Lee Yeon Soo, Lee Thay Q, Keyak Joyce H
School of Information and Mechatronics, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea.
Knee Surg Sports Traumatol Arthrosc. 2009 Jan;17(1):71-82. doi: 10.1007/s00167-008-0628-5. Epub 2008 Oct 1.
An increased stress in the patella due to the implantation of a patellar button may also be another potential source of pain in total knee arthroplasty patients. This study assessed the location inside the patella having largest stress change after implantation of an ultra high molecular polyethylene patella button. Finite elements models of the patellae before and after implantation of patellar button were created. Experimentally determined spring constants of muscles and ligaments, and patellofemoral contacting loads were applied to the models at 30 degrees , 60 degrees , and 90 degrees of knee flexion. The Von Mises stress of the intact patella decreased with increased knee flexion, while that of implanted patella increased. Also, the stress range in the implanted patella was 3-9 times higher than in the intact one. The highly stressed region of the intact patella moved proximally with higher knee flexion angles, while that of the implanted model stayed near the central anterior patella. At 90 degrees of knee flexion, the stress in the anterodistal patella increased considerably after implantation of a patella button so that the anterodistal patella may be susceptible to be painful source after the total knee replacement.
由于髌骨纽扣植入导致的髌骨应力增加也可能是全膝关节置换患者疼痛的另一个潜在来源。本研究评估了植入超高分子聚乙烯髌骨纽扣后髌骨内应力变化最大的位置。创建了植入髌骨纽扣前后的髌骨有限元模型。将通过实验确定的肌肉和韧带的弹簧常数以及髌股接触载荷在膝关节屈曲30度、60度和90度时应用于模型。完整髌骨的冯·米塞斯应力随膝关节屈曲增加而降低，而植入髌骨的应力则增加。此外，植入髌骨的应力范围比完整髌骨高3至9倍。完整髌骨的高应力区域随着膝关节屈曲角度增加向近端移动，而植入模型的高应力区域则停留在髌骨中央前方附近。在膝关节屈曲90度时，植入髌骨纽扣后髌前远端的应力显著增加，因此髌前远端可能是全膝关节置换后疼痛的来源。
