Clinical characteristics and patient-reported outcomes of total shoulder arthroplasty after anterior stabilization: a retrospective matched control study.

Background: Instability arthropathy is a known cause of glenohumeral osteoarthritis (OA) among patients with and without prior shoulder stabilization. This study aims to compare the clinical, radiographic, and patient-reported outcome measure (PROM) scores among total shoulder arthroplasty (TSA) patients with and without a history of shoulder stabilization.

Methods: A case-control study was performed comparing 20 patients with a history of anterior shoulder stabilization (11 open, 9 arthroscopic) who underwent TSA to a matched cohort of 20 TSA patients without a history of shoulder surgery (mean follow-up = 2.8 years). Patients were matched by sex, age, and baseline American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score within 10 points (mean age 59.6 ± 9.6 years). Patient characteristics, operative findings, and preoperative and postoperative radiographic characteristics for both groups were reported. Comparisons were made regarding PROM scores (ASES, 12-Item Short Form Health Survey (SF-12), Shoulder Activity Scale [SAS], numeric rating scale for pain) at baseline, 2 years, and 5 years and patient satisfaction at 2 years.

Results: Intraoperative findings of subscapularis scarring or attenuation was common among patients with prior anterior stabilization. The instability cohort did have a higher percentage of B2/B3 glenoid types than the OA cohort (45% vs. 15%), but this was not significantly different possibly because of the small sample size. At 2 years, both instability and OA groups reported significant improvement in pain, function, and activity level. There was no difference between groups on any PROMs or patient satisfaction level. At 5 years, instability patients had significantly lower scores on the ASES and the SF-12 PCS than the OA group.

Conclusion: There was notable alterations in both soft tissue and bony morphology among patients with prior anterior stabilization. After TSA, both instability and primary OA groups showed significant improvements at 2 years. However, PROMs for instability patients deteriorated at 5 years compared with the control group. Complex bony and soft tissue imbalances may contribute to more unpredictable long-term PROM scores. Thoughtful preoperative consideration of these factors should influence decision making regarding selection of TSA for management of OA in this complex patient cohort.