Minimum clinically important difference for the American Shoulder and Elbow Surgeons score after revision shoulder arthroplasty

BackgroundPatients undergoing revision total shoulder arthroplasty (TSA) typically achieve smaller improvements in outcome measurements than those undergoing primary TSA. The minimum clinically important difference (MCID) in the American Shoulder and Elbow Surgeons (ASES) questionnaire for primary shoulder arthroplasty ranges from 13.6 to 20.9, but the MCID for revision shoulder arthroplasty remains unclear. This study aims to define the MCID in ASES score for revision TSA and ascertain patient factors that affect achieving the MCID threshold.MethodsPatients were identified from an institutional shoulder arthroplasty database. Prospective data collected included demographic variables, prior shoulder surgeries, primary and revision implants, indication for revision, and pre- and postoperative ASES scores. All patients provided informed consent to participate. An anchor-based method was used with a binary answer choice. The MCID was calculated using the receiver-operator curve (ROC) method, and the sensitivity, specificity, and area under the curve were obtained from the ROC. MCID values were compared between groups using Student's t-test. Multivariate logistic regression modeling was used to determine significant predictors for reaching MCID. Significance was defined as P< .05.ResultsA total of 46 patients underwent revision TSA with minimum 2-year follow-up. The MCID using ROC method was 16.7 with 71% sensitivity and 62% specificity. There was a trend toward males being more likely to reach MCID after revision arthroplasty (P= .058). There were also trends toward increased forward flexion and abduction range of motion in patients who met MCID (P= .08, P= .07). Multivariate logistic regression modeling demonstrated male sex to be associated with achieving MCID (P= .03), while younger age and fewer prior shoulder surgeries demonstrated a trend to association with achieving MCID (P= .06, P= .10).ConclusionThe MCID for ASES score in patients undergoing revision shoulder arthroplasty is similar to previously reported MCID values for patients undergoing primary shoulder arthroplasty. Younger, male patients with fewer prior shoulder surgeries were more likely to achieve MCID after revision TSA.Level of EvidenceLevel III; Retrospective Comparative Treatment Study     

The incidence of humeral bone resorption in uncemented reverse shoulder arthroplasty and the impact on functional outcomes

BackgroundFull-thickness bone resorption around the humeral stem in shoulder arthroplasty is an increasingly recognized phenomenon, but the impact on outcomes remains unclear. This study aims to investigate prevalence of bone resorption in patients with the Zimmer-Biomet Comprehensive reverse shoulder arthroplasty and the impact on the functional outcomes.MethodsA retrospective analysis was carried out on 65 consecutive patients with primary reverse total shoulder arthroplasty using the Comprehensive Shoulder System from 2014 to 2020, with a minimum of 12-month follow-up. The prevalence of humeral bone resorption was graded from 0 to 4, and risk factors for these changes and their impact on functional outcomes were further investigated.ResultsThe majority of patients (75%) were female with an average age of 75 years (53-93), with an overall average follow-up of 26 months (12-60). Bone resorption occurred in 53 patients (82%), and full-thickness bone resorption occurred in only 8 patients (12%). Metaphyseal bone (zones 1 and 7) is mostly at the risk of high-grade resorption. There was no difference in the final Oxford Shoulder Score between patients who had differential resorption grades from 0 to 4 (P = .5742). None of the risk factors from the previous literature including age, sex, indication for surgery, rotator cuff tear and repair, and intramedullary occupation ratio of the implant showed any impact on the rate of resorption.ConclusionFull-thickness humeral bone resorption occurred in approximately 12% of patients when using the Comprehensive reverse shoulder arthroplasty, but it has no impact on the functional outcomes or revision rate in the short-to-medium term.