The role of Hill-Sachs localization on the failure of arthroscopic shoulder stabilization. The results of a prospective cohort study

OBJECTIVES: Recurrent glenohumeral instability is frequently associated with glenoid and humeral bone loss. It is predictive of capsulolabral repair failure. However, the best way to quantify these shortcomings remains controversial. The aim of our study is to determine the best predictor of recurrent instability after arthroscopic shoulder stabilization. METHODS: Over the past 10 years, all the patients recruited for shoulder stabilization surgery in 4 academic centers have been included in the prospective cohort called "LUXE". The ISIS score is used to stratify patients for surgery (Bankart, Bankart + Remplissage, Latarjet). Only patients with a preoperative CT scan with 3D reconstruction and clinical follow-up ≥1 year were included. Of a total of 262 patients included in the “LUXE” cohort, 103 met the inclusion criteria. The majority of patients were male (79%) with an average age of 28 years. The median number of dislocations before stabilization surgery was six. Bone deficits were measured on the 3D reconstructions using the Glenoid Clock and Ratio, the Humeral Clock and Ratio and the Glenoid Track methods and the angle of engagement of the Hill-Sachs lesion in the axial plane. RESULTS: Seventy patients had arthroscopic stabilization and 33 a Latarjet procedure. The ISIS scores for the two groups were 2.7 and 4.8 (p<0.001) respectively. The average glenoid bone loss was 9+/-10% (0-37%), humeral bone loss was 15+/-6% (0-36%) and the angle of engagement of the Hill-Sachs lesion was 71+/-30° in external rotation. Fifty-three patients (51%) had an off-track lesion. Eighteen patients had recurrent instability after arthroscopic stabilization (23%) versus only 2 patients (6%) for Latarjets (OR= 4.6, p=0.034). Preoperative bone loss was not related to failure after a Latarjet procedure. The risk factors identified after arthroscopic stabilization were a lower engaging Hill-Sachs angle in external rotation (65° vs. 72°; p=0.05), less humeral bone loss (humeral clock of 42° vs. 58°; p=0.034) and an extended follow-up time (p=0.006). Glenoid bone loss, or the combined measurement (glenoid track) was not predictive of failure. CONCLUSION: Despite a lower ISIS score, arthroscopic management with Bankart +/- Remplissage is correlated with a significantly higher recurrence rate compared to the Latarjet procedure. Failure was related to humeral bone loss and to the morphology/orientation of the Hill-Sachs lesion rather than the volume of bone loss.