Summary

Osteochondral autograft transplantation provided significantly better clinical and MRI outcomes than allograft transplantation for osteochondral lesions of the talus

Abstract

Background

Osteochondral autograft plug transplantation has been shown to provide excellent clinical and radiological outcome in the treatment of osteochondral lesions of the talus (OLT). Recently, concern over donor-site morbidity has prompted the use of fresh osteochondral allograft as an alternative to autograft. However, there is a paucity of clinical studies comparing the efficacy of osteochondral autograft and allograft plug transplantation in the treatment of OLT.

Methods

A retrospective analysis comparing patients treated with autograft or allograft plug was performed. All patients were given the option of autograft or allograft prior to the procedure, after discussion of the risks and benefits of each. The decision in graft choice was made based on patient preference. Data was collected on patient age, gender, duration of symptoms, follow-up time, lesion size, lesion location, the presence of cyst in the lesion, previous ankle procedures including bone marrow stimulation, and concomitant procedures. The Foot and Ankle Outcome Scores (FAOS) and Short-Form 12 (SF-12) at final follow-up were evaluated and MRI outcome was assessed using modified magnetic resonance observation of cartilage repair tissue (MOCART) score. The rate of cyst occurrence, graft degradation, graft failure and revision surgeries were also evaluated.

Results

Twenty-three patients with autograft and 15 patients with allograft were included with mean follow-up of 24 months. There were no significant differences in all demographic variables between the autograft or allograft group. The mean FAOS and SF-12 significantly improved in both groups from before to after surgery (p<0.001). The mean postoperative FAOS and SF-12 in autograft group were significantly higher than those in allograft group (FAOS; 83 vs 71, p=0.005, SF-12; 76 vs 66, p=0.018). There was a significant difference in favour of the autograft group for mean MOCART score (86 vs 75, p=0.006). The rate of chondral wear on MRI was higher in allograft than that of the autograft group (4% vs 53%, p<0.001). There was no statistically significant difference in the rate of cystic occurrence but cyst formation in the graft itself is more likely to occur in allograft group (8% vs 47%, p=0.017). In addition, two patients developed nonunion at the graft site in the allograft group. However, all autograft patients had complete osseous incorporation. The failure rate was significantly higher in the allograft group (0% vs 27%, p<0.001).

Conclusions

The autograft procedure provided significantly better clinical and MRI outcomes than the allograft procedure for OLT. In addition, allograft procedure had a higher incidence of failure than the autograft procedure. These results raise concerns about the biological potential of osteochondral allograft plugs for the treatment of OLT.