PURPOSE To investigate the femoral component alignment in patients undergoing soft tissue-guided, navigated total knee arthroplasty (TKA). It was hypothesized that with a mechanically aligned tibial component, the soft tissues tensioned and symmetric medial and lateral gaps in flexion/extension, the femoral component would be aligned to the preoperative distal femoral joint line, as measured on knee radiographs. METHODS Between 2015 and 2017, 77 patients (78 knees) underwent navigated soft tissue-guided TKA at a single centre. Pre and postoperative radiographs were collected and varus knees were taken into account. The tibial cut was performed with navigation in neutral alignment. The femoral cuts were adjusted based on tensioned soft tissues, aiming for equal medial and lateral gaps in flexion and extension. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and Knee Society Score (KSS) were collected pre and postoperatively as a secondary outcome measure. RESULTS A total of 58 TKAs on varus knees were assessed. On average, the femoral component was placed at 1.7° (SD 1.7) varus in the coronal plane. The comparison between the radiographic native distal femoral alignment and the orientation of the femoral component coronal cut demonstrated a statistically significant (p < 0.0001), linear inverse relationship (r = 0.5). Satisfactory knee function and excellent pain remission were demonstrated by KOOS and KSS scores at a mean of 2.8 years (SD 0.5) follow-up. One TKA was revised, resulting in a 98.3% survivorship at three years. CONCLUSION The proposed soft tissue-guided, navigated technique, aiming to preserve the integrity of the ligaments and a neutrally aligned tibial cut, provided a joint line respecting femoral coronal cut and encouraging short-term clinical results. LEVEL OF EVIDENCE III.

中文翻译：

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导航，软组织引导的全膝关节置换术以改良的机械对准技术恢复了股骨远端关节线的方向。

目的探讨接受软组织引导的全膝关节置换术（TKA）患者的股骨成分排列。假设通过机械对齐的胫骨组件，软组织张紧，屈曲/伸展中的内侧和外侧间隙对称，如膝部X线片所测，股骨组件将与术前股骨远端关节线对齐。方法在2015年至2017年之间，有77名患者（78膝）在单个中心接受了经软组织引导的TKA导航。收集术前和术后X光片，并考虑膝内翻。胫骨切开以中性定位导航。根据张紧的软组织调整股骨切开，目的是在屈曲和伸展时获得相等的内侧和外侧间隙。术前和术后收集膝关节损伤和骨关节炎结果评分（KOOS）和膝关节社会评分（KSS）作为次要结果指标。结果共评估了58个膝内翻TKA。平均而言，将股骨组件置于冠状平面内1.7°（SD 1.7）内翻。放射线原始股骨远端股骨排列与股骨冠状切口的方向之间的比较显示出统计学上的显着性（p <0.0001），线性反比关系（r = 0.5）。平均2.8年（SD 0.5）的随访结果显示，KOOS和KSS评分显示出令人满意的膝关节功能和出色的疼痛缓解。修订了一项TKA，三年存活率达到98.3％。结论拟议的软组织引导导航技术，旨在保持韧带的完整性和中性对齐的胫骨切口，提供了一条尊重股骨冠状切口并鼓励短期临床结果的联合手术。证据级别III。