膝关节侧副韧带解剖特点与膝关节置换股骨假体旋转定位轴线的关系

目的分析股骨远端内、外侧侧副韧带起点及股骨内、外上髁轴线在全膝关节置换术(totalknee arthroplasty,TKA)中与股骨假体旋转角度的关系。方法对20只正常尸体膝关节标本进行解剖,经外上髁尖分别向内侧侧副韧带深、浅层起点钻孔,行MRI检查,测量矢状位像钻孔部位与内、外后髁几何圆心之间的距离及轴位像股骨髁后髁角(posteriorcondylarangle,PCA)和股骨髁扭转角(condylartwistangle,CTA)。结果内、外侧侧副韧带分浅、深两层,屈曲位深层紧张。PCA及CTA分别为4.50±1.26°及7.10±0.30°,二者差异有统计学意义(P<0.05),且均大于国外的相关报道。矢状位上,内侧后髁关节面圆弧半径为19.38±2.13mm,外侧为19.54±2.13mm,二者差异无统计学意义(P>0.05)。内侧侧副韧带股骨侧深层起点距股骨后髁几何圆心距离(d1)为4.22±0.20mm,较内上髁尖距后髁圆心的距离(d2)7.36±0.13mm小,且差异有统计学意义(P<0.05)。结论内、外后髁关节面的固定旋转轴心恰好通过内、外侧侧副韧带股骨侧深层起点,可以看作膝关节的屈曲固定轴,通过松解不同层面的侧副韧带,可以在TKA中针对性地松解软组织及调整伸屈间隙的平衡,从而矫正各种膝内、外翻及屈曲挛缩畸形。股骨内、外侧侧副韧带深层止点可作为TKA中股骨假体旋转定位的参考标志。

RELATIONSHIP BETWEEN ANATOMY OF KNEE COLATERAL LIGAMENT AND GEOMETRY OF POSTERIOR FEMORAL CONDYLAR ARTICULAR SURFACE

OBJECTIVE: To analyze the relationship between the collateral ligament attachment and the epicondylar axis with rotational alignment of the femoral component in the total knee arthroplasty(TKA). METHODS: Twenty normal cadaver knee joints were anatomized and 2 holes were drilled on the distal femur from the deep and superficial insertions of the medial collateral ligaments to the lateral condylar part, respectively. Then, all the knees were scanned by MRI on the sagittal plane, making the drilled hole located relatively to the posterior condylar joint surface on the axial plane, and the posterior condylar angle (PCA) and the condylar twist angle (CTA) were measured. RESULTS: The colateral ligament had the deep and superficial parts, and the deep part was strained during the knee flexing. PCA and CTA were 4.50 +/- 1.26 degrees and 7.10 +/- 0.30 degrees respectively, and there was a significant difference between them (P < 0.05), which were significantly greater than those reported abroad. On the sagittal plane, there was no significant difference between the radiuses of the posterior medial and lateral condylar circles (P > 0.05). The distance from the center of the posterior condylar circle to the deep insertion of the medial collateral ligament (MCL) (dl) was 4.22 +/- 0.20 mm, and the distance to the superficial insertion of MCL (d2) was 7.36 +/- 0.13 mm. The difference between dl and d2 was significant (P < 0.05). CONCLUSION: The center of the posterior condylar circle passes from the deep insertion of the collateral ligament, which can be regarded as a fixed flexion-extension axis of the knee. By releasing the different parts of the collateral ligaments, the balance of the flexion and extension gap can be obtained, and then varus, valgus or flexed contracture deformity of the knee can be realigned. Besides, the rotational orientation of the femoral prothesis can be made by a reference to the epicondylar insertion of the collateral ligament.