Failure of Cemented Hip Implants Under Complex Loading: Experimental and Numerical Analysis

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Abstract

A new generation of experimental pre-clinical testing methods for cemented hip replacement femoral components have been proposed, and preliminarily validated by comparing a ‘good’ prosthesis design with a ‘bad’ prosthesis design. The basis for these new tests is the measurement of relative motion between im plant and bone over time while loading is applied. However, it is yet to be proven whether these next generation tests can satisfactorily distinguish between the performance of several prosthesis designs. Additionally, opinions vary widely as to the necessary loading conditions required, particularly over whether or not muscle loading should be simulated.

A novel experimental rig which mimicked physiological loading of the implanted proximal femur was developed. Using this rig, the influence of simulated muscle loading on the migration of a femoral component was investigated. Numerical simulations were performed to ascertain possible reasons for differences between migration patterns. Experimental tests consisting of one million loading cycles with muscle loading were performed using four different prosthesis designs; the Charnley Extra Small, the Exeter Polished, the Lubinus SPII, and the Miiller Curved.

Muscle loading was found to reduce the migration of the femoral component within the medullary canal of the femur. Differences in migration and inducible displacement (recoverable cyclic motion) were detected between the four prosthesis designs, although not at a significant level. A performance ranking of the designs based on migration did not agree with observed clinical performance as measured by revision rate. However, ranking the prostheses based on whether their inducible displacements were increasing or decreasing did correlate with their clinical revision rates.

In conclusion, the experimental test can distinguish between the performance of several prosthesis designs. However, the sample size required to achieve statistical significance is prohibitive. Muscle loading should be included in experimental tests.

Cited Works (11)

Year	Entry
2000	Maher SA. Design and Development of a Pre-Clinical Test for Cemented Femoral Hip Replacements [PhD thesis]. Trinity College Dublin; April 2000.
2001	Heller MO, Bergmann G, Deuretzbacher G, Dürselen L, Pohl M, Claes L, Haas NP, Duda GN. Musculo-skeletal loading conditions at the hip during walking and stair climbing. J Biomech. July 2001;34(7):883-893.
1990	Huiskes R. The various stress patterns of press-fit, ingrown, and cemented femoral stems. Clin Orthop Relat Res. December 1990;261:27-38.
2001	Bergmann G, Deuretzbacher G, Heller M, Graichen F, Rohlmann A, Strauss J, Duda GN. Hip contact forces and gait patterns from routine activities. J Biomech. July 2001;34(7):859-871.
1987	Walker PS, Schneeweis D, Murphy S, Nelson P. Strains and micromotions of press-fit femoral stem prostheses. J Biomech. 1987;20(7):693-702.
1992	Mow VC, Ratcliffe A, Robin Poole A. Cartilage and diarthrodial joints as paradigms for hierarchical materials and structures. Biomaterials. 1992;13(22):67-97.
1996	Cristofolini L, Viceconti M, Cappello A, Toni A. Mechanical validation of whole bone composite femur models. J Biomech. April 1996;29(4):525-535.
1998	Duda GN, Heller M, Albinger J, Schulz O, Schneider E, Claes L. Influence of muscle forces on femoral strain distribution. J Biomech. September 1998;31(9):841-846.
1993	Bergmann G, Graichen F, Rohlmann A. Hip joint loading during walking and running, measured in two patients. J Biomech. August 1993;26(8):969-990.
1988	Davy DT, Kotzar GM, Brown RH, Heiple KG, Goldberg VM, Heiple KG Jr, Berilla J, Burstein AH. Telemetric force measurements across the hip after total arthroplasty. J Bone Joint Surg. January 1988;70A(1):45-50.
1997	Duda GN, Schneider E, Chao EY. Internal forces and moments in the femur during walking. J Biomech. September 1997;30(9):933-941.