The first affiliated hospital of guangxi medical universtiy
目的 探讨内侧膝关节单髁置换手术对于登楼梯动作时膝关节生物力学方面的影响，明确UKA是否能维持膝关节的生物力学的特性。方法 9例接受固定平台内侧单髁置换的骨关节炎患者，术前3周及术后（7±2个月）对其进行登楼梯动作的生物力学测试，其中男5例，女4例，平均年龄为62.3±5岁。采用双平面的X线装置收集其术前术后行走时影像资料，健侧膝关节作为对照组。通过CT扫描建立股骨、胫骨的三维模型，通过自动匹配软件，将股骨胫骨的3D模型与X线中的股骨胫骨相匹配并同步。测量股骨胫骨3D模型的运动力学参数，包括前后向移位、内外翻、旋转及内侧间室的间隙及接触中心点及外侧间室间隙，每次测量均重复进行三次。结果 术前UKA侧膝关节与健侧膝关节相比，内翻4.8°（P=0.001），差异具有统计学意义，术后UKA侧较术前相比，外翻3.1°（P=0.012），差异具有统计学意义；术前UKA侧膝关节较健侧外旋4.4°（P=0.004），差异具有统计学意义；术前内侧间室的接触中心点UKA侧较健侧后移2.5mm（P=0.016）。外侧间隙术前术后及与健侧相比，均无明显变化，差异无统计学意义。结论 UKA可以有效改善膝关节的内外翻，同时能够恢复患侧膝关节的旋转的生物力学特性，不影响外侧间室间隙的建立，但内外侧间室的接触中心仍有变化。
Objective To explore the effect of medial UKA surgery on restore the knee kinematics.Methods: Nine patients who received fixed-bearing medial UKA consented to participate in this study. All patients completed pre-surgical (3 weeks before) and post-surgical (7±2 months) testing (5 M, 4 F; average age 62.3 ± 5 years). Synchronized biplane radiographs were collected at 100 images per second during three repetitions of a chair rise movement . Motion of the femur, tibia, and implants were tracked using an automated volumetric model-based tracking process that matches subject-specific 3D models of the bones and prostheses to the biplane radiographs with sub-millimeter accuracy . Anatomic coordinate systems were created within the femur and tibia and used to calculate tibiofemoral kinematics . Additional outcome measures included the center of contact in the medial . The results of the three movement trials were averaged for each knee in each test session. Results: The UKA knee was in 4.8° more varus than the contralateral knee prior to surgery （P=0.001）. After surgery, the UKA knee was in 3.1° more valgus than before surgery（P=0.012）. The UKA knee was 4.4° more externally rotated than the contralateral knee prior to surgery (p=0.004) . However, our data showed that the medial tibia contact center of the UKA knee has moved posteriorly 2.5 mm compared to the contralateral knee (p=0.016). There was no different in lateral compartment joint space before and after surgery. Conclusion UKA could improve the varus of the knee joint and restore the rotation biomechanical characteristics of the knee. The lateral compartment joint space didn’t changed before and after surgery. The center of closest contact in the medial tibia compartment of the UKA knee was changed after surgery.