Experimental Study Of The Motion Of The First Tarsometatarsal Joint And Its Correlation Factors

The first tarsometatarsal (TMT1) joint in the midfoot is the important section of the foot arch. During standing and walking, the stress of forefoot is transmitted to the hindfoot by the TMT1 joint. Many scholars found that the biomechanical abnormality of the TMT1 joint, especially the motion, is close to the function disorder in the midfoot and forefoot, such as the hallux valgus. So it is necessary to deeply study the motion of the TMT1 joint and correlation factors.To investigate the properties of the TMT1 joint motion and its correlation factors, two specimen experiments and one model experiment was performed. Firstly, the fresh frozen adult leg-foot specimens were fixed and loaded in grades, a great deal of clear digital images of specimens was collected, and the digital speckle correlation measurement was used to calculate displacement of joints in the first ray; Secondly, the TMT1 joints integrally dissociated from the leg-foot specimens, marked, fixed and loaded, then the 3-D digitalising system was used to measure and calculate displacement of the isolated TMT1 joints; Lastly, we adopted the principle of the reverse engineering, applied 3-D finite element analysis to establish the model of normal foot, then simulated the biomechanical loading, calculated displacement of joints in the first ray of the foot model. All experimental data was analyzed by statistics in spss system. The result of the study discovered that the ROM of the TMT1 joint is small, which isn't equal to the one of the first ray, and the plantar ligaments play a important part in maintaining the stabilization of the TMT1 joint and the first ray.There is the theory and practice directive function for clinic by this study. In terms of theory, it has contribution to understand the property of the TMT1 joint in kinematics. In terms of practice, it can help doctor to choose the right treatment plan for the disorder in the midfoot and forefoot.