Loudon J R
Clin Orthop Relat Res. 1986 Oct(211):134-9.
A quantitative method has been used to measure femoral prosthetic subsidence after insertion. Increased amounts of subsidence are associated with the development of radiologic signs by one year after surgery. The most marked effect occurs with fractures of the cement tip. Follow-up examination up to five years shows that the rate of subsidence usually stabilizes, or stops at about 5 mm. Less commonly, subsidence is progressive, averaging up to 2 cm at five years. Demonstrable subsidence is also associated with prostheses that subsequently go on to break. The implications are that the nonflanged femoral prostheses are end bearing, with eccentric loading of the distal cement column, which leads to radiologic signs around the cement tip, demarcation, and, eventually, fracture of the cement tip. There may also be resorptive changes in the proximal femur, characteristically demonstrated in the medial femoral neck. It is suggested that the recent improvements in cement technique and the addition of the prosthetic dorsal flange may increase the success of low-friction arthroplasty.
一种定量方法已被用于测量股骨假体植入后的下沉情况。术后一年，下沉量增加与放射学征象的出现相关。最显著的影响发生在骨水泥尖端骨折时。长达五年的随访检查表明，下沉率通常会稳定下来，或在约5毫米处停止。较少见的情况是，下沉呈进行性，五年时平均可达2厘米。可证实的下沉也与随后发生断裂的假体有关。这意味着无凸缘股骨假体为端承式，远端骨水泥柱承受偏心负荷，这会导致骨水泥尖端周围出现放射学征象、分界，最终导致骨水泥尖端骨折。股骨近端也可能出现吸收性改变，典型表现为股骨内侧颈。有人认为，近期骨水泥技术的改进以及假体背侧凸缘的增加可能会提高低摩擦关节成形术的成功率。
