Tu Kao-Chang, Shih Han-Ting, Tang Shih-Chieh, Lee Cheng-Hung, Liao Wei-Jen, Wang Shun-Ping
Department of Orthopaedics, Taichung Veterans General Hospital, Taichung 40705, Taiwan.
Department of Food Science and Technology, Hungkuang University, Taichung 433304, Taiwan.
J Clin Med. 2021 Sep 17;10(18):4228. doi: 10.3390/jcm10184228.
Maintaining gap balance is critical for total knee arthroplasty (TKA). This study aimed to elucidate if the extension-flexion gaps would be changed with posterior cruciate ligament (PCL) intact (PI) and PCL resection (PR) during TKA. The flexion gaps were measured using two methods, open-(Fo) and closed-chain position (Fc), based on the definition of kinetic chain position, respectively.
This retrospective study enrolled a total of 33 patients who underwent posterior-stabilized (PS) TKA for symptomatic advanced osteoarthritis of knees. After bone cuts were completed, the extension-flexion gaps before and after PCL resection during TKA were measured using a calibrated tensioning device set at a 100 Nm distraction force. To further differentiate the effect of thigh weight on the 90° flexion gap, two varied methods of examination, either in closed chain (Fc) or open chain (Fo) were performed.
The increases in the 90° knee flexion gap after PCL resection were measured by both methods, i.e., ΔFc (PR-Fc-PI-Fc): 2.04 ± 2.06 mm, < 0.001; and mean ΔFo (PR-Fo-PI-Fo): 1.64 ± 1.36 mm, < 0.001. However, there were no differences between ΔFc and ΔFo before and after PCL resection. A greater amount of flexion gap was identified in open chain than in closed chain after PCL resection, and the PR-Fo and PR-Fc were 14.36 ± 3.13 and 11.40 ± 3.47 ( < 0.001), respectively.
The resection of PCL during TKA distinctly increased the flexion gap, but not the extension gap. This disproportionate increase of the gap will cause a gap balance mismatch. The tensioning maneuver in open-chain was more effective to detect the gap differences than in closed-chain before and after PCL resection during TKA.
维持间隙平衡对全膝关节置换术（TKA）至关重要。本研究旨在阐明在TKA过程中，后交叉韧带完整（PI）和后交叉韧带切除（PR）时屈伸间隙是否会发生变化。根据动力链位置的定义，分别采用两种方法测量屈曲间隙，即开链（Fo）和闭链位置（Fc）。
本回顾性研究共纳入33例因症状性晚期膝关节骨关节炎接受后稳定型（PS）TKA的患者。截骨完成后，使用设置为100 Nm牵张力的校准张紧装置测量TKA过程中PCL切除前后的屈伸间隙。为进一步区分大腿重量对90°屈曲间隙的影响，采用两种不同的检查方法，即闭链（Fc）或开链（Fo）。
两种方法均测量了PCL切除后90°膝关节屈曲间隙的增加，即ΔFc（PR-Fc-PI-Fc）：2.04±2.06 mm，P<0.001；平均ΔFo（PR-Fo-PI-Fo）：1.64±1.36 mm，P<0.001。然而，PCL切除前后ΔFc和ΔFo之间无差异。PCL切除后，开链中的屈曲间隙量大于闭链，PR-Fo和PR-Fc分别为14.36±3.13和11.40±3.47（P<0.001）。
TKA过程中PCL切除明显增加了屈曲间隙，但未增加伸直间隙。间隙的这种不成比例增加将导致间隙平衡不匹配。在TKA过程中PCL切除前后，开链中的张紧操作比闭链更有效地检测间隙差异。
