Articulated hip distraction: a treatment option for femoral head avascular necrosis in adolescence.

Purpose: To describe the clinical outcomes of adolescent patients treated with articulated hip distraction (AHD) for avascular necrosis (AVN) of the femoral head. Outcomes were examined in order to better understand the usefulness of and indications for performing hip arthrodiastasis in this patient population.

Methods: : Retrospective review was performed on 31 hips with femoral head AVN treated with AHD. Mean age at treatment was 14.7 years. Preoperative and follow-up pain and physical limitations, as well as follow-up range of motion, were assessed.

Results: Follow-up assessment was obtained at 18.7 years. Time of follow-up was 57.4 months after distraction. The etiologies of AVN were the following: 10 slipped capital femoral epiphysis (SCFE), 5 idiopathic AVN, 3 with hip dysplasia, and 12 others. There was a significant difference in pain preoperatively and postoperatively (P<0.001), most patients (78.6%, n=22) had less pain after the treatment. Multivariate regression model demonstrated that patients with SCFE were likely to have less improvement in pain than patients with other etiologies (odds ratio, 22.7; P=0.035). All patients had activity limitations before the treatment; at the postoperative assessment, half of our patients (n=14) reported no limitations in their regular daily activities. Eight patients had minor complications with the fixator. At follow-up, 5 patients (17.2%) converted to total hip replacement or arthrodesis. Survival rates were 90.6% at 5 years, 77.7% at 10 years, and 38.8% at 15 years.

Conclusions: Hip distraction arthroplasty in adolescent patients with symptomatic AVN reduces the amount of pain and limitation in daily activities at a follow-up of 4.7 years. Arthrodiastasis is not the final solution to AVN. With longer follow-up, patient's symptoms increases. Patients with AVN secondary to SCFE do not seem to benefit from this procedure as much as other patients do. Articulated hip distraction is a safe and appropriate procedure to perform in these patients. The procedure might be able to delay definitive surgical procedures at an early age, restoring function and improving the patient's quality of life.