‘Impingement’ sign resolves after hip arthroscopy based on 2-year results

Outcomes approach those of open surgery, but surgeons must address complications like heterotopic ossification.

SAN FRANCISCO — Arthroscopically treating patients with femoro-acetabular impingement can lead to at least a short-term improvement in symptoms, according to a study presented here.

Christopher M. Larson, MD, of Eden Prairie, Minn., and colleague Marc R. Giveans, MD, reviewed outcomes for patients treated arthroscopically for various causes of hip impingement, such as pincer and cam impingement. Larson presented their findings at the Arthroscopy Association of North America 26th annual meeting.

Experts are increasingly recognizing this disorder of the hip, known as the "impingement" sign, but more data on treatment outcomes are needed. The technique Larson reported on may be the state of the art at the moment, said Thomas G. Sampson, MD, who moderated the session.

From 2004 to 2006, surgeons treated 46 hips in 45 patients with documented, radiographically confirmed cases of femoro-acetabular impingement (FAI). The study included 37 men and eight women with a mean age of 38 years. All hips had labral tears and 96% had chondral pathology. Also, 33 patients had cam impingement and fewer patients had either pincher impingement or combination pathology.

For treating FAI, surgeons used arthroscopic techniques to manage intra-articular pathology, including debriding or repairing the labrum, performing proximal femoral osteoplasty or trimming the acetabulum.

Investigators examined patients preoperatively and at 6 weeks, 3 months, 6 months and annually thereafter using the impingement sign, modified Harris hip score (HHS), the Short Form-12 (SF-12) and Visual Analog Scale (VAS) pain score.

At 2-year mean follow-up, the impingement sign resolved in 85% of patients (P<.001). In addition, modified HHS, SF-12 scores and VAS scores all improved significantly from preop scores, according to the study abstract.

Complications included one case each of heterotopic ossification and lateral femoral cutaneous nerve neuropraxia.

Sampson said he was glad no femoral neck fractures associated with the procedure had occurred, but he was concerned with the one case of partial sciatic nerve neuropraxia, even though it had resolved.

However, the study shows that the technique can be safely used as an effective alternative to open procedures, with nearly similar results, Sampson said.

For more information:
Larson CM, Giveans MR. Arthroscopic management of femoro-acetabular impingement: Early outcomes measures. #SS-16. Presented at the Arthroscopy Association of North America 26th Annual Meeting. April 26-29, 2007. San Francisco.