Purpose: The Instability Severity Index Score (ISIS) includes preoperative clinical and radiological risk factors to select patients who can benefit from an arthroscopic Bankart procedure with a low rate of recurrence. Patients who underwent an arthroscopic Bankart for anterior shoulder instability with an ISIS lower than or equal to four were assessed after a minimum of 5-year follow-up.
Methods: Forty-five shoulders were assessed at a mean of 79 months (range 60-118 months). Average age was 29.4 years (range 17-58 years) at the time of surgery. Postoperative functions were assessed by the Walch and Duplay and the Rowe scores for 26 patients; an adapted telephonic interview was performed for the 19 remaining patients who could not be reassessed clinically. A failure was defined by the recurrence of an anterior dislocation or subluxation. Patients were asked whether they were finally very satisfied, satisfied or unhappy.
Results: The mean Walch and Duplay score at last follow-up was 84.3 (range 35-100). The final result for these patients was excellent in 14 patients (53.8 %), good in seven cases (26.9 %), poor in three patients (11.5 %) and bad in two patients (7.7 %). The mean Rowe score was 82.6 (range 35-100). Thirty-nine patients (86.7 %) were subjectively very satisfied or satisfied, and six (13.3 %) were unhappy. Four patients (8.9 %) had a recurrence of frank dislocation with a mean delay of 34 months (range 12-72 months). Three of them had a Hill-Sachs lesion preoperatively. Two patients had a preoperative ISIS at 4 points and two patients at 3 points.
Conclusion: The selection based on the ISIS allows a low rate of failure after an average term of 5 years. Lowering the limit for indication to 3 points allows to avoid the association between two major risk factors for recurrence, which are valued at 2 points. The existence of a Hill-Sachs lesion is a stronger indicator for the outcome of instability repair.
Level of evidence: Level IV, Retrospective Case Series, Treatment Study.