Purpose: Use of six-axis analysis and computer assisted deformity correction via a circular external fixator is a new method for deformity correction. We investigated its accuracy and safety in reconstruction of femoral deformity in children and young adults.

Method: We retrospectively reviewed all cases including the indications for use and the methodology of application of the computer assisted six-axis analysis and circular external fixator for reconstruction of 22 femora in 20 patients. Twelve patients were female, and 8 were male. The average age was 13.9 (range, 5.9–24.6). Etiology included traumatic (7), idiopathic (6), multiple enchondromatosis (2), rickets (2), congenital femoral deficiency (2), spondyloepiphyseal dysplasia (1), congenital pseudohypoparathyroidisim (1), and multifocal osteomyelitis (1). Clinical and radiographic data were analyzed.

Results: Average follow-up was 14.4 months (range, 4.5–32). Average time in frame was 6.2 months (range, 2.6–19). Bone lengthening of 3.9 cm (range, 1–8.5) was performed in 12 femora. In genu valgum patients, the mLDFA improved from a mean of 73.7° to a mean of 89°. In genu varum patients, the mLDFA improved from a mean of 99.8° to a mean of 89.5°. Complications included pin tract infection in 6, knee stiffness in 3, delayed union in 2, skin irritation in 1, posterior knee subluxation in 2, both of which had stable knees preoperatively. One patient was lost to follow-up and returned back with deformity. No complications occurred in 8 patients.

Conclusion: Computer assisted femoral deformity correction with six-axis analysis and application of circular external fixator is a useful technique with the advantage of managing multiplanar deformities in children and young adults. It has the potential complications of the use of any external fixator. Close follow-up is necessary to avoid subluxation of the knee joint even in patients with stable knees. Accurate and safe correction can be achieved in almost all patients.

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

Method: Retrospective review was performed on thirty-one hips with femoral head AVN treated with hip distraction arthroplasty. Mean age at treatment was 14.2 years. Preoperative and follow-up pain, and physical limitations, as well as follow-up range of motion (ROM) were assessed.

Results: Follow up assessment was obtained at 18.3 years of age. Time of follow up was 55.3 months after distraction. The etiologies of AVN were: 11 Slipped Capital Femoral Epyphysis (SCFE); 5 Idiopathic AVN; 3 with hip dysplasia; and 12 others. There was a significant difference in pain preoperatively and postoperatively (p< .001), the majority of patients (79.5%, n=23) 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: 24.8; p=.035). All patients had activity limitations before the treatment; at the postoperative assessment more than half of our patients (n=15) reported no limitations in their activities. Nine patients had minor complications with the fixator. At follow up, 5 (16.1 %) patients converted to total hip replacement or arthrodesis.

Conclusion: Hip distraction arthroplasty in adolescent patients with symptomatic AVN reduces the amount of pain and limitation in daily activities, at a follow up of 4.6 years. Arthrodiastasis is not the final solution to AVN, with longer follow up patient’s symptomatology increases. Patients with AVN secondary to SCFE do not beneficiate of this procedure as much as other patients do. 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.