Osteochondral lesions (OCL) of the knee are a common pathology that can be challenging to address. Due to the innate characteristics of articular cartilage, OCLs generally do not heal in adults and often progress to involve the subchondral bone, ultimately resulting in the development of osteoarthritis. The goal of articular cartilage repair is to provide a long-lasting repair that replicates the biological and mechanical properties of articular cartilage, but there is no widely adopted technique that results in true pre-injury state hyaline cartilage. Current treatment modalities have seen reasonable clinical success, but significant limitations remain. Microfracture provides short-term benefit with a fibrocartilage-based repair. While osteochondral autograft or allograft and autologous chondrocyte implantation can be effective, each have their strengths and shortcomings. Emerging concepts in cartilage repair, including scaffold engineering and one stage cell-based options, are continually advancing. These have the benefits of reduced surgical morbidity and potentially improved integration with surrounding articular cartilage but have not yet reached widespread clinical application. Tissue engineering strategies and gene therapy have the potential to advance the field, however, they remain in the early stages. The current article reviews the structure and physiology of articular cartilage, the strengths and limitations of present treatment modalities, and the newer ongoing innovations that may change the way we approach osteochondral lesions and osteoarthritis.
