A proximal femoral implant preserves physiological bone deformation: A biomechanical investigation in cadaveric bones

Abstract

Abstract:The aim of this study was to compare the perturbances in bone deformation patterns of the proximal femur due to a conventional cemented femoral stem and a novel uncemented implant designed on the principles of osseointegration. Five matched pairs of fresh frozen human femora were mechanically tested. Bone deformation patterns, measured with a video digitizing system under 1.5 kN joint force, showed that the cemented Spectron femoral implant caused signi cant alterations to the proximal femoral deformation pattern, whereas the Gothenburg osseointegrated titanium femoral implant did not signi cantly alter the bone behaviour ( p<0.05). Vertical micromotions measured under 1 kN after 1000 cycles were within the threshold of movement tolerable for bone ingrowth (21 ím for the Gothenburg system and 26 ím for the cemented implant).

Stepwise introduction of a bone-conserving osseointegrated hip arthroplasty using RSA and a randomized study: I. Preliminary investigations—52 patients followed for 3 years

“…Application of the principles of osseointegration to prosthetic design offers the possibility of immediate secure fixation (as achieved with cemented fixation) combined with long-term physiological loading, but requires forms achievable in bone with sharp minimally traumatic surgery. Such a form was designed, and, using finite element analysis, the stresses induced in the bone and component and the overall integrity of the femoral component were verified and confirmed in laboratory and cadaver tests (Macdonald et al 2002(Macdonald et al , 2003. Indeed, the immediate stability and micromotion were shown to be comparable to that of an optimal cemented femoral system, while the femoral loading was shown to be more physiological than the cemented system (Macdonald et al 2002).…”

“…Such a form was designed, and, using finite element analysis, the stresses induced in the bone and component and the overall integrity of the femoral component were verified and confirmed in laboratory and cadaver tests (Macdonald et al 2002(Macdonald et al , 2003. Indeed, the immediate stability and micromotion were shown to be comparable to that of an optimal cemented femoral system, while the femoral loading was shown to be more physiological than the cemented system (Macdonald et al 2002). At each stage and for both the femoral and the acetabular component, instruments, procedure and component stability were tested in cadaver bone (Macdonald et al 1999a,b).…”

“…Once the applicability of osseointegration principles to orthopedic implants was established (Carlsson 1989, Röstlund 1990), a total hip arthroplasty system was designed and evaluated (Albrektsson et al 1998) using laboratory and cadaver tests (Macdonald et al 2002(Macdonald et al , 2003. The postoperative stability and mechanics of the femoral implant (Macdonald et al 2002) and the acetabular component (Macdonald et al 1999a,b) were tested in cadaver bone, as were the instruments and surgical procedure.…”

“…The postoperative stability and mechanics of the femoral implant (Macdonald et al 2002) and the acetabular component (Macdonald et al 1999a,b) were tested in cadaver bone, as were the instruments and surgical procedure.…”

Fatigue testing of a proximal femoral hip component

“…The Gothenburg osseointegrated titanium (GOT ) femoral component is clinically inserted within the femoral neck, with an average implant/shaft angle of 149° [ 33]. The test geometry de ned by the more rigorous ISO standard [15] requires 10°adduction and 9°hip exion combined with a vertical test load; this level of adduction places the stem in 'neutral' or at the Q-angle, the normal mechanical functional position [33].…”