Karia Monil, Doyle Ruben, Reynolds Adam, Jeffers Jonathan, Cobb Justin
MSk Lab, Imperial College London, London, UK.
Department of Mechanical Engineering, Imperial College London, London, UK.
Bone Joint Res. 2025 Jun 19;14(6):551-559. doi: 10.1302/2046-3758.146.BJR-2024-0118.R3.
Increasing the interference fit of the acetabular component can increase primary stability, but it introduces excessive periacetabular strain during impaction, which can lead to fractures. An optimal outcome following cementless acetabular component impaction is maximal primary implant stability with minimal periacetabular bone strain. The aim of this study was to investigate whether a simple modification to a surgeon's reaming technique can achieve this desirable outcome.
A custom drop rig simulated impaction strikes, seating acetabular components of either 1 mm or 2 mm interference fit into synthetic sawbones with cavities reamed to either a true hemisphere or a hemisphere with an enhanced reaming depth of 2 mm or 4 mm. Synthetic bone strain was recorded using strain gauges, and push-out tests were conducted to assess implant stability. Polar gaps were measured using optimal trackers.
Compared to a true hemispherical cavity, enhancing the reaming depth significantly increased the primary stability of the implant (p < 0.001) while reducing both the periacetabular strain and strain deterioration for both 1 mm and 2 mm interference fit components. A 4 mm reaming depth enhanced the primary stability of 1 mm press-fit components to a level almost equivalent to a 2 mm press-fit, albeit reducing strain to the bone. Enhancing reaming depth did not significantly affect polar gap.
Enhancing cavity reaming depth is a simple technique to increase the implant primary stability of press-fit uncemented acetabular components, while avoiding any excess in periacetabular strain and the associated fracture risk.
增加髋臼部件的压配力可提高初始稳定性，但在打压过程中会导致髋臼周围应变过大，进而可能引发骨折。非骨水泥型髋臼部件打压后的理想结果是实现最大的初始植入物稳定性，同时使髋臼周围骨应变最小。本研究的目的是调查对外科医生的扩孔技术进行简单改进是否能实现这一理想结果。
使用定制的落锤装置模拟打压冲击，将干涉配合为1毫米或2毫米的髋臼部件安装到合成锯骨模型中，这些模型的腔被扩孔为标准半球形或扩孔深度增加2毫米或4毫米的半球形。使用应变片记录合成骨应变，并进行推出试验以评估植入物稳定性。使用最佳跟踪器测量极向间隙。
与标准半球形腔相比，增加扩孔深度显著提高了植入物的初始稳定性（p < 0.001），同时降低了1毫米和2毫米干涉配合部件的髋臼周围应变及应变恶化程度。4毫米的扩孔深度将1毫米压配部件的初始稳定性提高到几乎与2毫米压配相当的水平，尽管降低了对骨的应变。增加扩孔深度对极向间隙没有显著影响。
增加腔的扩孔深度是一种简单的技术，可提高压配式非骨水泥髋臼部件的植入物初始稳定性，同时避免髋臼周围应变过大及相关骨折风险。
