The Illustrative Single-Stage Cartilage Repair Technique with Chitosan-Based Bioscaffold (BST-CarGel)

Articular cartilage damage and osteochondral defects remain major orthopaedic challenges. In a study reviewing over 30,000 arthroscopic procedures, approximately 60% of the patients were found to have some cartilaginous defects, a majority (41.0% of all chondral lesions had grade III changes, and 19.2% of all had grade IV changes) of them being high-grade defects [1]. If left untreated, these can progress to degenerative arthritis requiring arthroplasty at an earlier age [2]. The goal of any cartilage repair treatment is to achieve a repair tissue with structural characteristics comparable with the native hyaline cartilage, which may result in long-term durability, joint function and pain relief [3]. Although several strategies have been described to treat the chondral lesions, microfracture is currently the first line of surgical treatment recommended for the small chondral defects [4, 5]. However, microfracture technique is not without its drawbacks. Microfracture results in a fibrocartilaginous repair tissue lacking hyaline articular structure [6–8] and clinical benefit that is variable beyond 5 years [9]. It is postulated that the inconsistency and suboptimal repair tissue both in quantity and in quality may result from the instability of the fibrin clot formed from marrow blood in the lesion [6, 7, 10, 11], which may shrink as a result of platelet-driven clot retraction [11, 12]. It has been demonstrated by studies that improved repair can be achieved with a more adherent and a voluminous clot [13]. This clot in turn modulates the repair events that result in optimum cartilage regeneration and repair. Hence the critical component for the bone marrow-derived cartilage repair is the quantity of the initial blood clot present in the cartilage lesion after the microfracture [13, 14].