Is the Evidence in Favor or Against Surgery for Femoroacetabular Impingement?
Impingement refers to some portion of the soft tissue around the hip socket getting pinched or compressed. Femoroacetabular tells us the impingement is occurring where the femur (thigh bone) meets the acetabulum (hip socket). There are several different types of impingement. They differ slightly depending on what gets pinched and where the impingement occurs.
Current understanding of this hip deformity has resulted in surgery to correct the deformity. The short-term goals are to relieve pain and improve function. The long-term goal is to prevent hip osteoarthritis.
But does the evidence support this treatment approach? Are there complications or problems after the surgery that might outweigh the benefits received? In order to find out, researchers at the Washington University School of Medicine in St. Louis conducted this study.
They reviewed five major database systems looking for any articles published on the topic with reports on long-term results. This type of literature review is called a systematic review.
They examined the study design, level of evidence, number of patients in each study, and number of years in the follow-up period. A minimum of two years follow-up was required to be included in the final studies chosen for review.
The ages of the patients, any unique features presented, and type of surgery performed were all analyzed. Results were measured in terms of hip function and number of additional surgeries and failures.
Failure was not always defined the same from study to study. In some cases, continued pain after surgery was considered a failure. In other studies, osteoarthritis requiring a joint replacement was counted as a failure.
The authors also considered the type of surgical procedures performed to see if one technique was more successful than others. Arthroscopic versus open incision approaches were also compared. And data on complications such as infection, fracture, broken or bent screws, or loss of blood to the area was also collected.
They found that reduced pain and better hip function were two by-products reported in all studies. More than two-thirds (68 per cent) of the patients and as many as 96 per cent had positive short-term results. But there were quite a few complications reported in some studies. As many as one-fourth of the patients had to convert to a total hip replacement.
In summary, modern understanding of femoroacetabular impingement has led to the development of surgical correction of the deformity to prevent osteoarthritis. Is there enough evidence to support this treatment approach? In the short-term, yes but there isn't enough proof yet that the benefits persist long-term.
The authors suggest there is plenty of room for further study before decisions can be made about the best way to surgically treat femoroacetabular impingement. It makes logical sense that restoring the hip to a more normal anatomical shape would prevent arthritis from developing over time. But the evidence to support this approach is limited and not necessarily high-level evidence.
The main problems are the lack of consistent study design and use of inconsistent reporting measures. With so much variability in how studies are conducted, it's difficult to compare one study to the next.
At the very least, they could see that patients who already had severe arthritic changes at the time of surgery were the least likely to have a good result. Other pre-operative factors that could predict a poor result included older age and severe pain. Those findings suggest surgeons should give patients with these factors careful consideration before performing surgery to redesign the hip.
John C. Clohisy, MD, et al. Surgical Treatment of Femoroacetabular Impingement. In Clinical Orthopaedics and Related Research. February 2010. Vol. 468. Pp. 555-564.