Bilayer Matrix Autologous Chondrocyte Implantation without Bone Graft for Knee Osteochondral Lesion Less than 8 mm Deep

This article investigates the clinical and radiological results of bilayer matrix autologous chondrocyte implantation (MACI) membrane technique in the treatment of shallow osteochondral defects. An analysis was made of eight patients who were operated on using the bilayer MACI (Genzyme Biosurgery, Cambridge, MA) technique (mean age: 20.2 years, mean defect size: 3.8 cm², mean defect depth: 6.2 ± 0.9 mm, and mean follow-up time: 22.1 ± 5.3 [14-26.1] months). According to the defect, the first membrane was secured to the base of the defect with the cells facing up, and the second membrane was implanted on top of the first membrane with the cells facing down using fibrin glue. Clinical assessment was performed with modified Cincinnati and Tegner Lysholm scores. Patients were evaluated using 3-Tesla magnetic resonance imaging (3T MRI) with a 15-channel transmit knee coil in the 6th, 12th, and 24th months postoperatively. Magnetic observation of cartilage repair tissue (MOCART) scoring was used to evaluate the cartilage tissue. The mean modified Cincinnati score was 36.4 (21-48) preoperatively and 84.2 (81-90) at 6 months postoperatively, 87.2 (82-92) at 12 months, and 89.6 (85-94) at 24 months (p < 0.05). The postoperative results were evaluated as excellent. The mean Tegner Lysholm score was 36.4 (21-48) preoperatively and 88.2 (84-92), 90.2 (84-95), and 90.4 (86-95) at 6, 12, and 24 months postoperatively (p < 0.05). According to the 3T MRI findings, the mean modified MOCART scores were 8 in the preimplantation period, 38 in the 6th postoperative month, 70 in the 12th postoperative month, and 79 in the 24th postoperative month (p < 0.05). The 2-year follow-up MRI showed good regeneration, healing, and integration developing in time in cartilage tissue. In the treatment of shallow osteochondral defects, the bilayer MACI technique can be an alternative to filling the defect with bone graft.