LaPrade Christopher M, Foad Abdullah, Smith Sean D, Turnbull Travis Lee, Dornan Grant J, Engebretsen Lars, Wijdicks Coen A, LaPrade Robert F
Steadman Philippon Research Institute, Vail, Colorado, USA.
Quality Care Clinic and Surgicenter, Clinton, Iowa, USA.
Am J Sports Med. 2015 Apr;43(4):912-20. doi: 10.1177/0363546514566191. Epub 2015 Jan 26.
Posterior medial meniscal root tears have been reported to extrude with the meniscus becoming adhered posteromedially along the posterior capsule. While anatomic repair has been reported to restore tibiofemoral contact mechanics, it is unknown whether nonanatomic positioning of a meniscal root repair to a posteromedial location would restore the loading profile of the knee joint.
PURPOSE/HYPOTHESIS: The purpose of this study was to compare the tibiofemoral contact mechanics of a nonanatomic posterior medial meniscal tear with that of the intact knee or anatomic repair. It was hypothesized that a nonanatomic root repair would not restore the tibiofemoral contact pressures and areas to that of the intact or anatomic repair state.
Controlled laboratory study.
Tibiofemoral contact mechanics were recorded in 6 male human cadaveric knee specimens (average age, 45.8 years) using pressure sensors. Each knee underwent 5 testing conditions for the posterior medial meniscal root: (1) intact knee; (2) root tear; (3) anatomic transtibial pull-out repair; (4) nonanatomic transtibial pull-out repair, placed 5 mm posteromedially along the edge of the articular cartilage; and (5) root tear concomitant with an ACL tear. Knees were loaded with a 1000-N axial compressive force at 4 flexion angles (0°, 30°, 60°, 90°), and contact area, mean contact pressure, and peak contact pressure were calculated.
Contact area was significantly lower after nonanatomic repair than for the intact knee at all flexion angles (mean = 44% reduction) and significantly higher for anatomic versus nonanatomic repair at all flexion angles (mean = 27% increase). At 0° and 90°, and when averaged across flexion angles, the nonanatomic repair significantly increased mean contact pressures in comparison to the intact knee or anatomic repair. When averaged across flexion angles, the peak contact pressures after nonanatomic repair were significantly higher than the intact knee but not the anatomic repair. In contrast, when averaged across all flexion angles, the anatomic repair resulted in a 17% reduction in contact area and corresponding increases in mean and peak contact pressures of 13% and 26%, respectively, compared with the intact knee.
For most testing conditions, the nonanatomic repair did not restore the contact area or mean contact pressures to that of the intact knee or anatomic repair. However, the anatomic repair produced near-intact contact area and resulted in relatively minimal increases in mean and peak contact pressures compared with the intact knee.
Results emphasize the importance of ensuring an anatomic posterior medial meniscal root repair by releasing the extruded menisci from adhesions and the posteromedial capsule. Similar caution toward preventing displacement of the meniscal root repair construct should be emphasized.
据报道，后内侧半月板根部撕裂会导致半月板挤出，并沿后关节囊向后方内侧粘连。虽然解剖修复已被报道可恢复胫股接触力学，但半月板根部修复至后内侧的非解剖定位是否能恢复膝关节的负荷情况尚不清楚。
目的/假设：本研究的目的是比较非解剖性后内侧半月板撕裂与完整膝关节或解剖修复的胫股接触力学。假设非解剖性根部修复不能将胫股接触压力和面积恢复到完整或解剖修复状态。
对照实验室研究。
使用压力传感器记录6具男性人体尸体膝关节标本（平均年龄45.8岁）的胫股接触力学。每个膝关节在后内侧半月板根部进行5种测试条件：（1）完整膝关节；（2）根部撕裂；（3）解剖经胫骨拉出修复；（4）非解剖经胫骨拉出修复，沿关节软骨边缘向后内侧放置5mm；（5）根部撕裂合并前交叉韧带撕裂。膝关节在4个屈曲角度（0°、30°、60°、90°）施加1000N轴向压缩力，并计算接触面积、平均接触压力和峰值接触压力。
在所有屈曲角度下，非解剖修复后的接触面积均显著低于完整膝关节（平均减少44%），且在所有屈曲角度下，解剖修复与非解剖修复相比显著更高（平均增加27%）。在0°和90°以及平均屈曲角度时，与完整膝关节或解剖修复相比，非解剖修复显著增加了平均接触压力。平均所有屈曲角度时，非解剖修复后的峰值接触压力显著高于完整膝关节，但低于解剖修复。相比之下，平均所有屈曲角度时，与完整膝关节相比，解剖修复导致接触面积减少17%，平均和峰值接触压力分别相应增加13%和26%。
在大多数测试条件下，非解剖修复未能将接触面积或平均接触压力恢复到完整膝关节或解剖修复的水平。然而，解剖修复产生了接近完整的接触面积，与完整膝关节相比，平均和峰值接触压力的增加相对较小。
结果强调了通过解除挤出的半月板与粘连和后内侧关节囊的粘连来确保解剖性后内侧半月板根部修复的重要性。应同样强调防止半月板根部修复结构移位的注意事项。
