Advanced glenohumeral osteoarthritis: the relationship between radiographic pathoanatomy and clinical presentation

Shoulder arthroplasty is indicated to treat pain and dysfunction associated with advanced glenohumeral osteoarthritis (GHOA). However, the relationship between preoperative pathoanatomy and clinical presentation remains unclear. The purpose of this study was to evaluate associations between radiographic pathoanatomy, physical examination findings, patient-reported outcomes (PROMs), and health-related quality of life (HRQoL) in patients with advanced GHOA who elect to undergo shoulder arthroplasty. This retrospective study included 280 patients with primary GHOA (148 males, 52.9%; mean age 68.5 ± 8.6 years) who were treated with anatomic total shoulder arthroplasty (aTSA, n = 147), reverse total shoulder arthroplasty (RSA, n = 81), or ream and run arthroplasty (RNR, n = 52). Preoperative pathoanatomy was characterized using plain radiographs and CT scans and classified according to the Samilson-Prieto (SP), Kellgren-Lawrence (KL) and Walch classifications. Additional radiographic parameters were evaluated. Associations between pathoanatomy and clinical presentation were analyzed using multivariable regression. The minimal clinically important difference (MCID) was used to evaluate the clinical significance of associations. Greater humeral head flattening was associated with significantly and clinically relevant less active forward elevation (AFE) (B = -0.56, P = .048), active external rotation (AER) (B = -0.38, P = .048), and internal rotation (IR) (B = -0.06, P = .027). Larger humeral neck spur size was associated with significant and clinically relevant less AER (B = -0.40, P = .01). There were no clinically significant associations between SP grade, KL grade, Walch classification, critical shoulder angle, humeral medialization, glenoid version, or glenoid inclination and ROM or PROMs. There were no significant associations between pathoanatomy and HRQoL. There were limited associations between the severity of pathoanatomy in advanced GHOA and clinical presentations. The only significant associations between pathoanatomy and the clinical presentation related to the humerus, correlating with reduced ROM, but not with PROMs or HRQoL. These findings suggest that existing classification systems for GHOA may not fully capture the variability in clinical symptoms. Further research with larger cohorts, including patients with earlier stage GHOA, is needed to clarify the relationship between pathoanatomy and clinical manifestations of GHOA.