Colyn William, Cleymans A, Bruckers L, Houben R, Smeets K, Bellemans J
Department of Orthopedic Surgery, AZ Turnhout, Steenweg Op Merksplas 44, 2300, Turnhout, Belgium.
Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium.
J Exp Orthop. 2022 May 30;9(1):51. doi: 10.1186/s40634-022-00489-5.
It is usually assumed that the severity of varus osteoarthritis (OA) of the knee is correlated with the axis deviation of the limb. Despite this, there is currently no clear radiographic definition to define a so-called 'high degree' varus knee, which is characterized by a pronounced lateral ligamentous laxity. The purpose of this study was to radiographically determine if the lateral joint line opening (LJLO) is an indicative parameter when defining so-called high grade varus knees.
Two hundred forty Full length radiographs of patients with end-stage varus osteoarthritis who were scheduled for Total knee arthroplasty (TKA) were evaluated. The Hip-knee-ankle-angle (HKA-angle), Joint-line-convergence-angle (JLCA) and the lateral joint line opening were measured. The lateral joint line opening is the shortest distance between the lateral tibial plateau and the deepest point of the lateral femoral condyle. Linear regression models were used to investigate the relationships between the radiographic measurements.
Hip-knee-angle-angle, joint-line-conversion-angle, and lateral joint line opening were all positively correlated (p < 0.001). An increase of 1 mm lateral joint line opening causes an increase of 0.6° joint-line-conversion-angle (p = 0.029) below a cut-off point of 4.7 mm. For lateral opening values beyond 4.7 mm, the gradient increased to 1.2 (p < 0.001). A lateral joint line opening of 4.7 mm corresponds to a hip-knee-ankle-angle of 6.0° (95% CI [5.5; 6.5]).
A lateral joint line opening of more than 5 mm in end-stage OA knees is indicative of increased lateral joint laxity. Those knees can be radiographically classified as so-called 'high-grade' varus knees.
Therapeutic study, Level III.
通常认为膝关节内翻骨关节炎（OA）的严重程度与肢体轴线偏差相关。尽管如此，目前尚无明确的影像学定义来界定所谓的“高度”内翻膝，其特征为外侧韧带明显松弛。本研究的目的是通过影像学确定在定义所谓的高度内翻膝时，外侧关节间隙开口（LJLO）是否为一个指示性参数。
对计划行全膝关节置换术（TKA）的240例终末期内翻骨关节炎患者的全长X线片进行评估。测量髋-膝-踝角（HKA角）、关节线汇聚角（JLCA）和外侧关节间隙开口。外侧关节间隙开口是外侧胫骨平台与外侧股骨髁最深点之间的最短距离。使用线性回归模型研究影像学测量之间的关系。
髋-膝角、关节线转换角和外侧关节间隙开口均呈正相关（p＜0.001）。在4.7mm的临界点以下，外侧关节间隙开口增加1mm会导致关节线转换角增加0.6°（p = 0.029）。对于超过4.7mm的外侧开口值，梯度增加到1.2（p＜0.001）。外侧关节间隙开口4.7mm对应髋-膝-踝角为6.0°（95%可信区间[5.5；6.5]）。
终末期OA膝关节中外侧关节间隙开口超过5mm表明外侧关节松弛增加。这些膝关节在影像学上可分类为所谓的“高度”内翻膝。
治疗性研究，III级。
