Autologous Chondrocyte Implantation (ACI) for Focal Articular Cartilage Lesions

This policy covers autologous chondrocyte implantation (ACI), including matrix‑assisted multi‑step ACI with diagnostic arthroscopy/biopsy and cultured chondrocyte implantation, for disabling focal full‑thickness (Outerbridge III–IV) unipolar cartilage defects ≥1.5 cm² of the weight‑bearing femoral condyles, trochlea, or patella in skeletally mature patients (e.g., adolescents with closed growth plates or adults typically too young for total knee arthroplasty, often <55 years) who have minimal surrounding degeneration and a BMI <35 kg/m², with normal knee alignment and stability achieved or corrected. Major limitations/requirements: ACI is not indicated for lesions <1.5 cm², bipolar/multifocal defects, diffuse osteoarthritis or inflammatory arthritis, skeletally immature patients, severe obesity (BMI >35), or non‑knee joints (considered experimental); it requires radiographic/arthroscopic documentation, adherence to benefit plan provisions, and compliance with FDA/biologic licensing for cultured cells.