Biomechanical Study On The Stabilit Y Of Elbow Flexion And Extension Of Human Body

In recent years, the incidence of elbow instability caused by the medial and lateral collateral ligament, articular capsule and so on was significantly increased due to daily activities,intense physical activity and trauma, etc. According to some clinical experiments,it has little effect on the flexion movement but has great effect on the extension movement for most people after recovery of elbow joint injury, which greatly affects the daily life and work. At present, the injury mechanism and repair of elbow ligaments and joint capsule are not clear. Therefore, building a finite element model of adult elbow joint of high degree of simulation, and to study the biomechanical properties of the related structures in the process of flexion and extension of upper limb has important theoretical significance and practical application value for the reduction and protection of upper limb injury and the maintenance of the stability of elbow function.This topic is based on the CT scan data of normal adult’s upper limb. The medical image processing software and reverse engineering software were used to extract the upper limb geometry to construct the finite element model of elbow joint with high simulation(including the humnerus, ulna and radius, the articular cartilage of distal end of humerus and proximal end of ulna and radius, anterior bundle, posterior bundle, and transverse bundle of ulnar collateral ligament and radial collateral ligament). The finite element model of elbow joint was verified by the finite element method. And the simulation and calculation of flexion and extension was carried out for the elbow joint from the neutral 90 degrees to 0 degrees. The analysis is based on the following two cases. First is under normal circumstances, with the anterior bundle, posterior bundle, and transverse bundle of ulnar collateral ligament and radial collateral ligament. Second is in the case of damage (1) with the posterior bundle and transverse bundle of ulnar collateral ligament and radial collateral ligament, and without the anterior bundle of ulnar collateral ligament; (2) with the anterior bundle and transverse bundle of ulnar collateral ligament and radial collateral ligament, and without the posterior bundle of ulnar collateral ligament; (3) with the anterior bundle and posterior bundle of ulnar collateral ligament and radial collateral ligament, and without the transverse bundle of ulnar collateral ligament; (4) with the anterior bundle, posterior bundle,and transverse bundle of ulnar collateral ligament, and without radial collateral ligament.The results were compared with the previous literature to verify validity of the model. And the distribution and size of the contact stress of articular cartilage and the related ligaments for the elbow joint from the neutral 90 degrees to 0 degrees in the process of stretching were studied.The stress situation of articular cartilage,the ulnar collateral ligament and the radial collateral ligament of normal elbow joint were analyzed. The results showed that the three--dimensional finite element model of elbow joint was effective. The maximum of contact stress were mostly concentrated in the trochlear notch of ulna prominents for the elbow joint from the neutral 90 degrees to 0 degrees in the process of stretching, which was generally consistent with the clinical results. The stress of ulnar collateral ligament and radial collateral ligament mainly concentrated on the starting and ending side, and the radial collateral ligament played a major role before 15 degrees,after the extension of the elbow angle of more than 15 degrees,the anterior bundle of ulnar collateral ligament played a major role, followed by the posterior bundle of ulnar collateral ligament, last was the transverse bundle of ulnar collateral ligament.This study is of guiding significance for the clinical treatment of arthritis disease caused by severe abrasion of articular cartilage, and the mechanism of ligaments injury,repair and reconstruction.It also provides theoretical basis for sports medicine, clinical medicine, rehabilitation medicine and so on. And at the same time, it provides theoretical support for further revealing the laws of human elbow joint movements, the prevention and rehabilitation of sports injuries, the optimal design of artificial joints and the maintainment of stability of elbow joint.