ABSTRACT
BACKGROUND:In recent decades, total knee arthroplasty is widely used in the treatment of terminal knee joint diseases, such as osteoarthritis, rheumatoid arthritis, traumatic arthritis and other bone diseases. The methods of osteotomy, soft tissue balance and prosthesis rotation positioning have always been debated and discussed in total knee arthroplasty. OBJECTIVE:To explore the repair effect of total knee arthroplasty for terminal knee disease. METHODS:Total knee arthroplasty was performed for treating terminal knee disease in 31 cases (31 knees), including 26 cases of osteoarthritis (26 knees) and 5 cases of rheumatoid arthritis (5 knees). Al cases accompanied flexion contracture deformity to different degrees. The maximum angle of flexion deformity was < 25°. Al patients were scored by hospital for special surgery knee score before and after replacement. Al 31 knees were treated with fixed platform posterior-stabilized prostheses. RESULTS AND CONCLUSION:No complications, such as early infection and prosthesis dislocation, were found after surgery. Joint pain apparently lessened, flexion and varus deformity obviously improved after replacement. Postoperative X-ray films showed good prosthesis position and low limb alignment. Al cases were folowed up for 6-12 months. The hospital for special surgery knee score improved significantly from preoperatively 46.4±5.3 to postoperatively 84.6±10.5 after 6 months of folow-up. Excelent and good rate was 84%. Results indicate that total knee arthroplasty for treating terminal knee disease has a good clinical effect. However, the operation is complex and precise technique is required.
ABSTRACT
[Objective]To simulate the biomechanics mechanism and environment of humeral fracture caused by indirect impact force for the purpose of biomechanics understanding and treatment of such fracture.[Method]Based on the data source, which was high-resolution anatomic slice images from approximal clavicle to distal humerus, 1 mm thickness and totally 380 layers, the geometric model of total shoulder joint was established according to the order:point, line,area, and further meshed to set up the three dimension finite element model of shoulder, fracture sites and instantaneous stress and strain of humerus were simulated and analyzed under the condition which longitudinal impact force was loaded on the humerus based on the 12 functional positions of shoulder(abduction 30?、 45?、 60?、 90?, and simultaneous neutrality, internal rotation 45?,external rotation 45?).[Result]According to the humeral shaft load-strain curve in different functional positions of shoulder, linear relation was found when load changed from 0 N to 250 N, after which non-linear come out, and even load was removed , bone was deformed eternally. With the rise in load amount, the increase in stress was detected. When abduction degree changed from 90? to 30?, the strain of humerus, both the lateral and the medial increased gradually,and increase in internal rotation 45?and external rotation 45? was more significant than that in neutrality. Meanwhile, stress difference could be seen between the lateral and the medial , and medial was larger than the lateral. Increase in stress in rotation positions was quicker and more than that in other functional positions.[Conclusion]Based on 4 abduction degrees (30?, 45?, 60?, 90?) and 3 rotation degrees(neutrality, internal rotation 45?,external rotation 45?) ,the three dimensional finite element shoulder could simulate precisely stress, strain, general trend of fracture line, three dimension images of bone failure. Three dimension finite element simulation and analysis of shoulder is a valuable mechanical method for research on biomechanics theory related to humerus fracture.