Aims. A large number of surgical operations are available to treat osteochondral defects of the knee. However, the knee joint arthroplasty materials cannot completely mimic the articular cartilage and subchondral bone, which may bring some obvious side effects. Thus, this study proposed a biocompatible osteochondral repair material prepared from a double-layer scaffold of collagen and nanohydroxyapatite (CHA), consisting of collagen hydrogel as the upper layer of the scaffold, and the composite of CHA as the lower layer of the scaffold. Methods. The CHA scaffold was prepared, and properties including morphology, internal structure, and mechanical strength of the CHA scaffold were measured by scanning electron microscopy (SEM) and a MTS electronic universal testing machine. Then, biocompatibility and repair capability of the CHA scaffold were further evaluated using a rabbit knee cartilage defect model. Results. The CHA scaffold was well suited for the repair of articular cartilage and subchondral bone; the in vitro results showed that the CHA scaffold had good cytocompatibility. In vivo experiments demonstrated that the material had high biocompatibility and effectively induced cartilage and subchondral bone regeneration. Conclusion. The CHA scaffold has a high potential for commercialization and could be used as an effective knee repair material in clinical applications. Cite this article: Bone Joint Res 2025;14(2):155–165

Injury to the anterior cruciate ligament (ACL) is one of the most devastating and frequent injuries of the knee. Surgical reconstruction is the current standard of care for treatment of ACL injuries in active patients. The widespread adoption of ACL reconstruction over primary repair was based on early perception of the limited healing capacity of the ACL. Although the majority of ACL reconstruction surgeries successfully restore gross joint stability, post-traumatic osteoarthritis is commonplace following these injuries, even with ACL reconstruction. The development of new techniques to limit the long-term clinical sequelae associated with ACL reconstruction has been the main focus of research over the past decades. The improved knowledge of healing, along with recent advances in tissue engineering and regenerative medicine, has resulted in the discovery of novel biologically augmented ACL-repair techniques that have satisfactory outcomes in preclinical studies. This instructional review provides a summary of the latest advances made in ACL repair.

Cite this article: Bone Joint Res 2014;3:20–31.