Is technique performance a prognostic factor in bone marrow stimulation of the talus?

Although results of bone marrow stimulation in osteochondral defects of the talus (OCLT) have been satisfactory, the technique performance has not yet been subjected to review as a prognostic factor. The aim of this systematic review is to determine whether variation within technique influences outcome of bone marrow stimulation for OCLT. Electronic databases were searched for articles on OCLT treated with bone marrow stimulation techniques, providing a technique description. Six articles on microfracture were included (198 patients). Lesion size averaged 0.9 cm (2) to 4.5 cm (2), and follow-up varied from 2 to 6 years. Key elements were removal of unstable cartilage, hole depth variation between 2 and 4 mm until bleeding or fat droplets occurred, and a distance between the created holes of 3 to 4 mm. The success rate (excellent/good results by any clinical outcome score) was 81%. There is a vast similarity in the technique with similar outcomes as in previous general reviews; therefore variation in technique as currently described in the literature does not seem to influence the outcome of bone marrow stimulation for OCLT. Whether the instruments used or the hole depth and geometry influence clinical outcome remains to be determined. Microfracture is safe and effective for OCLTs smaller than 15 mm. However, in this review, only 81% of patients obtained satisfactory results. Larger clinical trials are needed with clearly defined patient groups, technique descriptions, and reproducible outcome measures to provide insight in the specific indications and the preferred technique of bone marrow stimulation.