ANKLE ALLOGRAFT: DOES IT WORK?

Abstract

INTRODUCTION: Post-traumatic arthritis of the ankle in the young active patient represents a reconstructive challenge. Fresh total shell osteochondral allografts are an increasingly popular option in the reconstruction of various amounts of cartilage defects, although concerns for bipolar allografting are reported. The purpose of this study is to describe the preliminary results of a series of 18 bipolar shell ankle allografts performed by using a specifically designed instrumentation.

METHODS: 18 patients, 13 males and 5 females (mean age 31±10 years) affected by post traumatic arthritis of the unilateral ankle joint grade III received bipolar shell allograft of the ankle. The mean follow-up was 12 months (range 24–8). The ideal patient to allograft match was permitted through CT scan and x-rays. Two steps surgery, one for allograft preparing and one for the recipient site, were performed by using specifically designed jigs. Patients evaluation was carried out clinically by AOFAS and radiographically by X-Rays, CT scans, MRI.

RESULTS: No intraoperative, complications occurred. All the patients demonstrated good consolidation rates of the allograft at X-Rays, CT scan and MRI controls performed at 4, 6, 8, and 12 months. At 8 months follow-up, all the patients were allowed complete weight bearing. Normal ROM of the ankle and regular gait with no pain and no need of support was resumed in 13 patients. In 2 patients a fracture of the fibula was reported. In one case, cause of the fracture was patient non compliance to the weight-bearing restriction. In the other case the fracture occurred distal to the osteotomy site, possibly due to a trauma. Both the cases required revision of the graft which appeared damaged in the lateral site. In the first case an ankle arthrodesis was performed. A bioptic harvest of the transplanted cartilage in 5 patients at 1 year follow up demonstrated chondrocytes vitality > 90%.

DISCUSSION: Accurate preoperative planning, sizing, and the use of specifically designed jigs makes viable and reproducible the bipolar shell allograft in the ankle joint in selected cases. Although preliminary results are encouraging, longer follow-up is required in order to confirm longer term cartilage viability and the validity of the technique.