INFLUENCE OF INTRAOPERATIVE FEMORAL FRACTURES AND CERCLAGE WIRING ON BONE INGROWTH INTO CANINE POROUS-COATED FEMORAL COMPONENTS

Intraoperative femoral fractures occur more frequently with cementless than with cemented components. In this study, the influence of contro lled femoral fractures fixed with cerclage wires on rotational stabili ty and bone ingrowth into porous-coated canine femoral components was evaluated. These data were compared with results of previous studies o n unrecognized femoral fractures (not stabilized) and on the intact ca nine femur. Micromotion analysis revealed a significant increase in ro tational instability in fractures not stabilized with cerclage wires ( P < .05) compared with the intact femur. Experimentally created femora l fractures had a significantly deleterious effect on bone ingrowth ev en after cerclage wiring. This appears to be caused by a lack of bone ingrowth deep to the fracture and an increase in femoral component mic romotion. In clinical practice, femoral fractures occurring during cem entless total hip arthroplasty are a serious problem, and use of a cem ented prosthesis is recommended if rotational stability of the stem ca nnot be ensured.