation with a mean of 140°. Mean active external rotation was 30°. Low-grade scapular notching was reported in <1% of the cases. Major complications were reported in one patient with an acromial fracture. No complications or loosening of stem locking screws were noted. There were no reoperations.

Conclusion

In the elderly population, reverse shoulder arthroplasty utilizing a fracture-specific locking stem, low-profile metaphysis, suture-friendly groove, meticulous suture technique, and local bone grafting allows adequate fixation, variable prosthesis height adjustment, and enhances greater tuberosity healing. This approach yields positive short-term clinical outcomes without complications related to the stem's locking screws.

Level of Evidence

Level IV Retrospective Case Series.

Preventing Infections in Reverse Shoulder Arthroplasty

PURPOSE OF REVIEW

Reverse shoulder arthroplasty (rTSA) is a commonly performed procedure to treat degenerative conditions of the shoulder. With its growing utilization, techniques to reliably diagnose and treat prosthetic joint infection (PJI) have become increasingly important. In this review we outline the current research and prevention methods of prosthetic joint infection in rTSA. This includes preoperative considerations, intraoperative, and postoperative treatment algorithms.

RECENT FINDINGS

There is currently no established standardized protocol for preoperative infection prevention or post operative management. However, recent studies have identified risk factors for infection, as well as successful prevention techniques that can be implemented to minimize infection risk. Although there is no standardized protocol currently utilized to diagnose and treat shoulder PJI, we outline a potential set of preventative measures and postoperative management strategies that clinicians can use to properly diagnose and treat patients with this difficult condition.

Impact of accumulating risk factors on the incidence of dislocation after primary reverse total shoulder arthroplasty using a medial glenoid-lateral humerus onlay prosthesis

BACKGROUND

The aim of this study was to facilitate preoperative identification of patients at risk for dislocation after reverse total shoulder arthroplasty (rTSA) using the Equinoxe rTSA prosthesis (medialized glenoid, lateralized onlay humerus with a 145° neck-shaft angle) and quantify the impact of accumulating risk factors on the occurrence of dislocation.

METHODS

We retrospectively analyzed 10,023 primary rTSA patients from an international multicenter database of a single platform shoulder prosthesis and quantified the dislocation rate associated with multiple combinations of previously identified risk factors. To adapt our statistical results for prospective identification of patients most at-risk for dislocation, we stratified our data set by multiple risk factor combinations and calculated the odds ratio for each cohort to quantify the impact of accumulating risk factors on dislocation.

RESULTS

Of the 10,023 primary rTSA patients, 136 (52 female, 83 male, 1 unknown) were reported to have a dislocation for a rate of 1.4%. Patients with zero risk factors were rare, where only 12.7% of patients (1268 of 10,023) had no risk factors, and only 0.5% of these (6 of 1268) had a report of dislocation. The dislocation rate increased in patient cohorts with an increasing number of risk factors. Specifically, the dislocation rate increased from 0.9% for a patient cohort with 1 risk factor to 1.0% for 2 risk factors, 1.6% for 3 risk factors, 2.7% for 4 risk factors, 5.3% for 5 risk factors, and 7.3% for 6 risk factors. Stratifying dislocation rate by multiple risk factor combinations identified numerous cohorts with either an elevated risk or a diminished risk for dislocation.

DISCUSSION

This multicenter study of 10,023 rTSA patients demonstrated that 1.4% of the patients experienced dislocation with one specific medialized glenoid-lateralized humerus onlay rTSA prosthesis. Stratifying patients by multiple combinations of risk factors demonstrated the impact of accumulating risk factors on the incidence of dislocation. rTSA patients with the greatest risk of dislocation were those of male sex, age ≤67 years at the time of surgery, patients with body mass index ≥31, patients who received cemented humeral stems, patients who received glenospheres having a diameter >40 mm, and/or patients who received expanded or laterally offset glenospheres. Patients with these risk factors who are considering rTSA using a medial glenoid-lateral humerus should be made aware of their elevated dislocation risk profile.

Operative treatment of acromial and scapular spine fracture nonunions complicating reverse total shoulder arthroplasty

BACKGROUND

Fractures of the acromion and spine can have a major impact on the outcome of reverse shoulder arthroplasty (RSA) with respect to pain, motion, and function. Reports on internal fixation for these fractures are isolated to small series or case reports with variable outcomes. The purpose of this study was to report on the outcome of open reduction and internal fixation (ORIF) of acromion or spine fractures encountered before or after RSA and describes our evolution of fixation techniques.

METHODS

Between 2011 and 2023, 22 fractures or nonunions of the acromion or spine of the scapula underwent ORIF at a single institution and were followed for a minimum of 1 year. In 16 shoulders, fractures occurred after RSA, whereas 5 shoulders underwent ORIF prior to RSA. One shoulder had undergone prior failed ORIF elsewhere and revision ORIF was performed at our institution. There were 10 males and 12 females with a mean age of 67 (SD = 15.1) years. Fixation strategies included single (n = 11) and double plate fixation (n = 11). Kruskal-Wallis one-way analyses of variance were used to analyze continuous variables and Chi-square tests employed for categorical variables.

RESULTS

Of the 5 fractures treated with ORIF pre-RSA, 1 shoulder suffered an additional fracture medial to the hardware and 1 required additional bone grafting for incomplete union at the time of RSA. These 5 shoulders all underwent RSA uneventfully, but 1 fracture experienced late displacement of the scapular spine nonunion, leading to plate removal. Of the 16 post-RSA ORIF shoulders, radiographic union was confirmed in 14 and substantial residual inferior angulation identified in 3. New fractures occurred after ORIF in 5 shoulders. For patients who underwent ORIF after RSA, pain scores improved from a mean of 8 to 1.9 points, with more modest elevation gains (58.2°-91.3° pre and postoperatively, respectively).

CONCLUSIONS

ORIF of acromion and scapular spine fractures or nonunions in the setting of RSA have the potential to lead to union. When these fractures and nonunions are encountered prior to RSA, ORIF allows for uneventful RSA implantation, but secondary displacement may occur. ORIF seems to lead to improvements in pain, but more modest improvements in motion and function. Our fixation strategy has evolved to (1) dual plating, (2) spanning the whole length of the spine with 1 of the plates, (3) use of hook features under the acromion or os trigonum if possible, and (4) liberal use of bone graft.

Does glenoid inclination affect the anterior stability of reverse total shoulder arthroplasty? A biomechanical study

PURPOSE

The anterior stability of reverse total shoulder arthroplasty is affected by multiple factors. However, the effect of glenosphere inclination on stability has rarely been investigated, which is what this study aims to look into.

METHODS

Reverse shoulder arthroplasty was performed on 15 cadaveric human shoulders. The anterior dislocation forces and range of motion in internal rotation in the glenohumeral joint (primary measured parameters) were tested in a shoulder simulator in different arm positions and implant configurations, as well as with a custom-made 10° inferiorly inclined glenosphere. The inclination and retroversion of the baseplate as well as the distance between the glenoid and coracoid tip in two planes (secondary measured parameters) were evaluated on CT scans.

RESULTS

In biomechanical testing, the custom-made inclined glenosphere showed no significant influence on anterior stability other than glenoid lateralisation over all arm positions as well as the neck-shaft angle in two arm positions. The 6 mm lateralised glenosphere reduced internal rotation at 30° and 60° of glenohumeral abduction. In 30° of glenohumeral abduction, joint stability was increased using the 155° epiphysis compared with the 145° epiphysis. The mean inclination was 16.1°. The inclination was positively, and the distance between the glenoid and coracoid tip in the anterior-to-posterior direction was negatively correlated with anterior dislocation forces.

CONCLUSIONS

The custom-made inferiorly inclined glenosphere did not influence anterior stability, but baseplate inclination itself had a significant effect on stability.

Radial and median nerves distal peripheral tension after reverse shoulder arthroplasty: a cadaveric study

Background

Peripheral nerve injury is a recognized complication after reverse shoulder arthroplasty (RSA) that has mainly been studied at the level of the brachial plexus and its proximal branches. However, the impact of RSA on distal peripheral nerves and the influence of elbow and wrist position is not known. This cadaveric study aimed to analyze the effect of RSA implantation and upper limb position on tension in the distal median and radial nerves. The hypothesis was that RSA increased distal nerve tension, which could be further affected by elbow and wrist position.

Methods

12 upper limbs in 9 full fresh-frozen cadavers were dissected. Nerve tension was measured in the median nerve at the level of the proximal arm, elbow, and distal forearm, and in the radial nerve at the level of the elbow, using a customized three-point tensiometer. Measurements were carried out before and after RSA implantation, using a semi-inlay implant (Medacta, Castel San Pietro, Switzerland). Two different configurations were tested, using the smallest and largest available implant sizes. Three upper-limb key positions were considered (plexus at risk, plexus relief, and neutral), from which the effect of elbow and wrist position was further tested.

Results

RSA implantation significantly increased median and radial nerve tension throughout the upper limb. The distal nerve segments were particularly dependent on elbow and wrist position. The plexus at risk position induced the most tension in all nerve segments, especially with the large implant configuration. On the other hand, the plexus relief position induced the least amount of tension. Flexing the elbow was the most efficient way to decrease nerve tension in all tested nerve segments and key positions. Wrist flexion significantly decreased nerve tension in the median nerve, whereas wrist extension decreased tension in the radial nerve.

Conclusion

RSA significantly increases tension in the median and radial nerves and makes them more susceptible to wrist and elbow positioning. The mechanism behind distal peripheral neuropathy after RSA may thus result from increased compression of tensioned nerves against anatomical fulcrums rather than nerve elongation alone. Elbow flexion was the most effective way to decrease nerve tension, while elbow extension should be avoided when implanting the humeral component. Further studies are needed to assess the ulnar nerve.

Clinical Outcomes Do Not Deteriorate Over Time Following Primary Reverse Total Shoulder Arthroplasty: Minimum 10-Year Follow-up of 135 Shoulders

Background

Reverse total shoulder arthroplasty (RTSA) offers satisfactory mid-term outcomes for a variety of pathologies, but long-term follow-up data are limited. This study demonstrates the long-term clinical and radiographic outcomes as well as the predictive factors for an inferior outcome following RTSA.

Methods

Using the prospective database of a single, tertiary referral center, we included all primary RTSAs that were performed during the study period and had a minimum 10-year follow-up. Clinical outcomes included the absolute Constant-Murley score (CS), relative CS, Subjective Shoulder Value (SSV), range of motion, pain, complication rate, and reintervention rate. Radiographic measurements included the critical shoulder angle (CSA), lateralization shoulder angle (LSA), distalization shoulder angle (DSA), reverse shoulder angle (RSA), acromiohumeral distance (ACHD), center of rotation, glenoid component height, notching, radiolucent lines, heterotopic ossification, and tuberosity resorption.

Results

A total of 135 shoulders (133 patients) were available for analysis at a mean follow-up of 10.9 ± 1.6 years. The mean age was 69 ± 8 years, and 76 shoulders (76 patients; 56%) were female. For most of the clinical outcomes, initial improvements were observed in the short term and were sustained in the long term without notable deterioration, with >10-year follow-up values of 64 ± 16 for the absolute CS, 79% ± 18% for the relative CS, 79% ± 21% for the SSV, and 14 ± 3 for the CS for pain. However, after initial improvement, deterioration was seen for flexion and external rotation, with values of 117° ± 26° and 25° ± 18°, respectively, at the final follow-up. Scapular notching, heterotopic ossification, and radiolucent lines of <2 mm progressed during the study period. Younger age (p = 0.040), grade-II notching (p = 0.048), tuberosity resorption (p = 0.015), and radiolucent lines of <2 mm around the glenoid (p = 0.015) were predictive of an inferior outcome. The complication rate was 28%, with a reintervention rate of 11%.

Conclusions

RTSA provided improved long-term results that did not significantly deteriorate over time for most of the clinical parameters. Negative clinical outcome predictors were younger age, grade-II notching, tuberosity resorption, and radiolucent lines of <2 mm around the glenoid.

Level of Evidence

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

Postoperative revision, complication and economic outcomes of patients with reverse or anatomic total shoulder arthroplasty at one year: a retrospective, United States hospital billing database analysis

BACKGROUND

Data on the 1-year postoperative revision, complication, and economic outcomes in a hospital setting after total shoulder arthroplasty (TSA) are sparse.

METHODS

A retrospective cohort study using the Premier Healthcare Database, a hospital-billing data source, evaluated 1-year postoperative revision, complication, and economic outcomes of reverse (RTSA) and anatomic (ATSA) TSA for patients who underwent the procedure from 2015 until 2021. All-cause revisits, including revision-related events (categorized as either irrigation and débridement or revision procedures and device removals) and shoulder/nonshoulder complications were collected. The incidences and costs of these revisits were evaluated. Generalized linear models were used to evaluate the associations between patient characteristics and revision and complication occurrences and costs.

RESULTS

Among 51,478 RTSA and 34,623 ATSA patients (mean [standard deviation] ages RTSA 71.5 [8.1] years, ATSA 66.8 [9.0] years), 1-year adjusted incidences of all-cause revisits, irrigation/débridement, revision procedures/device removals, and shoulder/nonshoulder complications were RTSA: 45.0% (95% confidence interval (CI): 44.6%-45.5%), 0.1% (95% CI: 0.1%-0.2%), 2.1% (95% CI: 2.0%-2.2%), and 17.8% (95% CI: 17.5%-18.1%) and ATSA: 42.3% (95% CI: 41.8%-42.9%), 0.2% (95% CI: 0.1%-0.2%), 1.9% (95% CI: 1.8%-2.1%), and 14.4% (95% CI: 14.0%-14.8%), respectively; shoulder-related complications were RTSA: 12.4% (95% CI: 12.1%-12.7%) and ATSA: 9.9% (95% CI: 9.6%-10.3%). Significant factors associated with a high risk of revisions and complications included, but were not limited to, chronic comorbidities and noncommercial insurance. Per patient, the mean (standard deviations) total 1-year hospital cost was $25,225 ($15,911) and $21,520 ($13,531) for RTSA and ATSA, respectively. Revision procedures and device removals were most costly, averaging $22,920 ($18,652) and $26,911 ($18,619) per procedure for RTSA and ATSA, respectively. Patients with revision-related events with infections had higher total hospital costs than patients without this event (RTSA: $60,887 (95% CI: $56,951-$64,823) and ATSA: $59,478 (95% CI: $52,312-$66,644)), equating to a mean difference of $36,148 with RTSA and $38,426 with ATSA. Significant factors associated with higher costs of revision-related events and complications included age, race, chronic comorbidities, and noncommercial insurance.

CONCLUSIONS

Nearly 45% RTSA and 42% ATSA patients returned to the hospital, most often for shoulder/nonshoulder complications (overall 17.8% RTSA and 14.4% ATSA, and shoulder-related 12.4% RTSA and 9.9% ATSA). Revisions and device removals were most expensive ($22,920 RTSA and $26,911 ATSA). Infection complications requiring revision had the highest 1-year hospital costs (∼$60,000). This study highlights the need for technologies and surgical techniques that may help reduce TSA health care utilization and economic burden.

Glenoid structural bone grafting in reverse total shoulder arthroplasty: clinical and radiographic outcomes

BACKGROUND

Current options for reconstruction of large glenoid defects in reverse total shoulder arthroplasty (RTSA) include structural bone grafting, use of augmented components, or 3D-printed custom implants. Given the paucity in the literature on structural bone grafts in RTSA, this study reflects our experience on clinical and radiographic outcomes of structural bone grafts used for glenoid defects in RTSA.

METHODS

We identified 33 consecutive patients who underwent RTSA using structural bone grafts for glenoid bone loss between 2008 and 2019. Twenty-six patients with a mean clinical follow-up of 4.4 ± 3.9 years and a mean radiographic follow-up of 2.7 ± 3.2 years were included. Patient demographic data, perioperative functional outcomes, radiographic outcomes, complications, and reoperation rates were determined.

RESULTS

Between 2008 and 2019, 26 RTSAs were performed using structural autograft or allograft for glenoid defects. There were 20 females (77%) and 6 males (23%), with a mean presenting age of 68 years (range 41-86), mean BMI of 29 (range 21-44), and mean Charlson Comorbidity Index of 3 (range 0-8). There were 19 cases of central glenoid defects, and 7 were combined central and peripheral defects. Structural grafts included humeral head autograft (7), proximal humerus autograft (7), iliac crest autograft (7), distal clavicle autograft (2), and femoral head allograft (3). All 18 revision RTSA cases had simultaneous humeral-sided revision. There was significant postoperative improvement in American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form scores (27.0 ± 12.6 preoperation vs. 59.8 ± 24.1 postoperation; P < .001) and visual analog scale scores (8.1 ± 3.6 preoperation vs. 3.0 ± 3.2 postoperation; P < .001). Range of motion improved significantly for active forward elevation (63° ± 36° preoperation vs. 104° ± 36° postoperation; P < .001) and external rotation (21° ± 20° preoperation vs. 32° ± 23° postoperation, P = .036). Eighty-eight percent of cases (23 of 26) had successful reconstruction of the glenoid, defined as no visible radiolucent lines nor glenoid component migration at final follow-up. The reoperation rate was 19% (5 of 26). Postoperative complications included 2 cases of acromial stress fractures that were treated nonoperatively, for a total complication rate (including reoperation) of 27% (7 of 26 cases).

CONCLUSIONS

The use of structural bone autografts and allografts in RTSA was associated with improved outcome scores and range of motion. A reoperation rate of 19% and total complication rate of 27% were reported for these challenging cases. However, 86% of these complications were not related to structural glenoid reconstruction failure. Structural grafts are a reasonable option for glenoid reconstruction in RTSA cases with glenoid bone loss.

Does prior rotator cuff surgery influence the outcomes and complications after reverse total shoulder arthroplasty in patients with cuff tear arthropathy or massive rotator cuff tear? A propensity score-matched study

BACKGROUND

The aim of this study was to compare outcomes and complications in patients with and without a history of prior rotator cuff surgery who underwent reverse total shoulder arthroplasty (RTSA).

METHODS

Two-hundred and nine consecutive patients who had undergone RTSA for rotator cuff insufficiency with a minimum 12-months follow-up period were reviewed. A total of 35 patients with a history of prior rotator cuff surgery were made the study group (PS group). Using propensity score matching for age and sex, these patients were matched 1:3 with a control group of 105 patients with no history of prior surgery (NPS group). The mean follow-up period was 41.4 months.

RESULTS

Both groups showed a significant improvement of clinical scores and range of motion after RTSA. The PS group showed a significantly higher final visual analog scale (VAS) pain score compared with the NPS group (P = 0.020). The PS group showed a significantly higher incidence of acromial stress fracture compared with the NPS group (17.1% vs 4.8%, P = 0.018), but no significant difference in the overall complication rate was observed (25.7% vs 13.3%, P > 0.05). The PS group showed a significantly higher reoperation rate compared with the NPS group (14.3% vs 1.9%, P = 0.004).

CONCLUSIONS

Our study demonstrated that a history of prior rotator cuff surgery was associated with a high incidence of acromial stress fracture and reoperation after RTSA as well as a high final VAS pain score, although satisfactory clinical outcomes after RTSA were achieved in both groups.

Navigated augmented reality through a head-mounted display leads to low deviation between planned, intra- and postoperative parameters during glenoid component placement of reverse shoulder arthroplasty: a proof-of-concept case series

BACKGROUND

Navigated augmented reality (AR) through a head-mounted display (HMD) has led to accurate glenoid component placement in reverse shoulder arthroplasty (RSA) in an in-vitro setting. The purpose of this study is to evaluate the deviation between planned, intraoperative, and postoperative inclination, retroversion, entry point, and depth of the glenoid component placement during RSA, assisted by navigated AR through an HMD, in a surgical setting.

METHODS

A prospective, multicenter study was conducted. All consecutive patients undergoing RSA in 2 institutions, between August 2021 and January 2023, were considered potentially eligible for inclusion in the study. Inclusion criteria were as follows: age >18 years, surgery assisted by AR through an HMD, and postoperative computed tomography (CT) scans at 6 weeks. All participants agreed to participate in the study and informed consent was provided in all cases. Preoperative CT scans were undertaken for all cases and used for 3-dimensional (3D) planning. Intraoperatively, glenoid preparation and component placement were assisted by a navigated AR system through an HMD in all patients. Intraoperative parameters were recorded by the system. A postoperative CT scan was undertaken at 6 weeks, and 3D reconstruction was performed to obtain postoperative parameters. The deviation between planned, intraoperative, and postoperative inclination, retroversion, entry point, and depth of the glenoid component placement was calculated. Outliers were defined as >5° for inclination and retroversion and >5 mm for entry point.

RESULTS

Seventeen patients (9 females, 12 right shoulders) with a mean age of 72.8 ± 9.1 years (range, 47.0-82.0) met inclusion criteria. The mean deviation between intra- and postoperative measurements was 1.5° ± 1.0° (range, 0.0°-3.0°) for inclination, 2.8° ± 1.5° (range, 1.0°-4.5°) for retroversion, 1.8 ± 1.0 mm (range, 0.7-3.0 mm) for entry point, and 1.9 ± 1.9 mm (range, 0.0-4.5 mm) for depth. The mean deviation between planned and postoperative values was 2.5° ± 3.2° (range, 0.0°-11.0°) for inclination, 3.4° ± 4.6° (range, 0.0°-18.0°) for retroversion, 2.0 ± 2.5 mm (range, 0.0°-9.7°) for entry point, and 1.3 ± 1.6 mm (range, 1.3-4.5 mm) for depth. There were no outliers between intra- and postoperative values and there were 3 outliers between planned and postoperative values. The mean time (minutes : seconds) for the tracker unit placement and the scapula registration was 03:02 (range, 01:48 to 04:26) and 08:16 (range, 02:09 to 17:58), respectively.

CONCLUSION

The use of a navigated AR system through an HMD in RSA led to low deviations between planned, intraoperative, and postoperative parameters for glenoid component placement.

Inlay vs. onlay humeral components in reverse total shoulder arthroplasty: a biorobotic shoulder simulator study

BACKGROUND

Both inlay and onlay humeral implants are available for reverse total shoulder arthroplasty (rTSA), but biomechanical data comparing these components remain limited. This study investigated the effects of inlay and onlay rTSA humeral components on shoulder biomechanics using a biorobotic shoulder simulator.

METHODS

Twenty fresh-frozen cadaveric shoulders were tested before and after rTSA with either an inlay or onlay humeral implant. Comparisons were performed between the most commonly implanted configurations for each implant (baseline) and with a modification to provide equivalent neck-shaft angles (NSAs) for the inlay and onlay configurations. Specimens underwent passive range-of-motion (ROM) assessment with the scapula held static, and scapular-plane abduction was performed, driven by previously collected human-subject scapulothoracic and glenohumeral kinematics. Passive ROM glenohumeral joint angles were compared using t tests, whereas muscle force and excursion data during scapular-plane elevation were evaluated with statistical parametric mapping and t tests.

RESULTS

Maximum passive elevation was reduced for the inlay vs. onlay humeral components, although both implants caused reduced passive elevation vs. the native joint. Inlay rTSA also demonstrated reduced passive internal rotation at rest and increased external rotation at 90° of humerothoracic elevation vs. the native joint. All preoperative planning estimates of ROM differed from experiments. Rotator cuff forces were elevated with an onlay vs. inlay humeral implant, but simulated muscle excursions did not differ between systems. Compared with the native joint, rotator cuff forces were increased for both inlay and onlay implants and deltoid forces were reduced for inlay implants. Muscle excursions were dramatically altered by rTSA vs. the native joint. Comparisons of inlay and onlay humeral implants with equivalent NSAs were consistent with the baseline comparisons.

CONCLUSIONS

Rotator cuff forces required to perform scapular-plane abduction increase following rTSA using both inlay and onlay implants. Rotator cuff forces are lower with inlay implants compared with onlay implants, although inlay implants also result in reduced passive-elevation ROM. Deltoid forces are lower with inlay implants in comparison to the native joint but not with onlay implants. The differences between inlay and onlay components are largely unaffected by NSA, indicating that these differences are inherent to the inlay and onlay designs. In those patients with an intact rotator cuff, decreased rotator cuff forces to perform abduction with an inlay humeral implant compared with an onlay implant may promote improved long-term outcomes owing to reduced deltoid muscle fatigue when using an inlay implant.

Reverse total shoulder replacement for patients with "weight-bearing" shoulders

BACKGROUND

Reverse total shoulder arthroplasty (rTSA) has gained popularity in recent years and is indicated for a wide variety of shoulder pathologies. However, use of rTSA in patients with "weight-bearing" shoulders that support wheelchair use or crutches has higher risk. The aim of this study was to assess the results of rTSA in such patients.

METHODS

Between 2005 and 2014, 24 patients (30 shoulders) with weight-bearing shoulders were treated with rTSA at our unit. Patients had cuff arthropathy (n=21), rheumatoid arthritis (n=3), osteoarthritis (n=1), acute fracture (n=3), or fracture sequela (n=2). Postoperatively, patients were advised not to push themselves up and out of their wheelchair for 6 weeks. This study was performed in 2016, and 21 patients (27 shoulders) were available for a mean follow-up of 5.6 years (range, 2-10 years). The mean age at surgery was 78 years (range, 54-90 years).

RESULTS

Constant-Murley score improved from 9.4 preoperatively to 59.8 at the final follow-up (P=0.001). Pain score improved from 2/15 to 13.8/15 (P=0.001). Patient satisfaction (Subjective Shoulder Value) improved from 0.6/10 to 8.7/10 (P=0.001). Significant improvement in mean range of motion from 46° to 130° of elevation, 14° to 35° of external rotation, and 29° to 78° internal rotation was recorded (P=0.001). Final mean Activities of Daily Living External and Internal Rotation was 32.4/36. Only three patients showed Sirveaux-Nerot grade-1 (10%) glenoid notching and three grade 2 (10%).

CONCLUSIONS

rTSA can be used for treatment of patients with weight-bearing shoulders. Such patients reported pain free movement, resumed daily activities, and high satisfaction rates. Level of evidence: IV.

Shoulder Arthroplasty: A Bibliometric Analysis Using the Scopus Database

Primary joint replacements are performed increasingly often worldwide, driven by an aging population, improvement in surgical techniques, and advancements in implant designs. While more attention has traditionally been focused on weight-bearing joints such as the hip and knee, shoulder replacement surgeries have gained increasing attention in recent years due to the population's demand for a better quality of life. Thus far, a comprehensive bibliometric analysis of shoulder arthroplasty-related publications using the Scopus database has not yet been conducted. This bibliometric analysis aims to fill this gap by reviewing the Scopus database from its inception until 2023 to examine the literature on shoulder arthroplasty. A total of 5300 publications meeting the selection criteria were included in this analysis. The turn of the century marked a significant turning point for the field of shoulder arthroplasty, with an increasing number of publications produced annually. This trend can be attributed to the improvement of implant designs, which have become more consistent and reliable over time. While the majority of articles were authored by researchers and clinicians from the United States of America (USA), publications by French authors had a higher scholarly impact in the field. There is a noticeable gap in research on shoulder arthroplasty in developing countries, possibly due to the prohibitively high cost of implants and the prioritization of other healthcare sectors. This bibliometric analysis, utilizing Scopus data, serves as a guiding light for researchers, clinicians, and policymakers, potentially fostering collaborative projects and guiding the development of future studies to further advance the field of shoulder arthroplasty, particularly in developing countries.

Periprosthetic proximal humerus fractures require an individualized treatment approach-results of a multicenter retrospective study

BACKGROUND

In the last years, there has been increasing use of shoulder arthroplasty. As a result, an increasing incidence of periprosthetic humerus fractures (PPHF) is expected. Therefore, this retrospective, multicenter analysis aimed to collect demographic data from patients with PPHF, their treatment strategies, and associated complications.

METHODS

Demographics of patients with PPHF were collected retrospectively from the database of six trauma hospitals between January 2000 and December 2020. All fractures were categorized according to the Wright and Cofield, and Worland classifications. In addition, the type of treatment for PPHF, as well as subsequent complications, were evaluated.

RESULTS

A total of 72 patients with a PPHF were identified. The mean age of the 55 female and 17 male patients was 77 years. PPHF occurred a mean of 50 months after primary arthroplasty implantation, almost exclusively as a result of a fall from standing height (n = 67). In-situ implant was a RTSA in 40 patients and a hemiarthroplasty in 32 patients. More than half of the fractures (n = 38) were type B fractures, according to Wright and Cofield. According to Worland, the majority of patients also had a type B fracture (type B1 (n = 22), type B2 (n = 28), type B3 (n = 10)). Associated comorbidities were found in 21 patients. A total of 31 patients were treated non-operatively, 27 with Open Reduction Internal Fixation (ORIF), and 14 with a revision arthroplasty. Nine primary radial nerve palsies were found (pre-operatively), and seven secondarily (post-operatively). Nine patients suffered from non-union (ORIF 4, non operative 4, stem replacement 1).

CONCLUSION

The treatment strategy for PPHF is primarily tailored to the individual patient. Decisive factors such as patient's age, fracture type, and primary palsies have to be considered for optimal treatment. In type B1 fractures, there is a recommendation for ORIF because of high non-union rates under non-operative treatment. In contrast, in type B2 fractures, a non-operative approach should be preferred, provided there are no radial nerve lesions.

LEVEL OF EVIDENCE

Level IV, epidemiologic study.

Inverted-bearing reverse shoulder arthroplasty: long-term survivorship, complications, clinical, and radiological outcomes

BACKGROUND

Inverted-bearing reverse shoulder arthroplasty (IB-RSA) is characterized by a polyethylene glenosphere and a metallic humeral liner to minimize polyethylene wear and debris secondary to impingement between the humerus and glenoid neck. IB-RSA long-term survivorship, complication and revision rates, as well as clinical and radiographic outcomes have not been reported yet.

METHODS

This is a monocentric retrospective study on a consecutive series of 151 patients who underwent primary IB-RSA from January 2009 to September 2015 and were evaluated clinically and radiologically at the minimum 8-year follow-up. All complications and reoperations were recorded. Survivorship analysis with any revision surgery as endpoint was done using Kaplan-Meier survival curves.

RESULTS

Seventy-eight patients (follow-up rate 51.7%) were reviewed at a mean follow-up of 10.1 ± 1.9 years. At 10 years, the revision-free survival was 98.7% (95% confidence interval: 94.8-99.7). Sixteen complications (10.6%) were observed: 2 axillary nerve injuries, 2 infections, 2 glenoid loosening (which stabilized within 1 year), 2 cases of otherwise unexplained painful stiffness, 4 acromial fractures, 1 post-traumatic scapular pillar fracture, and 3 post-traumatic humeral periprosthetic fractures. Two patients were revised due to infection. No cases of late glenoid loosening and humeral loosening were observed. The revision rate was 1.3%. All the clinical scores and range of motion significantly improved at the last follow-up compared with preoperative status: final Constant score was 66.1 ± 17.4, Subjective Shoulder Value 79.1 ± 20.9, and the American Shoulder and Elbow Surgeons 82.2 ± 17.7. Scapular notching was observed in 51.4% of patients: only 1 case of grade 3 notching was observed in an early glenoid subsidence case.

CONCLUSIONS

Primary IB-RSA appears to be a safe and effective procedure and does not present specific implant-associated complications at long-term follow-up. Radiographic analysis showed that inverting the biomaterials leads to a distinct kind of notching with mainly mechanical features.

No difference in 10-year survivorship of total shoulder arthroplasty vs. hemiarthroplasty for avascular necrosis of the humeral head

BACKGROUND

Avascular necrosis (AVN) of the humeral head is characterized by osteonecrosis secondary to disrupted blood flow to the glenohumeral joint. Following collapse of the humeral head, arthroplasty, namely, total shoulder arthroplasty (TSA) or humeral head arthroplasty (hemiarthroplasty), is recommended standard of care. The literature is limited to underpowered and small sample sizes in comparing arthroplasty modalities. Therefore, the aims of this study were (1) to compare the 10-year survivorship of TSA and hemiarthroplasty in the treatment of AVN of the humeral head and (2) to identify differences in their revision etiologies.

METHODS

Patients who underwent primary TSA and hemiarthroplasty for AVN were identified using the PearlDiver database. TSA patients were matched by age, gender, and Charlson Comorbidity Index (CCI) to the hemiarthroplasty cohort in a 4:1 ratio because TSA patients were generally older, sicker, and more often female. The 10-year cumulative incidence rate of all-cause revision was determined using Kaplan-Meier survival analysis. Multivariable analysis was conducted using Cox proportional hazard modeling. χ2 analysis was conducted to compare the indications for revisions between matched cohorts including periprosthetic joint infection (PJI), dislocation, mechanical loosening, broken implants, periprosthetic fracture, and stiffness.

RESULTS

In total, 4825 patients undergoing TSA and 1969 patients undergoing hemiarthroplasty for AVN were included in this study. The unmatched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 7.0% and 7.7%, respectively. The matched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 6.7% and 8.0%, respectively. When comparing the unmatched cohorts, TSA patients were at significantly higher risk of 10-year all-cause revision (HR: 1.39; P = .017) when compared to hemiarthroplasty patients. After matching, there was no significant difference in risk of 10-year all-cause revision (HR: 1.29; P = .148) and no difference in the observed etiologies for revision (P > .05 for all).

CONCLUSION

After controlling for confounders, only 6.7% of TSA and 8.0% hemiarthroplasties for humeral head AVN were revised within 10 years of index surgery. The demonstrated high and comparable long-term survivorship for both modalities supports the utilization of either for the AVN induced humeral head collapse.

Do the humeral radiographic changes at 5-year follow-up affect the clinical outcomes of press-fit humeral stems in primary reverse shoulder arthroplasties?

INTRODUCTION

The purposes of this study were to analyze and compare the functional outcomes and radiological changes around the press-fit humeral components in two contemporary medialized reverse total shoulder arthroplasty (RTSA) systems at a minimum of 5-year follow-up.

MATERIALS AND METHODS

Between December 2003 and December 2015, 249 consecutive RTSAs were performed at our hospital. Of these, 68 primary uncemented RTSA met our inclusion criteria. The Constant-Murley score (CMS), the modified Constant score, a visual analog scale (VAS) and active shoulder range of motion (ROM) were measured pre- and postoperatively. Radiological assessment was performed by plain radiographs at a minimum of 5 years postoperatively.

RESULTS

At a mean follow-up of 80.2 months, there was no significant difference (p = .59) between the postoperative functional scores and range of motion of the two groups (Delta Xtend and Lima SMR). Radiological data of stress-shielding were observed in 38 patients (55.9%) being slightly more frequent in the Lima SMR group (21 patients) than in the Delta Xtend group (17 patients) (p = .62).

CONCLUSIONS

Our study shows that the good functional results are similar between the two uncemented RTSA systems used and that they do not depend on the presence of radiological changes (stress-shielding) in the humeral stem at a minimum 5-year follow-up.

Converting to reverse shoulder arthroplasty from primary anatomic shoulder arthroplasty and fracture hemiarthroplasty: a radiographic and clinical outcome analysis at 8-years

INTRODUCTION

Revision shoulder arthroplasty can be challenging. One of the main considerations for surgeons is the type of implant that was placed in the initial surgery. Anatomic shoulder arthroplasty (ASA) is used for cases of osteoarthritis as well as for fractures of the humeral head. Hemiarthroplasty can be used for complex proximal humerus fractures. The purpose of this study is to determine whether there is a difference in clinical and radiographic outcomes between patients that failed primary fracture hemiarthroplasty (FHA), or ASA for osteoarthritis and then required reoperation with a conversion to reverse shoulder arthroplasty (RSA).

METHODS

Patients with failed anatomic shoulder replacement, who had undergone conversion to RSA, were enrolled after a mean follow-up of 107 (85-157) months. Two different groups, one with failed ASA implanted for osteoarthritis and one with failed FHA, were created. At follow-up patients were assessed with standard radiographs and clinical outcome scores.

RESULTS

Twenty-nine patients (f = 17, m = 12; 51%) suffered from a failed ASA (Group A), while the remaining 28 patients (f = 21, m = 74; 49%) had been revised due to a failed FHA (Group B). Patients of Group B had a poorer Constant score (Group A: 60 vs. Group B: 46; p = 0.02). Abduction (Group A: 115° vs. Group B: 89°; p = 0.02) was worse after conversion of a failed FHA to RSA in comparison to conversions of failed ASA. The mean bone loss of the lateral metaphysis was higher in patients with failed FHA (Group A: 5 mm vs. Group B: 20 mm; p = 0.0).

CONCLUSION

The initial indication for anatomic shoulder arthroplasty influences the clinical and radiological outcome after conversion to RSA. Conversion of failed FHA to RSA is related to an increased metaphyseal bone loss, decreased range of motion and poorer clinical outcomes when compared to conversions of failed ASA implanted for osteoarthritis.

LEVEL OF EVIDENCE

III Retrospective Cohort Comparison Study.

Are Lower Passive Anterior Elevation and External Rotation at 6 Weeks Postoperatively Associated With Healing of Isolated Arthroscopic Supraspinatus Repairs?

BACKGROUND

Despite advancements in surgical technique, failure of tendon healing remains a common problem after arthroscopic rotator cuff repair (ARCR).

PURPOSE/HYPOTHESIS

The purpose of this study was to examine the relationship between range of motion (ROM) recovery and healing after ARCR. It was hypothesized that an early loss of ROM would be associated with tendon healing.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This was a retrospective comparative study of primary ARCR of isolated full-thickness supraspinatus (SSN) tendon tears. Cases were retrieved from a prospective rotator cuff repair database and divided into 2 groups based on healing (healed/nonhealed). A standardized clinical evaluation was performed before and at 6 weeks, 3 months, and 6 months after surgery. Collected data included passive and active ROM, visual analog scale for pain, and Constant score. Healing was assessed by ultrasound at 6 months.

RESULTS

Of 1397 eligible ARCRs, 1207 were included. The healing rate was 86.7%. Age was higher in the nonhealed group (57.8 ± 7.9 years vs 61.6 ± 8.8 years; P < .001). Patients with healed repairs had a larger decrease in passive anterior elevation (AE) from the preoperative to the 6-week postoperative visit (-31°± 28° vs -18°± 26°; P < .001), followed by a more substantial increase throughout the remaining follow-up period (32°± 23° vs 18°± 21°; P < .001). At 6 months postoperatively, there was no difference in AE between groups (159°± 17° vs 161°± 14°; P > .999). External rotation elbow at side (ER1) and internal rotation hand in the back (IR1) followed similar courses of recovery. Passive and active ROM had a strong positive correlation at each follow-up. Age (odds ratio [OR], 1.79; 95% CI, 1.45-2.23; P < .001) and 6-week passive AE (OR, 1.33; 95% CI, 1.20-1.48; P < .001) and ER1 (OR, 1.15; 95% CI, 1.03-1.29; P = .017) were predictors for nonhealing.

CONCLUSION

Lower passive AE and ER1 at 6 weeks postoperatively and younger age are associated with healing after ARCR of isolated SSN tendon tears. At 6 months postoperatively, there were no differences in ROM, regardless of tendon healing.

The role of hypertensive status in the preoperative patient selection of TSA

Background

This study investigates the relationship between hypertension and postoperative complications following total shoulder arthroplasty (TSA).

Methods

All patients who underwent TSA between 2015 and 2020 from the American College of Surgeons National Surgical Quality Improvement database were surveyed. The study population was divided into patients with no hypertension and patients with hypertension. Patient demographics, comorbidities, and 30-day postoperative complications were collected. Logistic regression analysis was used to investigate the relationship between hypertension and postoperative complications.

Results

Compared to no hypertension, hypertension was significantly associated with an increased likelihood of experiencing sepsis (P = .021), pneumonia (P = .019), myocardial infarction (P = .038), blood transfusions (P = .006), readmission (P < .001), reoperation (P < .001), non-home discharge (P < .001), and any complication (P < .001). After accounting for significant patient variables, compared to no hypertension, hypertension was independently significantly associated with an increased likelihood of experiencing reoperation (odds ratio 1.48; 95% CI, 1.142-1.905; P = .003) and any complication (odds ratio 1.10; 95% CI, 1.008-1.205; P = .033).

Conclusion

In this study, we identified hypertension as an independent significant predictor for both reoperation and any complication following TSA. This study provides evidence for incorporating a patient's hypertensive status into preoperative screening, aiming to improve surgical candidate selection and surgical outcomes following TSA.

Preoperative Risk Factors for Pain After Reverse Total Shoulder Arthroplasty: A Systematic Review

Despite being a generally successful procedure, pain following reverse total shoulder arthroplasty (rTSA) is a known complication. The aim of this systematic review is to identify preoperative risk factors for pain following rTSA to encourage evidence-based interventions, inform clinicians, and aid in surgical planning. Studies that reported preoperative risk factors and pain after rTSA were included. Studies which reported outcome measures that incorporated pain scores yet did not display them independently, studies which only reported intraoperative risk factors, and studies involving participants under 18 were excluded. The search was conducted on May 31, 2023, across the following databases: PubMed, Web of Science, Embase, Scopus, and Cochrane Central Register of Controlled Trials. Four independent researchers conducted this systematic review, and a descriptive analysis was subsequently performed. Twenty-five studies were included following the evaluation of full-text articles, involving a total of 9,470 shoulders. Preoperative risk factors identified were categorised into the following groups: BMI, smoking, radiographic findings, age and sex, prior surgery, functional ability and pain, and psychosocial. The strongest associations identified were preoperative opioid use and smoking, which were both associated with worse pain outcomes following rTSA; other preoperative risk factors highlighted in this review showed either weak or no correlation. Preoperative opioid use and smoking are likely risk factors for the development of pain after rTSA. Although the studies included varying levels of quality, the identification of modifiable risk factors is useful in optimising management prior to surgery and guiding patient expectations. The lack of evidence regarding associations with non-modifiable risk factors further reinforces the potential benefits of the procedure on diverse population groups and is useful in itself for assessing the candidacy of patients for the procedure, particularly when postoperative pain is a factor being considered.

Outcomes following revision reverse shoulder arthroplasty for infection

BACKGROUND

In comparison to primary reverse shoulder arthroplasty (RSA) procedures, revision arthroplasty can be a longer and more complex procedure leading to an increased risk of complications. The reported rates of infection in primary RSA range from 1% to 19% and the cost impact on patients and health care systems is significant, leading to multiple revision surgeries. The purpose of this study was to evaluate the postoperative outcomes, complications, and revision rates for revision reverse shoulder arthroplasty (rRSA) due to infection compared with rRSA for noninfectious causes.

METHODS

Patients who underwent rRSA between 2009 and 2020 by a single fellowship-trained orthopedic surgeon at a single institution were retrospectively identified through a prospectively collected database. Patients were separated into 2 cohorts based on revision diagnosis: (1) rRSA due to infection (rRSAi) and (2) rRSA due to noninfectious causes (rRSAn). Patient-reported outcome scores (PROs), including the Simple Shoulder Test, Constant score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, University of California-Los Angeles shoulder score, Shoulder Arthroplasty Smart score, and active range of motion (ROM) were collected preoperatively and at a minimum 1-year follow-up. Postoperative complications and revision rates were also collected.

RESULTS

A total of 93 patients (n = 19 rRSAi group, n = 74 rRSAn group) with a mean age of 68 years were included in this analysis. All baseline demographics were comparable between groups. No significant differences were found in preoperative or postoperative PROs and ROM between the 2 groups. Postoperative complication rates and revision rates were comparable between the groups.

CONCLUSION

RSA due to infection results in similar patient-reported outcome scores, range of motion, and revision rates when compared to rRSA for noninfectious causes. Our results suggest that despite the unique challenges associated with rRSA for infection, patient outcomes do not differ from cases attributed to noninfectious causes. More efforts are warranted to further validate and contextualize these findings, considering the protentional influence of patient-specific and implant-specific factors.

Low complication rate following reverse total shoulder arthroplasty at 90-days follow-up - A systematic review

IMPORTANCE

As reverse total shoulder arthroplasty (RTSA) has become an increasingly common procedure, rates of post-operative complications leading to potential hospital readmission are of greater importance. No previous systematic reviews have focused exclusively on post-operative complications and mortality rates at 90 days post RTSA.

OBJECTIVES

The purpose of this study was to review complication, readmission, and mortality rates within 90 days post RTSA.

EVIDENCE REVIEW

Two independent reviewers performed a literature search using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines using PubMed, Embase, and Web of Science databases. Only studies reporting on outcomes of RTSA at 90-days follow-up specifically were considered for inclusion.

FINDINGS

Our search included 79,037 shoulders (62.1 ​% female) from a total of 15 studies with an average age of 72.4 ​± ​5.8 years. The overall 90-day re-admission rates were reported in nine studies as 6.1 ​% (4205/69,127) following RTSA. Additionally, a total of five studies reported the overall 90-day mortality rate as 1.1 ​% (19/1733). The overall pooled rate of medical complications was 3.9 ​% (2998/77,826) as reported in 13 studies, at 90-days post-RTSA, with the occurrence of anaemia being the most commonly reported outcomes as 2.9 ​% (1013/34,385) in six studies. The overall rate of surgical complications was 1.1 ​% reported in 13 studies (1327/77,826), with the pooled rate of surgical revisions of 1.5 ​% (607/40,563) at 90-days follow-up. A total of 8, 5, and 3 studies reported rates of dislocation, requirement for closed reduction and glenoid loosening as 0.9 ​% (344/37,995), 0.6 ​% (7/1180), and 0.3 ​% (30/9115) respectively at 90-days following RTSA.

CONCLUSIONS AND RELEVANCE

This study established that the overall rates of mortality and medical and surgical complications are low in the short-term following RTSA, with only 6 ​% of patients requiring re-admission in the first 90 days.

LEVEL OF EVIDENCE

IV - Systematic Review of all levels of evidence.

Tuberosity refixation improves functional outcome following primary reverse shoulder arthroplasty in proximal humeral fracture

INTRODUCTION

The purpose of this prospective study was to examine clinical results of tuberosity refixation in RSA for the treatment of displaced PHF in elderly patients. We hypothesized that tuberosity refixation would increase clinical outcome.

METHODS

In this prospective study, 50 patients were included after receive a primary RSA for complex proximal humeral fracture between March 2013 and December 2015 for follow-up after three, 12 and 24 months. A functional and radiological assessment was performed on the patients.

RESULTS

At final follow-up after a mean period of 25.1 months, data were available for 30 women and 6 men (74% of the included overall study collective) with a mean age of 77 years (range 55-93 years) at time of surgery. The tuberosities were refixated in 74% (n = 37) and in 26% (n = 13) resected. RSA with tuberosity refixation resulted in better clinical shoulder function compared to RSA with non-refixated tuberosities. The data show an external rotation with a significant difference (24.9° vs. 14°, p < 0.05) in favor of participants with refixation. The raw CMS was statistically significant (71.3 vs. 56.3, p < 0.05) after refixation, and SSV was significant improved (82.7% vs. 68%, p < 0.05) in the same group. Among 3 of 50 patients a total of 3 complications occurred with a total of 6% surgical revision.

CONCLUSIONS

In this prospective study, tuberosity refixation as part of fracture treatment using RSA results in better external rotation, subjective assessment of shoulder recovery (measured by SSV and by raw CMS) in elderly patients, compared with tuberosity excision.

LEVEL OF EVIDENCE

II, Prospective comparative study.

Complications and Reinterventions of Reverse Total Shoulder Arthroplasty in a Korean Population: 14-Year Experience in Reverse Shoulder Arthroplasty

Background

There are few reports on the revision or reintervention of reverse total shoulder arthroplasty (RTSA) in South Korea. The purpose of this study was to evaluate the true incidence of complications and reintervention of RTSA and clinical and radiological outcomes based on our 14-year experience in RTSA in a Korean population.

Methods

Between March 2008 and June 2022, 412 consecutive cases of RTSA were performed in 388 patients with an average age of 74.4 years at our institute. Excluding 23 patients lost to follow-up, 365 patients (373 shoulders including 8 bilateral cases) who underwent primary RTSA with more than 6 months of follow-up were enrolled in this study. We evaluated those who had complications or reintervention including revision RTSA for failed RTSA. Patient charts were reviewed, and clinical outcomes including clinical scores, complications, and reintervention and radiologic outcomes were evaluated at the last follow-up.

Results

Among the 373 shoulders that underwent primary RTSA, complications were found in 50 patients (13.94%, 10 men and 40 women with a mean age of 75.9 ± 6.7 years [range, 51-87 years]). The causes of complications were as follows: 13 acromion, coracoid, or scapular spine fractures, 10 loosening (glenoid: 5, humeral stem: 5), 5 infections, 4 periprosthetic fractures, 2 instability, 2 neurologic complications, and 14 miscellaneous complications. Twenty patients (5.63%, 4 men and 16 women with a mean age of 74.2 ± 8.2 years [range, 51-87 years]) underwent reintervention. The interval to the first reintervention was 27.8 ± 23.1 months (range, 0.1-78 months). The causes of reintervention (20 cases) were 8 loosening (glenoid: 4, humeral stem: 4), 5 infections, 5 fractures, and 2 instability. Among them, 15 component revisions (4.02%) were performed. At the last follow-up, American Shoulder and Elbow Surgeons, University of California at Los Angeles, and Simple Shoulder Test scores were improved from 25.4, 12.4, and 1.6 preoperatively to 40.4, 16.2, and 3.2, respectively. Forward flexion (48° to 87°), abduction (52° to 79°), external rotation (18° to 22°), and internal rotation (buttock to L2) were improved.

Conclusions

After primary RTSA in a Korean population, the complication, reintervention, and revision rates were 13.94%, 5.63%, and 4.02%, respectively. Careful evaluation of the complications and adequate treatments should be performed.

Impact of Resident Involvement on 30-Day Postoperative Outcomes in Orthopedic Shoulder Surgery

The literature concerning resident involvement in shoulder surgery is limited. The purpose of this study was to examine whether resident involvement across all orthopedic shoulder surgeries is associated with adverse 30-day outcomes. Utilizing the American College of Surgeons National Surgical Quality Improvement Program database, patients who underwent shoulder surgery with or without a resident present were analyzed. Independent t-test and chi-square or Fischer's exact test were used appropriately. A logistic regression model was used to calculate adjusted odds ratios. This study examined 5,648 patients: 3,455 patients in the "Attending alone" group and 2,193 in the "Attending and resident in the operating room" group. Resident presence in the operating room was not associated with increased complications, except for bleeding transfusions (OR 1.71, CI 1.32-2.21, P ≤ 0.001). This study demonstrates that resident involvement in orthopedic shoulder surgery does not present an increased risk for 30-day complications when compared to surgeries performed with the attending surgeon alone.

The Value of Computed Tomography-Based Planning in Shoulder Arthroplasty Compared to Intra-/Interobserver Reliability of X-ray Planning

Background: Reversed total shoulder arthroplasty (RTSA) is an established surgery for many pathologies of the shoulder and the demand continues to rise with an aging population. Preoperative planning is mandatory to support the surgeon's understanding of the patient's individual anatomy and, therefore, is crucial for the patient's outcome. Methods: In this observational study, we identified 30 patients who underwent RTSA with two- and three-dimensional preoperative planning. Each patient underwent new two-dimensional planning from a medical student and an orthopedic resident as well as through a mid-volume and high-volume shoulder surgeon, which was repeated after a minimum of 4 weeks. The intra- and interobserver reliability was then analyzed and compared to the 3D planning and the implanted prosthesis. The evaluated parameters were the size of the pegged glenoid baseplate, glenosphere, and humeral short stem. Results: The inter-rater reliability showed higher deviations in all four raters compared to the 3D planning of the base plate, glenosphere, and shaft. The intra-rater reliability showed a better correlation in more experienced raters, especially in the planning of the shaft. Conclusions: Our study shows that 3D planning is more accurate than traditional planning on plain X-rays, despite experienced shoulder surgeons showing better results in 2D planning than inexperienced ones.

Time-elapsed microstructural imaging of failure of the reverse shoulder implant

BACKGROUND

Reverse Shoulder Arthroplasties (RSA) have become a primary choice for improving shoulder function and pain. However, the biomechanical failure mechanism of the humeral component is still unclear. The present study reports a novel protocol for microstructural imaging of the entire humerus implant under load before and after fracture.

METHODS

A humerus specimen was obtained from a 75-year-old male donor. An expert surgeon implanted the specimen with a commonly used RSA implant (Aequalis reversed II, Stryker Orthopaedics, USA) and surgical procedure. The physiological glenohumeral contact force that maximized the distal implant migration was selected from a public repository ( orthoload.com ). Imaging and concomitant mechanical testing were performed using a large-volume micro-CT scanner (Nikon XT H 225 ST) and a custom-made compressive stage. Both when intact and once implanted, the specimen was tested under a pre-load and by imposing a constant deformation causing a physiological reaction load (650 N, 10 degrees adducted). The deformation of the implanted specimen was then increased up to fracture, which was identified by a sudden drop of the reaction force, and the specimen was then re-scanned.

RESULTS

The specimen's stiffness decreased from 874 N/mm to 464 N/mm after implantation, producing movements of the bone-implant interface consistent with the implant's long-term stability reported in the literature. The micro-CT images displayed fracture of the tuberosity, caused by a combined compression and circumferential tension, induced by the distal migration of the implant.

CONCLUSION

The developed protocol offers detailed information on implant mechanics under load relative to intact conditions and fracture, providing insights into the failure mechanics of RSA implants. This protocol can be used to inform future implant design and surgical technique improvements.

Analysis of three different reverse shoulder arthroplasty designs for cuff tear arthropathy - the combination of lateralization and distalization provides best mobility

BACKGROUND

The two major reverse shoulder arthroplasty (RSA) designs are the Grammont design and the lateralized design. Even if the lateralized design is biomechanically favored, the classic Grammont prosthesis continues to be used. Functional and subjective patient scores as well as implant survival described in the literature so far are comparable to the lateralized design. A pure comparison of how the RSA design influences outcome in patients has not yet been determined. The aim of this study was a comparison focused on patients with cuff tear arthropathy (CTA).

METHODS

We analyzed registry data from 696 CTA patients prospectively collected between 2012 and 2020 in two specialized orthopedic centers up to 2 years post-RSA with the same follow-up time points (6,12 24 months). Complete teres minor tears were excluded. Three groups were defined: group 1 (inlay, 155° humeral inclination, 36 + 2 mm eccentric glenosphere (n = 50)), group 2 (inlay, 135° humeral inclination, 36 + 4 mm lateralized glenosphere (n = 141)) and group 3 (onlay, 145° humeral inclination, + 3 mm lateralized base plate, 36 + 2 mm eccentric glenosphere (n = 35)) We compared group differences in clinical outcomes (e.g., active and passive range of motion (ROM), abduction strength, Constant-Murley score (CS)), radiographic evaluations of prosthetic position, scapular anatomy and complications using mixed models adjusted for age and sex.

RESULTS

The final analysis included 226 patients. The overall adjusted p-value of the CS for all time-points showed no significant difference (p = 0.466). Flexion of group 3 (mean, 155° (SD 13)) was higher than flexion of group 1 (mean, 142° (SD 18) and 2 (mean, 132° (SD 18) (p < 0.001). Values for abduction of group 3 (mean, 145° (SD 23)) were bigger than those of group 1 (mean, 130° (SD 22)) and group 2 (mean, 118° (SD 25)) (p < 0.001). Mean external rotation for group 3 (mean, 41° (SD 23)) and group 2 (mean, 38° (SD 17)) was larger than external rotation of group 1 (mean, 24° (SD 16)) (p < 0.001); a greater proportion of group 2 (78%) and 3 (69%) patients reached L3 level on internal rotation compared to group 1 (44%) (p = 0.003). Prosthesis position measurements were similar, but group 3 had significantly less scapular notching (14%) versus 24% (group 2) and 50% (group 1) (p = 0.001).

CONCLUSIONS

Outcome scores of different RSA designs for CTA revealed comparable results. However, CTA patients with a lateralized and distalized RSA configuration were associated with achieving better flexion and abduction with less scapular notching. A better rotation was associated with either of the lateralized RSA designs in comparison with the classic Grammont prosthesis.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

Revision reverse shoulder arthroplasty for the management of baseplate failure: an analysis of 676 revision reverse shoulder arthroplasty procedures

BACKGROUND

Baseplate failure in reverse shoulder arthroplasty (RSA) is a rare but potentially catastrophic complication owing to poor patient outcomes and significant glenoid bone loss. The purpose of this study was to report on the prevalence, causes, and outcomes of revision RSA (rRSA) for baseplate failure or loosening.

METHODS

A retrospective review of our institutional database was performed to identify all patients treated for a failed RSA from 2006 to 2021 who required revision to another RSA (rRSA) performed by a single surgeon. A total of 676 failed RSA procedures were identified, and further analysis identified 46 patients (6.8%) who underwent rRSA for baseplate failure with a confirmed loose baseplate at the time of rRSA. The primary outcome was repeated failure of the reimplanted baseplate following rRSA. The mode of failure associated with baseplate failure was stratified into 1 of 3 groups: aseptic, septic, or traumatic. Twenty-four patients underwent primary revision, and 22 had undergone >1 previous arthroplasty prior to undergoing re-revision. Five patients underwent previous rRSA for baseplate failure performed by an outside surgeon. The criteria for secondary outcome analysis of final American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, and range of motion were met by 32 patients and 23 patients at 1- and 2-year follow-up, respectively.

RESULTS

Three patients (6.5%) had repeated baseplate failure requiring re-revision; 2 had baseplate failure at <1 year with associated periprosthetic infections and underwent conversion to hemiarthroplasty. The third patient experienced traumatic failure at 10 years and underwent successful rRSA. The mean American Shoulder and Elbow Surgeons scores at 1 and 2 years were 62.3 and 61.7, respectively. There was no significant difference in outcomes based on mode of baseplate failure (P = .232) or total arthroplasty burden (P = .305) at 1 year. There were 13 total complications in 11 patients, 5 of which required reoperation for reasons other than baseplate failure.

CONCLUSION

In this study, rRSA for baseplate failure constituted 6.8% of all revisions performed over a period of 15 years. Re-revision for recurrent baseplate failure was required in 3 of 46 patients (6.5%). Complications and reoperation rates were higher than those for primary RSA but outcomes were comparable for revision of failed anatomic shoulder arthroplasty.

Ten technical aspects of baseplate fixation in reverse total shoulder arthroplasty for patients without glenoid bone loss: a systematic review

The aim of this systematic review was to collect evidence on the following 10 technical aspects of glenoid baseplate fixation in reverse total shoulder arthroplasty (rTSA): screw insertion angles; screw orientation; screw quantity; screw length; screw type; baseplate tilt; baseplate position; baseplate version and rotation; baseplate design; and anatomical safe zones. Five literature libraries were searched for eligible clinical, cadaver, biomechanical, virtual planning, and finite element analysis studies. Studies including patients >16 years old in which at least one of the ten abovementioned technical aspects was assessed were suitable for analysis. We excluded studies of patients with: glenoid bone loss; bony increased offset-reversed shoulder arthroplasty; rTSA with bone grafts; and augmented baseplates. Quality assessment was performed for each included study. Sixty-two studies were included, of which 41 were experimental studies (13 cadaver, 10 virtual planning, 11 biomechanical, and 7 finite element studies) and 21 were clinical studies (12 retrospective cohorts and 9 case-control studies). Overall, the quality of included studies was moderate or high. The majority of studies agreed upon the use of a divergent screw fixation pattern, fixation with four screws (to reduce micromotions), and inferior positioning in neutral or anteversion. A general consensus was not reached on the other technical aspects. Most surgical aspects of baseplate fixation can be decided without affecting fixation strength. There is not a single strategy that provides the best outcome. Therefore, guidelines should cover multiple surgical options that can achieve adequate baseplate fixation.

The Delta III and Delta Xtend reverse shoulder arthroplasty-risk of revision and failure mechanisms: a report on 3650 cases from the Norwegian Arthroplasty Register 1994-2021

BACKGROUND

The Delta reverse shoulder arthroplasty (RSA) is commonly used worldwide and is the most frequently used RSA in Norway. The aim of this registry-based study was to report 10- and 20-year implant survival, risk of revision, and reasons for revision in 2 consecutive time periods for Delta III (1994-2010) and Delta Xtend (2007-2021) prostheses.

METHODS

We included 3650 primary RSAs reported to the Norwegian Arthroplasty Register: 315 Delta III (42% cemented stems) and 3335 Delta Xtend (88% cemented stems). We used Kaplan-Meier analyses to investigate implant survival. The reasons for revision were compared for the 2 designs and fixation technique. Factors that could influence the risk of revision, such as implant design, fixation technique, and patient factors, were investigated using Cox regression analyses with adjustments for age, sex, and diagnosis.

RESULTS

Patients operated with Delta III were more likely to be diagnosed with inflammatory disease or fracture sequela, whereas acute fracture, osteoarthritis, and cuff arthropathy were the most frequent indications for Delta Xtend. Ten-year survival was 93.0% (95% confidence interval [CI]: 87.0-99.0) (cemented stem) and 81.6% (95% CI: 75.3-87.9) (uncemented stem) for Delta III and 94.7% (95% CI: 93.3-96.1) (cemented stem) and 95.7% (95% CI: 88.3-100) (uncemented stem) for Delta Xtend. Twenty-year survival for Delta III (uncemented stem) was 68.2% (95% CI: 58.8-77.6). Compared with DeltaXtend (cemented stem) at 10-year follow-up, we found a higher risk of revision for Delta III (uncemented stem) (hazard ratio [HR]: 2.9, 95% CI: 1.7-5.0), whereas no significant difference was found for Delta III (cemented stem) and Delta Xtend (uncemented stem). The most common reason for revision of Delta III (uncemented stem) was glenoid loosening followed by deep infection and instability. Instability was the most frequent revision cause for Delta Xtend (both cemented and uncemented stem). Men had an overall higher revision risk than women (HR: 2.8 [95% CI: 2.0-3.9]), and patients with fracture sequela had increased risk for revision (HR: 2.8, 95% CI: 1.7-4.7) compared with patients with osteoarthritis.

DISCUSSION

We found that Delta III (uncemented stem) had a higher risk of revision compared with Delta Xtend (cemented stem). The risk of revision for glenoid component loosening was lower for Delta Xtend, but revisions due to instability/dislocation are still a concern. This register study cannot determine whether the differences found were caused by differences in implant design or other factors that changed during the study period. Risk of revision may have been affected by the indication for primary operation.

Rotator cuff tears

Rotator cuff tears are the most common upper extremity condition seen by primary care and orthopaedic surgeons, with a spectrum ranging from tendinopathy to full-thickness tears with arthritic change. Some tears are traumatic, but most rotator cuff problems are degenerative. Not all tears are symptomatic and not all progress, and many patients in whom tears become more extensive do not experience symptom worsening. Hence, a standard algorithm for managing patients is challenging. The pathophysiology of rotator cuff tears is complex and encompasses an interplay between the tendon, bone and muscle. Rotator cuff tears begin as degenerative changes within the tendon, with matrix disorganization and inflammatory changes. Subsequently, tears progress to partial-thickness and then full-thickness tears. Muscle quality, as evidenced by the overall size of the muscle and intramuscular fatty infiltration, also influences symptoms, tear progression and the outcomes of surgery. Treatment depends primarily on symptoms, with non-operative management sufficient for most patients with rotator cuff problems. Modern arthroscopic repair techniques have improved recovery, but outcomes are still limited by a lack of understanding of how to improve tendon to bone healing in many patients.

Complication rates following reverse and anatomic shoulder replacement in treatment of glenohumeral arthritis: a 10-year Medicare review study

BACKGROUND

We sought to compare the complication rates after anatomic total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (RSA) for primary glenohumeral arthritis in a Medicare population.

METHODS

Patients who underwent a shoulder arthroplasty were identified from the 5% subset of Medicare parts A/B between 2009 and 2019. Patients with less than 1-year follow-up were excluded. A total of 8846 patients with a diagnosis of glenohumeral arthritis were then subdivided into those who received aTSA (5935 patients) and RSA (2911 patients). A multivariate Cox regression analysis was then performed comparing complication rates at 3 months, 6 months, 1 year, 2 years, and 5 years.

RESULTS

Statistically significant increased rates of instability (hazard ratio [HR] = 1.46), fracture of the scapula (HR = 7.76), infections (HR = 1.45), early revision (HR = 1.79), and all complications (HR = 1.32) were seen in the RSA group. There was no significant difference in revision rate at 5 years between the 2 groups. There was no difference in patient characteristics or comorbid conditions (smoking status, diabetes, Charlson score, etc.) or hospital characteristics (location, teaching status, public vs. private, etc.) between the 2 groups.

CONCLUSION

An increased rate of early complications was observed with the use of RSA compared with aTSA for the treatment of primary glenohumeral arthritis, including instability, scapula fracture, infection, and all cause complication. No difference in revision rate between RSA and aTSA at 5 years was observed.

How to avoid baseplate failure: the effect of compression and reverse shoulder arthroplasty baseplate design on implant stability

BACKGROUND

Failure to achieve fixation of the glenoid baseplate will lead to clinical failure. The fixation of the baseplate to the scapula must be able to withstand sufficient shear forces to allow bony ingrowth. The importance of compression to neutralize the forces at the baseplate-bone interface has been assumed to be critical in limiting excessive micromotion. The purpose of this study is to determine the effect of compression on implant stability with different baseplate designs.

METHODS

Various baseplate designs (1-piece monolithic central screw [1P], 2-piece locking central screw [2PL], and 2-piece nonlocking center screw [2PNL]) were investigated at 3 different compressive forces (high [810 N], medium [640 N], and low [530 N]). Synthetic bone cylinders were instrumented, and peripheral screws were used in all models. The combination of 1 locking and 3 nonlocking peripheral screw fixation was selected as worst-case scenario. Dynamic testing protocol followed the ASTM F2028-17 standard. The baseplate micromotion at high compression was compared to low compression. Additionally, the baseplate micromotion for each design was compared at baseline (first 50 cycles) and at 10,000 cycles for the 3 different compressive forces where motion above 150 μm was defined as failure.

RESULTS

Baseplate micromotion was found to negatively correlate with compression (rpb = -0.83, P < .0001). At baseline, all baseplate designs were considered stable, regardless of compression. With high compression, average micromotion at the glenoid baseplate-bone interface remained below the 150-μm threshold for all baseplate designs at 10,000 cycles (1P: 50 ± 10 μm; 2PL: 78 ± 32 μm; 2PNL: 79 ± 8 μm; P = .060). With medium compression, average micromotion at 10,000 cycles for all 3 designs remained below the 150-μm threshold (1P: 88 ± 22 μm; 2PL: 132 ± 26 μm; 2PNL: 107 ± 39 μm). The 2PL design had the highest amount of micromotion (P = .013). With low compression, both 2-piece designs had an average micromotion above the 150-μm threshold whereas the 1-piece design did not (1P: 133 ± 35 μm; 2PL: 183 ± 21 μm; 2PNL: 166 ± 39 μm). The 2PL design had significantly higher micromotion when compared to 1P design (P = .041).

DISCUSSION

The stability of a central screw baseplate correlates with the amount of compression obtained and is affected by implant design. For the same amount of compression, more micromotion is observed in a 2-piece design than a 1-piece design.

Subacromial Balloon Spacer for the Massive Irreparable Cuff Tear

PURPOSE OF REVIEW

The purpose of the review is to provide an updated overview of a relatively novel but controversial surgical device (InSpace subacromial balloon, Stryker, Kalamazoo, MI) that can be readily incorporated into the armamentarium of the shoulder surgeon. The authors review the critical clinical and surgical decision-making aspects of InSpace. A recommended surgical technique and rehabilitation protocol are outlined. The authors present a nuanced view of the balloon spacer in the continuum of care of the irreparable rotator cuff tear.

RECENT FINDINGS

Within the last year, two Level I clinical trials have been published, and the data from these studies offer conflicting evidence regarding the utility of the subacromial balloon spacer. The current review contrasts these two recent studies and offers a framework by which the available evidence can be practically understood with respect to clinical decision-making. The literature currently supports a limited indication for use of InSpace: the elderly, low-demand patient with preserved active range of motion with an operatively irreparable, posterosuperior rotator cuff tear with an intact subscapularis. The InSpace subacromial balloon spacer is a simple device that can yield substantial improvements in clinical outcomes among a subset of patients with irreparable rotator cuff tears. InSpace is not a panacea for the complex, irreparable rotator cuff tear. Individualized decision-making is necessary in this diverse and challening patient population.