Medialized vs. lateralized humeral implant in reverse total shoulder arthroplasty: the comparison of outcomes in pseudoparalysis with massive rotator cuff tear

Reversing chronic pseudoparesis secondary to massive, irreparable rotator cuff tear: superior capsular reconstruction vs. reverse total shoulder arthroplasty

INTRODUCTION

Recent studies have defined pseudoparesis as limited active forward elevation between 45° and 90° and maintained passive range of motion (ROM) in the setting of a massive rotator cuff tear (RCT). Although pseudoparesis can be reliably reversed with reverse total shoulder arthroplasty (RSA) or superior capsular reconstruction (SCR), the optimal treatment for this indication remains unknown. The purpose of this study was to compare the clinical outcomes of RSA to SCR in patients with pseudoparesis secondary to massive, irreparable RCT (miRCT).

METHODS

This was a retrospective cohort study of consecutive patients aged 40-70 years with pseudoparesis secondary to miRCT who were treated with either RSA or SCR by a single fellowship-trained shoulder surgeon from 2016 to 2021 with a minimum 12-month follow-up. Multivariate linear regression modeling was used to compare active ROM, visual analog pain scale (VAS), Subjective Shoulder Value (SSV), and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score between RSA and SCR while controlling for confounding variables.

RESULTS

Twenty-seven patients were included in the RSA cohort and 23 patients were included in the SCR cohort with similar mean follow-up times (26.2 ± 21.1 vs. 21.9 ± 14.7 months, respectively). The patients in the RSA group were significantly older than those in the SCR group (65.2 ± 4.4 vs. 54.2 ± 7.8 years, P < .001) and had more severe arthritis (1.8 ± 0.9 vs. 1.2 ± 0.5 Samilson-Prieto, P = .019). The pseudoparesis reversal rate among the RSA and SCR cohorts was 96.3% and 91.3%, respectively. On univariate analysis, the RSA cohort demonstrated significantly greater mean improvement in active FF (89° ± 26° vs. 73° ± 30° change, P = .048), greater postoperative SSV (91 ± 8% vs. 69 ± 25%, P < .001), lower postoperative VAS pain scores (0.6 ± 1.2 vs. 2.2 ± 2.9, P = .020), and less postoperative internal rotation (IR; 4.6° ± 1.6° vs. 6.9° ± 1.8°, P = .004) compared with SCR. On multivariate analysis controlling for age and osteoarthritis, RSA remained a significant predictor of greater SSV (β = 21.5, P = .021) and lower VAS scores (β = -1.4, P = .037), whereas SCR was predictive of greater IR ROM (β = 3.0, P = .043).

CONCLUSION

Although both RSA and SCR effectively reverse pseudoparesis, patients with RSA have higher SSV and lower pain scores but less IR after controlling for age and osteoarthritis. The results of this study may inform surgical decision making for patients who are suitable candidates for either procedure.

Managing rotator cuff tear arthropathy: a role for cuff tear arthropathy hemiarthroplasty as well as reverse total shoulder arthroplasty

BACKGROUND

Disabling cuff tear arthropathy (CTA) is commonly managed with reverse shoulder arthroplasty (RSA). However, for patients with CTA having preserved active elevation, cuff tear arthropathy hemiarthroplasty (CTAH) may offer a cost-effective alternative that avoids the complications unique to RSA. We sought to determine the characteristics and outcomes of a series of patients with CTA managed with these procedures.

MATERIALS AND METHODS

We retrospectively reviewed 103 patients with CTA treated with shoulder arthroplasty, the type of which was determined by the patient's ability to actively elevate the arm. Outcome measures included the change in the Simple Shoulder Test (SST), the percent maximum improvement in SST (%MPI), and the percentage of patients exceeding the minimal clinically important difference for the change in SST and %MPI. Postoperative x-rays were evaluated to assess the positions of the center of rotation and the greater tuberosity for each implant.

RESULTS

Forty-four percent of the 103 patients were managed with CTAH while 56% were managed with RSA. Both arthroplasties resulted in clinically significant improvement. Patients having RSA improved from a mean preoperative SST score of 1.7 (interquartile range [IQR], 0.0-3.0) to a postoperative score of 6.3 (IQR, 2.3-10.0) (P < .01). Patients having CTAH improved from a preoperative SST score of 3.1 (IQR, 1.0-4.0) to a postoperative score of 7.6 (IQR, 5.0-10.) (P < .001). These improvements exceeded the minimal clinically important difference. Instability accounted for most of the RSA complications; however, it did not account for any CTAH complications. The postoperative position of the center of rotation and greater tuberosity on anteroposterior radiographs did not correlate with the clinical outcomes for either procedure.

CONCLUSION

For 103 patients with CTA, clinically significant improvement was achieved with appropriately indicated CTAH and RSA. In view of the lower cost of the CTAH implant, it may provide a cost-effective alternative to RSA for patients with retained active elevation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Inlay versus onlay humeral design for reverse shoulder arthroplasty: a systematic review and meta-analysis

BACKGROUND

Since the introduction of the Grammont-style reverse total shoulder arthroplasty, the humeral stem design has been modified with improved clinical outcomes. Two distinct humeral designs have been used extensively: the inlay design, in which the humeral tray is seated within the metaphysis, and the onlay design, in which the humeral tray sits on the metaphysis at the level of the humeral neck cut. The purpose of this systematic review was to determine whether there are differences in clinical outcomes and complication rates between these designs.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used to perform this systematic review. A search of MEDLINE, PubMed, and Embase was performed to identify all studies comparing the clinical results of both humeral designs. Primary outcomes included patient-reported outcome measures, shoulder range of motion, and incidence of complications.

RESULTS

From the 156 identified publications, 12 studies were included in the final review. A total of 1447 patients were included, with a minimum follow-up period of 12 months. At final follow-up, both implants demonstrated significant improvements in comparison to preoperative baseline. On comparison of the inlay vs. onlay groups, the American Shoulder and Elbow Surgeons score was higher in the inlay group (mean difference, 2.53 [95% confidence interval, 0.27-4.78]; P = .03). Postoperative motion, even if statistically greater in the onlay group (differences of 5° in forward flexion [P < .001], 3° in abduction [P = .003], and 4° in external rotation [P < .001]), was not clinically different. On comparison of complications, the inlay group showed more instances of scapular notching (93 of 322 patients vs. 70 of 415 patients; odds ratio, 0.35; P < .001) but fewer scapular spine fractures (26 of 727 patients vs. 21 of 559 patients, P = .09).

DISCUSSION

Inlay and onlay humeral tray designs in reverse total shoulder arthroplasty demonstrate similar clinical improvements postoperatively. Onlay implants have a low rate of scapular notching but a higher rate of scapular spine fracture. Understanding the strengths and weaknesses of the 2 humeral tray designs is important to provide surgeons with options to tailor surgical plans for high-risk patients.

Medialized versus Lateralized Center of Rotation in Reverse Total Shoulder Arthroplasty: A Systematic Review and Meta-Analysis

One of the original biomechanical principles of reverse total shoulder arthroplasty (RTSA) is medialization of the center of rotation (COR) relative to the native level of the glenoid. Several authors have proposed the lateralized center of rotation, which is characterized by a lateralized (L) glenoid and medialized (M) humeral component. The aim of this review is to compare the clinical and functional outcomes of COR in medialized (M-RTSA) and lateralized (L-RTSA) RTSA in patients with uniform indications and treatment through a meta-analysis. A PRISMA-guided literature search of PubMed, Medline, Embase, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Cochrane Clinical Answers was conducted from April to May 2021. Twenty-four studies were included in the qualitative synthesis, and 19 studies were included in the meta-analysis. Treatment with RTSA resulted in positive post-operative outcomes and low complication rates for both groups. Statistically relevant differences between L-RTSA group and M-RTSA group were found in post-operative improvement in external rotation with arm-at-side (20.4° and 8.3°, respectively), scapular notching rates (6.6% and 47.7%) and post-operative infection rates (1% and 7.7%). Both lateralized and medialized designs were shown to improve the postoperative outcomes. Nevertheless, a lateralized COR resulted in greater post-operative external rotation.