Migration of Cemented Femoral Components After THR

Abstract

We studied the migration of 58 cemented Hinek femoral components for total hip replacement, using roentgen stereophotogrammetric analysis over four years. The implants migrated faster during the first year than subsequently, and the pattern of migration in the second period was very different. During the first year they subsided, tilted into varus and internally rotated. After this there was slow distal migration with no change in orientation. None of the prostheses has yet failed.The early migration is probably caused by resorption of bone damaged by surgical trauma or the heat generated by the polymerisation of bone cement. Later migration may be due to creep in the bone cement or the surrounding fibrous membrane.The prosthesis which we studied allows the preservation of some of the femoral neck, and comparison with published migration studies of the Charnley stem suggests that this decreases rotation and may help to prevent loosening.

A preliminary hip joint simulator study of the migration of a cemented femoral stem

“…The substantially larger migration of the femoral component at an early test stage con rms other clinical observations [35,38,39]. The rapid early migration in vivo is probably caused by resorption of the bone layer, which has been injured by surgical trauma and the heat of polymerization of polymethylmethacrylate (PMMA) cement.…”

“…The stems within a weak bone cortex migrate much more than those within a strong bone cortex. The pattern or direction of migration changed with loading cycles, and this change in pattern is larger than the change in rate, which is also observed clinically [35]. The di erence suggests that di erent mechanisms cause the migration at di erent periods and di erent restrained conditions.…”

Insertion of tantalum beads in RSA of the hipVariations in incidence of extra-osseous beads with insertion site

“…The use of radiostereometric analysis (RSA) in the assessment of total hip arthroplasty is well-recognized as an accurate technique in the measurement of small movements of implants (Chafetz et al 1985, Mjöberg et al 1986, Nistor et al 1991, Søballe et al 1993, Kiss et al 1995, 1996. This technique requires the insertion of tantalum beads into a stable location in the bone during surgery (Kärrholm et al 1997).…”

The medium-term results of a cemented Freeman femoral neck-retaining prosthesis

“…[1][2][3][4] Theoretically, a neck-retaining prosthesis has biomechanical advantages over other hip implants. Two components of the resultant forces acting on the femoral prosthesis are significant in normal activities of daily living and mobility.…”

“…6 It has been hypothesised that retention of the femoral neck may prolong survival of the prosthesis. 1,4 In this study we report the two-to nine-year clinical and radiological results and survival of cemented Freeman neck-retaining prostheses.…”