Contemporary Management of Knee Chondral Defects, Part II: Structural Cartilage Restoration with Focal Resurfacing Implants and Osteochondral Autograft Transfer.

Abstract

Structural cartilage restoration strategies provide mechanical solutions for focal knee chondral defects in which biologic repair alone is unlikely to withstand load-bearing demands. These approaches are most applicable to discrete lesions in otherwise preserved joints where restoration of articular congruity and immediate mechanical stability are required. This review evaluates focal resurfacing implants and osteochondral autograft transfer system procedures as structural joint-preserving interventions. Contemporary metal and polymer-based focal implants demonstrate meaningful short- to mid-term improvements in pain and function. However, registry data and meta-analyses reveal variable survivorship and revision risk, frequently related to progressive osteoarthritis or implant-related complications. Outcomes are highly dependent on appropriate patient selection and precise implant positioning. Osteochondral autograft transfer system procedures and mosaicplasty restore mature hyaline cartilage and subchondral bone using autologous osteochondral plugs. Long-term series extending beyond a decade support durable outcomes in small, contained lesions. Donor-site morbidity, graft contouring limitations, and size constraints, however, restrict broader applicability. Comparative data highlight trade-offs between mechanical resurfacing and cartilage transfer. Implants avoid donor harvest, but introduce device survivorship concerns and complex revision pathways. Autograft transfer offers established durability with native tissue, but carries technical constraints and harvest-related morbidity. Structural restoration strategies occupy a defined position within the cartilage preservation continuum. Their success depends on alignment between defect characteristics, patient activity demands, and the surrounding joint environment. When applied within appropriate indications, these techniques can provide durable symptom relief, though none of them eliminates the risk of progression to arthroplasty.