Large osteochondral defects (OCD) in the knee remain a therapeutic challenge. Treatment by the autologous chondrocyte implantation (ACI) “sandwich” technique with autologous bone grafting was reported to offer encouraging results in case series. However, it is unclear if the attempt to restore of the osteochondral unit by this technique would offer similar outcomes to the treatment of isolated full thickness chondral defects (CD) by ACI alone.
A consecutive cohort of 30 patients were treated between 2017 and 2019 for extensive OCDs and CDs in the knee by a single surgeon. Mean age 25.3±7.5 years. Sex ratio 1.7. Follow up of 2±1.1 years. 18 patients underwent the “sandwish” technique with ACI for OCDs (OCD group). 12 patients underwent ACI alone for isolated CD (CD group). Mean lesion size was 5.1 ± 2.5 cm2 (3.6 ± 1.8 cm2 patellofemoral, 6.5 ± 2.5 cm2 femorotibial). Realignment osteotomy was performed for varus/valgus > 3 degrees. Preoperative and postoperative knee function was assessed by using IKDC and KOOS scores. MRI and CT scan were performed preoperatively and at 2 years postoperatively.
No significant differences were observed between groups for baseline scores, age, sex, BMI, lesion size, or need for realignment osteotomy. Clinical scores improved postoperatively with a different kinetic for each group. Improvement of IKDC score and each KOOS domain was significantly more important in the OCD group at 6 and 12 months. No statistical difference was observed anymore between groups at 24 months (Figure 1). While MRIs offered similar MOCART scores, CT scans showed subchondral marrow changes and bone plate irregularities in all cases of the OCD group at 2 years.
Treatment of large OCDs by the ACI “sandwich” offers similar IKDC and KOOS scores to CD treated by ACI alone at 2 years despite persitent minor subchondral bone and bone plate changes.