[Technique of all arthroscopic autologous chondrocyte implantation (ACI) for the treatment of cartilage defects in the knee]

Abstract

Objective: All arthroscopic treatment of deep cartilage defects in the knee for reconstruction of the articular surface.

Indications: Focal cartilage defects of the knee (ICRS ≥ grade 3) from a size of 2.5 cm² and more.

Contraindications: Osteoarthritis (Kellgren-Lawrence > grade 2), osseus defect situation, cartilage lesion of the opposing articular surfaces (ICRS > grade 2), instability, malalignment (>3-4°), inflammatory joint diseases.

Surgical technique: First procedure (cell harvesting): Treatment of additional pathologies, preparation of the cartilage defect, harvesting of osteochondral cylinders for cell culture. Second procedure (cell implantation): Dry arthroscopy, cleaning and drying of the already prepared defect, implantation of the in situ crosslinking cartilage cell suspension.

Postoperative management: First procedure (cell harvesting): Early functional treatment with weight bearing as tolerated. Second procedure (cell implantation): No drains, extension brace for 4 days, then free range of motion, partial weight bearing for 4 weeks in patellofemoral implantation and for 8 weeks in tibiofemoral implantation, continuous passive motion beginning in postoperative week 2, cycling from postoperative week 9.

Results: In the literature, results for ACI in the knee are reported to be good, especially for larger cartilage defects. Arthroscopic techniques should lead to a decrease of complications and perioperative morbidity. No technique-specific complications occurred in our cohort. From 2012-2015, 98 patients were treated using the above mentioned technique, whereby 62 patients were retrospectively evaluated after 31.0 ± 14.8 (12.5-61.4) months. In 15 patients (28%) additional procedures were performed (7 anterior cruciate ligament reconstructions, 3 correction osteotomies and 5 medial patellofemoral ligament reconstructions). Average cartilage defect size was 4.7 ± 2.8 cm², in 18 patients (29%) more than one cartilage defect was treated. The subjective IKDC and total KOOS scores resulted in 66 ± 10 and 73 ± 19 points.

Keywords: Arthroscopy; Cartilage defect; Cartilage repair; Complications; Treatment outcome.