Holthof Sander R, Nejima Shuntaro, Rock Mick, vanArkel Richard Jan, Brivio Angela, Barrett David, Amis Andrew A
Department of Mechanical Engineering, Biomechanics Group, Imperial College London, London, UK.
Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
Knee Surg Sports Traumatol Arthrosc. 2025 Jul 7. doi: 10.1002/ksa.12761.
This study implemented a novel robotic test method to quantify the effect of three distinct total knee arthroplasty (TKA) designs on knee kinematics and stability. It was hypothesised that the implant geometries would affect stability and rollback, with differences between the native and replaced knees, as well as between implant designs.
Eight fresh-frozen cadaveric knees were tested across the arc of flexion-extension under 710 N compressive load, combined with either no anterior-posterior (AP) tibial force, 90 N anterior or 90 N posterior drawer force using a robotic actuator. The same testing protocol was used post-TKA using three distinct implant designs (gradually reducing femoral condylar radius medially stabilised, multi-radius medially conforming and single-radius symmetrical), matched to the same bone cuts. Laxity and rollback were analysed using statistical parametric mapping and implant designs were compared to the intact knee and each other.
No significant differences in AP laxity were found between the intact knee (4.7 ± 0.7 mm), gradually reducing radius (6.3 ± 1.3 mm) and multi-radius designs (5.7 ± 1.1 mm). The single-radius implant showed significantly larger average AP laxity envelope (11.6 ± 2.3 mm) than the intact knee, the multi-radius design and the gradually reducing radius design and was more variable between knees. The rollback among the intact knee and TKAs were not significantly different: gradual radius 81% of native, multi-radius 85% and single-radius 90%.
Significant differences of AP laxity were found between the pre- and post TKA knee and between implant designs. Rollback did not differ significantly. Implanted knee behaviour also showed differences of sensitivity to cadaveric specimen and implantation variation among the prosthesis designs.
Instability post-TKA remains an issue for good patient outcomes. Robotic testing of implanted knees shows the effects of implant design on knee stability and motion, potentially improving outcomes by providing the surgeon with objective data on which to base their choice of TKA.
Controlled laboratory study.
本研究实施了一种新型机器人测试方法，以量化三种不同的全膝关节置换术（TKA）设计对膝关节运动学和稳定性的影响。研究假设植入物几何形状会影响稳定性和后滚，在原生膝关节与置换膝关节之间以及植入物设计之间存在差异。
使用机器人驱动器，在710N压缩载荷下，对八个新鲜冷冻尸体膝关节进行屈伸弧测试，并分别施加无前后（AP）胫骨力、90N前向或90N后向抽屉力。TKA术后使用三种不同的植入物设计（内侧稳定的股骨髁半径逐渐减小、内侧贴合的多半径和单半径对称）进行相同的测试方案，与相同的截骨匹配。使用统计参数映射分析松弛度和后滚，并将植入物设计与完整膝关节以及彼此进行比较。
完整膝关节（4.7±0.7mm）、半径逐渐减小的设计（6.3±1.3mm）和多半径设计（5.7±1.1mm）之间在AP松弛度上未发现显著差异。单半径植入物的平均AP松弛度包络（11.6±2.3mm）显著大于完整膝关节、多半径设计和半径逐渐减小的设计，并且膝关节之间的变异性更大。完整膝关节和TKA之间的后滚无显著差异：逐渐减小半径的为原生的81%，多半径的为85%，单半径的为90%。
TKA术前和术后膝关节之间以及植入物设计之间在AP松弛度上存在显著差异。后滚无显著差异。植入膝关节的行为在假体设计中对尸体标本和植入变异的敏感性也存在差异。
TKA术后的不稳定仍然是影响患者良好预后的一个问题。对植入膝关节的机器人测试显示了植入物设计对膝关节稳定性和运动的影响，通过为外科医生提供客观数据以作为其选择TKA的依据，可能会改善预后。
对照实验室研究。
