Tibial Shaft Fractures: A Biomechanical and Clinical Approach

Medicine, Biomechanics

Shah, Khalid Mahmud

University:University of Glasgow

关键词: Medicine, Biomechanics;   

Others  :  http://theses.gla.ac.uk/78186/1/11007578.pdf

来源: University of Glasgow

【 摘 要 】

Among the problems associated with the use of tibial functional bracing for the management of tibial shaft fractures, are post-fracture ankle stiffness and the duration of immobilisation. This study was undertaken to investigate in detail these two problems. It involved the design and assessment of a new type of brace called the 2 in 1 functional brace. The study was designed in 3 parts. Part 1 deals with the problem of clarifying the biomechanical function of the brace. It led to the development of a method for estimating the three dimensional forces and moments carried by the limb-brace complex at the level of the fracture. For this five volunteer patients, treated with a 2 in 1 brace for tibial shaft fractures, were each tested on 3 separate occasions. This study led to the conclusion that the brace is neither an off-loading, nor an anti-buckling device, but functions with a combination of these two mechanisms. The data also highlighted the importance of the removable "foot-piece" in the design of the brace for optimum healing of tibial fractures. The information obtained allowed rationalisation of the new design. Part 2 of the study concentrated on the problem of determining the optimum duration of immobilisation in the brace. A non-invasive method of assessing healing by measurement of fracture stiffness was developed. This method gave encouraging results and it was decided to computerise the system. The efficacy of the system was assessed clinically in a trial on 10 patients. The results were encouraging and it is recommended that the system be tested in a larger controlled trial, before its routine use. Part 3 of the study tested the new design of brace in a clinical trial on 80 patients. The trial was conducted to test the efficacy of the design in a clinical environment and to assess its effect on the stiffness of the ankle and sub-talar joints following fracture healing. The brace gave good clinical results with a mean healing time of 97.5 days in the series. The ranges of lower limb joint motion were found to be near normal at a mean follow-up of 16 months, indicating the success of the design in decreasing the incidence of post-fracture ankle and sub-talar joint stiffness. The conclusions from the study suggest that a controlled trial is justified to compare the efficacy of the "2 in 1 brace" against other methods of managing tibial shaft fractures. The data from this series showed that the nature (simple or open) of the fracture, axial stability of the fracture, fracture fragment apposition, treatment modality and time of brace application did affect the outcome of fracture healing.