Histological evaluation of a mosaicplasty of the femoral condyle-retrieval specimens obtained after total knee arthroplasty--a case report.

Copyright © Taylor & Francis 2004. ISSN 0001–6470. Printed in Sweden – all rights reserved. A 43-year-old man presented with persistent pain on the medial side of his left knee, 1 year after a bone-patellar tendon-bone autograft ACL reconstruction. Besides a dysfunctional ACL, earlier arthroscopy had already revealed a focal full-thickness chondral lesion (25 × 12 mm) of the medial femoral condyle (Figure 1A) and mild degenerative changes in the lateral compartment of the knee. The patient was offered a mosaicplasty of the medial femoral condyle. After a medial arthrotomy of the knee, 3 cylindrical osteochondral plugs (8 mm diameter) were harvested from the lateral throchlea (donor site) and transplanted to the chondral defect in the medial femoral defect (recipient site), using the mosaicplasty technique (Hangody et al. 1998, Bobic 1999, Hangody and Fules 2003, Horas et al. 2003). The donor site defects were each fi lled with a press-fi tted cylindrical osteo-periosteal plug obtained from the proximal tibia. It was hypothesized that these plugs would enhance healing of the subchondral bone and that the covering periosteum would enhance resurfacing of the donor site defects with fi brocartilagenous tissue. Initially, the patient’s symptoms clearly improved and a postoperative MRI showed restoration of the joint surface at the original chondral lesion in the medial condyle 3 months after surgery (Figure 1B). The 3 transplanted osteochondral plugs were still clearly visible in the subchondral bone, with signs of osseous integration. One plug appeared to have been placed rather too deeply, as seen from the step-off in the subchondral bone (Figure 1B, 2A). At the lateral aspect of the trochlea, the 3 donor site defects were also still clearly visible (Figure 1C). The osteo-periosteal plugs from the proximal tibia appeared to have remained in situ and some resurfacing of the defects had occurred. After 3 years the knee became symptomatic again, with pain and swelling. Radiographic evaluation revealed mild degenerative changes (Figure 1D). Conservative treatment was not accepted and a total knee arthroplasty was performed. This procedure eventually provided good-quality retrieval specimens for histological evaluation of a mosaicplasty.