Single-surgeon study compares open and arthroscopic approaches for treating FAI

“Surgical dislocation for the treatment of femoroacetabular impingement (FAI) has arguably been the gold standard,” explained Benjamin G. Domb, MD, speaking at the annual meeting of the Arthroscopy Association of North America, “but arthroscopic techniques have advanced to the point of potentially reproducing the outcomes of open surgery.”

Dr. Domb and his team set out to compare the outcomes between a group of patients treated arthroscopically and a similar group treated with open surgery. From a cohort of 289 patients who had preservation hip surgery performed by Dr. Domb, 28 patients met the inclusion criteria—patients younger than 30 years old who had combined cam and pincer impingement. Patients were excluded if they had accepted worker’s compensation, or if they had hip dysplasia or previous hip surgery other than diagnostic arthroscopy. There were 23 patients in the arthroscopic group and 5 patients in the open group. The research team matched the patients across groups based on demographics and preoperative characteristics.

A faster recovery?
“Matching the groups in the study was one of our hardest challenges,” said Dr. Domb. “The open group was younger—15 years old on average, as opposed to 21 years old in the arthroscopic group, and that was the best we could do to match them. We explained the pros and cons of each approach and allowed the patient to make a decision. The one potential selection bias is that patients younger than age 18 tend to have the decision made by their parents, whereas patients older than 18 years tend to make the decision themselves.”

All of the patients in both groups had labral tears, and all underwent acetabular rim trimming and femoral osteoplasty. In addition, all but four patients in the arthroscopic group underwent labral refixation.

“We hypothesized that the arthroscopic approach would result in a faster recovery,” said Dr. Domb. “We expected 1-year outcomes to be equivalent, and long-term outcomes to be slightly better with the open approach due to increased precision.”

At 3 months follow-up, patients in the arthroscopic group showed greater improvement in all scores—Modified Harris Hip Score and both the activities of daily living [ADL] and sports-specific subscales of the Hip Outcomes Score—but the difference was not statistically significant. At an average follow-up of 9.9 months, scores for all patients were equivalent in all outcomes except the sports-specific subscale; on that subscale, patients in the arthroscopic group continued to show a trend toward greater improvement.

“We attributed the difference in early scores to a faster rehabilitation protocol and the absence of trochanteric osteotomy in the arthroscopic group,” explained Dr. Domb.

Strengths and limitations
According to Dr. Domb, the limitations of the study included the small sample size and the short length of follow-up.

“It should be noted that, if open surgical dislocation has the advantage of slightly greater precision in bony decompression, the effect on outcomes may only manifest at 5 to 10 years follow-up,” he said.

The strengths of the study included the fact that the data was gathered prospectively from a single-surgeon performing similar surgeries through either an open or arthroscopic approach and that the two groups were well-matched in all factors except for age.

“The only difference we noted between the two groups was in the size of the labral tear,” said Dr. Domb. “The tears were larger in the open group than in the arthroscopic group, and the arthroscopic group had slightly more cartilage damage. But I believe that those differences were most likely due to our ability to observe them. In the open group, we had an appreciation of a greater span of pincer impingement, and therefore a greater span of the labral tear. In the arthroscopic group, we had a better look in magnification at the cartilage, so we probably saw that a little bit better.”

Based on the study data, Dr. Domb concluded that, in the short term, both open surgical dislocation and an arthroscopic approach are viable options, although the arthroscopic approach may allow a faster recovery and return to sports. The team is currently conducting a longer-term study with the same group of patients.

Dr. Domb is a staff physician of Hinsdale Orthopaedic in Chicago, and is on the faculty of Loyola University’s Stritch School of Medicine.

Dr. Domb’s coauthors included Itamar Boster, MD, and Thomas W. Smith, BS.

Disclosure information: Dr. Domb—Arthrex, Inc.

Peter Pollack is a staff writer for AAOS Now. He can be reached at ppollack@aaos.org