Surgery for femoroacetabular impingement (FAI) has been reported "successful" but results are only available for the early or short-term postoperative period. This study from Switzerland followed a group of 185 patients treated with open hip surgery for this problem. The follow-up period was at least five years. The measures of "success" included hip range-of-motion, X-ray results, patient satisfaction, and activity level. The need for further surgery (and especially conversion to a total hip replacement) was also recorded.

Femoroacetabular impingement (FAI) causes abnormal contact between the femoral neck and the acetabular (hip socket) rim. Pinching of the labrum (cartilage around the edge of the socket causes damage to the cartilage and to the bone. The result can be a stiff, painful hip with loss of motion and function.

One treatment used for this condition is surgery to alter the anatomic abnormalities that contribute to the problem. For the patients in this study, the hip was surgically dislocated, the tissue was trimmed, and the bone was reshaped to eliminate the abnormal contact that causes this type of pinching.

The goals of surgery are to return the patients to full, normal activities without pain and to prevent (or at least slow down) hip osteoarthritis. Most of the patients with FAI are young, athletes. Patient satisfaction depends on good-to-excellent long-term results. This study provides mid-term results with the intention of following these patients into the long-term.

Outcomes of activity and function were measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the SF-12 Physical and Mental Scores, and the University of California - Los Angeles (UCLA) activity scale. Before and after measurements showed improvement in hip motion and function. Eighty-three per cent (83%) of the group said their hips were normal (or near normal) in the follow-up period.

In general, surgeons say that the surgical method of dislocating the hip allows them to examine the shape and surface of the joint carefully. Surgical hip dislocation gives them an excellent opportunity to repair or detach the excess or frayed labral rim and reshape the bone itself. Restoring normal head-neck angle and position of the femoral head in the socket makes normal hip motion possible.

In summary, surgery to correct femoroacetabular impingement (FAI) has become a standard method of treatment with good results in the short-term. This study shows that this procedure also provides good-to-excellent mid-term outcomes. Defects or lesions (holes) in the cartilage that go all the way through to the bone even after surgical trimming were the most reliable predictor of patient dissatisfaction. This type of deep damage is also the main reason why hip replacement was the next step in treatment.

Long-term follow-up will be able to determine whether open surgery with surgical dislocation to correct FAI helps prevent degeneration of the joint. Slowing the formation of osteoarthritis would be an acceptable outcome as well.

Finding ways to prevent the need for hip replacement in such young, active individuals will be another focus of future studies. And finally, in this study they reported that slim, older women seemed to be most likely to experience a poor outcome. The reasons for this must be explored further with the hope of improving the results for this patient group.

Reference: Florian D. Naal, MD, et al. Midterm Results of Surgical Hip Dislocation for the Treatment of Femoroacetabular Impingement. In The American Journal of Sports Medicine. July 2012. Vol. 40. No. 7. Pp. 1501-1510.