On-Track Lesions with a Small Distance to Dislocation Are Associated with Failure After Arthroscopic Anterior Shoulder Stabilization.

BACKGROUND Off-track lesions are strongly associated with failure after arthroscopic Bankart repair. However, on-track lesions with a small distance-to-dislocation (DTD) value, or "near-track lesions," also may be at risk for failure. The purpose of the present study was to determine the association of DTD with failure after arthroscopic Bankart repair. METHODS We performed a retrospective analysis of 173 individuals who underwent primary arthroscopic Bankart repair between 2007 and 2015. Glenoid bone loss and Hill-Sachs lesion size were measured with use of previously reported methods. Patients with failure were defined as those who sustained a dislocation after the index procedure, whereas controls were defined as individuals who did not. DTD was defined as the distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track. Receiver operating characteristic (ROC) curves were constructed for DTD to determine the critical threshold that would best predict failure. The study population was subdivided into individuals ≥20 years old and <20 years old. RESULTS Twenty-eight patients (16%) sustained a recurrent dislocation following Bankart repair. Increased glenoid bone loss (p < 0.001), longer Hill-Sachs lesion length (p < 0.001), and decreased DTD (p < 0.001) were independent predictors of failure. ROC curve analysis of DTD alone demonstrated that a threshold value of 8 mm could best predict failure (area under the curve [AUC] = 0.73). DTD had strong predictive power (AUC = 0.84) among individuals ≥20 years old and moderate predictive power (AUC = 0.69) among individuals <20 years old. Decreasing values of DTD were associated with a stepwise increase in the failure rate. CONCLUSIONS A "near-track" lesion with a DTD of <8 mm, particularly in individuals ≥20 years old, may be predictive of failure following arthroscopic Bankart repair. When using the glenoid track concept as the basis for surgical decision-making, clinicians may need to consider the DTD value as a continuous variable to estimate failure instead of using a binary on-track/off-track designation. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of Levels of Evidence.