Hsu H C, Luo Z P, Rand J A, An K N
Department of Orthopedics, Mayo Clinic, Rochester, Minnesota 55905, USA.
J Arthroplasty. 1996 Jan;11(1):69-80. doi: 10.1016/s0883-5403(96)80163-x.
Although total knee arthroplasty (TKA) has become a very common procedure, patellar problems remain a major cause of disability. Patellar thickness is one of the most challenging factors. The influence of patellar thickness on patellofemoral kinematics and contact characteristics following TKA was investigated. Seven unembalmed whole-lower-extremity cadaveric specimens were used. The kinematics was measured with a magnetic tracking device (3Space Tracker System, Polhemus Navigation Sciences Division, Colchester, VT). Contact area was calculated from the kinematic data and the digitized joint surface geometrics based on a theoretical method. The patellofemoral joint contact force was measured directly using a uniaxial force transducer. Kinematically, the influence of patellar thickness on patellar flexion, rotation, and proximodistal shift was not significant. Orthopaedic surgeons are often challenged by derangement of the patellofemoral joint, especially following TKA. It is commonly assumed that restoration of overall patellar thickness is most desirable. A thin patella can reduce the contact force, but it also poses the potential risks of stress fracture and anteroposterior instability. Increasing patellar thickness might be expected to increase the effective quadriceps moment arm at low flexion angles of the knee, but potentially reduces the range of motion of the knee and predisposes to patellar subluxation. Either a thicker or a thinner patella had a smaller contact area than intact and normal-thickness patella. Therefore, the surgical technique of patellar resurfacing during TKA should attempt to reproduce the original patellar thickness.
尽管全膝关节置换术（TKA）已成为一种非常常见的手术，但髌骨问题仍然是导致残疾的主要原因。髌骨厚度是最具挑战性的因素之一。研究了TKA后髌骨厚度对髌股关节运动学和接触特征的影响。使用了7个未防腐处理的全下肢尸体标本。运动学数据通过磁跟踪装置（3Space Tracker System，Polhemus Navigation Sciences Division，科尔切斯特，佛蒙特州）进行测量。根据运动学数据和基于理论方法数字化的关节表面几何形状计算接触面积。使用单轴力传感器直接测量髌股关节接触力。在运动学方面，髌骨厚度对髌骨屈曲、旋转和近远侧移位的影响不显著。骨科医生经常面临髌股关节紊乱的挑战，尤其是在TKA之后。通常认为恢复髌骨的整体厚度是最理想的。较薄的髌骨可以降低接触力，但也存在应力骨折和前后不稳定的潜在风险。增加髌骨厚度可能会在膝关节低屈曲角度时增加股四头肌的有效力臂，但可能会减少膝关节的活动范围并易导致髌骨半脱位。较厚或较薄的髌骨的接触面积均小于完整和正常厚度髌骨。因此，TKA期间髌骨表面置换的手术技术应尝试恢复原始的髌骨厚度。
