Haraldsplass Deaconess Hospital, Bergen, Norway.
Fortius Clinic, London, UK.
Am J Sports Med. 2018 Oct;46(12):2922-2928. doi: 10.1177/0363546518790248. Epub 2018 Aug 20.
Anterolateral complex injuries are becoming more recognized. While these are known to affect tibiofemoral mechanics, it is not known how they affect patellofemoral joint behavior.
To determine the effect of (1) sectioning the anterolateral complex and (2) performing a MacIntosh tenodesis under various conditions on patellofemoral contact mechanics and kinematics.
Controlled laboratory study.
Eight fresh-frozen cadaveric knees were tested in a customized rig, with the femur fixed and tibia free to move, with optical tracking to record patellar kinematics and with thin pressure sensors to record patellofemoral contact pressures at 0°, 30°, 60°, and 90° of knee flexion. The quadriceps and iliotibial tract were loaded with 205 N throughout testing. Intact and anterolateral complex-sectioned states were tested, followed by 4 randomized tenodeses applying 20- and 80-N graft tension, each with the tibia in its neutral intact alignment or left free to rotate. Statistical analyses were undertaken with repeated measures analysis of variance, Bonferroni post hoc analysis, and paired samples t tests.
Patellar kinematics and contact pressures were not significantly altered after sectioning of the anterolateral complex (all: P > .05). Similarly, they were not significantly different from the intact knee in tenodeses performed when fixed tibial rotation was combined with 20- or 80-N graft tension (all: P > .05). However, grafts tensioned with 20 N and 80 N while the tibia was free hanging resulted in significant increases in lateral patellar tilt ( P < .05), and significantly elevated lateral peak patellofemoral pressures ( P < .05) were observed for 80 N.
This work did not find that an anterolateral injury altered patellofemoral mechanics or kinematics, but adding a lateral tenodesis can elevate lateral contact pressures and induce lateral patellar tilting if the tibia is pulled into external rotation by the tenodesis. Although these in vitro changes were small and might not be relevant in a fully loaded knee, controlling the position of the tibia at graft fixation is effective in avoiding overconstraint at time zero in a lateral tenodesis.
Small changes in lateral patellar tilt and patellofemoral contact pressures were found at time zero with a MacIntosh tenodesis. These changes were eliminated when the tibia was held in neutral rotation at the time of graft fixation. The risk of overconstraint after a lateral tenodesis therefore seems low and in accordance with recent published reports.
前外侧复合体损伤越来越受到重视。虽然这些损伤已知会影响胫股力学，但尚不清楚它们如何影响髌股关节的行为。
确定（1）切断前外侧复合体和（2）在各种情况下进行 MacIntosh 腱固定术对髌股接触力学和运动学的影响。
对照实验室研究。
在定制的夹具中测试 8 个新鲜冷冻的尸体膝关节，股骨固定，胫骨自由移动，光学跟踪记录髌骨运动学，薄压力传感器记录 0°、30°、60°和 90°膝关节屈曲时的髌股接触压力。整个测试过程中，股四头肌和髂胫束加载 205N。测试中分别测试了完整和前外侧复合体切开状态，然后进行了 4 次随机腱固定术，施加 20-N 和 80-N 移植物张力，胫骨分别在中立完整位置或自由旋转位置。使用重复测量方差分析、Bonferroni 事后分析和配对样本 t 检验进行统计分析。
前外侧复合体切开后，髌骨运动学和接触压力没有明显改变（均 P >.05）。同样，在胫骨固定旋转与 20-N 或 80-N 移植物张力结合时进行的腱固定术中，它们与完整膝关节也没有明显差异（均 P >.05）。然而，当胫骨自由悬挂时，用 20-N 和 80-N 张紧移植物会导致外侧髌骨倾斜明显增加（P <.05），并且观察到 80-N 的外侧峰值髌股压力显著升高（P <.05）。
这项工作没有发现前外侧损伤改变髌股力学或运动学，但如果胫骨通过腱固定术被拉入外旋，添加外侧腱固定术会增加外侧接触压力并导致外侧髌骨倾斜。尽管这些体外变化很小，在完全负重的膝关节中可能并不相关，但在外侧腱固定术中，在移植物固定时保持胫骨中立旋转可以有效地避免即刻过约束。
MacIntosh 腱固定术时即刻发现外侧髌骨倾斜和髌股接触压力有轻微变化。当胫骨在移植物固定时保持中立旋转时，这些变化被消除。因此，外侧腱固定术后发生过约束的风险似乎很低，与最近的报道一致。
