Bertollo Nicky, Pelletier Matthew H, Walsh William R
Surgical and Orthopaedic Research Laboratories, Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, Australia.
Proc Inst Mech Eng H. 2013 Apr;227(4):438-47. doi: 10.1177/0954411912466352. Epub 2012 Nov 28.
Post-operative patellar tendon shortening induces a distal positioning of the patella in the femoral trochlear groove, which has been associated with pain and impeded mobility. An idealized in vitro model was used to examine the effects of shortening on patellar kinematics. The PT length was progressively reduced by up to 5 mm (1-mm instalments) using a device secured onto the tendon in n = 9 ovine stifles. In vitro 6 degrees-of-freedom motion data for the patellofemoral and tibiofemoral joints under conditions of passively induced flexion-extension was acquired electromagnetically. Patellar motion was analysed as a function of both tibial and patellar flexion angles relative to the femoral co-ordinate frame. Linear regression with contrasts was used to compare kinematic changes for each shortening level, with significance set at P<0.01. A mean maximum percentage length reduction of 8.2% was achieved. Patellar flexion was linearly correlated with tibial flexion angle in the intact joint, and this correlation persisted after tendon shortening (R = 0.977, P < 0.01). Patellar kinematics expressed as a function of tibial flexion angle were significantly altered by a mean length decrease of 8.2%, while flexion and proximo-distal shift patterns were significantly affected at lesser shortening levels of 3.1% and 4.7%, respectively. Patellar kinematics expressed as a function of patellar flexion angle remained unchanged. These results suggest that patellar motion within the trochlear groove in the ovine stifle joint follows a repeatable three-dimensional path and that patellar tendon shortening advances the position of the patella along this path, without significantly altering it.
术后髌腱缩短会导致髌骨在股骨滑车沟内的位置向远端移动，这与疼痛和活动受限有关。使用理想化的体外模型来研究缩短对髌骨关节运动学的影响。在n = 9只绵羊膝关节中，使用固定在肌腱上的装置将髌腱长度逐渐缩短至5毫米（每次缩短1毫米）。在被动屈伸条件下，通过电磁方式获取髌股关节和胫股关节的体外六自由度运动数据。将髌骨运动分析为相对于股骨坐标系的胫骨和髌骨屈曲角度的函数。使用带有对比的线性回归来比较每个缩短水平的运动学变化，显著性设定为P<0.01。平均最大长度减少百分比达到8.2%。在完整关节中，髌骨屈曲与胫骨屈曲角度呈线性相关，肌腱缩短后这种相关性仍然存在（R = 0.977，P < 0.01）。以胫骨屈曲角度为函数表示的髌骨运动学在平均长度减少8.2%时发生显著改变，而在缩短水平分别为3.1%和4.7%时，屈曲和近远侧移位模式受到显著影响。以髌骨屈曲角度为函数表示的髌骨运动学保持不变。这些结果表明，绵羊膝关节滑车沟内的髌骨运动遵循可重复的三维路径，并且髌腱缩短会使髌骨沿着这条路径向前移动，但不会显著改变其运动模式。
