Summary

This study is a systematic review which attempts to identify and stratify predictors of the outcomes, healing, and post-operative activity levels of patients who undergo fresh allograft osteochondral transplantation for osteochondral defects of the talus.

Abstract

Study design: Systematic review

Introduction

Osteochondral defects (OCD) of the talus are defined by chondral lesions and underlying subchondral bone involvement. Although several techniques for autologous grafting exist, limitations such as transfer site comorbidity and biological heterogeneity between donor and talar cartilage introduce challenges in achieving optimal outcomes. Fresh talus osteochondral (OC) transplantation allograft transplantation offers several advantages, such as biological similarity to native talus chondrocytes and extended durability. This systematic review seeks to identify and stratify predictors of the outcomes, healing, and post-operative activity following fresh allograft OC transplantation.

Materials And Methods

A systematic review was performed using PubMed and Scopus databases. Articles were identified using various combinations of the following keywords: allograft, osteochondral, ankle, talar, and talus. Inclusion criteria included English language studies published between 1990 through March 2019. Exclusion criteria included surgical technique studies and those describing surgical outcomes without reporting any associations with pre- and post-operative factors.

Results

A total of 22 studies (607 patients) met our inclusion criteria. The mean patient age at time of surgery as 39.4 years old (range: 30 to 45 years). There was a total of 82 graft failures (range: 0% to 100%) with an average failure rate of 25%. Average duration to follow-up was 56.7 months (range: 14 to 187 months) One-hundred patients (16.47%) underwent additional surgery following primary graft placement. Eleven studies reported AOFAS scores, the pre-operative mean for which was 46.6 and post-operative mean was 75.55. Allograft failure may be classified into two groups: early failure resulting from lack of chondrocyte viability, and late failure resulting from graft fracture, collapse, or resorption. Common reasons for second surgery included graft failure, hardware irritation, and lateral synovial tissue deposition requiring debridement. Osteochondral lesions occurred mostly in the posteromedial zone, followed by the anterolateral zone. No significant relationships were noted between patient demographics and post-operative outcomes. Good functional outcomes with low-impact activities such as walking have been reported, though conflicting evidence exists regarding outcomes following return to high-demand activities such as running and mountain biking.

Conclusions

Fresh talus osteochondral allograft transplantation serves as a biologically similar and high durability technique for the treatment of talus OCD lesions. Significant improvements in AOFAS scores with consistent return to low-impact activity have been supported in the literature. Patients should be counseled in detail regarding risk of complications and repeat surgeries. Surgeons should exhibit sound judgement regarding patient selection and operative planning, paying special mind to patient OCD lesion location, anatomic variations, and pre-operative activity level.