Traumatic posterior hip instability and femoroacetabular impingement in athletes.

We describe 3 cases of posterior hip instability associated with femoroacetabular impingement. In each case, we obtained a detailed medical history, performed a physical examination, evaluated imaging, recorded intraoperative findings, and clinically followed the patient for 1 year. Two of the 3 patients sustained a traumatic posterior hip subluxation caused by noncontact injuries. All patients had decreased internal rotation on physical examination, radiographic evidence of acetabular retroversion, a cam lesion, an elevated α angle, and a posterior acetabular rim fracture with associated labral injury. All patients underwent hip arthroscopy and direct repair of the bony acetabular fragment using 3 to 5 suture anchors. One-year follow-up in all cases demonstrated good to excellent results and full return to activities without restriction. Patients with femoroacetabular impingement may be predisposed to traumatic posterior dislocation or subluxation and a concomitant posterior acetabular rim fracture with labral injury. We propose that FAI predisposed these athletes to posterior hip instability.