Purpose: Osteoarthritis may be observed after surgery for instability and in the natural history of pathology. The primary objective was to analyze the late clinical and radiographic results of reverse shoulder arthroplasties (RSA) for patients who had instability arthropathy.
Methods: This is a retrospective cohort of 25 patients with a mean follow-up of 6.6 years. Patients had a history of instability surgery (80%) or multiple closed reductions. All were clinically evaluated with the constant score (CS), and radiologically (true AP view and Y view).
Results: No significant differences in pre- and post-operative function, radiologic status, and complication rate between the patients treated with a prior bone block procedure for the anterior instability and those treated by a capsular plication or non-operatively. A 36-mm sphere was implanted in 67%. Bone grafting of the glenoid was needed in 71%. No intra-operative complication has been reported. Clinically, the active anterior elevation increased from 70° to 140° (p < 0.01) and external rotation from 9° to 21° (p = 0.02). The adjusted CS increased from 38 to 98 (p < 0.01). Two early post-operative complications were collected: one spine fracture and one superficial infection. No early or late dislocation or neurologic complication was observed. At the latest follow-up, there were 38.10% of glenoid spurs, and 55% of scapular notch.
Conclusions: The overall complication rate in this specific group is relatively low. Patients' satisfaction rate is high and clearly higher than those reported with anatomic TSA for this indication. Clinical results are comparable to other studies describing results of RSA.
Keywords: Anterior instability; Complication; Glenoid bone grafting; Glenoid bone loss; Reverse shoulder; Shoulder dislocation.