Schlegel Ulf J, Siewe Jan, Bitsch Rudi G, Koebke Juergen, Eysel Peer, Morlock Michael M
Department of Orthopaedic Surgery, University of Heidelberg, Germany.
Clin Biomech (Bristol). 2011 Feb;26(2):136-40. doi: 10.1016/j.clinbiomech.2010.09.008. Epub 2010 Oct 8.
Since the introduction of modern hip resurfacing systems, there has been a controversy regarding the fixation of the centering pin in the femoral component. It has been suggested that cementing the pin may increase strength of the femoral neck. This in-vitro analysis investigated the influence of a cemented, femoral pin on resistance to fracture in the resurfaced hip.
Five pairs of cadaveric, fresh-frozen femora underwent hip resurfacing (ASR™) using a high viscosity cementing technique. In one side of each pair only the inner surface of the implant was cemented, in the other side, cement was additionally hand-pressurized down the pinhole prior to implantation of the femoral component. Specimen were then mounted on a material testing machine and cyclic loading with increasing load steps was applied until fracture of the femoral neck.
Fracture load was increased (P = 0.013) in the cemented pin group (Median = 4200 N) when compared with the cementless pin group (Median = 2800 N). The number of cycles to failure in the group with the cemented pin (Median = 8072) was likewise higher (P = 0.01) when compared to the group, in which the pin was not cemented (Median = 5906).
Cementing the pin may provide additional fixation in hips with low bone mineral density or osteonecrotic lesions, as resistance to fracture could be improved in the presented in-vitro scenario. Although this was shown for a specific hip resurfacing system, this effect might be extrapolated to other, similar implant designs.
自现代髋关节表面置换系统问世以来，股骨部件中定心销的固定一直存在争议。有人认为用骨水泥固定销可能会增加股骨颈的强度。这项体外分析研究了骨水泥固定的股骨销对髋关节表面置换术后抗骨折能力的影响。
使用高粘度骨水泥技术对五对新鲜冷冻的尸体股骨进行髋关节表面置换（ASR™）。在每对股骨的一侧，仅对植入物的内表面进行骨水泥固定；在另一侧，在植入股骨部件之前，额外将骨水泥手动压入销孔。然后将标本安装在材料试验机上，以逐渐增加的载荷步长进行循环加载，直至股骨颈骨折。
与未使用骨水泥固定销的组（中位数 = 2800 N）相比，使用骨水泥固定销的组（中位数 = 4200 N）的骨折载荷增加（P = 0.013）。与销未使用骨水泥固定的组（中位数 = 5906）相比，使用骨水泥固定销的组的失效循环次数（中位数 = 8072）同样更高（P = 0.01）。
在骨密度低或有骨坏死病变的髋关节中，用骨水泥固定销可能会提供额外的固定，因为在本体外实验中抗骨折能力得到了改善。尽管这是针对特定的髋关节表面置换系统显示的，但这种效果可能会推广到其他类似的植入物设计。
