Purpose To evaluate the effect of "off-track" Hill-Sachs lesions, according to the glenoid track concept, as a risk factor for recurrent instability and need for revision surgery after arthroscopic Bankart repair. Methods We retrospectively reviewed 254 patients with anteroinferior glenohumeral instability who were managed with an arthroscopic stabilization procedure between 2006 and 2013. Preoperative magnetic resonance imaging and/or computed tomography scans were available for 100 of these patients to calculate the glenoid track and the presence of "on-track" or off-track Hill-Sachs lesions. Recurrence of instability was evaluated at a mean follow-up of 22.4 months. Results Of 100 patients whose magnetic resonance imaging and/or computed tomography scans were available, 88 had an on-track Hill-Sachs lesion and 12 had an off-track Hill-Sachs lesion. Revision surgery for recurrent instability was performed in 5 patients (6%) with an on-track Hill-Sachs lesion and in 4 patients (33%) with an off-track Hill-Sachs lesion (odds ratio, 8.3; 95% confidence interval, 1.85-37.26; P = .006). Conclusions An off-track Hill-Sachs lesion is a significant and important risk factor for recurrence of instability and need for revision surgery after arthroscopic Bankart repair when compared with an on-track Hill-Sachs lesion. Level of Evidence Level IV, prognostic case series.