Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
J Arthroplasty. 2014 Jun;29(6):1278-84. doi: 10.1016/j.arth.2013.12.017. Epub 2013 Dec 19.
We developed 'lesser trochanter index' (LTI) and estimated its accuracy in predicting the underestimation of offset in the anteroposterior (AP) pelvic radiographs. We reconstructed 320 simulated radiographs from the CT scans of 40 adult hips at different rotational projections of 10° increments from 30° internal rotation to 40° external rotation. Underestimation of femoral offset as a percentage was derived from the neck profile angle for all radiographs. Radiographs with an LTI value above 35 were 94% (95% CI, 89%-97%) likely to underestimate femoral offset by more than 5%. Radiographs with LTI between 0 and 30 demonstrated femoral offset within 5% of the true offset (predictive value 100%, CI 87%-100%). LTI could be a useful guide in preoperative templating of hip arthroplasty.
我们提出了“小转子指数”（LTI），并评估其在预测前后位（AP）骨盆 X 线片上的偏心距低估方面的准确性。我们从 40 个成人髋关节的 CT 扫描中重建了 320 张模拟 X 线片，旋转投影从 30°内旋到 40°外旋，每 10°递增。所有 X 线片中，颈侧位角都可以得出偏心距的低估百分比。LTI 值大于 35 的 X 线片有 94%（95%CI，89%-97%）的可能会低估超过 5%的股骨偏心距。LTI 值在 0 到 30 之间的 X 线片显示股骨偏心距与真实偏心距相差在 5%以内（预测值 100%，CI 87%-100%）。LTI 可以成为髋关节置换术前模板的有用指南。
