Simulation Study on Influence of Orientation Parameter of Total Hip Components on the Range of Motion of Hip at Different Head/Neck Ratios Using Computer-Assisted Model
1 The Third Affiliated Hospital of Wenzhou Medical College, Rui′an 325200,China
2 Institute of Digitized Medicine, Wenzhou Medical College, Wenzhou 325035,China
3 School of Mechanical and Power Energy Engineering, Shanghai Jiaotong University，Shanghai 200240,China
Abstract In this study a simulation model was proposed to examine the influence of orientation parameter of total hip components on the range of hip motion and obtain optimum combination of cup and neck anteversions in total hip arthroplasty at different general head/neck ratios (GR). A threedimensional generic parametric and kinematic simulation module of total hip arthroplasty （THA） was developed. The corresponding operative anteversion (OA) of the cup was related to the operative inclination (OI) of the cup which every 5° was calculated, and described using dots and lines in a coordinate system in which OI of acetabular cup was horizontal ordinate and OA of acetabular cup was vertical ordinate. The results showed that when CCDangle was 135°, the optimum relationship between OA of acetabular (Y) and FA of normal criteria and severe criteria (X）could be estimated by the formula: Y1=0.728X1+40.916（R2=0.999 9）and Y2=-0.738 4X2+46.456(R2=0.999 9）respectively, and the minimum allowable operative inclination (OImin) of acetabular should be more than 254.27GR-3.172（R2 = 0.991 7）and 230.58GR-2.519(R2 = 0.993 5）respectively. Large GR greatly increased the range of motion of the hip and the size of cup safe-zone. The more severe of the hip motion, the smaller size of the cup safezone, but could be retrieve by increasing the GR. The minimum allowable operative inclination (OImin) of acetabular was largely reduced with an increasing GR. The OA was negative with the femoral anteversion (FA).
LI Yong Jiang1 CAI Chun Yuan1 LIN Rui Xin1 ZHANG Li Cheng1* YANG Guo Jing1 ZHOU De Biao1 WU Li Jun2 . Simulation Study on Influence of Orientation Parameter of Total Hip Components on the Range of Motion of Hip at Different Head/Neck Ratios Using Computer-Assisted Model[J]. journal1, 2012, 31(1): 103-109.
