The glenoid track concept is insufficient to predict Bankart failures: a computed tomography scan study

Abstract

BackgroundThe glenoid track concept identifies patients with “off-track” (engaging) Hill-Sachs lesions (HSLs) as poor candidates for arthroscopic Bankart repair (ABR) due to high risk of shoulder instability recurrence. PurposeTo retrospectively calculate the glenoid track index, using preoperative computed tomography (CT) scans, in a cohort of patients with failed ABR. We hypothesized that all patients with a failed ABR would have engaging (“off-track”) Hill-Sachs lesions on preoperative CT-scan. Type of StudyComputed tomography scan study MethodsPreoperative computed tomography (CT) scan of 45 patients, seen in our facility for failed ABR, were used to retrospectively calculate the glenoid track index. The risk of recurrence was also calculated for each patient using Instability Severity Index Score (ISI-Score) and Glenoid Track Instability Management Score (GTIMS). There were 37 failed isolated ABRs and 8 associated Hill-Sachs remplissage. The mean t age at surgery was 24 years (range, 15-52) and instability recurred at a mean of 29 months postoperative (range, 3-167). ResultsPreoperative CT-scan imaging identified “off-track” bony lesions in 85% of patients (38/45), and “on-track” lesions in 15% (7/45). No significant differences were noted between the two groups (off-track versus on-track) regarding patient age, hyperlaxity, sports participation, size of HS lesion, or ISI score. The mean glenoid bone loss was 15.7% (range, 4-36%) with mean Hill-Sachs width was greater than 20mm in 66% of CT scans. The preoperative ISI-Score was predictive of failures (> 3 points in all patients) with no difference between on-track and off-track patients (6.3 ±1.7 versus 6.6 ±1.7, p=0.453). By contrast, the GTIMS did not predict failures as there was a significant difference between GTIMS for on-track and off-track patients (2.1 ±1.3 versus 6.6 ±1.7). ConclusionsThe glenoid track concept alone is insufficient to predict Bankart failures: in the present series of failed ABR, 15% of shoulders had “on-track” (non-engaging) lesions on preoperative CT-scan. In patients, with “on track” bony lesions, the ISI-Score is a useful predictive tool to detect patients at risk of failure, while the GTIMS is not.