Department of Rehabilitation, Kobe City Medical Center General Hospital, Minatojima Minamimachi 2-1-1, Chuo-Ku, Kobe, Hyogo, 650-0047, Japan.
Department of Rehabilitation Science, Graduate School of Health Science, Kobe University, Tomogaoka 7-10-2, Suma-Ku, Kobe, Hyogo, 654-0142, Japan.
Arch Orthop Trauma Surg. 2024 Jan;144(1):377-384. doi: 10.1007/s00402-023-05067-7. Epub 2023 Sep 26.
Total knee arthroplasty (TKA) reduces pain and improves physical function; however, not all patients have successful outcomes after surgery. To identify these patients would be critical information for improving rehabilitation programs. The purpose of this study was to clarify the cut-off values of lower extremity muscle strength for predicting postoperative good walking ability.
Timed Up and Go test of 105 patients was measured at 6 months postoperatively, and participants were divided into good (< 9.1 s) and poor (≥ 9.1 s) walking ability. Both sides of knee extensor strength (KES) and hip abductor strength (HAS) were measured using hand-held dynamometer preoperatively. Receiver operating characteristic (ROC) curve analysis was used to identify cut-off values for classifying the participants into the two groups.
Of the 105 patients, 54 were allocated in the poor walking ability group, whereas 51 were allocated in the good walking ability group. KES and HAS were significantly greater in the good walking ability group than in the poor walking ability group. ROC curve analysis revealed that the cut-off value for KES was 0.79 Nm/kg (area under the curve (AUC) 0.68; sensitivity 64.7%; specificity 68.5%) on the involved side and 0.86 Nm/kg (AUC 0.73; sensitivity 84.6%; specificity 55.6%) on the uninvolved side, and for HAS was 0.57 Nm/kg (AUC 0.71; sensitivity 60.8%; specificity 71.7%) on the involved side and 0.61 Nm/kg (AUC 0.76; sensitivity 66.7%; specificity 77.4%) on the uninvolved side.
The cut-off values of preoperative KES and HAS for predicting good walking ability after TKA are 0.79 Nm/kg on the involved side and 0.86 Nm/kg on the uninvolved side, and 0.57 Nm/kg on the involved side and 0.61 Nm/kg on the uninvolved side, respectively. We should provide enhanced pre- and post-operative rehabilitation programs for patients with muscle strength lower than these values.
全膝关节置换术（TKA）可减轻疼痛并改善身体功能；然而，并非所有患者术后都能取得满意的效果。识别这些患者对于改善康复计划至关重要。本研究旨在明确下肢肌肉力量的临界值，以预测术后良好的行走能力。
对 105 例患者的计时起立行走测试（TUGT）在术后 6 个月进行测量，并根据测试结果将患者分为行走能力良好（<9.1s）和较差（≥9.1s）。术前使用手持测力计测量膝关节伸肌力量（KES）和髋关节外展肌力量（HAS）的双侧值。采用受试者工作特征（ROC）曲线分析确定临界值，以将参与者分为两组。
105 例患者中，54 例患者被归入行走能力较差组，51 例患者归入行走能力较好组。行走能力较好组的 KES 和 HAS 明显大于行走能力较差组。ROC 曲线分析显示，KES 的临界值为患侧 0.79 Nm/kg（曲线下面积（AUC）为 0.68；敏感性 64.7%；特异性 68.5%）和健侧 0.86 Nm/kg（AUC 为 0.73；敏感性 84.6%；特异性 55.6%），HAS 的临界值为患侧 0.57 Nm/kg（AUC 为 0.71；敏感性 60.8%；特异性 71.7%）和健侧 0.61 Nm/kg（AUC 为 0.76；敏感性 66.7%；特异性 77.4%）。
预测 TKA 后良好行走能力的术前 KES 和 HAS 的临界值为患侧 0.79 Nm/kg 和健侧 0.86 Nm/kg，以及患侧 0.57 Nm/kg 和健侧 0.61 Nm/kg。我们应为肌肉力量低于这些值的患者提供强化的术前和术后康复计划。
