SLR - January 2019 - Stephanie A. Oexeman

Allograft Compared with Autograft in Osteochondral Transplantation for the Treatment of Osteochondral Lesions of the Talus

Reference: Shimozono Y, Hurley ET, Nguyen JT, Deyer TW, Kennedy JG. Allograft Compared with Autograft in Osteochondral Transplantation for the Treatment of Osteochondral Lesions of the Talus. J Bone Joint Surg Am. 2018 Nov 7;100(21):1838–1844.

Scientific Literature Review

Reviewed By: Stephanie A. Oexeman, DPM
Residency Program: CHI Franciscan, St. Francis Hospital, Federal Way, WA

Podiatric Relevance: Osteochondral lesions of the talus (OLTs) are a commonly encountered ankle pathology treated by foot and ankle surgeons. Due to varying degrees of severity, there are multiple surgical approaches for managing OLTs. Options include reparative or replacement procedures. Allograft and autograft transplantations are utilized for managing larger defects or in patients who did not improve after bone marrow stimulation. This article compares the radiographic and clinical outcomes of autograft and allograft transplantation for treating OLTs. The author hypothesizes the autograft exceeds the allograft transplant outcomes.

Methods: This is a level three retrospective comparative study comparing autograft and allograft osteochondral transplantation in patients who failed bone marrow stimulation or had cystic lesions. Transplantation was indicated if lesions were greater than 150 mm2 or greater than 15 mm in diameter. Autografts were taken from the patient’s ipsilateral lateral femoral condyle, and allografts procured were freshly frozen. Both grafts were soaked in bone marrow aspirate prior to transplantation. Clinical outcomes were based on the Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12). Radiographic outcomes were based on MRI evaluation using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system. Advanced imaging was used to locate cysts and to analyze chondral wear and fissures of the graft. Additional imaging, such as CT, were performed for possible delayed union or nonunion of grafts.

Results: A total of 41 patients were included in the study. Twenty-three autograft patients and fifteen allograft patients were evaluated over an approximately a two-year period. There were no significant differences within the set demographic variables. There was a significant improvement in clinical outcomes scores within both groups, but the postoperative FAOS and SF-12 scores were significantly higher in the autograft than the allograft group. MOCART scores showed a significantly better outcome in the autograft versus allograft group. Allografts had a statistically significant higher occurrence of cyst formation, chondral wear and likelihood of patients requiring a secondary procedure.

Conclusions: There is a significant improvement in both clinical and radiographic outcomes of the autograft group compared to the allograft group. Cyst formation and chondral wear were significantly higher in the allograft population. The authors propose the allograft cartilage can deteriorate over time regardless of its fresh osteochondral properties, and a host-graft interface may play a role in osseous void and cyst formation. This may ultimately lead to pain and cause reduced outcomes scores. The cellular makeup of allografts (decrease in viability of chondrocytes) may also play a role in the lower outcomes, increased number of cysts and chondral wear. There were several limitations in this retrospective comparison study, including, but not limited to, a short follow-up period of approximately two years and nonrandomized groups. In conclusion, autograft transplantation in the treatment of osteochondral lesions of the talus had significantly better clinical and MRI outcomes than allograft transplantation.  

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