Peersman Geert, Slane Josh, Vuylsteke Philippe, Fuchs-Winkelmann Susanne, Dworschak Philipp, Heyse Thomas, Scheys Lennart
Institute for Orthopaedic Research and Training, KU Leuven, Campus Pellenberg, Louvain, Belgium.
Department of Orthopaedic Surgery, Ziekenhuis Netwerk Antwerp, Campus Stuivenberg, Antwerp, Belgium.
Arch Orthop Trauma Surg. 2017 Nov;137(11):1557-1563. doi: 10.1007/s00402-017-2794-8. Epub 2017 Sep 21.
Fixed-bearing unicompartmental knee arthroplasty (UKA) closely replicates native knee kinematics. As few studies have assessed kinematics following mobile-bearing (MB) UKA, the current study aimed to investigate whether MB UKA preserves natural knee kinematics.
Seven fresh-frozen full-leg cadaver specimens were prepared and mounted in a kinematic rig that allowed all degrees of freedom at the knee. Three motion patterns, passive flexion-extension (0°-110° flexion), open-chain extension (5°-70° flexion) and squatting (30°-100° flexion), were performed pre- and post-implantation of a medial MB UKA and compared in terms of rotational and translational knee joint kinematics in the different anatomical planes, respectively.
In terms of frontal plane rotational kinematics, MB UKA specimens were in a more valgus orientation for all motion patterns. In the axial plane, internal rotation of the tibia before and after UKA was consistent, regardless of motion task, with no significant differences. In terms of frontal plane, i.e., inferior-superior, translations, the FMCC was significantly higher in UKA knees in all flexion angles and motor tasks, except in early flexion during passive motion. In terms of axial plane, i.e., anteroposterior (AP), translations, during open-chain activities, the femoral medial condyle center (FMCC) tended to be more posterior following UKA relative to the native knee in mid-flexion and above. AP excursions of the FMCC were small in all tested motions, however. There was substantial AP translation of the femoral lateral condyle center during passive motion before and after UKA, which was significantly different for flexion angles > 38°.
Our study data demonstrate that the kinematics of the unloaded knee following MB UKA closely resemble those of the native knee while relative medial overstuffing with UKA will result in the joint being more valgus. However, replacing the conforming and rigidly fixed medial meniscus with a mobile inlay may successfully prevent aberrant posterior translation of the medial femoral compartment during passive motion and squatting motion.
固定平台单髁膝关节置换术（UKA）能紧密复制自然膝关节的运动学特征。由于很少有研究评估活动平台（MB）UKA术后的运动学情况，本研究旨在探讨MB UKA是否能保留自然膝关节的运动学特征。
准备7个新鲜冷冻的全腿尸体标本，并安装在一个能使膝关节进行所有自由度运动的运动试验台上。在内侧MB UKA植入前后分别进行三种运动模式，即被动屈伸（0°至110°屈曲）、开链伸展（5°至70°屈曲）和下蹲（30°至100°屈曲），并分别在不同解剖平面上比较膝关节旋转和平移的运动学情况。
在冠状面旋转运动学方面，MB UKA标本在所有运动模式下都处于更外翻的方向。在轴平面上，UKA前后胫骨的内旋情况一致，无论运动任务如何，均无显著差异。在冠状面，即上下方向的平移方面，除了被动运动早期屈曲时，UKA膝关节在所有屈曲角度和运动任务下的股骨内侧髁中心（FMCC）明显更高。在轴平面，即前后（AP）方向的平移方面，在开链活动中，UKA术后相对于自然膝关节，股骨内侧髁中心在屈曲中期及以上时往往更靠后。然而，在所有测试运动中，FMCC的AP偏移量都很小。在UKA前后的被动运动过程中，股骨外侧髁中心有明显的AP平移，屈曲角度> 38°时差异显著。
我们的研究数据表明，MB UKA术后非负重膝关节的运动学特征与自然膝关节非常相似，而UKA相对内侧填充过多会导致关节更加外翻。然而，用活动衬垫取代贴合且刚性固定的内侧半月板可能成功防止被动运动和下蹲运动过程中股骨内侧间室异常向后平移。
