Hanson George R, Moynihan Angela L, Suggs Jeremy F, Kwon Young-Min, Johnson Todd, Li Guoan
Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, GRJ 1215, Boston, MA 02114, USA.
J Knee Surg. 2009 Jul;22(3):237-42. doi: 10.1055/s-0030-1247755.
This study investigated the weight-bearing flexion of 7 knees with previous medial unicondylar knee arthroplasty (UKA), using a dual fluoroscopic imaging system. The data indicated that the patients had consistent posterior translation of the medial femoral condyle and consistent internal rotation of the tibia with flexion. The articular contact location remained just anterior and medial to the center of the polyethylene insert throughout the range of motion. Femoral condylar lift-off was found in 2 patients at a maximum flexion angle of 130.7 +/- 10.2 degrees. The other 5 patients had a maximum flexion angle of 113.9 +/- 7.2 degrees. The small range of tibiofemoral contact excursion in both anteroposterior and mediolateral directions indicated a medial pivot contact pattern during flexion, corresponding to the observed internal tibial rotation. This may help reduce tibial loosening, thus increasing implant longevity. The observed coincidence between condylar lift-off and higher flexion angles may reveal the causative factors that enhance knee flexion after UKA.
本研究采用双荧光透视成像系统，对7例曾行内侧单髁膝关节置换术（UKA）的膝关节进行负重屈曲研究。数据表明，患者在屈曲时股骨内侧髁有一致的向后平移，胫骨有一致的内旋。在整个运动范围内，关节接触位置始终位于聚乙烯垫片中心的前内侧。在2例患者中，最大屈曲角度为130.7±10.2度时出现股骨髁抬离。其他5例患者的最大屈曲角度为113.9±7.2度。胫股关节在前后和内外侧方向上的接触移动范围较小，表明屈曲过程中为内侧枢轴接触模式，这与观察到的胫骨内旋一致。这可能有助于减少胫骨松动，从而延长植入物使用寿命。观察到的髁抬离与较高屈曲角度之间的一致性，可能揭示了UKA后增加膝关节屈曲的致病因素。
