Glenoid Pathology Is Similar Between Osteoarthritis and Postcapsulorrhaphy Arthropathy: A Propensity-Matched Analysis

BACKGROUND: Postcapsulorrhaphy arthropathy (PCA) may result as a long-term sequela of instability surgery, eventually necessitating shoulder arthroplasty. Alterations to the soft tissue and bony anatomy during the index surgery may lead to unique wear patterns of the glenohumeral joint compared with what is observed in primary glenohumeral osteoarthritis (GHOA). We sought to characterize the three-dimensional glenoid morphology of patients with PCA to understand whether arthritic wear patterns are distinct from those observed in GHOA. METHODS: Patients diagnosed with GHOA or PCA were retrospectively propensity matched in a 4:1 ratio by age and sex. Radiographic measurements-including glenoid inclination, version, humeral head subluxation, glenoid vault loss, and maximum erosion depth-were assessed using Materialise Surgicase Preoperative Planner. The presence of biplanar glenoid deformity, defined as glenoid inclination and version ≥10° was assessed. The PCA cohort was further stratified by capsulorrhaphy technique (open vs. arthroscopic). Univariate analysis was conducted to compare glenoid morphology between cohorts and subcohorts. RESULTS: After matching, the GHOA and PCA cohorts consisted of 264 and 67 patients, respectively, with no notable differences in age (GHOA 64.9 ± 7.0 years vs. PCA 63.6 ± 8.1 years; P = 0.236) or sex (85.0% male GHOA vs. 82.1% male PCA; P = 0.714). The PCA cohort demonstrated a markedly greater degree of superior inclination compared with the GHOA cohort (7.5 ± 5.4 vs. 4.3 ± 5.7; P = <0.001), although this is not likely clinically relevant. No other notable differences in any of the other radiographic measurements or parameters between GHOA and PCA cohorts were found. The arthroscopic and open PCA subcohorts consisted of 34 and 25 patients, respectively, with no notable differences in radiographic parameters observed between the open and arthroscopic cohorts (P > 0.05). CONCLUSION: Arthritic glenoid wear patterns in patients with PCA and GHOA demonstrate no notable differences despite the altered soft tissue and bony anatomy inherent to instability surgery. Subcohort analysis of open versus arthroscopic capsulorrhaphy revealed no notable differences in glenoid morphology. Although PCA presents unique surgical challenges, these may be more closely tied to soft-tissue alterations than to variations in glenoid morphology. LEVEL OF EVIDENCE: Level III; Retrospective Comparative Study.