SLR - October 2014 - Matthew F. Villani

Autologous Chondrocyte Implantation of the Ankle: 2 to 10 Year Results

References: Kwak S, Kern B, Ferkel R, Chan K, Kasraeian S, Applegate G. Autologous Chondrocyte Implantation of the Ankle: 2 to 10 Year Results. The American Journal of Sports Medicine. 2014;42: 2156-2163.

Scientific Literature Review

Reviewed By: Matthew F. Villani, DPM
Residency Program: Florida Hospital East Orlando

Podiatric Relevance: Various techniques for cartilage restoration have been studied, such as debridement, abrasion arthroplasty, microfracture, subchondral drilling, mosaicplasty and autologous chondrocyte implantation, but there is no definitive solution to cartilage repair at this time. This study evaluates the use of first generation autogenous chondrocyte implantation (ACI) for treatment of osteochondral lesions (OCL) in patients that have failed previous surgical intervention. The authors hypothesize that the use of autologous chondrocyte implantation for talar dome lesion could effectively restore a functional cartilage surface and provide significant improved quality of life for these patients.

Methods: A review of 32 patients who underwent autologous chondrocyte implantation (ACI) for treatment of osteochondral lesions (OCD) by one surgeon over an eight year period. Inclusion criteria were patients 15-55 years of age with focal contained unipolar lesions greater than 1-2cm squared, that had failed non-operative management and have persistent pain after previous subchondral drilling and microfracture. All patients had an MRI, which demonstrated a cartilage defect and subchondral irregularity. Exclusion criteria were patients with diffuse degenerative joint changes, inflammatory arthritis, infections, malalignment and chronic ligamentous instability. 29/32 (91%) patients returned for follow up visits with a mean follow up of 70 months (24-129 months). Following debridement of the lesion, the mean size of the lesion was 18 x 11mm. Patients were evaluated with American Orthopedic Foot and Ankle society ankle hindfoot scale, Tegner activity score and Finsen score. Kysholm knee scores were obtained postoperatively to evaluate donor site morbidity. Second arthroscopic surgery was performed at a mean time of 16 months after surgery to assess the incorporation of graft. Twenty-four (83 percent) of patients underwent a secondary evaluation with a MRI at a mean post operative time of 65 months.

During the first procedure an arthroscopy of the ipsilateral knee was performed and a biopsy from the intercondylar notch was obtained, this biopsy was sent for storage and future culture. At a mean time of 14.6 weeks after cartilage harvest, an oblique medial malleolar or fibular osteotomy was performed to gain access to the lesion. The lesions were debrided and all delaminated irregular cartilage was removed. A periosteal graft was harvested from the proximal or distal tibia and the cambium layer was sutured to the defect with 6-0 absorbable suture, a hole was left at one end for the injection of autologous chondrocytes. Fibrin glue was applied to the edges. Patients were kept NWB two weeks then transitioned to removable boot and range of motion exercises, full weight bearing was allowed at six-eight weeks, once osteotomy healed.

Results: No intraoperative or postoperative complications were documented. Improvement of all patients was noted with a mean AOFAS score improvement from 50.1 to 85.9 at final follow up, mean Tegner score improved from 1.6 to 4.3. There was no significant correlation found between lesion size and AOFAS score. Subjectively patient satisfaction improved to a 90percent.  Post operatively nine patients rated their ankle as excellent and 14 as good and five as fair, one as poor. Niney-three percent of patients would undergo the procedure again. Of the 25 patients who underwent secondary arthroscopic evaluation, cartilage was found to be normal in four patients, nearly normal in 18, abnormal in two and severely abnormal in one patient. Only six of the 29 patients had radiographic changes consistent with progression of arthritis at a mean follow up of 8.3 years. On follow up MRI, marrow edema was increased in five patients, unchanged in four and decreased in 15 patients on MRI.

Conclusion: Osteochondral lesions greater than 1.5cm squared have shown to have less favorable outcome in response to marrow stimulation techniques. Multiple studies have been performed to evaluate the effectiveness of ACI on OCL and have shown excellent outcomes but donor site morbidity of the ipsilateral knee has been a problem. Osteochondral autograft transfer systems provides the advantage of replacing OCL with viable cartilage along with its bony bed, however donor site morbidity has been shown in multiple studies to be between 12-39 percent. Other potential complications such as graft fragmentation, angulation, graft recession or prominence have been shown. Osteochondral allografts alleviate the need for harvest site, but are limited by availability and concerns of disease transmission. The results of the study indicate ACI is a good and predictable option for patients with OCL, who have failed previous surgical intervention. All patients underwent transplantation of knee chondrocytes to the ankle. Ankle cartilage is more resistant to progressive degeneration and osteoarthritis than the knee, so further investigation may be warranted. One limitation to the study was a lack of a control group but from the results ACI is a good option for patients OCL who have failed previous bone marrow stimulation procedures.

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