Abstract
Recurrent anterior shoulder instability (RASI) is related to progressive bone loss on the glenoid and on the humeral head. Bone deficit magnitude is a well-recognized predictor of recurrence of instability after an arthroscopic Bankart surgery, but the best way to measure it is unknown. In this study, we want to determine which measurement method is the best predictor of recurrence of instability and function.
For 10 years now, all patients undergoing surgery for RASI in 4 centers are included in a prospective study: the LUXE cohort. Patients with a pre-operative CT-scan and a minimum of 1-year follow-up were included. ISIS score was used to stratify patients. WOSI and Quick-Dash questionnaires were used to characterise function. Bone defects were assessed using the Clock method, the Glenoid Ratio, the Humeral Ratio, the Glenoid Track method and the angle of engagement in the axial plane.
A total of 262 patients are now included in the LUXE study. One hundred and three patients met the inclusion criteria for analysis with a majority of male (79%) and a mean age is 28 years old. The median number of dislocations prior to surgery was 6. Seventy patients had an arthroscopic Bankart repair and 33 patients underwent an open Latarjet procedure. The ISIS score for these groups were of 2.7 and 4.8 respectively (p<0.001). The mean bone defect on the glenoid was of 1h51 with the Clock method (range: 0h-4h48; SD=1h46) and of 9% for the glenoid ratio (0–37%, 10%). On the humeral side, the bone defect was of 1h59 (0h-4h08; 0h49) for the Humeral clock method, 15% (0–36%; 6%) with the ratio method and 71 degrees of external rotation (SD=30 degrees) with the angle of engagement measurement. On the combined evaluations, 53 patients presented an off-track lesion, with mean combined hours of 3h53 (SD= 2h13). The greatest correlation obtained was between the glenoid ratio and the glenoid clock method (r=0.919, p<0.001). Eighteen patients had a recurrence of shoulder dislocation after the initial surgery, leading to a recurrence rate of 23% in arthroscopic surgery versus six percent after a Latarjet (OR= 4.6, p=0.034). No bone defect was correlated to Latarjet failure. For the arthroscopic group, the risk of recurrence was related to a smaller angle of engagement of the Hill-Sachs (p=0.05), a smaller Humeral clock measurement (p=0.034) and a longer follow-up (p=0.006). No glenoid or combined measurements were correlated with arthroscopic procedure failure. Recurrence of dislocation was associated to worst function according to the WOSI (1036 vs 573, p=0.002) and DASH (32 vs 15, p=0.03).
Even with lower ISIS score, arthroscopic procedures are still leading to high risk of recurrence in this “all comer” consecutive cohort study AND it is related to humeral side parameters. Recurrence is also affecting daily function and creating higher anxiety related to the shoulder.
