Computer Simulation Of Total Hip Replacement In Femoral Head Neck Ratio Of Joint Activity

Objective:To investigate maximum movement range before hip joint impingementhappened under different head neck ration(HNR)、 acetabular angle、anteversion angle of hip prothesis through the three-dimensionalreconstruction technology and motion engineer software simulating total hiparthroplasty. To provide the reference of hip prothesis during THA、elevateaccuracy of the operation and survival rate of implant、decrease complicationand operation time、reduce the economic burden by current study.Material and methodsBy data came from CT,we reconstructed total hip joint throughcomputer engineering software simulating THA and hip joint impingementunder different hip location: flexion、extension、abduction、adduction whenthe hip joint flexed90degree.Head neck ration(HNR) were0.61,0.65,0.70,0.78,0.88respectively;Acetabular anteversion anglewere0°、8°、15°、22°、30°respectively;Acetabular abduction angle were0°、8°、15°、22°、30°respectively; Hip stem anteversion angle were5°、13°、20°、28°、35°respectively.Through the three-dimensional reconstructiontechnology and motion engineer software simulating total hip arthroplastyand investigated the maximum movement range of total hip beforedislocation and impingement happened.ResultThis current study showed:the relationship between the minimum acetabular abduction angle（OImin）and the ratio of head/neck（HNR） was217.28、2.504(r2=0.9985) respectively,the optimal combinaiton of acetabualranteversion angle(A)and femoral stem anteversion angle(B)present linearrelationship:A=-0.7963B+42.869(r2=0.9988).Conclusion:1.HNR was positive correlation with the range of the hip movement;theangle of acetabular anteversion and abduction was positive correlation withHNR; the angle of acetabular abduction showed linear correlationship withthe range of the hip movement when the anteversion of hip stem andacetabulum、HNR were fixed.When HNR diminished,the angle of hip joint dislocation and impingementreduced accordingly in general.3.HNR was positive correlation with the posterior stability of the hipjoint.4.The angle of acetabular anteversion was negative correlation with angleof femoral neck anteversion.