Sharkey N A, Donahue S W, Smith T S, Bay B K, Marder R A
Orthopaedic Research Laboratories, University of California, Davis, School of Medicine, Sacramento, USA.
Arch Phys Med Rehabil. 1997 Mar;78(3):256-63. doi: 10.1016/s0003-9993(97)90030-7.
To characterize the morbific consequences of harvesting a patellar tendon graft for use in reconstructing the anterior cruciate ligament (ACL) of the knee, specifically, (1) to measure changes in patellar strain and patellofemoral contact due to graft harvest, (2) to evaluate the ability of bone-grafting the patellar defect to mitigate these effects, and (3) to characterize failure of the extensor mechanism after harvest of a patellar tendon graft.
Twenty-two cadaver knee joints were tested before and after harvest of a patellar tendon graft and after filling the patellar defect with polymethylmethacrylate to simulate a healed bone graft, Knees were positioned in 30 degrees, 60 degrees, and 90 degrees flexion and loaded while measuring axial strain in the anterior patella and patellofemoral contact. Knees were then loaded to failure.
Harvest of the graft produced increases in axial strain at all flexion angles. Filling the defect restored axial strain to normal values. Patellofemoral contact in the presence of a defect, either filled or empty, was not different from contact for intact patellae. Most knees failed by transpatellar fracture; mean extension moment at failure was 112.8Nm. The best predictors of failure were age and gender.
Patients undergoing ACL reconstruction with a patellar tendon graft are at increased risk of anterior knee pain and disruption of the extensor mechanism. Bone-grafting the patellar defect created by graft harvest can reduce these risks. Our findings underscore the importance of carefully controlled rehabilitation and suggest that if an accelerated program of rehabilitation is anticipated, the patellar defect should be bone-grafted. Older patients, particularly women, are at increased risk of catastrophic failure of the knee extensor mechanism after ACL reconstruction using patellar tendon graft.
描述用于重建膝关节前交叉韧带（ACL）的髌腱移植的致病后果，具体而言，（1）测量由于移植取材导致的髌股应变和髌股接触的变化，（2）评估对髌腱缺损进行骨移植以减轻这些影响的能力，以及（3）描述髌腱移植取材后伸膝机制的失效情况。
对22个尸体膝关节在髌腱移植取材前后以及用聚甲基丙烯酸甲酯填充髌腱缺损以模拟愈合的骨移植后进行测试。将膝关节置于30度、60度和90度屈曲位并加载，同时测量髌前轴向应变和髌股接触情况。然后将膝关节加载至失效。
移植取材后在所有屈曲角度下轴向应变均增加。填充缺损后轴向应变恢复至正常值。存在缺损（无论是否填充）时的髌股接触与完整髌骨的接触无差异。大多数膝关节因髌骨骨折而失效；失效时的平均伸展力矩为112.8牛米。失效的最佳预测因素是年龄和性别。
接受髌腱移植进行ACL重建的患者发生膝前疼痛和伸膝机制破坏的风险增加。对移植取材造成的髌腱缺损进行骨移植可降低这些风险。我们的研究结果强调了仔细控制康复的重要性，并表明如果预期采用加速康复方案，则应进行髌腱缺损的骨移植。老年患者，尤其是女性，在使用髌腱移植进行ACL重建后发生膝伸肌机制灾难性失效的风险增加。
