Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Knee Surg Sports Traumatol Arthrosc. 2024 Mar;32(3):645-655. doi: 10.1002/ksa.12095. Epub 2024 Feb 26.
The degree to which varus knees can be corrected manually is important when considering total versus unicompartmental knee arthroplasty (UKA). The primary aim was to clarify the relationship between the degree of coronal alignment correction and radiographic parameters involved in UKA prognosis using preoperative full-length lower extremity valgus stress radiography. The secondary aim was to identify the factors affecting alignment correction.
This retrospective observational study included 115 knees with medial osteoarthritis that underwent knee osteotomy or arthroplasty. Percent mechanical axis without valgus stress (%MA: neutral, 50%; varus, <50% and valgus, >50%), mechanical lateral distal femoral angle, lateral bowing femoral angle, medial proximal tibial angle (MPTA), joint line convergence angle, medial and lateral joint space width (LJSW) and medial femoral and tibial joint osteophyte size were measured using preoperative full-length weight-bearing radiographs. Correlation and multiple linear regression analyses were used to assess associations between parameters and %MA with valgus stress or amount of %MA change (%MA with valgus stress minus %MA without valgus stress).
%MA with valgus stress was correlated with all radiographic parameters. %MA change was correlated with parameters except for MPTA and LJSW. Multiple regression analyses showed that %MA without valgus stress and MPTA were associated with both %MA with valgus stress and %MA change. When %MA with valgus stress was set at 30%, 40% and 50%, MPTA cutoff values were 81.6°, 83.5° and 84.9°, and cutoffs for %MA without valgus stress were 10.7%, 17.1% and 25.1%, respectively.
Small MPTA is strongly associated with less alignment correction under valgus stress in varus knees. The finding is useful in surgical planning, especially to avoid undercorrection with UKA when valgus stress radiographs are unavailable.
Level III.
在考虑全膝关节置换术（TKA）与单髁膝关节置换术（UKA）时，膝关节内翻畸形手动矫正的程度非常重要。本研究的主要目的是通过术前全长下肢外翻应力量线 X 线片，明确冠状面对线矫正程度与 UKA 预后相关的影像学参数之间的关系。次要目的是确定影响对线矫正的因素。
本回顾性观察研究纳入了 115 例内侧骨关节炎患者，他们接受了膝关节截骨术或关节置换术。使用术前全长负重位 X 线片测量机械轴百分比（%MA：中立位，50%；内翻位，<50%；外翻位，>50%）、机械外侧股骨远端角、外侧股骨干弯曲角、内侧胫骨近端角（MPTA）、关节线会聚角、内侧和外侧关节间隙宽度（LJSW）以及内侧股骨和胫骨关节骨赘大小。采用相关性和多元线性回归分析评估参数与 %MA 在外翻应力量线和 %MA 变化量（外翻应力量线时的 %MA 减去无外翻应力量线时的 %MA）之间的相关性。
%MA 在外翻应力量线上与所有影像学参数相关。%MA 变化与除 MPTA 和 LJSW 以外的参数相关。多元回归分析显示，无外翻应力量线时的 %MA 和 MPTA 与 %MA 在外翻应力量线上和 %MA 变化量均相关。当 %MA 在外翻应力量线上为 30%、40%和 50%时，MPTA 的截断值分别为 81.6°、83.5°和 84.9°，无外翻应力量线时 %MA 的截断值分别为 10.7%、17.1%和 25.1%。
小的 MPTA 与膝关节内翻畸形在受到外翻应力时对线矫正程度小密切相关。该发现对于手术计划非常有用，特别是在没有外翻应力量线 X 线片时，可以避免 UKA 矫正不足。
III 级。
