ABSTRACT
BACKGROUND:Calcar plays an important role in hip arthroplasty.The reconstruction of calcar includes bone cement reconstruction and restoration of fracture fragments,but there is some lack of knowledge about their comparative study.OBJECTIVE:To analyze the biomechanical characteristics of remodeled calcar using bone cement reconstruction and restoration of fracture fragments in senile intertrochanteric fractures through three-dimensional finite element models.METHODS:The remodeled calcar using restoration of fracture fragments (model A) or bone cement reconstruction (model B) in senile intertrochanteric fractures was obtained.The stress distribution on the bone interface and prosthesis,the overall stress and displacement of the two models were observed.RESULTS AND CONCLUSION:(1) The maximal strain and stress on the bone interface and prosthesis of model A all were more than those of model B.The mean stresses at each node on the bone interface and prosthesis of model A all were significantly higher than those of model B (P ＜ 0.05).(2) The maximum stress and maximum displacement values of the model A all were higher than those of model B.(3) These results show that the maximal stress and displacement values of the remodeled calcar using restoration of fracture fragments are higher than those of bone cement reconstruction in senile intertrochanteric fractures;the latter holds even stress distribution and better repair outcomes.
ABSTRACT
BACKGROUND: Related studies have confirmed that the experimental results and short-term clinical outcomes of artificial ligaments are satisfactory that the artificial ligaments can restore the stability of knee joint as soon as possible and ensure motor function. OBJECTIVE: To summarize the basic and clinical research progress of artificial ligaments. METHODS: The articles regarding artificial ligaments in repair of knee joint cruciate ligament injury were retrieved from Wanfang database, CNKI and PubMed database during 1985 to 2015 by computer. The keywords were “cruciate ligament injuries, artificial ligament, biological materials” in Chinese and English, respectively. RESULTS AND CONCLUSION: Compared with autologous and al ogenic ligaments, artificial ligament has good mechanical properties, and can get sufficient tensile strength and joint stability immediately after implantation, so as to ensure the cruciate ligament reconstruction of the knee joint. Artificial ligament technology has experienced carbon fiber ligament, polyester material and stent artificial ligaments. As a new type of polyester artificial ligament, LARS artificial ligament shows a good biocompatibility, on which, cel s can adhere, proliferate and differentiate wel . However, the controversies over the use of artificial ligament stil exist, and its long-term clinical effects stil need further observation. Further researches regarding the material selection, shape bionic design, weaving and surgical techniques of artificial ligaments are stil further needed.
ABSTRACT
BACKGROUND: The use of tissue engineering technology to build a functional meniscus is a new idea for repair of meniscus injury. OBJECTIVE: To analyze the research progress of seed cells and scaffold materials in tissue-engineered meniscus repair. METHODS: A computer-based search of CNKI and PubMed was performed for articles related to tissue-engineered meniscus repair published from 1996 to 2015. The keywords were meniscal repair, meniscal injury, tissue engineering, tissue-engineered meniscus, biomaterials, stem cells in Chinese and English, respectively. RESULTS AND CONCLUSION: Tissue-engineered meniscus reconstruction is a more viable method for repair of meniscus injury. Mesenchymal stem cells are pluripotent cells that are ideal seed cells for tissue-engineered meniscus reconstruction. Scaffolds are one of important factors for meniscus repair, and natural meniscal scaffolds play an important role. Selection and development of scaffold materials for meniscus tissue engineering have experienced a rapid development period from a single material to composite materials. Composite materials make up a lot of shortcomings and deficiencies that a single material has, and open up new ideas for developing new materials. Meniscal tissues with geometric shapes can be constructed using tissue engineering technology. However, the long-term observation of the biological properties of meniscal tissues is necessary, and from basic to clinic, there is still a lack of reliable data to prove the effect of tissue engineering technology in the meniscus repair.
ABSTRACT
BACKGROUND: Autologous tendon and artificial tendon are both the important grafts that can reconstruct the ruptured anterior cruciate ligament, but each has their defects and excellents. OBJECTIVE: To investigate the biomechanical change and histological rejection of reconstructing the anterior cruciate ligament of the rabbits with autologous tendon and artificial ligament. DESIGN, TIME AND SETTING: A controlled observation was performed from September 2007 to February 2008 in the Orthopedics Laboratory and the Biological Laboratory of Zhengzhou University (Zhengzhou, Henan, China). MATERIALS: Twenty-eight adult New Zealand rabbits of SPF grade were offered by Zhengzhou University Animal Experimental Center, weighing 2.4-3.1 kg with a mean of 2.8 kg, irrespective of genders. MB66 braid was produced by Smith & Nephew Medical (Shanghai) Limited. METHODS: The tendons of extending toe were harvested in both lower extremities, one tendon was wrapped with artificial ligament, while the other was only processed into the terminal wove dovetail. Anterior cruciate ligament was excised from bilateral knee joints in rabbits through the parapatellar incision, then femoral and tibial bones were drilled to implant the autologous tendon and artificial ligament on one side (serving as combined tendon group), whereas only autologous tendon on the other side (serving as pure tendon group). Both sides were sutured through bone bridge. Every 7 rabbits were killed under anesthesia at 2, 4, 6, and 8 weeks postoperatively. MAIN OUTCOME MEASURES: Gross observation and histological determination were carried out in the reconstructed anterior cruciate ligament of rabbits. The maximal breaking force of both grafts were detected. RESULTS: At 2 and 4 weeks postoperatively, the cells of reconstructed grafts disappeared and showed necrosis. Inflammatory cells infiltrated between autologous tendon and artificial ligament, there were cells growing from the edge to the center. At 6 weeks postoperatively, the autologous tendon had a little loose and disfiguration. The synovial membrane and cells hyperplasia were obvious. The synovial membrane filled the combined tendon and the infiltrative inflammatory cells reduced. The proliferative cells remarkably trended to the center. At 8 weeks postoperatively, the grafts were mostly substituted by new cells, and the artificial ligament was completely parceled by the synovial membrane, but there were still some gaps; The combined tendon exhibited no loose or disfiguration, the infiltrative inflammatory cells disappeared. The cells in grafts were close to normal cells in anterior cruciate ligament, but fibrocytes arranged in disorder and fibers showed a verticality. Biomechanics test results demonstrated the maximal breaking force of combined tendon was more than that of pure tendon (P