| Objective: To investigate the changes on the loading peak pressure in the hip dome region and the tibialfemoral region to knee osteoarthritis in different degrees of varus and valgu with pressure-sensitive film technology.Methods: Three pelves plus the proximal femora and knee were harvested from recent refrigerant cadaver for this study. All of these specimens were visually examined and then X-rayed to exclude the presence of hip and knee pathology. All muscles and connective tissues were dissected. Hip and knee joint capsules and ligaments were preserved. The pelvis and proximal femur and knee joint simulated the single leg stance phase of gait. The plane formed by the anterior superior iliac spine and the pubic symphysis aligned vertically. The line between iliac crests was horizontal. In the frontal plane,the femoral shaft was placed in 15 degrees of adduction relative to the pelvis. In the sagittal plane,the femoral shaft was vertical. The femur was oriented in 5 to 10 degrees of intenal rotation. The high tibial osteotomy(HTO) were operated to make the model of knee varus and valgus with unilateral external fixation apparatus. Before loading, the entire capsule of the hip joint was removed, 2.0-millimeter holes were drilled through the hip articular cartilage and the underlying bone of the acetabulum at points 30 degrees on each side of the acetabular dome region. And the articular surface of femoral head and inboard and outboard of knee joint were covered with pressure-sensitive films. During loading, a blunt probe was used to mark the pressure-sensitive film(PSF) through these holes. The outline of the acetabular rim was also marked on the film. After loading, the films were removed from the femoral head and the face of tibialfemoral joint and glued on the paper. Test was initially performed with the different states supervised by specail 3-D laser scan apparatus to inspect the loding joint state. After the normal patten(Group A)was recorded, different kinds of knee varus and vulgus were performed through unilateral fixation frame: Group A: Hip in Knee Nomal: Group B: Hip in Knee varus 10~0; Group C: Hip in Knee varus 20~0; Group D: Hip in Knee Valgus10~0;Group E: Hip in Knee Valgus20~0。While the face of tibialfemoral joint were divided into five pattern: a(Knee in Nomal) ;b(Knee in Varus10~0); c(Knee in Varus20~0); d(Knee in Valgus10~0);e(Knee in Valgus20~0)。To these ten groups, the loading area, the mean pressure, and the peak pressure in the acetabular dome region and knee joint were measured with pressure translation system (Fuji, Japan). All of these data were recorded. For each group, test of homogeneity of variances was performed. Then multiple comparisons among ten groups were performed with ANOVA method. The difference is significant at the 0.05 level. The statistical work was performed with the help of software-SPSS 13.0.Results:1.For the Hip pattern:Group A(Hip in Knee Normal), the loading area, mean pressure, and peak pressure were as follows: 6.33±0.12cm2;3.62±0.33MPa;4.58±0.20MPa。Compare to the group A, the loading area in the group C and E are decreased. There was significant difference between the group B and C, the result between D group and E group are the same(p>0.05). Compare to the group A, the mean pressure in the group C and E are decreased.There was significant difference between the group B and C, the result between D group and E group are the same(p>0.05).Compare to the group A, the peak pressure in the group C and E are decreased. There was significant difference between the group B and C, the result between D group and E group are the same(p>0.05).2. for the knee pattern:Group a(knee in Normal), the loading area in the face of tibialfemoral joint, inboard and outboard part of the tibialfemoral joint were as follows: 2.46±0.5cm2;1.71±0.16 cm2;4.22±0.16 cm2。As the degree of varus increase, the loading area of inboard of tibialfemoral joint incrased compare to normal status while the loading area of outboard of tibialfemoral joint decrased. As the degree of valgus increase, the loading area of outboard of tibialfemoral joint incrased compare to normal status while the loading area of inboard of tibialfemoral joint decrased. And it beacame more clear in the status of varus 20~0 and varus Valgus20~0 (p>0.05).Group a(knee in Normal), the mean pressure in the face of tibialfemoral joint, inboard and outboard part of the tibialfemoral joint were as follows: 2.22±0.5 MPa;1.71±0.16 MPa;4.22±0.16 MPa。As the degree of varus increase, the mear pressure of inboard of tibialfemoral joint incrased compare to normal status while the mean pressure of outboard of tibialfemoral joint decrased. As the degree of valgus increase, the mear pressure of outboard of tibialfemoral joint incrased compare to normal status while the mean prssure of inboard of tibialfemoral joint decrased. And it beacame more clear in the status of varus 20~0 and varus Valgus20~0(p>0.05).Group a(knee in Normal), the peak pressure in the face of tibialfemoral joint, inboard and outboard part of the tibialfemoral joint were as follows: 4.59±0.1 Mpa;2.57±0.1 MPa;1.95±0.05 MPa。As the degree of varus increase, the peak pressure of inboard of tibialfemoral joint incrased compare to normal status while the peak pressure of outboard of tibialfemoral joint decrased. As the degree of valgus increase, the loading area of outboard of tibialfemoral joint incrased compare to normal status while the peak pressure of inboard of tibialfemoral joint decrased. And it beacame more clear in the status of varus 20~0 and varus Valgus20~0(p>0.05).Conclusion:1.The is a very predominant change in the loading area, the mean pressure, and the peak pressure stress distribution in hip dome region and tibialfemoral joint with the tendency of knee varus's and valgus'increasing. The stress and pressure-percentage of medial tibiofemoral joint were increasing predominantly, contrasted by the normal tibiofemoral joint. The phenoment become significant when the abnormality of varus and valgus in knee to 20 degrees in the dome region.2. The incessancy high contact stress in the surface of jont may cause chronic injury of arthrodial cartilages resulting in traumatic arthritis. This may be a factor that the pain of hip joint occurs in the patient suffered serious knee abnormality and we should pay more attention to these patient in clinic.
|
PDF Full Text Request