Q. Fu, Changhai Hospital,Shanghai, Shanghai, China; C. Zhang, S. Xu, Changhai Hospital, The Second Military Medical University, Shanghai, China; X. W. Liu, Second Military Medical University,, China, Shanghai, China
Objective:To further verify the rapid bone healing with high quality under the internal fixation of nitinol swan-like memory compressive connector(SMC) and to evaluate the stress-shielding effect of SMC from clinical aspects. Methods:In clinical application study, patients’ upper extremity fractures were chosed to be fixed with SMC and stainless steel plate(SP).When bone healing was achieved, the internal fixators were taken out, histological observation, radiographical observation and CT scaning quantitation were made so as to assess the stress-shielding effect of SMC. Results:¢ÅHistological observation:Under all parts of group SMC, the cortical bone had regular architecture of lamellar bone and had none bone absorption.While in cortical bone beneath the plate of group SP,obvious osteoporosis and bone absorption were observed,and there were large or small absorption cavity, expanding Haversian canal and shrinked osteocyte as so on.The cortical bone of opposite side in group SP had less bony absorption than that of the side beneath SP. ¢ÆRadiographical observation:Group SMC had no external callus.It’s cortical thickness and bone density were similar to normal sclerotin.While in group SP,the cortical thickness become thinner and obvious bone absorption was observed. The opposite side cortical bone in group SP had higher thickness and density than the side beneath SP. ¢ÇCT scaning quantitation£ºBetween the CT value of cortical bone beneath Swan body part and compressing part,there was no statistical difference,whilein group SP the CT value of the side beneath plate was lower than that of the opposite side of plate.When group SMC and SP were compared,it was found that CT value in two parts of group SP was lower that of that of any part of group SMC.Conclusion: nitinol swan-like memory compressive connector(SMC) had lower stress-shielding effect to fixed bone than SP, and this effect may be ascribed to the special material characteristics of NiTi alloy and geometrical configuration of SMC.
Summary: To further verify the rapid bone healing with high quality under the internal fixation of nitinol swan-like memory compressive connector(SMC) and to evaluate the stress-shielding effect of SMC from clinical aspects.
