Inlay Total Shoulder Arthroplasty for Primary Glenohumeral Arthritis

Abstract Background Anatomic total shoulder arthroplasty (TSA) with a non-spherical humeral head and inlay glenoid replacement has been introduced in the past, however clinical evidence remains limited. We hypothesized that patients with advanced glenohumeral arthritis demonstrate significant improvements in pain and function. Methods Prospective patient-reported outcomes (PRO) included the American Shoulder and Elbow Surgeons score (ASES), a pain visual analog scale (VAS-Pain), and satisfaction. Range of motion (ROM) was compared to the preoperative status. A sensitivity analysis examined responder rates and compared them to literature thresholds using the minimal clinically important difference (MCID) and substantial clinical benefit (SCB). The preoperative glenoid morphology was determined using the Walsh classification. Zone-specific periprosthetic radiolucent lines were quantified at last follow-up. Results Thirty-nine shoulders in 36 patients (3 bilateral) with a mean age of 65.9 years (26 males, 13 females) and a mean follow-up of 41.0 months were included. 93% had Grade III osteoarthritis, 7% Grade II. The glenoid Walsh classification included A1 (25%), A2 (25%), B1 (22%), B2 (25%) and C (3%). All PROs improved significantly (p > 85%. Forward elevation improved from 1070 to 1550, and external rotation from 220 to 510. One intraoperative glenoid rim fracture led to advanced radiolucency; no other clinically relevant lucency was observed. Conclusion Treatment with inlay total shoulder arthroplasty demonstrated significant functional improvement, excellent pain relief, and patient satisfaction in patients with advanced shoulder arthritis and various glenoid morphology types. Our initial results provide further support for this new option in primary shoulder replacement.