Autologous Chondrocyte Implantation

INTRODUCTION: Autologous chondrocyte implantation (ACI) for the treatment of articular cartilage lesions of the knee joint provides successful and durable long-term outcomes. INDICATIONS & CONTRAINDICATIONS: STEP 1: PREOPERATIVE PLANNING (VIDEO 1): Obtain standing radiographs and magnetic resonance imaging (MRI) scans to identify all associated abnormalities (background factors). STEP 2: ARTHROSCOPIC ASSESSMENT AND CARTILAGE BIOPSY (VIDEO 2): Evaluate the knee joint systematically and harvest cartilage tissue from the non-weight-bearing area. STEP 3: MAKE THE INCISION FOR THE ARTHROTOMY (VIDEO 3): Use a medial or lateral parapatellar arthrotomy and expose the lesion adequately. STEP 4: PREPARE THE DEFECT (VIDEO 4): Debride all fissured and unstable articular cartilage surrounding the full-thickness chondral injury down to healthy contained cartilage. STEP 5: ADDRESS ASSOCIATED ABNORMALITIES: Address associated abnormalities (predisposing background factors) to optimize recovery and a successful outcome. STEP 6: PREPARE AND FIX THE COLLAGEN MEMBRANE(S) (VIDEO 5): Orient the membrane patch with the rough surface to the subchondral bone and the smooth surface toward the articular surface; then sew it, tying the sutures knots on the membrane and not the cartilage, to tension it adequately throughout the entire defect. STEP 7: CHONDROCYTE IMPLANTATION (VIDEO 6): Gently deliver the cells and fill the defect. STEP 8: POSTOPERATIVE CARE: (1) Initiate range-of-motion exercises to enhance chondrocyte regeneration and decrease the likelihood of intra-articular adhesion, (2) protect the graft from loading for 6 to 12 weeks after surgery to prevent graft overload and central degeneration or delamination of the graft, and (3) initiate isometric muscle exercises to regain muscle tone and prevent atrophy. RESULTS: ACI provided durable outcomes in 210 patients followed prospectively for 10 to 17 years after treatment with the first-generation ACI-periosteum technique(6). PITFALLS & CHALLENGES: