Department of Trauma and Orthopaedic Surgery, Witten/Herdecke University, Cologne Merheim Medical Centre, Ostmerheimer Strasse 200, 51109, Cologne, Germany.
Department of Radiology, Cologne Merheim Medical Centre, Ostmerheimer Strasse 200, 51109, Cologne, Germany.
Knee Surg Sports Traumatol Arthrosc. 2019 Nov;27(11):3432-3440. doi: 10.1007/s00167-019-05378-6. Epub 2019 Feb 4.
In medial patellofemoral ligament (MPFL) reconstruction, it remains controversial whether more accurate femoral tunnel positioning is correlated with improved clinical outcomes. The purpose was to verify the accuracy of methods for evaluating tunnel positioning, one of which is the use of postoperative radiographs, in determining the femoral tunnel position following MPFL reconstruction and to compare the variability of tunnel positions to the intraoperatively documented positions on a true-lateral view.
Seventy-three consecutive MPFL reconstructions were prospectively enrolled. Femoral tunnel positions were intraoperatively determined using fluoroscopy to obtain true-lateral radiographs. Postoperatively, lateral radiographic images were taken. Seven independent radiologists and seven independent orthopaedic knee surgeons evaluated the femoral tunnel position and amount of malrotation for each radiograph. Deviations from the Schoettle's point were measured and repeated after 4 weeks. Intraobserver and interobserver analyses of variance were calculated to determine the reliability of measurements on both intraoperative and postoperative radiographs.
Fifty-six patients were included in the final analysis. Tunnel positions were unable to be identified on postoperative radiographs in 14% of cases on average, independent of the degree of radiograph rotation. Intraoperative images showed mean deviations from the tunnel position to the centre of Schoettle's point of 1.9 ± 1.4 mm and 1.6 ± 1.0 mm in anterior-posterior and proximal-distal direction, respectively. Postoperative radiographs showed mean anterior-posterior and deviations of 7.4 ± 4.4 mm and 8.9 ± 5.8 mm assessed by orthopaedic surgeons and 10.6 ± 6.3 mm and 11.6 ± 7.1 mm assessed by radiologists at first and repeated measurement, respectively. The mean proximal-distal deviations were 4.8 ± 4.4 mm and 6.5 ± 6.0 mm and 7.2 ± 6.3 mm and 8.1 ± 7.1 mm, respectively. Measurement of tunnel position on intraoperative fluoroscopic images was significantly different compared to postoperative radiographs for each of the 14 observers (p < 0.05). Significant intraobserver and interobserver differences between the first and repeat measurements for both orthopaedic surgeons and radiologists were observed (p < 0.05).
Measurement of the femoral tunnel position on postoperative lateral radiographs is not an accurate or reliable method for evaluating tunnel position after MPFL reconstruction due to exposure, contrast, and malrotation of the radiograph from a true-lateral image. In contrast, intraoperative fluoroscopic control allows for a precise lateral view and correct tunnel positioning. Thus, postoperative radiographic images may be unnecessary for the evaluation of femoral tunnel positions, particularly when intraoperative fluoroscopy has been used.
Level II, prospective cohort study.
在膝关节内侧髌股韧带（MPFL）重建术中，股骨隧道定位的准确性与临床结果的改善是否相关仍存在争议。本研究旨在验证评估隧道定位的方法的准确性，其中之一是使用术后 X 线片来确定 MPFL 重建后股骨隧道的位置，并比较隧道位置的可变性与术中获得的真正侧位 X 线片上记录的位置。
前瞻性纳入 73 例连续接受 MPFL 重建的患者。术中使用透视获得真正的侧位 X 线片确定股骨隧道位置。术后拍摄侧位 X 线片。7 名独立的放射科医生和 7 名独立的矫形膝关节外科医生评估了每位患者的 X 线片上的股骨隧道位置和旋转程度。测量了与 Schoettle 点的偏差，并在 4 周后重复测量。计算了术中及术后 X 线片测量的组内和组间方差分析，以确定测量的可靠性。
56 例患者最终纳入分析。平均有 14%的病例在术后 X 线片上无法识别隧道位置，与 X 线片旋转程度无关。术中图像显示，Schoettle 点中心前后和远近方向的隧道位置偏差分别为 1.9±1.4mm 和 1.6±1.0mm。术后 X 线片由矫形外科医生评估的前后偏差平均值为 7.4±4.4mm，由放射科医生评估的为 10.6±6.3mm；术后 X 线片由矫形外科医生评估的远近偏差平均值为 8.9±5.8mm，由放射科医生评估的为 11.6±7.1mm。近端-远端偏差的平均值分别为 4.8±4.4mm 和 6.5±6.0mm，7.2±6.3mm 和 8.1±7.1mm。与每位 14 名观察者的术中透视图像相比，术后 X 线片上的隧道位置测量明显不同（p<0.05）。对于每位观察者，矫形外科医生和放射科医生的首次和重复测量之间均存在显著的组内和组间差异（p<0.05）。
由于术后 X 线片的曝光、对比度和旋转程度与真正的侧位图像不同，因此，测量术后侧位 X 线片上的股骨隧道位置并不是评估 MPFL 重建后隧道位置的准确或可靠方法。相比之下，术中透视控制可获得精确的侧位图像和正确的隧道定位。因此，对于股骨隧道位置的评估，术后 X 线片可能不是必需的，尤其是在使用术中透视的情况下。
II 级，前瞻性队列研究。
