Knee Articular Cartilage Repair and Restoration Techniques: A Review of the Literature

CONTEXT: Isolated chondral and osteochondral defects of the knee are a difficult clinical challenge, particularly in younger patients for whom alternatives such as partial or total knee arthroplasty are rarely advised. Numerous surgical techniques have been developed to address focal cartilage defects. Cartilage treatment strategies are characterized as palliation (eg, chondroplasty and debridement), repair (eg, drilling and microfracture [MF]), or restoration (eg, autologous chondrocyte implantation [ACI], osteochondral autograft [OAT], and osteochondral allograft [OCA]). EVIDENCE ACQUISITION: PubMed was searched for treatment articles using the keywords knee, articular cartilage, and osteochondral defect, with a focus on articles published in the past 5 years. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: In general, smaller lesions (<2 cm(2)) are best treated with MF or OAT. Furthermore, OAT shows trends toward greater longevity and durability as well as improved outcomes in high-demand patients. Intermediate-size lesions (2-4 cm(2)) have shown fairly equivalent treatment results using either OAT or ACI options. For larger lesions (>4 cm(2)), ACI or OCA have shown the best results, with OCA being an option for large osteochondritis dissecans lesions and posttraumatic defects. CONCLUSION: These techniques may improve patient outcomes, though no single technique can reproduce normal hyaline cartilage.