Summary
Repair strategies should augment for the patients with higher instability severity index score and higher glenoid track index.
Abstract
Purpose
Several risk factors for re-dislocation after arthroscopic Bankart repair (ABR) were identified. The Instability Severity Index Score (ISIS) was developed to preoperatively analyze the risk of failure with clinical and radiological factors. The glenoid track concept was used to determine the engagement of Hill-Sachs lesion, correlated to recurrent dislocation. We evaluated the validation of ISIS and the glenoid track concept for re-dislocation after ABR, and sought to identify risk factors.
Methods
160 patients with who experienced ABR with suture anchors were followed from June 2005 through Dec 2013. We evaluated re-dislocation after ABR at the outpatient department (follow-up rate, 90%) and correlated re-dislocation with several risk factors, including sex, age, ISIS, dislocation times, type of sports, and amount of suture anchor. Based on the glenoid track concept, we designed a novel parameter “glenoid track index” (Hill-Sachs lesion interval divided by glenoid track width).
Results
The average age of patients and follow-up period was 27.7 (range, 14–48) years and 77.2 (range, 24–150) months, respectively. Re-dislocation after ABR occurred in 22 shoulders (13.7%). Univariable logistic regression analysis showed that higher ISIS (P = 0.004), off glenoid track (P < 0.001), and higher glenoid tract index (P < 0.001) had significant correlations with re-dislocation. On multivariate analysis, higher glenoid tract index was an independent risk factor for failure of operation. If the glenoid tract index was equal or more than 0.7, there was a significantly higher re-dislocation rate. Age, sex, and frequent dislocation were not negative predictors for re-dislocation.
Conclusions
The glenoid track concept had a good clinical application with magnetic resonance imaging pre-operative survey, and “glenoid tract index” may be a reliable parameter for predicting re-dislocation. The repair strategies should be modified for patients with higher ISIS and higher glenoid track index.