The relation between micromotion and screw fixation in acetabular cup

One of the major causes inducing loosening in the cementless acetabular cup implanting is its insufficient initial stability. In this study, three-dimensional finite element models of the pelvis and acetabular components were developed to investigate the relationship between relative micromotion, initial stability, and screw fixation under six daily activity loadings. A commercial available hemispheric cup with five screw holes was used as the target acetabular cup. The simulation results showed that if screws were placed closed together, when the screw number increased from 1 to 5, the peak micromotion decreased less than 14%, from 126.5 to 108.8 microm, while the stable region, micromotion less than 28 microm, enlarged only by 40%, from 46.1% to 64.7%. However, if the screw could be placed near the cup rim, a single rim screw, 202.1 microm micromotion, could provide better stability than that of four dome screws, 209.6 microm micromotion, placed closed together. To conclude, multiple cup screws should be placed near cup rim and as separate as possible to enlarge the stable region and reduce the peak micromotion between cup and acetabulum.

[1]  J. Hsu,et al.  Determination of young's modulus of cortical bone directly from computed tomography: A rabbit model , 2003 .

[2]  Jui-Ting Hsu,et al.  Effects of splinted prosthesis supported a wide implant or two implants: a three-dimensional finite element analysis. , 2005, Clinical oral implants research.

[3]  R-M Lin,et al.  Biomechanical investigation of pedicle screw-vertebrae complex: a finite element approach using bonded and contact interface conditions. , 2003, Medical engineering & physics.

[4]  D J Berry,et al.  Acetabular fracture associated with cementless acetabular component insertion: a report of 13 cases. , 1999, The Journal of arthroplasty.

[5]  R Vanderby,et al.  Ingrowth reduces implant‐to‐bone relative displacements in canine acetabular prostheses , 1994, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[6]  G. Bergmann,et al.  Hip contact forces and gait patterns from routine activities. , 2001, Journal of biomechanics.

[7]  A. Litsky,et al.  Initial mechanical stability of acetabular prostheses. , 1994, Orthopedics.

[8]  J. Hollis,et al.  Initial Stability of Porous Coated Acetabular Implants: The Effect of Screw Placement, Screw Tightness, Defect Type, and Oversize Implants , 1994, Clinical orthopaedics and related research.

[9]  T. Brown,et al.  Areas of contact and extent of gaps with implantation of oversized acetabular components in total hip arthroplasty. , 1994, Clinical orthopaedics and related research.

[10]  D. Hungerford,et al.  The initial stability of uncemented acetabular components. , 1992, The Journal of bone and joint surgery. British volume.

[11]  W. Maloney,et al.  A quantitative in vitro assessment of fit and screw fixation on the stability of a cementless hemispherical acetabular component. , 1994, The Journal of arthroplasty.

[12]  Harry E Rubash,et al.  The optimal fixation of the cementless acetabular component in primary total hip arthroplasty. , 2002, The Journal of the American Academy of Orthopaedic Surgeons.

[13]  A Yew,et al.  Analysis of contact mechanics in McKee-Farrar metal-on-metal hip implants , 2003, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[14]  T D Brown,et al.  Fracture of the acetabulum during insertion of an oversized hemispherical component. , 1995, The Journal of bone and joint surgery. American volume.

[15]  W H Harris,et al.  Factors influencing stability at the interface between a porous surface and cancellous bone: a finite element analysis of a canine in vivo micromotion experiment. , 1997, Journal of biomedical materials research.

[16]  Chyun-Yu Yang,et al.  Failure of hydroxyapatite-coated acetabular cups. Ten-year follow-up of 85 Landos Atoll arthroplasties. , 2002, The Journal of bone and joint surgery. British volume.

[17]  R. Huiskes,et al.  Failed innovation in total hip replacement. Diagnosis and proposals for a cure. , 1993, Acta orthopaedica Scandinavica.

[18]  T. Hearn,et al.  Micromotion of cementless hemispherical acetabular components. Does press-fit need adjunctive screw fixation? , 1995, The Journal of bone and joint surgery. British volume.

[19]  D R Sumner,et al.  A quantitative study of bone and soft tissues in cementless porous-coated acetabular components retrieved at autopsy. , 1993, The Journal of arthroplasty.

[20]  J. M. Lee,et al.  Observations on the Effect of Movement on Bone Ingrowth into Porous‐Surfaced Implants , 1986, Clinical orthopaedics and related research.

[21]  R Huiskes,et al.  Total hip reconstruction in acetabular dysplasia. A finite element study. , 1993, The Journal of bone and joint surgery. British volume.

[22]  S. Szmukler‐Moncler,et al.  Timing of loading and effect of micromotion on bone-dental implant interface: review of experimental literature. , 1998, Journal of biomedical materials research.

[23]  F. Kummer,et al.  Stability of press-fit acetabular cups. , 1992, The Journal of arthroplasty.

[24]  D. Yugue.  Traitement des pseudarthroses par la decortication osteomusculaires de Judet. International , 1977 .

[25]  W. Capello,et al.  Hydroxyapatite in Total Hip Arthroplasty: Clinical Results and Critical Issues , 1998, Clinical orthopaedics and related research.

[26]  M. Ries,et al.  Photoelastic analysis of stresses produced by different acetabular cups. , 1999, Clinical orthopaedics and related research.

[27]  E. Schneider,et al.  The effect of interfacial parameters on cup-bone relative micromotions. A finite element investigation. , 2001, Journal of biomechanics.

[28]  P. Lachiewicz,et al.  In vitro initial fixation of porous-coated acetabular total hip components. A biomechanical comparative study. , 1989, The Journal of arthroplasty.

[29]  E. Morscher,et al.  Current status of acetabular fixation in primary total hip arthroplasty. , 1992, Clinical orthopaedics and related research.

[30]  A. Shirazi-Adl,et al.  Experimental determination of friction characteristics at the trabecular bone/porous-coated metal interface in cementless implants. , 1993, Journal of biomedical materials research.

[31]  Hwj Rik Huiskes,et al.  Total hip reconstruction in acetabular dysplasia. , 1993 .

[32]  L A Cooperstein,et al.  Acetabular anatomy and the transacetabular fixation of screws in total hip arthroplasty. , 1990, The Journal of bone and joint surgery. American volume.