Kinoshita Tomofumi, Hino Kazunori, Kutsuna Tatsuhiko, Watamori Kunihiko, Tsuda Takashi, Miura Hiromasa
Department of Orthopedic Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
J Exp Orthop. 2021 Oct 6;8(1):87. doi: 10.1186/s40634-021-00409-z.
Range of motion after total knee arthroplasty (TKA) can impact patients' daily lives. Nevertheless, flexion contracture (FC) often recurs after TKA, even upon achieving full extension intraoperatively. This study aimed to evaluate the relationship among preoperative, intraoperative, and postoperative knee extension angles, and clarify the risk factor for postoperative FC.
One hundred forty-seven knees undergoing TKA using a navigation system were evaluated. We measured the pre- and postoperative (6 months after TKA) extension angles using a goniometer, and intraoperative (before and after TKA) extension angle using a navigation system; the correlation between these angles at each time point was evaluated.
The mean preoperative, intraoperative (before and after TKA) and postoperative extension angles were -9.9°, -6.8°, -0.1°, and -2.0°. Regarding intraoperative extension angle after TKA, 58 knees showed ≤ 5° hyperextension and six knees showed > 5° hyperextension. At 6 months, no cases showed hyperextension and 105 knees showed full extension. The mean intraoperative extension angle after TKA in the postoperative full extension group was 0.4°. A significant correlation was found among extension angles at each point (p<0.01, respectively). However, the intraoperative extension angle after TKA correlated with the postoperative extension angle only in females. Contrarily, the recurrence rate of FC was significantly higher in males than in females (p<0.01).
Intraoperative extension angles significantly correlated with pre- and postoperative extension angles in TKA. Moreover, intraoperative mild (≤ 5°) hyperextension is acceptable for postoperative full extension. There was a gender-specific difference in correlation between intra- and postoperative knee extension angles.
III.
全膝关节置换术（TKA）后的活动范围会影响患者的日常生活。然而，即使术中实现了完全伸直，TKA后屈曲挛缩（FC）仍常复发。本研究旨在评估术前、术中和术后膝关节伸直角度之间的关系，并阐明术后FC的危险因素。
对147例行导航系统辅助TKA的膝关节进行评估。我们使用量角器测量术前和术后（TKA后6个月）的伸直角度，使用导航系统测量术中（TKA前后）的伸直角度；评估各时间点这些角度之间的相关性。
术前、术中（TKA前后）和术后伸直角度的平均值分别为-9.9°、-6.8°、-0.1°和-2.0°。关于TKA后的术中伸直角度，58个膝关节显示≤5°的过伸，6个膝关节显示>5°的过伸。在6个月时，无病例显示过伸，105个膝关节显示完全伸直。术后完全伸直组TKA后的术中平均伸直角度为0.4°。各点的伸直角度之间存在显著相关性（p均<0.01）。然而，TKA后的术中伸直角度仅在女性中与术后伸直角度相关。相反，男性FC的复发率显著高于女性（p<0.01）。
TKA术中伸直角度与术前和术后伸直角度显著相关。此外，术中轻度（≤5°）过伸对于术后完全伸直是可接受的。术中和术后膝关节伸直角度之间的相关性存在性别差异。
III级。
