Bull Hosp Jt Dis (2013). 2020 Dec;78(4):250-254.
Restoration of hindfoot alignment correlates with improved clinical and biomechanical outcomes after fracture care and reconstruction. Intraoperative assessment of alignment with fluoroscopy is challenging. This study was designed to determine the effect of rotation on the measurement of hindfoot alignment and to determine if any radiographic landmarks can be utilized to help surgeons identify appropriate rotation during intraoperative imaging.
Ten unmatched cadaveric limbs that had been disarticulated at mid-tibia were used and placed supine in a radiolucent jig. Fluoroscopic images were obtained with the C-arm positioned at 45°. Images were obtained in sequential rotational adjustments from 12° of internal rotation to 12° of external rotation. The location of the fibula relative to the base of the fifth metatarsal was measured on images and recorded as an interval percentage overlap (0% to 50%, 50% to 100%, and greater than 100%). Hindfoot alignment was recorded by measuring the angle between the tibial and calcaneal axis.
Varus and valgus hindfoot alignment demon-strated a linear relationship to leg rotation (r2 = 0.998, p < 0.001). In these uninjured cadaveric specimens, 8° to 15° of internal rotation relative to the medial border of the foot produced a normal valgus angle (0° to 5°). Using 50% to 100% overlap of the fibula over the fifth metatarsal base as a radiographic test was a reliable indicator of predicted measurement, with 89% sensitivity and 99% specificity.
The measurement of hindfoot alignment changes with foot rotation. Use of the fibula overlap of the fifth metatarsal base may be a helpful tool to judge appro-priate rotation intraoperatively.
跟骨对线的恢复与骨折治疗和重建后临床和生物力学结果的改善相关。术中通过透视评估对线是具有挑战性的。本研究旨在确定旋转对线测量的影响，并确定是否可以利用任何影像学标志帮助外科医生在术中成像时识别适当的旋转。
10 个未配对的尸体下肢在中胫骨处离断，并仰卧放置在不透射线的夹具中。C 臂在 45°位置获取透视图像。从内旋 12°到外旋 12°，依次进行旋转调整，获取图像。在图像上测量腓骨相对于第五跖骨基底的位置，并记录为间隔百分比重叠（0%到 50%、50%到 100%和大于 100%）。跟骨对线通过测量胫骨和跟骨轴之间的角度来记录。
内翻和外翻跟骨对线与腿部旋转呈线性关系（r2 = 0.998，p < 0.001）。在这些未受伤的尸体标本中，相对于脚的内侧边界内旋 8°至 15°会产生正常的外翻角度（0°至 5°）。使用腓骨相对于第五跖骨基底 50%到 100%的重叠作为影像学测试是预测测量的可靠指标，其敏感性为 89%，特异性为 99%。
跟骨对线的测量随脚的旋转而变化。使用第五跖骨基底腓骨重叠可能是术中判断适当旋转的有用工具。
