Wang Joon Ho, Shin Jung Min, Kim Hyun Ho, Kang Seung-Hoon, Lee Byung Hoon
Kangdong Sacred Heart Hospital, Hallym Univeristy Medical Center, Seoul, Republic of Korea.
Int Orthop. 2017 Jan;41(1):85-92. doi: 10.1007/s00264-016-3279-z. Epub 2016 Aug 18.
To evaluate the differences in the amount of varus malalignment and valgus (over) correction in relation to three different weight bearing conditions from whole leg AP radiographs (single-limb (SL) stance, double-limb (DL) stance, supine position (S)) before and after high tibial osteotomy (HTO), and to evaluate which alignment parameters affect the changes for patients in three different weight bearing conditions.
A total of 40 consecutive patients (43 knees) with varus osteoarthritis underwent navigation assisted open wedge HTO. Mechanical axis angle (MA) was measured before and after surgery from hip-to-ankle radiographs taken with patients in three different weight bearing conditions. To find significant factors that affect the alignment differences, several variables including patient demographics, soft tissue laxity, pelvic obliquity, and ground mechanical axis deviation of tibia (calculated by the angle between two lines, tibial anatomical axis and weight-bearing line) were evaluated.
Pre-operatively, mean MA measured on SL stance radiographs was significantly more varus than on DL stance (10.1° ± 2.4° and 8.0° ± 2.6°, respectively, p < 0.001), which was significantly more varus than on supine position (6.6° ± 2.6°, p < 0.001). Meanwhile, in patients with post-operatively valgus corrected knee, MA did not show the same pattern of change as with pre-operative varus knee. Mean MA measured on DL stance radiographs was more valgus than in supine position (-3.0 ± 2.4 and -2.6 ± 3.1, p = 0.455), while mean MA on SL stance radiographs (-2.0 ± 2.1) was significantly less valgus than on DL stance (p = 0.002). The ground mechanical axis deviation of tibia showed a significant correlation with MA difference between SL and DL stance radiographs before (β = -0.341, p = 0.045) and after surgery (β = -0.536, p = 0.001).
In pre-operative varus knee, the mean MA on SL stance was changed to more varus than on DL stance, which changed to less valgus in post-operative valgus knee. The understanding in discrepancy of alignment in different weight bearing conditions before and after HTO should be considered for the appropriate realignment of the limb.
Level II Prospective comparative study.
通过全腿前后位X线片（单腿（SL）站立、双腿（DL）站立、仰卧位（S））评估胫骨高位截骨术（HTO）前后三种不同负重条件下内翻畸形量和外翻（过度）矫正量的差异，并评估哪些对线参数会影响三种不同负重条件下患者的变化。
连续40例（43膝）内翻性骨关节炎患者接受了导航辅助的开放楔形HTO。在患者处于三种不同负重条件下拍摄髋至踝关节X线片，测量手术前后的机械轴角（MA）。为了找出影响对线差异的显著因素，评估了几个变量，包括患者人口统计学特征、软组织松弛度、骨盆倾斜度和胫骨的地面机械轴偏差（通过胫骨解剖轴和负重线两条线之间的角度计算）。
术前，SL站立位X线片上测得的平均MA内翻程度明显大于DL站立位（分别为10.1°±2.4°和8.0°±2.6°，p<0.001），且明显大于仰卧位（6.6°±2.6°，p<0.001）。同时，术后外翻矫正的膝关节患者，MA的变化模式与术前内翻膝关节不同。DL站立位X线片上测得的平均MA外翻程度大于仰卧位（-3.0±2.4和-2.6±3.1，p=0.455），而SL站立位X线片上的平均MA（-2.0±2.1）外翻程度明显小于DL站立位（p=0.002）。胫骨的地面机械轴偏差与术前（β=-0.341，p=0.045）和术后（β=-0.536，p=0.001）SL和DL站立位X线片之间的MA差异显著相关。
术前内翻膝关节中，SL站立位的平均MA比DL站立位更内翻，术后外翻膝关节中则外翻程度更小。在HTO前后不同负重条件下对线差异的理解，对于肢体的适当重新对线应予以考虑。
II级前瞻性比较研究。
