SLR - February 2016 - Kaitlyn L. Ward

Title: Treatment of Extended Osteochondral Lesions of the Talus with a Free Vascularised Bone Graft from the Medial Condyle of the Femur

Reference: Hintermann B, Wagener J, Knupp M, Schweizer C, J Schaefer D. Treatment of Extended Osteochondral Lesions of the Talus with a Free Vascularised Bone Graft from the Medial Condyle of the Femur. Bone Joint J. 2015 Sept; 97-B (9):1242-1249.

Scientific Literature Review

Reviewed By:  Kaitlyn L. Ward, DPM
Residency Program:  Franciscan Health System- St. Francis Hospital, Federal Way, WA

Podiatric Relevance: Large, cystic osteochondral lesions (OCLs) of the talus are a challenging pathology for foot and ankle surgeons to address, particularly if the shoulder is involved. This is due to the poor intrinsic ability of talar cartilage to heal and the tenuous blood supply of the talus itself. Recently, the use of fresh allograft for such extensive pathology has been proposed; however, concerns remain about graft incorporation/collapse, as well as poor availability of fresh frozen allograft bone.

The authors of this study suggest the use of a vascularised corticoperiosteal autograft as an alternate technique. They identified the medial condyle of the femur as an ideal harvest site, due to its similar contour to the talar surface as well as a consistent perfusing artery and periosteal cover. They hypothesized that this technique would restore the articular surface of the talus with a firmly incorporated graft, which would retain its shape and size as well as develop an overlying layer of fibrocartilage. The purpose of this study was to review a series of 14 patients that underwent this procedure and report the clinical and radiological outcomes.

Methods: Between 2004 and 2011, a prospective study involving a series of 14 patients (14 ankles; five women, nine men; mean age 34.8 years) was conducted. Inclusion criteria were: large, symptomatic, cystic OCLs, involving the medial or lateral shoulder of the talus and failure of at least one year of conservative or previous surgical treatment. Exclusion criteria were: age less than 18 years old and/or ankle joint pathology as evidenced by WB radiographs.

Preoperative CT scans were taken to measure the 3D size of the lesion for surgical planning. The subjects underwent treatment with vascularized corticoperiosteal bone grafting from the ipsilateral medial condyle of the femur. Post-operative radiographs and CT scans then evaluated graft incorporation and any joint deterioration if present. Full incorporation of the graft was considered present when there was a stable bony interface and trabeculae crossing between the graft and host over at least 80 percent of its surface area in both coronal and sagittal planes.

Clinical outcomes were assessed using a visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score.

Results: The mean OCL defect size was 13.6 mm in the mediolateral direction, 19.6 mm in the AP direction, and 10.9 mm in depth. The mean graft size was slightly larger (14.4 mm x 20.4 mm x 12.4 mm) in order to obtain a press-fit. There were no intra-operative complications of harvesting or insertion of the bone graft. In all cases, the vascular anastomosis between the bone graft pedicle and tibial artery was performed by a plastic surgeon. The overall mean procedure time was 243 minutes.

Post-operatively, there was dysesthesia of the infrapatellar nerve in two patients. One patient recovered completely; however, it was still present for the other at final follow-up. No other donor site complications occurred.

Complete incorporation of the bone graft was confirmed via CT scan at a mean of 8.57 weeks in all 14 ankles. Degenerative changes of the opposing tibial articular surface were seen in one patient.

Five patients required malleolar screw removal after a mean of 11 months. Three of these patients underwent concurrent arthroscopic debridement for anterior ankle impingement, at which time the articular surface was found to be stable when probed: histologically it consisted of fibrocartilage.

At a mean follow-up of 4.1 years, the mean VAS for pain had decreased from 5.8 to 1.8 and the mean AOFAS hindfoot score had increased from 65 to 81, both of which were statistically significant.

Conclusions: The results of the reviewed study indicate that reconstruction of a large OCL of the talar shoulder with a vascularized bone graft from the ipsilateral medial condyle is a safe, reliable method. In the early to mid-term follow-up, this technique has proved to restore the articular surface of the talus and provide a stable foundation for fibrocartilage without collapse or resorption of the graft, which may occur if an avascular graft is used.

Overall, this investigation aids in understanding why large OCLs are a difficult pathology and provides another option for patients who have failed previous intervention. Finally, it must be noted that this procedure would involve an expert in microvascular anastomosis (plastic surgeon) and an orthopaedic colleague (to assist in obtaining the graft from the femur), which logistically, may be challenging.

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