Introduction: Autologous chondrocyte implantation was introduced in 1994 by Brittberg and Peterson for the treatment of large full-thickness focal chondral defects. The purpose of the present study was to evaluate the mid-term results of this technique in a group of patients with post-traumatic chondral defects of the knee.

Materials and Methods: Fifteen patients underwent autologous chondrocyte implantation between 2001 and 2006 and were prospectively assessed preoperatively, at 3, 6, 9, 12 months, 3.5 years and last follow-up with use of standard rating scales (IKDC subjective score, pain Visual Analogic Scale (VAS), Brittberg and Peterson’s score). The inclusion’s criteria were: pain VAS more than 40/100, age between 18 and 50 years, focal chondral defect in weight bearing area grade 3 or 4 and informed and signed consent. Patients with varus or valgus deformities with malalignement more than 5 degrees, knee instabilities and signs of arthritis on radiographs were excluded. The same experienced surgeon performed all the procedures.

Results: Fourteen patients were reviewed at the latest follow-up. The mean age of the patients at the time of autologous chondrocyte transplantation was 37.7 years (range, 30 to 45). The mean duration of symptoms was 2.9 years (0.5 to 7). Nine patients (83%) had previous operations on the index knee. The defect was located on the medial femoral condyle in 11 patients and on the lateral femoral condyle in 3. The mean lesion size was 1.80 cm² (range, 1.5 to 3.5 cm²) after débridement. After a mean duration of follow-up of 6 years (3.3–7.8), 84% of the patients had improvement on a patient self-assessment questionnaire. The IKDC subjective score and Brittberg-Peterson’s score were all improved. The mean IKDC subjective score increased from 40 (27.6–65.5) preoperatively to 60.2 (35.6–89.6) at the latest evaluation. The mean pain VAS decreased from 66.3 (44–89) to 23.2 (0–77). The Brittberg and Peterson’s score decreased from 54.4 (11.8–98.2) to 32.9 (0–83.9). Two patients (16.7%) felt no improvement by the chondrocyte transplantation at the last follow-up. Two complications occurred: graft periosteum hypertrophy treated by débridement and a pulmonary embolus.

Discussion: Our results are similar than those reported in the literature. These outcomes are encouraging and need further follow-up to confirm the long-term efficacy of autologous chondrocyte implantation.