Arthroscopic Fixation of Os Acetabuli Technique: When to Resect and When to Fix

Acetabular rim fractures, or os acetabuli, are hypothesized to occur as a result of an unfused ossification center or a stress fracture from repetitive impingement of an abnormally shaped femoral neck against the acetabular rim. When treated surgically, these fragments are typically excised as part of the correction for femoroacetabular impingement. However, in some patients, removal of these fragments can create symptoms of gross instability or microinstability of the hip. In these cases, internal fixation of the fragment is necessary. The purpose of this technical note is to describe indications, the arthroscopic technique, and postoperative care for fixation of acetabular rim fractures.