Improved Clinical Outcomes After Lateralized Reverse Shoulder Arthroplasty: A Systematic Review

Complications following reverse total shoulder arthroplasty for proximal humeral fractures: a systematic review

Background

Reverse total shoulder arthroplasty (rTSA) is an increasingly common procedure for proximal humerus fractures (PHFs), but postoperative complications have not been well characterized. The purpose of this systematic review is to assess complications and revision rates following rTSA in the management of PHFs as documented in current literature.

Methods

A systematic review was performed on primary rTSA for PHFs. In adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic search was conducted between September and December of 2023, utilizing the databases PubMed, Scopus, and the Cochrane Library to include relevant articles from any period. A total of 102 studies were identified for inclusion after initial screening of 3800 query results. Extracted data from each article included the publishing journal, level of evidence, study design, number of patients, mean age, age range, percent female, mean follow-up, specific postoperative complications, total complications, complication rate, number of revisions, and revision rate. Overall complication rates were determined by dividing total complications by total patients and multiplying by 100, which also applied to revision rates.

Results

Among 10,797 primary rTSA cases for PHFs identified from 102 studies, the mean age of patients was 75.6 ± 3.6 years, and 82.6% of patients were female. The average follow-up was 38.9 ± 21.0 months. The overall complication rate was 7.0% (754/10,797) with a range of 0% to 46.9%. The most common postoperative complications were prosthetic instability/dislocation (2.3%, 244/10,797; range: 0%-7%) and infection (1.2%, 131/10,797; range: 0%-2.5%). Periprosthetic fracture (0.8%), nerve injury (0.3%), and other complications were also documented. The overall revision rate was 3.3% (355/10,797; range: 0%-28%).

Conclusion

This systematic review summarizes the most common postoperative complications of rTSA for PHFs. The most frequent complication was prosthetic instability/dislocation, followed by infection. While the average total complication and revision rates were relatively low, there was wide variability, with some studies reporting rates as high as 46% and 28%, respectively.

The Future of Clinical Active Shoulder Range of Motion Assessment, Best Practice, and Its Challenges: Narrative Review

Optimising outcomes after shoulder interventions requires objective shoulder range of motion (ROM) assessments. This narrative review examines video-based pose technologies and markerless motion capture, focusing on their clinical application for shoulder ROM assessment. Camera pose-based methods offer objective ROM measurements, though the accuracy varies due to the differences in gold standards, anatomical definitions, and deep learning techniques. Despite some biases, the studies report a high consistency, emphasising that methods should not be used interchangeably if they do not agree with each other. Smartphone cameras perform well in capturing 2D planar movements but struggle with that of rotational movements and forward flexion, particularly when thoracic compensations are involved. Proper camera positioning, orientation, and distance are key, highlighting the importance of standardised protocols in mobile phone-based ROM evaluations. Although 3D motion capture, per the International Society of Biomechanics recommendations, remains the gold standard, advancements in LiDAR/depth sensing, smartphone cameras, and deep learning show promise for reliable ROM assessments in clinical settings.

Pseudoparalysis and Pseudoparesis of the Shoulder: Definitions, Management, and Outcomes

Loss of shoulder function can be a complex condition to manage. Specifically, the definition between the terms pseudoparalysis and pseudoparesis remains inconsistent in the literature based on various factors including chronicity, present pathology, and the role of pain in the loss of function. There is also debate as to the optimal management strategies for these challenging conditions. In the setting of advanced glenohumeral arthritis or arthropathy in the correct patient, arthroplasty provides consistent and reliable results. However, in younger patients or the patient without arthritis, arthroplasty may not be the best option. In some cases, addressing pain with biceps procedures, balloon spacer placement, débridement, or others may be appropriate. However, other instances may require attempts at improving shoulder kinematics with procedures such as rotator cuff repair, superior capsular reconstruction, and tendon transfer. In this review, we discuss current definitions for pseudoparalysis and pseudoparesis, in addition to reviewing the indications for the various treatment options and their respective outcomes.

Intraoperative repair of functional subscapularis during RSA by deltopectoral approach could improve internal rotation but does not prevent anterior dislocation

INTRODUCTION

The role of the subscapularis following reverse shoulder arthroplasty (RSA) remains controversial as repair could restore adequate internal rotation and shoulder stability, but might compromise external rotation. The purpose of this multi-centre study, on a large cohort of RSAs performed using the deltopectoral approach, was to determine the effect of subscapularis preoperative status and intraoperative repair on range of motion, clinical scores and rates of complications at a minimum follow-up of 2 years.

HYPOTHESIS

Repair of a functional subscapularis grants better internal rotation and stability without compromising external rotation.

MATERIALS AND METHODS

We retrospectively reviewed records of all RSAs (n=916) performed by 14 surgeons that participated in a large national society symposium, and excluded 234 operated by the anterosuperior approach, 42 operated for rheumatoid arthritis, fractures, instability or post traumatic sequalae, and eight that had adjuvant latissimus dorsi tendon transfer (LDTT). This left 632 RSAs, in which the subscapularis was detached in 594, and repaired after detachment in 495. Patients completed pre- and postoperative Constant Score and postoperative Subjective Shoulder Value (SSV). Active forward elevation, active external rotation (ER), and active internal rotation (IR) were recorded pre- and postoperatively. Complications following RSA that required conservative treatment, reoperation without implant removal, as well as reoperation with implant removal were recorded.

RESULTS

Of the initial cohort of 632 shoulders, 120 (19%) were lost to follow-up, 12 (2%) died due to causes unrelated to RSA, and 26 (4%) were revised with implant removal. Of the remaining 474 shoulders, 259 (55%) had a functional repaired subscapularis (Group FR), 59 (12%) had a non-functional repaired subscapularis (Group nFR), whereas 68 (14%) had a not repaired subscapularis (Group nR). Comparison of patient demographics revealed no significant differences among the three groups. Postoperative Constant Score (p=0.031) and SSV (p=0.016) were significantly different among the three groups, but effect sizes were small and not clinically relevant. Differences in postoperative ER as well as postoperative IR were not significant among the three groups: 91 (35%) gained functional IR in Group FR, 11 (19%) in Group nFR, and 13 (19%) in Group nR. Three shoulders (1.2%) reported subjective instability and 1 (0.4%) dislocated in Group FR, but none in either Groups nFR or nR.

DISCUSSION

Despite statistically significant differences in Constant Score and SSV among the three groups, the clinical relevance of these differences is negligible, so repair of functional subscapularis has little or no influence on functional outcomes. During RSA by deltopectoral approach, repair of a functional subscapularis could slightly improve internal rotation in some patients but does not compromise external rotation, forward elevation or clinical scores, while repair of a non-functional subscapularis, compared to non-repair, did not improve range of motion or clinical scores.

LEVEL OF EVIDENCE

III; retrospective comparative.

Modified notching classification in inverted-bearing and conventional-bearing reverse total shoulder arthroplasty

BACKGROUND

Scapular notching is a common complication of reverse total shoulder arthroplasty (RTSA). Although the notching rate has reduced significantly thanks to modifications to the surgical technique and humeral and glenoid components, uncontrollable polyethylene (PE)-induced osteolysis can still occur. In contrast to conventional-bearing (CB-RTSA), inverted-bearing RTSA (IB-RTSA) systems, with PE glenospheres and metal or ceramic humeral liners, avoid PE abrasion through scapulohumeral contact. If present, the resulting notch has a different size and configuration than with CB-RTSA. Thus, a modified notching classification seems reasonable. Even in CB-RTSA, the early stages of notching show a different configuration than implied by the established Nerot-Sirveaux classification; therefore, a modification of the classification system is recommended.

METHODS

In a prospective multicentre study, 250 cases underwent IB-RTSA. Of these, 39 died, and 28 were lost to follow-up for other reasons, leaving 183 shoulders for the final follow-up examination at a mean of 120.7 months (range 84.1-172.4 months). In the CB-RTSA group, we retrospectively evaluated radiographs of 59 consecutive patients with a follow-up ranging from 2 to 7 years. We analysed the appearance, evolution over time, and location of bone loss on the scapular neck according to the modified Nerot-Sirveaux classification.

RESULTS

In IB-RTSA, notching resulted in a new morphological configuration: In contrast to the Nerot-Sirveaux classification, notching began far from the baseplate as an impression or abrasion of the humeral component in the inferior scapular rim. Due to simultaneous mechanical ablation, the defect gradually enlarged, but usually did not contact the baseplate or extend beyond the inferior peg. No signs of PE-induced osteolysis were found. The notching rate reached 19% after 2 years and approached 36% after 10 years. Most shoulders had grade 0 notching (64%), followed by grade 1 (29%); extensive erosion (grade 4) was not observed. In the CB-RTSA group, a small bony impression or erosion without signs of PE-induced osteolysis was observed medial to the scapular neck, without contact with the metaglene in the early phase, which was similar to the impression of the humeral component in IB-RTSA. The notching rate was 86% for CB-RTSA.

CONCLUSIONS

A new classification was developed for IB-RTSA, which corresponds to the pathophysiological processes and is compatible with the existing Nerot-Sirveaux classification. Bone erosion in CB-RTSA is not adequately represented by the established classification in the early stages. For this reason, a supplement to the existing classification is presented.

LEVEL OF EVIDENCE

Level 4, Case Series, Treatment Study.

Reverse shoulder arthroplasty for primary glenohumeral osteoarthritis: significantly different characteristics and outcomes in shoulders with intact vs. torn rotator cuff

PURPOSE

To compare outcomes of reverse shoulder arthroplasty (RSA) for primary osteoarthritis (OA) with and without rotator cuff (RC) tears to those with secondary OA due to RC tears.

METHODS

We reviewed records of all patients who received RSA for primary OA or secondary OA. All patients had preoperative radiographs, computed tomographic arthrography (CTA), and/or magnetic resonance imaging (MRI) scans of their shoulders to assess their etiology, glenoid morphology, and fatty infiltration. Pre- and postoperative (at minimum follow-up of 2 years) Constant scores and range of motion were compared between patients who had RSA for primary OA with and without RC tears to those with secondary OA due to RC tears.

RESULTS

Of the initial cohort of 605 shoulders (583 patients), 153 were lost to follow-up (25.3%), 25 required revision with implant removal (4.1%), and 13 died of causes unrelated to the surgery (2.1%), and left a final cohort of 414 patients. Of the final cohort, 97 had primary OA with intact RC, 62 had primary OA with RC tears, and 255 had secondary OA. Postoperative Constant scores were significantly higher for primary OA with intact RC (73.8 ± 14.3), compared with both primary OA with RC tears (66.1 ± 14.6, P < .001) and secondary OA (64.1 ± 14.8, P < .001). There were no differences in pre- or postoperative scores between primary OA with RC tears and secondary OA.

CONCLUSION

At 2 or more years following RSA, Constant scores were significantly higher for primary OA with intact RC, compared to either primary OA with RC tears or secondary OA, whereas there were no differences in pre- or postoperative scores of shoulders that had primary OA with RC tears vs. secondary OA. The authors recommend distinguishing primary OA with intact RC from primary OA with RC tears, as the two have considerably different characteristics and prognosis following RSA.

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.

Better Constant Scores and Active Forward Elevation Using Deltopectoral Versus Anterosuperior Approach for Reverse Shoulder Arthroplasty: Matched Cohort Study

Purpose

To determine, from a sizable cohort of reverse shoulder arthroplasty (RSA), whether the deltopectoral (DP) or anterosuperior (AS) approach grant better outcomes at a minimum follow-up of 24 months.

Methods

The authors reviewed 743 RSAs in patients with primary osteoarthritis (OA) with or without rotator cuff lesions and secondary OA due to rotator cuff tears. The DP approach was used in 540 and the AS approach in 203. Pre- and post-operative constant scores (CSs) and shoulder range of motion were recorded.

Results

Of the initial cohort of 743 shoulders, 193 (25.7%) were lost to follow-up, 16 (2.1%) died, and 33 (4.4%) were revised; 540 shoulders were operated using DP approach (73%), of which 22 were revised (4.1%), while 203 were operated using the AS approach (27%), of which 11 were revised (5.4%). Propensity score matching resulted in two groups: 172 shoulders operated by DP approach, and 88 shoulders operated by AS approach. Comparing outcomes of the matched groups at 2 or more years also revealed that, compared to the AS approach, the DP approach resulted in significantly better post-operative CSs (67.3 ± 14.0° vs 60.8 ± 18.3, P = 0.017), active forward elevation (137° ± 27.4° vs 129° ± 29.8; P = 0.031).

Conclusion

At 2 or more years following RSA, the DP approach granted significantly better CS (by 6.5 points) and active forward elevation (by 8°) compared to the AS approach. The differences observed are clinically relevant and must be considered to manage patient expectations following RSA and for selecting surgical approach depending on their functional needs.

Level of evidence

III, comparative study.

Baseplate inferior offset affects shoulder range of motion in reverse shoulder arthroplasty in Asian population

BACKGROUND

Impingement is a common complication of reverse shoulder arthroplasty. Placement of the baseplate with a wide impingement-free angle is ideal; however, there are few studies on Asian populations, which have smaller height and physique, and there is a lack of guidance on achieving optimal outcomes. The purpose of the present study was to explore the impingement-free range of motion reverse shoulder arthroplasty and analyze the suitable baseplate position or tilt for the Asian population using simulation software.

METHODS

We uploaded computed tomography scan data from 20 Asian patients to three-dimensional (3D) simulation software. The implantation of the reverse shoulder arthroplasty component was performed on the 3D humerus and scapula using software, and range of motion was assessed until impingement occurred.

RESULTS

The range of motion in flexion significantly improved when the baseplate was lowered up to 3 mm inferiorly. Range of motion in abduction and internal and external rotation significantly improved as the baseplate was lowered up to 4 mm. There was no significant difference in range of motion in any motion after changing the inferior tilt, except in internal and external rotation.

CONCLUSIONS

The range of motion in abduction, flexion, and internal and external rotations significantly improved with increased inferior offset. These results may prove valuable in determining the optimal baseplate position for RSA, particularly in Asian populations.

Short- to medium-term outcomes and future direction of reverse shoulder arthroplasty: Current concepts

Reverse shoulder arthroplasty is typically indicated for patients with severe shoulder osteoarthritis, rotator cuff tear arthropathy, or proximal humerus fractures that have failed to heal properly. The primary goal of reverse shoulder arthroplasty is to improve shoulder function and reduce pain, while also restoring the ability to perform daily activities. There is a growing body of evidence supporting the effectiveness of reverse shoulder arthroplasty in improving shoulder function and reducing pain in patients with severe shoulder osteoarthritis or rotator cuff tear arthropathy. Reverse shoulder arthroplasty is associated with significant improvements in shoulder function and pain reduction compared to non-surgical treatments. This paper aims to summarize current knowledge, practices and present a summary of the long-term effects of reverse shoulder arthroplasty (RSA) on patient outcomes, including how these outcomes are defined and what measures are typically used to assess them. It will also cover newer definitions of outcomes for RSA that have been developed in recent years in order to better understand the long-term effects of the procedure on patient-reported outcomes and functional ability, as well as information on revision surgery and implant survivorship, and the future of RSA (3D-navigation, patient-specific instrumentation, robotics and artificial intelligence) and its effects on outcomes.

Factors that affect external rotation following reverse shoulder arthroplasty: a retrospective multi-centre study on 501 shoulders

INTRODUCTION

The purpose of this multi-centre study was to assess external rotation in a large cohort following reverse shoulder arthroplasty (RSA) at a minimum follow-up of 2 years, and identify factors that influence postoperative and/or net-improvement of external rotation.

METHODS

The authors retrospectively reviewed records of 743 RSAs performed between January 2015 and August 2017 by 16 surgeons that participated in a large national society symposium; 193 (25.7%) were lost to follow-up, 16 (2.1%) died, and 33 (4.4%) were revised with implant exchange, which left 501 available for assessment at 2.0-5.5 years. Pre- and post-operative active forward elevation, active external rotation (ER1), active internal rotation (IR1) and constant score (CS) were collected. Regression analyses were performed to determine associations of patient demographics, surgical and implant parameters, rotator cuff muscles status and radiographic angles with ER1.

RESULTS

Multivariable analyses revealed postoperative ER1 decreased with age (β, - 0.35), increased with lateralisation shoulder angle (LSA) (β, 0.26), and was better in shoulders operated by the antero-superior (AS) approach (β, 11.41), but worse in shoulders with absent/atrophic teres minor muscles (β, - 10.06). Net-improvement of ER1 increased with LSA (β, 0.39), was better with inlay stems (β, 8.33) and BIO RSA (β, 6.22), but worse in shoulders operated for primary OA with rotator cuff (RC) tears (β, - 16.26), for secondary OA due to RC tears (β, - 16.06), or for mRCT (β, - 18.96).

CONCLUSIONS

This large multi-centre study revealed that, at a minimum of 2 years following RSA, ER1 improved by 16.1°. Postoperative ER1 was better in shoulders which had normal or hypertrophic teres minor muscles, were operated by the AS approach, or with greater LSA. Net-improvement of ER1 was better in shoulders with inlay stems, with BIO RSA, or with greater LSA, but worse in shoulders with rotator cuff deficiency.

LEVEL OF EVIDENCE

IV.

Reverse shoulder arthroplasty renders better clinical scores at a minimum follow-up of two years for patients with no rotator cuff deficiency operated by the deltopectoral approach

PURPOSE

The purpose of this multi-centre study was to report outcomes of a large cohort of reverse shoulder arthroplasty (RSA) at a minimum follow-up of two years and to determine patient and surgical factors that influence postoperative outcomes. The hypothesis was that surgical indication, surgical approach, and implant design would affect clinical outcomes significantly.

METHODS

The authors reviewed records of 743 RSAs in patients with primary osteoarthritis (OA) with or without rotator cuff (RC) tears, secondary OA due to RC tears, and irreparable massive rotator cuff tears (mRCT). The deltopectoral (DP) approach was used in 540 and the anterosuperior (AS) approach in 203. Pre- and postoperative Constant scores (CS) were recorded. Multivariable linear analyses were performed to determine if CS was associated with indications for surgery, surgical approach, or implant design.

RESULTS

Of the 743 shoulders, 193 (25.7%) were lost to follow-up, 16 (2.1%) died, and 33 (4.4%) were revised, leaving 501 for analysis. At a mean follow-up of 3.2 ± 0.9 years, net improvement in CS was 29.2 ± 17.0. Multivariable analyses revealed that postoperative CS decreased with age and was worse in shoulders that had preoperative rotator cuff deficiency and in shoulders operated by the AS approach. Multivariable analyses also revealed worse net improvement in shoulders operated for secondary OA due to RC tears or for irreparable mRCT, as well as shoulders operated by the AS approach.

CONCLUSION

This large multi-centre study confirms that, at two or more years following RSA, Constant scores are not associated with implant design, but rather with rotator cuff deficiency and surgical approach. Multivariable analysis revealed that postoperative CS was worse for shoulders with preoperative rotator cuff deficiency and for shoulders operated by the AS approach. Multivariable analysis also revealed that net improvement in CS was worse in shoulders treated for secondary OA due to RC tears and for shoulders with irreparable mRCT, as well as for shoulders operated by the AS approach.

Subacromial notching after reverse total shoulder arthroplasty

BACKGROUND

Scapular notching is a well-known postoperative complication of reverse total shoulder arthroplasty (RTSA). However, subacromial notching (SaN), a subacromial erosion caused by repeated abduction impingement after RTSA, has not been previously reported in a clinical setting. Therefore, this study aimed to assess the risk factors and functional outcomes of SaN after RTSA.

METHODS

We retrospectively reviewed the medical records of 125 patients who underwent RTSA with the same design between March 2014 and May 2017 and had at least 2 years of follow-up. SaN was defined as subacromial erosion observed at the final follow-up but not on the X-ray 3 months after surgery. Radiologic parameters representing the patient's native anatomy and degrees of lateralization and/or distalization during surgery were evaluated using preoperative and 3 months postoperative X-rays. The visual analogue scale of pain, active range of motion, and American Shoulder and Elbow Surgeons score were assessed preoperatively and at the final follow-up to evaluate the functional outcomes of SaN.

RESULTS

SaN occurred in 12.8% (16/125) of enrolled patients during the study period. Preoperative center of rotation-acromion distance (P = .009) and postoperative humerus lateralization offset, which evaluated the degree of lateralization after RTSA (P = .003), were risk factors for SaN. The preoperative center of rotation-acromion distance and postoperative humerus lateralization cutoff values were 14.0 mm and 19.0 mm, respectively. The visual analogue scale of pain (P = .01) and American Shoulder and Elbow Surgeons score (P = .04) at the final follow-up were significantly worse in patients with SaN.

CONCLUSIONS

SaN might adversely affect postoperative clinical outcomes. As SaN correlated with patients' anatomical characteristics and degree of lateralization during RTSA, the implant's degree of lateralization should be adjusted according to the patient's own anatomical characteristics.

Narrative review of influence of prosthesis lateralization on clinical outcomes in reverse shoulder arthroplasty: glenoid vs. humerus vs. combined

Background and Objective

Reverse shoulder arthroplasty has become a common orthopaedic procedure, with a growing number of cases annually for multiple indications, such as rotator cuff arthropathy, osteoarthritis, or fractures of the proximal humerus, to reduce pain and restore shoulder mobility. Prosthesis design and various recent improvements aim to enhance range of motion (ROM) and stability and to limit component loosening and other potential complications. Many of these well-known issues could theoretically be improved by glenoid, humeral, or combined component lateralization. The objective of this article is to provide an up-to-date literature overview, present available options, and discuss the rationale behind lateralization of certain components, as well as their combined impact on outcomes of reverse shoulder arthroplasty.

Methods

PubMed and Scopus databases from 2003 to 2023 were searched and screened for studies, including systematic reviews, on the influence of glenoid, humeral, and combined component lateralization that served for narrative review of rationale behind such design.

Key Content and Findings

Currently, a number of computer simulations, anatomic studies, and limited clinical references aim to support the rationale behind glenoid augmentation, variable humeral neck-shaft angle (NSA), or humeral tray design.

Conclusions

The utility of lateralization has not yet been clinically established. Randomized, long-term clinical outcome studies are still needed to reach a verdict going beyond surgeon preference and case-specific indications.

Update on Shoulder Arthroplasties with Emphasis on Imaging

Shoulder pain and dysfunction may significantly impact quality of life. If conservative measures fail, advanced disease is frequently treated with shoulder arthroplasty, which is currently the third most common joint replacement surgery following the hip and knee. The main indications for shoulder arthroplasty include primary osteoarthritis, post-traumatic arthritis, inflammatory arthritis, osteonecrosis, proximal humeral fracture sequelae, severely dislocated proximal humeral fractures, and advanced rotator cuff disease. Several types of anatomic arthroplasties are available, such as humeral head resurfacing and hemiarthroplasties, as well as total anatomic arthroplasties. Reverse total shoulder arthroplasties, which reverse the normal ball-and-socket geometry of the shoulder, are also available. Each of these arthroplasty types has specific indications and unique complications in addition to general hardware-related or surgery-related complications. Imaging-including radiography, ultrasonography, computed tomography, magnetic resonance imaging, and, occasionally, nuclear medicine imaging-has a key role in the initial pre-operative evaluation for shoulder arthroplasty, as well as in post-surgical follow-up. This review paper aims to discuss important pre-operative imaging considerations, including rotator cuff evaluation, glenoid morphology, and glenoid version, as well as to review post-operative imaging of the various types of shoulder arthroplasties, to include normal post-operative appearances as well as imaging findings of complications.

Does glenohumeral offset affect clinical outcomes in a lateralized reverse total shoulder arthroplasty?

BACKGROUND

Reverse total shoulder arthroplasty (rTSA) exhibits high rates of success and low complication rates. rTSA has undergone numerous design adaptations over recent years, and lateralization of implant components provides theoretical and biomechanical benefits in stability and range of motion (ROM) as well as decreased rates of notching. However, the magnitude of implant lateralization and its effect on these outcomes is less well understood. The purpose of this study was to evaluate how increasing glenohumeral offset affects outcomes after rTSA, specifically in a lateralized humerus + medialized glenoid implant model.

METHODS

Primary rTSA using a lateralized humeral + medialized glenoid implant model performed at a single academic institution between 2012 and 2018 were retrospectively reviewed. Patient-reported outcome (PRO) parameters and clinical outcomes including ROM were evaluated both pre- and postoperatively. Pre- and postoperative radiographs were analyzed for measurement of glenohumeral offset, defined as the acromial-tuberosity offset (ATO) distance on the anteroposterior radiograph.

RESULTS

A total of 130 rTSAs were included in the analysis, with a mean follow-up of 35 mo. The mean postoperative absolute ATO was 16 mm, and the mean delta ATO (difference from pre- to postoperatively) was 4.6 mm further lateralized. Among all study patients, improvements in all ROM parameters and all PROs were observed from pre- to postoperative assessments. When assessing for the effects of lateralization on these outcomes, multivariate analysis failed to reveal a significant effect from the absolute postoperative ATO or the delta ATO on any outcome parameter.

CONCLUSIONS

rTSA using a lateralized humeral + medialized glenoid implant model exhibits excellent clinical outcomes in ROM and PROs. However, the magnitude of lateralization as measured radiographically by the ATO did not significantly affect these outcomes; patients exhibited universally good outcomes irrespective of the degree of offset restoration.