Cement Penetration into Femoral Head with Longitudinal Slot Following Hip Resurfacing Arthroplasty

+Snyder, S; Jamali, A A; Hazelwood, S J +California Polytechnic State University, San Luis Obispo, CA, University of California Davis Medical Center, Sacramento, CA [email protected] INTRODUCTION Hip resurfacing arthroplasty is seen as advantageous in younger, active patients due to its preservation of bone. Failure of these implants, though, can be very traumatic and potentially life threatening. While failure of the femoral component may be due to excessive varus/valgus positioning, over/under sizing of the implant, or the structural integrity of the patient’s femur, cement penetration into the femoral head has been identified as one of the critical factors in the longevity of the resurfaced joint [1]. It is understood that adequate cement penetration is needed to secure the implant to the bone. Still, too much penetration may lead to thermal necrosis and possible failure. It also has been proposed that inadequate seating of the resurfacing femoral component may lead to increased stresses in the cement mantle, early fracture of the neck, or possibly failure of the femoral component [2,3]. Some resurfacing femoral components have little offset between the inner diameter of the implant and the outer diameter of the prepared femur, leading to the possible scenario of cement entrapment and inadequate seating. One approach to avoid this problem is to prepare a longitudinal slot in the femoral head to allow the cement to escape while allowing some degree of cement penetration into the trabecular bone. The goal of this study was to explore the effect of such a longitudinal slot within the femoral head on cement penetration for resurfacing arthroplasty.