Editorial Commentary: Autologous Chondrocyte Implantation Versus Microfracture for Knee Articular Cartilage Repair: We Should Focus on the Latest Autologous Chondrocyte Implantation Techniques.

The clinical efficacy of autologous chondrocyte implantation (ACI) versus microfracture (MFx) for repair of articular cartilage lesions in the knee has gained significant attention in the orthopaedic sports medicine community in recent years. Bone marrow stimulation with MFx often is considered a first-line treatment option, given the ease and low cost of the procedure, as well as the good short-term outcomes. However, multiple studies have recently shown the outcomes of knee MFx to worsen after 5 years postoperatively, particularly for larger lesions. Because of this, ACI has been proposed as a first-line rather than salvage procedure for focal chondral defects in the knee. Although it is important to understand the differences in clinical outcomes between ACI and MFx at mid-term follow-up, longer-term outcomes need to be further investigated. In addition, it may be more appropriate to focus on the comparison of MFx with newer-generation techniques of chondrocyte implantation matrix-associated ACI rather than a collation of historical 2-step ACI using periosteum and newer techniques.