Hodgson A, Helmy N, Masri B A, Greidanus N V, Inkpen K B, Duncan C P, Garbuz D S, Anglin C
Department of Mechanical Engineering, University of British Columbia, 6250 Applied Sciences Lane, Vancouver, BC, Canada.
Proc Inst Mech Eng H. 2007 Oct;221(7):713-24. doi: 10.1243/09544119JEIM284.
The orientation of the femoral component in hip resurfacing arthroplasty affects the likelihood of loosening and fracture. Computer-assisted surgery has been shown to improve significantly the surgeon's ability to achieve a desired position and orientation; nevertheless, both bias and variability in positioning remain and can potentially be improved. The authors recently developed a computer-assisted surgical (CAS) technique to guide the placement of the pin used in femoral head resurfacing arthroplasty and showed that it produced significantly less variation than a typical manual technique in varus/valgus placement relative to a preoperatively determined surgical plan while taking a comparable amount of time. In the present study, the repeatability of both the CAS and manual techniques is evaluated in order to estimate the relative contributions to overall variability of surgical technique (CAS versus manual), surgeon experience (novice versus experienced), and other sources of variability (e.g. across specimens and across surgeons). This will enable further improvements in the accuracy of CAS techniques. Three residents/fellows new to femoral head resurfacing and three experienced hip arthroplasty surgeons performed 20-30 repetitions of each of the CAS and manual techniques on at least one of four cadaveric femur specimens. The CAS system had markedly better repeatability (1.2 degrees) in varus/valgus placement relative to the manual technique (2.8 degrees), slightly worse repeatability in version (4.4 degrees versus 3.2 degrees), markedly better repeatability in mid-neck placement (0.7 mm versus 2.5 mm), no significant dependence on surgeon skill level (in contrast to the manual technique), and took significantly less time (50 s versus 123 s). Proposed improvements to the version measurement process showed potential for reducing the standard deviation by almost two thirds. This study supports the use of CAS for femoral head resurfacing as it is quicker than the manual technique, independent of surgeon experience, and demonstrates improved repeatability.
髋关节表面置换术中股骨假体的方向会影响松动和骨折的可能性。计算机辅助手术已被证明能显著提高外科医生实现理想位置和方向的能力；然而，定位中的偏差和变异性仍然存在，并且有可能得到改善。作者最近开发了一种计算机辅助手术（CAS）技术，用于指导股骨头表面置换术中所用销钉的放置，并表明相对于术前确定的手术计划，在内外翻放置方面，该技术产生的变异性明显小于典型的手动技术，且所用时间相当。在本研究中，对CAS技术和手动技术的可重复性进行了评估，以估计手术技术（CAS与手动）、外科医生经验（新手与经验丰富者）以及其他变异性来源（如跨标本和跨外科医生）对总体变异性的相对贡献。这将有助于进一步提高CAS技术的准确性。三名初次接触股骨头表面置换的住院医师/研究员和三名经验丰富的髋关节置换外科医生在四个尸体股骨标本中的至少一个上，对CAS技术和手动技术各进行了20 - 30次重复操作。相对于手动技术（2.8度），CAS系统在内外翻放置方面的可重复性明显更好（1.2度），在旋转角度方面的可重复性稍差（4.4度对3.2度），在股骨颈中部放置方面的可重复性明显更好（0.7毫米对2.5毫米），对手术医生技术水平无显著依赖性（与手动技术相反），且用时明显更少（50秒对123秒）。对旋转角度测量过程的改进建议显示出将标准差降低近三分之二的潜力。本研究支持在股骨头表面置换中使用CAS技术，因为它比手动技术更快，不依赖外科医生经验，并且具有更高的可重复性。
