Background:Medial patellofemoral ligament reconstruction (MPFL-R) aims to restore proper ligament function with minimal changes in length during range of motion, yet the ideal area for femoral fixation of the graft remains controversial.Purpose:To determine the region where the isometric circular path of a simulated MPFL graft (best-fit circle) follows the sagittal radius curvature of the trochlea in normal (nontrochlear dysplastic) knees and to evaluate the best-fit circle coverage of different femoral fixation points in knees with severe trochlear dysplasia (TD) and after deepening trochleoplasty.Study Design:Controlled laboratory study.Methods:Twelve patients (4 male, 8 female; mean age, 24 ± 8 years) who underwent surgical treatment for recurrent lateral patellar instability due to severe TD were prospectively enrolled in this study. Four previously defined reference points for the femoral MPFL-R (Schöttle, Fujino, Stephen, and Oka) were identified, and the best-fit circle was drawn along the sagittal trochlear groove curvature. The divergence between each best-fit circle and the trochlear groove was calculated, with negative values indicating relative slackening and positive values indicating relative tightening of the simulated MPFL graft. Measurements were made on true-lateral fluoroscopic images before and after deepening trochleoplasty and compared with those of a sex-matched control group.Results:The best-fit circle of the Schöttle point followed the sagittal curvature of the trochlea most closely in both the control and trochlear dysplastic knees, followed by the Fujino, Stephen, and Oka points. As the radius of the trochlear groove curvature increased, the divergence of all best-fit circles to the trochlear groove became negative (all P < .05). This effect was most pronounced at the Stephen and Oka points, followed by the Fujino and Schöttle points (all P < .05). After deepening trochleoplasty, the divergence of the Schöttle point changed toward positive values (11.6% at 40°; P < .001). Concurrently, the best-fit circle divergence of all other reference points improved toward baseline (all P < .05).Conclusion:The isometric circle of the Schöttle point provides the best congruence with the sagittal trochlear groove curvature in both the normal trochlea and the dysplastic trochlea. After trochleoplasty, the best-fit circles of more distal femoral fixation points resulted in better congruence with the deepened trochlear groove, whereas the best-fit circle of Schöttle indicated graft tension during flexion.Clinical Relevance:According to the present study, different femoral fixation points should be considered depending on whether the TD is corrected.

中文翻译：

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考虑到严重滑车发育不良患者加深滑车成形术前后矢状滑车槽曲率，股骨隧道放置对内侧髌股韧带重建的影响


背景：内侧髌股韧带重建（MPFL-R）旨在恢复适当的韧带功能，同时在运动范围内长度变化最小，但股骨移植物固定的理想区域仍存在争议。目的：确定等长圆形的区域模拟 MPFL 移植物（最佳拟合圆）的路径遵循正常（非滑车发育不良）膝关节滑车矢状半径曲率，并评估严重滑车发育不良 (TD) 膝关节不同股骨固定点的最佳拟合圆覆盖范围研究设计：对照实验室研究。方法：12 名因严重 TD 导致复发性髌骨外侧不稳而接受手术治疗的患者（4 名男性，8 名女性；平均年龄，24 ± 8 岁）前瞻性纳入本研究。确定了四个先前定义的股骨 MPFL-R 参考点（Schöttle、Fujino、Stephen 和 Oka），并沿着矢状滑车沟曲率绘制了最佳拟合圆。计算每个最佳拟合圆和滑车槽之间的偏差，负值表示相对松弛，正值表示模拟 MPFL 移植物的相对收紧。对加深滑车成形术前后的真实侧位透视图像进行测量，并与性别匹配的对照组进行比较。结果：对照组中Schöttle点的最佳拟合圆最接近滑车矢状曲率和滑车发育不良的膝盖，其次是藤野点、斯蒂芬点和冈点。随着滑车沟曲率半径的增加，所有与滑车沟最佳拟合圆的散度都变为负值（全部 P < .05）。 这种效应在 Stephen 和 Oka 点最为明显，其次是 Fujino 和 Schöttle 点（全部 P < .05）。加深滑车成形术后，Schöttle 点的发散度变为正值（40° 时为 11.6%；P < .001）。同时，所有其他参考点的最佳拟合圆散度都向基线改善（所有 P < .05）。结论：Schöttle 点的等距圆与正常滑车和滑车中的矢状滑车沟曲率具有最佳一致性。发育不良的滑车滑车成形术后，较远端股骨固定点的最佳拟合圆与加深的滑车沟具有更好的一致性，而 Schöttle 的最佳拟合圆表明屈曲期间的移植物张力。 临床相关性：根据本研究，不同的股骨固定应根据 TD 是否得到纠正来考虑分数。