Orthopaedics Surgery and Sports Medicine Department, FIFA Medical Center of Excellence, Croix-Rousse Hospital, Lyon University Hospital, Lyon, France.
Sydney Orthopaedic Research Institute at Landmark Orthopaedics, St. Leonards, Sydney, Australia.
Knee Surg Sports Traumatol Arthrosc. 2022 Sep;30(9):2991-2999. doi: 10.1007/s00167-022-07073-5. Epub 2022 Aug 13.
Evidence is emerging that tibio-femoral compartmental balancing is related to clinical outcomes after total knee arthroplasty (TKA). The purpose of this study was to assess if kinematic alignment (KA) delivered a balanced knee in flexion and extension after TKA on varus deformity, compared to functional alignment (FA).
This single-centre retrospective cohort study assessed 110 consecutive TKAs performed with an image-based robotic system for pre-operative varus deformity. The ligament balancing in the medial and lateral femorotibial compartments was assessed intra-operatively with a robotic system to evaluate if a KA plan would deliver a balanced knee. Balance was considered achieved if tibio-femoral compartments (medial/lateral) were equal to or less than 1.5 mm, or if the estimated final gap position more than 2 mm from the global implant thickness (17 mm). Implant positioning was modified within limits previously defined for a FA philosophy to achieve balancing. Resection thickness and implant positioning were compared with the KA plan and after the FA adjustments; and also, between the patients with a final balanced knee in extension and at 90° of flexion.
A total of 102 patients were eligible for final analysis. Mean age was 67.3 ± 8.2 years, average BMI was 29.1 ± 5.2 kg/m, mean pre-operative coronal alignment was 174.0° ± 3.3° and sagittal alignment 3.4° ± 5.9°. Mean post-operative coronal alignment was 177.7° ± 1.0° and sagittal alignment 0.8° ± 1.9°. A KA plan delivered medial-lateral tibio-femoral compartment balancing in 67 cases (65.7%) for the extension gap and in 50 cases (49.1%) for the flexion gap. All measured bone resection depths were significantly less for FA compared to KA. To achieve balancing targets, final femoral component position was more externally rotated relative to the posterior condylar axis, (0.5° with KA compared to 1.7° with FA (p < 0.0001), and the tibia in more varus (3.0° KA vs. 3.5° FA p = 0.0024). Only one soft tissue release was required.
KA failed to deliver a balanced TKA in more than 50% of cases, especially regarding the flexion gap. Consideration of soft tissue laxity led to significantly less bone resection, with more externally rotated femoral component and more varus tibial component.
有证据表明，在全膝关节置换术（TKA）后，胫股关节间室平衡与临床结果相关。本研究的目的是评估在伴有内翻畸形的 TKA 中，运动学对线（KA）与功能对线（FA）相比，在膝关节屈伸时是否能提供平衡的膝关节。
这是一项单中心回顾性队列研究，评估了 110 例连续接受基于图像的机器人系统治疗术前内翻畸形的 TKA。术中使用机器人系统评估内侧和外侧股胫关节间室的韧带平衡，以评估 KA 计划是否能提供平衡的膝关节。如果胫股关节间室（内侧/外侧）相等或小于 1.5mm，或者估计的最终间隙位置距离全球植入物厚度（17mm）超过 2mm，则认为平衡。在先前定义的 FA 理念范围内，调整植入物的位置以实现平衡。比较了在 KA 计划下和 FA 调整后的截骨厚度和植入物位置，以及在膝关节伸直和 90°屈曲时最终平衡膝关节的患者之间。
共有 102 例患者符合最终分析标准。平均年龄为 67.3±8.2 岁，平均 BMI 为 29.1±5.2kg/m，平均术前冠状面排列为 174.0°±3.3°，矢状面排列为 3.4°±5.9°。平均术后冠状面排列为 177.7°±1.0°，矢状面排列为 0.8°±1.9°。KA 计划在 67 例（65.7%）膝关节伸直间隙和 50 例（49.1%）膝关节屈曲间隙中实现了内外侧胫股关节间室的平衡。与 KA 相比，所有测量的骨切除深度在 FA 中均显著减小。为了达到平衡目标，最终股骨组件的位置相对于后髁轴更向外旋转，（KA 为 0.5°，FA 为 1.7°（p<0.0001），胫骨更内翻（KA 为 3.0°，FA 为 3.5°，p=0.0024）。仅需要一次软组织松解。
KA 未能在超过 50%的病例中提供平衡的 TKA，特别是在膝关节屈曲间隙方面。考虑到软组织松弛，骨切除量显著减少，股骨组件更向外旋转，胫骨组件更内翻。
