The majority of cases of glenohumeral arthritis in older adults are primary osteoarthritis and treatment algorithms are well defined, with shoulder arthroplasty providing reliable pain relief and functional improvement of satisfactorily duration. In younger adults, however, diagnoses are more complex and arthroplasty outcomes are less durable. Arthroscopy may be useful both as a diagnostic tool for characterizing lesions and as a therapeutic tool for debridement. Arthroscopic debridement is most likely to benefit patients with mild glenohumeral arthritis, small lesions, and involvement of only one side of the glenohumeral joint. Reconstruction of the humeral joint surface may consist of cartilage repair or reconstruction, resurfacing arthroplasty, or arthroplasty with a stemmed component. Patients treated with hemiarthroplasty avoid glenoid implant loosening, but the procedure provides less predictable pain relief than does total shoulder arthroplasty and may lead to increased postoperative glenoid erosion.