Femoroacetabular impingement (FAI) frequently results from childhood diseases such as developmental dysplasia of the hip, Legg-Calvé-Perthes, or slipped capital femoral epiphysis. Although FAI in adults is often treated with open surgical dislocation and a greater trochanteric osteotomy, a different approach may be beneficial for treating FAI in pediatric patients.

According to a study presented at the 2008 AAOS Annual Meeting, hip arthroscopy produces excellent improvement in function and a high level of patient satisfaction at 1-year follow-up.

“FAI is a result of excessive anterolateral coverage of the femoral head or an abnormal femoral head-neck junction,” reported Marc J. Philippon, MD. “Although impingement may not be an issue until adulthood, we are increasingly recognizing its symptoms in pediatric patients.”

Young athletes, persistent pain
In this study, 16 pediatric athletes (14 females and 2 males, ranging in age from 13 to 16 years) underwent hip arthroscopy; one patient had a bilateral procedure.

Indications for surgery included persistent pain despite conservative management, mechanical symptoms and radiographic evidence of FAI, and a positive clinical physical exam that included the anterior impingement and FABER tests. Both a magnetic resonance image and radiographs (anteroposterior pelvic view and cross-table lateral view of the affected side) were taken.

Preoperative radiographs did not show any evidence of dysplasia; none of the patients had had any previous hip surgery or provided a history of hip problems. All patients, however, did have radiographic evidence of FAI: five with isolated pincer impingement, two with isolated cam impingement (abutment of the femoral head-neck junction against the acetabulum during flexion), and nine with mixed pathology. The average time from injury to surgery was 10.6 months (range: 6 weeks to 30 months).

Surgery and measures of success
A limited femoral head/neck osteoplasty was performed arthroscopically on the two patients who had isolated cam lesions only. The remaining 14 patients had hip arthroscopy to trim the acetabular rim to relieve pincer impingement and achieve adequate decompression.

All patients had labral pathology, which was treated with either partial débridement (9 patients) or labral detachment and suture anchor refixation (7 patients). Articular cartilage defects (grades 1-3) were treated with chondroplasty.

“The advent of newer instruments and techniques in hip arthroscopy allowed for excellent visualization with access to all parts of the impingement lesions,” wrote the authors.

Subjective data—including the modified Harris hip score (MHHS), patient satisfaction, hip outcome scores (HOS) for activities of daily living (ADL) and sports—were collected from each patient during the initial visit and at 3, 6, 7, 12, and 24 months follow-up.

At minimum 1-year follow-up, all patients showed considerable improvement in pain and functional outcomes (Table 1). Patient satisfaction was high and significantly correlated with postoperative MHHS and HOS sport score. At latest follow-up, none of the patients had any subsequent surgery and all were able to return to sports at the same level as prior to experiencing hip pain. No cases of osteonecrosis or growth disturbances developed following surgery.

“This is a limited study and a larger patient population and longer follow-up is necessary to more clearly elucidate the long-term outcomes,” the authors concluded. “Hip arthroscopy for FAI is minimally invasive and provides a viable alternative to open surgical dislocation.”

Working with Dr. Philippon on “Outcomes following hip arthroscopy in the athletic pediatric patient” were Yi-Meng Yen, MD; Karen K. Briggs, MBA, MPH; David A. Kuppersmith, BS; and R. Brian Maxwell, BS. Disclosure information on all the authors can be found at www.aaos.org/disclosure

Carolyn Rogers is a staff writer for AAOS Now. She can be reached at rogers@aaos.org