| Objective: To measured the anatomic datas of the foot from CR and adult specimens, the cuboid bone plate has been clinical used and the anatonmic datas of cuboid from literature were reviewed. A new type of transarticular cuboid bone plate was design for adult. To evaluate if the instrument can provide stable fixation stability in cuboid fracture through comparative biomechanical study.Methods: 1.Design of the transarticular cuboid bone plate. The angle ?between the fifth metatarsocuboidjiont and the fifth metatarsal bone, the angle?between the fifth metatarsocuboidjiont and the calcaneocuboid joint was measured from 100 CR and 30 adult specimens. Based on the cuboid plate already clinical used and anatomical datas from literature, a new cuboid bone plate was designed for adult. 2.Biomechanical study of the transarticular cuboid bone plate in fixing cuboid fracture in adult. Six fresh lower limbs were chosen(within six months, keeped in the environment of-20?). X-ray was taken to exclude the bone injuries or diseases and to measured the size of cuboid for choose right type internal fixation. The specimens were randomly divided into A, B groups. The specimens were transected approximately 15 cm proximal to the ankle, then potted in the jig potting. Five strain gauges were located at the calcaneus, cuboid, four and five metatarsal bones. The models were fixed on multi-purpose, simulate the model of standing on single foot. Connected the wire of strain gauges to the static resistance strain gauges, then reconcile the balance. Pre-loaded were given to improve the measurement accuracy. The vertical pressure were loaded on the foot from 0N to 600 N, at 1mm/min loading rate, recording the datas. Then we made cuboid fracture model and connected the strain gauges again. Dial indicators were furnished to measure the vertical displacement of the fracture fragments, repeat the opration as before. The last step, we gave group A transarticular cuboid bone plate to fixation fractures and group B were given double plate special used in metacarpal and phalanx fracture to stable the fragment, then repeat the load operation and record the datas. The results were analyzed by independent-samples T test.Result: 1.Design of the transarticular cuboid bone plate. The angle?between the fifth metatarsocuboidjiont and the fifth metatarsal bone is close to 70 °, the angle ? between the fifth metatarsocuboidjiont and the calcaneocuboid joint is close to 30°. The foot cortical/cancellous bone screws matches the transarticular cuboid plate were used in clinic. The design was basised on the AO cuboid plate, stretched it to the calcaneus and the fifth metatarsal bone. Different part of the plate can be used to fixation the fracture fragments. 2.Biomechanical study of the transarticular cuboid bone plate in fixing cuboid fracture in adult. As the load on the foot from 0N to 600 N, the value of the five parts strain tended to increase. After the cuboids were made fracture, compared with the strain value before fracture, the point b and c located near frature have significantly increased(both b and c P value are 0). Group A and B have small changes. The vertical displacement of the fracture fragments between group A and B have statistically significant differences(P values are 0.003, 0.005) both P values are less than 0.05. The vertical displacement indicated the fixing effect.Conclusions: 1. The design of cuboid bone plate was based on The angle between the fifth metatarsocuboidjiont and the fifth metatarsal bone, the angle between the fifth metatarsocuboidjiont and the calcaneocuboid joint that was measured from 100 CR and 30 adult specimens. 2.The transarticular cuboid bone plate is a ideal internal fixation for adult cuboid fracture and its biomechanical property can meet difference cuboid fractures. 3.Through biomechanical experiment Compared with the plate special used in metacarpal and phalanx the transarticular cuboid plate have better fixed effect. |
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