Predictors of functional outcomes and recurrent shoulder instability after arthroscopic anterior stabilization

Purpose: To investigate what factors might predict the results of arthroscopic stabilization for anterior shoulder instability. Methods: One hundred and forty-three patients averaging 25 (15–58) years with traumatic anterior shoulder instability who underwent arthroscopic stabilization were reviewed at a median follow-up of 81 (24–172) months. Sixty-two (56.4 %) individuals were involved in contact sport activities, and there were 40 (30 %) patients who had only one dislocation prior to having surgery. Rowe score was measured preoperatively and at follow-up. Results: Thirty-three (23.1 %) patients experienced recurrent instability 12 (1–120) months after surgery, and 15 of those underwent further surgery. There was a statistically significant lower risk of failure (p = 0.027) for patients who had a surgical procedure after only one episode of shoulder dislocation. Patients treated after the second or further episode of shoulder dislocation exhibited a mean odds ratio for failure of 3.8 (95 % confidence interval 1.2–11.6, p = 0.044) with regard to first-time dislocators. The Rowe score significantly improved from a preoperative value of 25 (5–55) to a postoperative value of 100 (40–100) (p < 0.001). A significantly higher postoperative Rowe score was found in patients older than 24 years of age at the operation (p = 0.011) and in patients with less than eight dislocations prior to surgery (p = 0.05). Conclusions: These results suggest that better functional results following arthroscopic stabilization can be expected in patients over 24 years of age and in those with a fewer number of dislocations preoperatively. A lower rate of recurrence can be expected if the patient undergoes surgery after the first episode of dislocation. Level of evidence: Prognostic study, Level II.