Fate of large donor site defects in osteochondral transfer procedures in the knee joint with and without TruFit plugs

INTRODUCTION: Because of the potential donor site morbidity, cartilage lesions of more than 3 cm(2) in size are considered to be critical regarding autologous osteochondral transplantation (OCT). In this study, the potential donor site morbidity for large defects should be reduced by means of OBI TruFit Plugs.

MATERIALS AND METHODS: An autologous OCT was carried out on 37 patients and the cylinders were received from the dorsal medial femoral condyle. The donor site defects of 21 patients (average defect size 5.5 cm(2)) were filled with artificial TruFit cylinders (study group); the donor site defects (average defect size 4.6 cm(2)) were left untreated for 16 patients.

RESULTS: In the study group, the Tegner, Western Ontario and McMaster Universities (WOMAC), knee society score, and visual analogue scale pain scores improved from preoperatively 3.2 (±0.8), 60.9 (±41.6), 133.6 (±27.1), and 4.8 (±2.3) points, respectively, to 3.9 (±0.6), 35.5 (±27.1), 177.8 (±16.6), and 3.3 (±2.9) points, respectively, at the time of the second follow-up; the control group's preoperative score values came to 2.8 (±0.9), 73.3 (±50.2), 123.8 (±41.5), and 5.3 (±2.7) points, respectively, and changed to 3.6 (±0.8), 41.4 (±28.8), 179.3 (±17.5), and 3.1 (±2.0) points, respectively, at the time of the second follow-up. The smaller the initial chondral defect was in the study group, the better the WOMAC score values became (p < 0.05). The modified Henderson score at the study group's donor sites improved from 19.2 (±3.3) to 13.7 (±2.1) points (p < 0.001); the control group's score values for the donor sites were 18.3 (±3.4) and 15.4 (±4.4) points (p = 0.0015).

CONCLUSIONS: OCT is an effective therapy even for large chondral defects >3 cm(2). By filling the defects with TruFit implants, no clinical improvements could be found since the donor site morbidity was already low anyway. However, the regeneration of defects filled with TruFit implants took more than 2 years.