Xinwen Zhao1, Wensen Jing2, Zhe Yun3, Xun Tong4, Zhao Li1, Jiajia Yu1, Yaohui Zhang1, Yabin Zhang5, Zhixue Wang5, Yanhua Wen5, Heping Cai6, Jun Wang7, Baoan Ma8, Haien Zhao5. 1. Department of Joint Surgery, Yuncheng Hospital, The Eighth clinical Medical University, Shanxi province, 441000, China. 2. Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, 555 Youyi East Road, Beilin District, Xi'an, 710054, Shaanxi Province, China. 3. Department of Orthopedics, 941st Hospital of PLAJLSF, Xining, 810000, Qinghai proviince, China. 4. Department of Traditional Chinese Medicine Rehabilitation and Physiotherapy, Xuzhou Army 71st Group Army Hospital, Xuzhou, 221000, Jiangsu province, China. 5. Institution of Orthopedics, Tangdu Hospital, Air Force Medical University, Xi'an, 710038, Shaanxi province, China. 6. School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an,710061 shaanxi province, China. 7. Center of Orthopedic laboratory, Xijing Hospital, Air Force Medical University, Xi'an, 710038, Shaanxi province, China. 8. Institution of Orthopedics, Tangdu Hospital, Air Force Medical University, Xi'an, 710038, Shaanxi province, China. Mban1971@163.com.
Abstract
BACKGROUND: In orthopedic application, stress-shielding effects of implant materials cause bone loss, which often induces porosis, delayed bone healing, and other complications. We aimed to compare the stress-shielding effects of locked compression plate (LCP) and limited-contact dynamic compression plate (LC-DCP) in dogs with plate-fixed femurs. METHODS: Bilateral intact femurs of 24 adult dogs were fixed by adult forearm 9-hole titanium plates using minimally invasive plate osteosynthesis (MIPPO) technology, with LCP on the left and LC-DCP on the right femurs. Dogs were sacrificed at 6 weeks, 12 weeks, and 24 weeks after surgery, and bone specimens were used to evaluate the efficacies of different fixing methods on bones through X-ray, dual-energy X-ray absorptiometry (DEXA), histology, MicroCT, and biomechanics analyses. RESULTS: X-ray results showed significant callus formation and periosteal reaction in the LC-DCP group. Bone cell morphology, degree of osteoporosis, and bone mineral density (BMD) changes of the LCP group were significantly better than that of the LC-DCP group. MicroCT results showed that the LCP group had significantly reduced degree of cortical bone osteoporosis than the LC-DCP group. Tissue mineral density (TMD) in the LCP group was higher than that in the LC-DCP group at different time points (6 weeks, 12 weeks, and 24 weeks). Biomechanics analyses demonstrated that the compressive strength and flexural strength of bones fixed by LCP were better than that by LC-DCP. CONCLUSIONS: Stress-shielding effects of LCP are significantly weaker than that of LC-DCP, which is beneficial to new bone formation and fracture healing, and LCP can be widely used in clinic for fracture fixation.
BACKGROUND: In orthopedic application, stress-shielding effects of implant materials cause bone loss, which often induces porosis, delayed bone healing, and other complications. We aimed to compare the stress-shielding effects of locked compression plate (LCP) and limited-contact dynamic compression plate (LC-DCP) in dogs with plate-fixed femurs. METHODS: Bilateral intact femurs of 24 adult dogs were fixed by adult forearm 9-hole titanium plates using minimally invasive plate osteosynthesis (MIPPO) technology, with LCP on the left and LC-DCP on the right femurs. Dogs were sacrificed at 6 weeks, 12 weeks, and 24 weeks after surgery, and bone specimens were used to evaluate the efficacies of different fixing methods on bones through X-ray, dual-energy X-ray absorptiometry (DEXA), histology, MicroCT, and biomechanics analyses. RESULTS: X-ray results showed significant callus formation and periosteal reaction in the LC-DCP group. Bone cell morphology, degree of osteoporosis, and bone mineral density (BMD) changes of the LCP group were significantly better than that of the LC-DCP group. MicroCT results showed that the LCP group had significantly reduced degree of cortical bone osteoporosis than the LC-DCP group. Tissue mineral density (TMD) in the LCP group was higher than that in the LC-DCP group at different time points (6 weeks, 12 weeks, and 24 weeks). Biomechanics analyses demonstrated that the compressive strength and flexural strength of bones fixed by LCP were better than that by LC-DCP. CONCLUSIONS: Stress-shielding effects of LCP are significantly weaker than that of LC-DCP, which is beneficial to new bone formation and fracture healing, and LCP can be widely used in clinic for fracture fixation.