Femoroacetabular impingement failure hinges upon several determining factors

Certain joint characteristics could lead to difficulty with impingement procedures.

Femoroacetabular impingement surgery should be reserved for patients whose hips display structural impingement abnormalities and a lack of advanced secondary osteoarthritis in order to minimize the risk of failure.

These were the findings of John C. Clohisy, MD, who presented his research on what determines femoroacetabular impingement (FAI) patient viability at the 15th combined open meeting of The Hip Society and the American Association of Hip and Knee Surgeons in Las Vegas, during the American Academy of Orthopaedic Surgeons 76th Annual Meeting.

Clohisy’s research was based on his experience and the experiences of others, as he drew from nine clinical papers to determine the factors for what may define a patient eligible for a successful procedure and what factors may eliminate them due to risk of clinical failure.

“Surgical treatment of impingement has become quite common,” he said. “The overall clinical results of hip impingement surgery presently are encouraging in early follow-up, yet suboptimal results and early failures are reported” in a number of series.

Ideal procedural candidates

Though the etiology of these treatment failures has not been clearly defined, Clohisy said that he and many other surgeons would agree that patient selection is a critical component of successful surgical treatment. The ideal surgical candidate, he continued, is a young, well-conditioned patient with a symptomatic hip.

“In general, they have activity related hip pain – predominately groin pain – worsened with flexion and internal rotation,” he said. “They also have restricted hip flexion. The ideal candidate would have minimal intra-articular disease and a defined impingement deformity that we can correct surgically.

“Unfortunately, many of our patients do not meet these criteria,” he added. “That is the challenge.”

Preoperative (left) and postoperative frog-leg lateral X-rays of a 20-year-old male with cam impingement. Recontouring of head-neck offset is seen on the postoperative views. An acetabular labral tear was fixed with suture anchors. Images: Clohisy JC

Patients older than 30 years require a measure of caution from operating physicians, Clohisy said. Selectivity is key, and an aged patient’s articular cartilage should be carefully analyzed via MRI. Other dangers include male patients in their 30s and 40s.

“When we see male patients, we have to realize that the intra-articular disease is usually far more extensive than the studies suggest,” Clohisy said. “Men into their 30s and 40s with impingement – those hips are very much at risk for failure.”

How to predict effectiveness

According to the basic clinical data from the articles, Clohisy said clinical outcomes were rated as good to excellent in 82% of hips. Still, clinical failures occurred in 10% of the hips. Reportedly, the studies were able to give a consensus regarding associations with failure in impingement procedures. However, Clohisy noted, further research is required.

“There is clearly a need for information regarding the prognostic factors that affect hip impingement surgery and dictate outcome,” he said.

Symptom severity and duration can be a tip-off as to whether or not the hip in question is too far gone, Clohisy said. If a hip patient starts to sound more like a total hip patient, then they are likely not a good candidate for hip-preservation surgery.

Additionally, moderately diseased hips with a narrowing joint space or subluxation of the head indicate that a significant caution is recommended in the performance of hip impingement operations. A severe deformity is another indication that the operation may have a poor prognosis over time.

Who should get surgery?

Clohisy said it is important to note that the majority of clinical evidence regarding the results of hip impingement surgery is only level IV. Still, he said, patients under the age of 50 with symptomatic hips and problems consistent with the diagnosis of symptomatic impingement make for the best patients. Ideally with these patients there is no amount of secondary osteoarthritis.

He also outlined what to be wary of in patients, so as to avoid a failed or unacceptable result.

“As far as who should not get an operation: patients with unclear or alternative diagnoses,” he said. “Patients with moderate to severe secondary osteoarthritis – we really have to think about that – and I don’t think we’re ready to recommend treatment in asymptomatic hips at this point.”

Clohisy said further study is needed to better identify patient-specific and disease-specific factors that are predictive of treatment results. Furthermore, improved imaging modalities will also help in the evaluation of osteoarthritic stages and “responsiveness” of the joint being treated.

For more information:

• John C. Clohisy, MD, is a professor of orthopedic surgery at the Washington University School of Medicine in St. Louis. He can be reached at the Department of Orthopedic Surgery, Washington University School of Medicine, 1 Barnes-Jewish Plaza, Suite 11300 West Pavilion, Campus Box 8233, St. Louis, MO 63110; e-mail: clohisyj@wudosis.wustl.edu. He has no direct financial interest in any products or companies mentioned in the article.

Reference:

• Clohisy JC. Femoroacetabular impingement: who should get an operation and who should not? Presented at the 15th combined open meeting of The Hip Society and the American Association of Hip and Knee Surgeons. Feb. 28, 2009. Las Vegas.