ABSTRACT
BACKGROUND: Chitosan has become a research hotspot of cartilage repair materials because of a wide range of biological sources, simple preparation processes and excellent biocompatibility. OBJECTIVE: To review the characteristics of chitosan hydrogels and their application in cartilage repair. METHODS: PubMed and CNKI databases were searched by computer with the keywords of "chitosan; chitosan hydrogel; cartilage repair; tissue engineering" in English and Chinese, respectively. The time range was from January 2000 to March 2018. After initial screening, the retained articles were further analyzed, concluded and summarized. RESULTS AND CONCLUSION: Chitosan has good biocompatibility, low toxicity, low immunogenicity, and can load multiple growth factors and seed cells with different physical or chemical improvements. Encouraging progress in tissue engineering cartilage repair has been achieved. With the development of technology and the understanding of cartilage and subchondral bone structure, the application range of chitosan biomimetic hydrogel has been broadened. However, the molecular mechanism and degradation process of chitosan in vivo still have a lot of controversies, and further research and exploration are needed.
ABSTRACT
Objective To explore stress changes of articular surface of knees after unicompartmental knee arthroplasty (UKA) using the finite element analysis,so as to make clear the advantages and disadvantages of such a surgery.Methods Dynamic finite element analysis was performed for 6 patients after UKA and 6 healthy subjects,and compared with previous analysis of patients undergoing total knee arthroplasty (TKA).Results The stress of medial compartment was significantly bigger than that of the lateral of normal knees when bending to 30° (P＜0.05).It was the same case for postoperative knees of TKA in the whole flexion movement and those of UKA at the bending angle of 0°,60° and 90° (P＜ 0.05 for both).At the bending angle of 60° and 90°,the stress of the medial compartment of postoperative UKA knees was significantly bigger than that of the TKA knees and in the whole flexion movement,the stress of the lateral compartment of the former was significantly bigger than the latter,The stress of lateral compartment of postoperative UKA knees was bigger than the normal controls at the bending angle of 0°,30°,60° and 120° (P＜0.05).Conclusion UKA may increase the stress of knee joints and accelerate the development of osteoarthritis of the contralateral compartment,leading to poor long-term effect.However,the surgery still has advantages if strictly choosing surgery indications,optimizing the surgical operations,properly improving prosthesis and reasonably guiding patients rehabilitation.