Little is known about the forces carried by the Taylor Spatial Frame (TSF) hexapod fixator. Our aim was to measure the TSF resultant force and how this changed during the consolidation phase. Five patients undergoing correction of tibial deformities were recruited. Measurements were taken at 2, 4, 8 and 12 weeks post-correction during various activities. Instrumented struts incorporating strain gauges measuring axial force were temporarily used each time. Strut forces and lengths were used to determine frame kinetics. The resultant axial fixator forces and moments were calculated relative to sitting. Ground reaction forces (GRF) were measured using the treadmill force plates.Background:
Method:
Clinical evidence that patients with type 2 diabetes mellitus (T2DM) have increased risk of fractures is reported. Furthermore, thiazolidinediones, used to treat T2DM increases the risk of secondary osteoporosis & subsequent fractures. The osteogenic potency of metformin is reported in vitro, few studies have investigated the effects of metformin on bone mass and fracture healing in vivo. We aimed to investigate the effects of metformin on fracture healing in vivo. 20 female Wistar rats aged 3 months were randomly divided in two groups, one group receiving saline, the other group receiving metformin administered orally via the drinking water at a concentration of 2mg/ml. After 4 weeks of metformin treatment, a mid-diaphyseal, open External fixation fracture was performed. Rats were sacrified 4 weeks later. Right contralateral tibia and left osteotomised femora were excised, bone architecture analysed by micro-CT in the right tibia. No significant differences were noted between the two groups. Fracture callus volume and mineral content after 4 weeks were similar in metformin and saline groups. Discussion Our results indicate that while metformin has no adverse effects on bone, it does not promote bone mass, as suggested by in vitro studies. This confirms clinical data which have not shown direct links between metformin and decreased fracture riskMethod
Results
Fracture healing is governed by biological and mechanical factors. Circular frames are one method to fix fractures. Recently, the number of frame designs that are available has increased and these different designs may have different effects on the mechanical environment created. The senior author has been concerned by the stability of the construction when a short frame is used. This study examined the stability of different frames and the possible use of additional 7th struts to aid stability. The frame configuration was modified with increasing strut angles from 15° − 70°. Each frame was cyclically tested in compression to 200N. The Taylor Spatial Frame was retested with the addition of a seventh strut.Introduction
Method
