Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University, 23 Kyunghee-daero, Dongdaemun-gu, Seoul, 02447, South Korea.
Knee Surg Sports Traumatol Arthrosc. 2018 Nov;26(11):3230-3237. doi: 10.1007/s00167-018-4840-7. Epub 2018 Jan 18.
This study aimed to assess radiological changes of the ankle joint, subtalar joint and foot following the correction of varus deformity of the knee with total knee arthroplasty (TKA). It was hypothesized that following the correction of varus deformity by TKA, compensatory reactions would occur at the subtalar joint in accordance with the extent of the correction.
For this prospective study, 375 knees of patients who underwent TKA between 2011 and 2012 were enrolled. The varus angle of the knee, talar tilt of the ankle joint (TT), ground-talar dome angle of the foot (GD), anterior surface angle of the distal tibia and lateral surface angle of the distal tibia, heel alignment ratio (HR), heel alignment angle (HA), and heel alignment distance (HD) were measured on radiographs obtained pre-operatively and at post-operative 6 months.
The mean correction angle in varus deformity of the knee was 10.8 ± 4.1°. TT and GD changed significantly from 0.4 ± 1.9° and 6.5 ± 3.1° pre-operatively to 0.1 ± 1.8° and 0.2 ± 2.1°, respectively (p = 0.007, p < 0.001). No correlation was found between the preop-postop variance in mechanical axis of the lower extremity (MA) and TT, but there was a strong correlation between the preop-postop variance in MA and GD (r = 0.701). HR, HA and HD also changed significantly post-operatively, and the preop-postop variance in MA showed correlations with the preop-postop variances in HR, HA and HD (r = 0.206, - 0.348, and - 0.418). TT and the three indicators of hindfoot alignment all shifted to varus whereas GD was oriented in valgus.
Following the correction of varus deformity of the knee through TKA, significant compensatory changes occurred not only at the ankle and subtalar joints, but also at the foot. The findings of this study are useful in predicting the orientation of changes in the ankle and subtalar joints and the foot following TKA, and in determining the sequence of surgery when both the ankle and knee have a problem. In other words, changes in the parts of the lower extremity below the ankle joint following the correction of varus deformity of the knee must be considered when TKA is planned and performed. Patients who have problems at the ankle, subtalar, and foot joints in addition to varus deformity of the knee are recommended to undergo knee joint correction first.
II.
本研究旨在评估全膝关节置换术（TKA）矫正膝关节内翻畸形后踝关节、距下关节和足部的影像学变化。假设在 TKA 矫正内翻畸形后，根据矫正程度，距下关节会出现代偿反应。
本前瞻性研究纳入了 2011 年至 2012 年间接受 TKA 的 375 例膝关节患者。术前和术后 6 个月，测量膝关节内翻角度、踝关节距骨倾斜角（TT）、足底距骨穹顶角（GD）、胫骨远端前表面角和胫骨远端外侧表面角、跟骨对齐比（HR）、跟骨对齐角（HA）和跟骨对齐距离（HD）。
膝关节内翻畸形的平均矫正角度为 10.8°±4.1°。TT 和 GD 分别从术前的 0.4°±1.9°和 6.5°±3.1°显著变化至术后的 0.1°±1.8°和 0.2°±2.1°（p=0.007，p<0.001）。下肢机械轴（MA）的术前-术后变化与 TT 之间无相关性，但与 GD 之间存在强相关性（r=0.701）。HR、HA 和 HD 术后也有明显变化，MA 的术前-术后变化与 HR、HA 和 HD 的术前-术后变化相关（r=0.206，-0.348，-0.418）。TT 和后足对线的三个指标均向内侧移位，而 GD 则向外侧移位。
通过 TKA 矫正膝关节内翻畸形后，不仅踝关节和距下关节，而且足部也会发生明显的代偿性变化。本研究的结果有助于预测 TKA 后踝关节和距下关节以及足部的变化方向，并确定当踝关节和膝关节都有问题时的手术顺序。换句话说，在计划和进行 TKA 时，必须考虑膝关节内翻畸形矫正后踝关节以下下肢各部位的变化。对于除膝关节内翻畸形外还存在踝关节、距下关节和足部问题的患者，建议首先进行膝关节矫正。
II 级。
