Are we failing in hip protrusio treatment?

In a recent article published in Clinical Orthopaedics and Related Research, Hanke and colleagues (1) reported the longest follow up trial available in the literature about the survivorship of hips with protrusio acetabuli treated with circumferential acetabular trimming through surgical hip dislocation. This group of patients was compared with a group of pincer type femoroacetabular impingement (FAI) without severe overcoverage. Severe pincer impingement (protrusio acetabuli) is an established cause of hip pain and osteoarthritis (OA): the acetabular roof is negatively tilted and typically deep with relative global overcoverage of the femoral head that overlaps the ilioischial line medially and protrudes in the true pelvis; therefore the size of the lunate surface is increased and leads to a pincer type FAI. Safe surgical hip dislocation described by Ganz et al.(2) with circumferential rim trimming and labral refixation or reconstruction is the current gold standard treatment for this acetabular morphology. Unfortunately this study underlines a poor expectation of survival in half of the hips with protrusio acetabuli compared with the control group according to Kaplan and Meier method’s endpoints (1): conversion to total hip arthroplasty (THA), radiographic progression of osteoarthritis, and Merle d’Aubignè-Postel score less than 15 points.