MRI FOLLOWUP RESULTS (1 TO 4 YEARS) AFTER AUTOLOGOUS OSTEOCHONDRAL TRANSPLANTATION IN TRAUMATIC AND DEGENERATIVE DEFECTS OF FEMORAL CONDYLES AND TALUS

Abstract

The osteochondral defect in the knee and ankle joint is a difficult and common problem in young population. The bone-cartilage autologous grafting represents a recently introduced treatment option for osteochondral lesions of the weight bearing articular surfaces of femoral condyles and talus.

The aim of our study was to evaluate the MRI findings, and in particular to find out about the fate and the time needed for the graft incorporation, to assess the continuity, homogeneity and smoothness of the cartilage layer of the transplant compare to the remaining cartilage, to estimate the viability of the graft and to determine the correlation between the MRI findings and the functional outcome.

We performed a prospective study and followed up 33 patients, who underwent osteochondral autografting for defects in both medial and lateral femoral condyles as well as in the talus. The grafts were harvested from the anterolateral region of the ipsilateral knee using an insider rinsing diamond bone-cutting instrument (DBCS). The grafts were implanted using press fit technique.

16(48%) women and 17 men were included in our followup with an average age of 38.4 years (age range-16to58 yrs). There were 20(60%) osteochondral defects in the femoral condyles and 13 in the talus. 13(40%) patients gave a history of trauma. All the patients were followed up with MRI scans between 1 to 4 years postoperatively.

The MRI study illustrated a cartilage contour interruption by 16(48%) patients and 19(58%) had uneven joint surface. 9(27%) of the patients were shown to have homogeneity between the graft and the surrounding bone and cartilage tissues. A subchondral oedema was observed in 2(6%) of the cases. Only 1 patient had a subchondral bone-oedema in the graft-donor site. All the autologous grafts were incorporated by 4 years as proven by MRI scans

The MRI evaluation revealed regular incorporation of the osseous part of the graft in the subchondral bone. On the contrary, cartilage layer integration was less common. The MRI findings did not show any correlation to the clinical outcome. Hangody (2003) reports all grafts to incorporate into the recipient bed and most articular surfaces to have congruency and similar appearance to the surrounding articular cartilage and bone in 6 years.

Despite using very accurate harvested autologous osteochondral cylinders, which fit exactly the defects, match precisely the corresponding chondral and osseous layers and cause no immune reactions, it was shown in this short term MRI followup that the height and the shape of the original articular surface cannot be fully restored. However the relief of symptoms and improved functional outcome are promising findings and define bone cartilage autografting as a currently efficient treatment of osteochondral lesions of knee and talus.