Ortopedia e Traumatologia, Ospedale Santo Spirito, Rome, Italy.
Int Orthop. 2011 Feb;35(2):239-43. doi: 10.1007/s00264-010-1188-0. Epub 2011 Jan 14.
The renewed popularity of resurfacing hip arthroplasty in the last 10 years has generated a remarkable quantity of scientific contributions based on mid- and short-term follow-up. More than one paper has reported a consistent early revision rate as a consequence of biological or biomechanical failure. Two major complications are commonly described with resurfacing implants: avascular necrosis and femoral-neck fracture. A close relationship between these two events has been suggested, but not firmly demonstrated, whereas cementing technique seems to be better understood as potential cause of failure.
We performed an in vitro study in which four different resurfacing implants were evaluated with a simulated femoral head, two types of cement, (low and high viscosity) and two cementing techniques: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component).
High-viscosity cement showed homogeneous distribution over the entire femoral head. Low-viscosity cement showed a massive polar concentration with insufficient, if not absent, distribution in the equatorial zone.
Polar cement concentration could be a risk factor for early implant failure due to two effects on the femoral head: biological (excessive local exothermic reaction could cause osteocyte necrosis) and biomechanical (which could lead to uneven load distribution on the femoral head).
在过去的 10 年中，表面髋关节置换术的重新流行产生了大量基于中期和短期随访的科学贡献。不止一篇论文报告了由于生物或生物力学失败导致的早期一致翻修率。两种主要并发症通常与表面植入物有关：股骨头坏死和股骨颈骨折。这两种情况之间存在密切关系，但尚未得到证实，而粘结技术似乎被更好地理解为潜在的失败原因。
我们进行了一项体外研究，其中评估了四种不同的表面植入物，使用模拟股骨头、两种类型的水泥（低粘度和高粘度）和两种粘结技术：直接（水泥直接涂在股骨头）和间接（水泥倒入股骨部件）。
高粘度水泥在整个股骨头中均匀分布。低粘度水泥表现出巨大的极性集中，在赤道区域分布不足，如果不是不存在的话。
由于对股骨头的两种影响，极性水泥浓度可能成为早期植入物失败的风险因素：生物（过多的局部放热反应可能导致成骨细胞坏死）和生物力学（可能导致股骨头上的不均匀载荷分布）。
