Dartmouth College, Thayer School of Engineering, 14 Engineering Drive, Hanover, NH 03755, United States.
Dartmouth Hitchcock Medical Center, Department of Orthopaedics, 1 Medical Center Drive, Lebanon, NH 03766, United States; Dartmouth College, Geisel School of Medicine, 1 Rope Ferry Road, Hanover, NH 03755, United States.
J Biomech. 2019 Feb 14;84:129-137. doi: 10.1016/j.jbiomech.2018.12.027. Epub 2018 Dec 31.
Total knee arthroplasty (TKA) is the most common joint replacement in the United States. Range of motion (ROM) monitoring includes idealized clinic measures (e.g. goniometry during passive ROM) that may not accurately represent knee function. Accordingly, a novel, portable, inertial measurement unit (IMU) based ROM measurement method was developed, validated, and implemented. Knee flexion was computed via relative motion between two IMUs and validated via optical motion capture (p > 0.05). Prospective analyses of 10 healthy individuals (5M, 50 ± 19 years) and 20 patients undergoing TKA (3 lost to follow up, 10M, 65 ± 6 years) were completed. Controls wore IMUs for 1-week. Patients wore IMUs for 1-week pre-TKA, 6-weeks immediately post-TKA, and 1-week at 1-year post-TKA. Flexion was computed continuously each day (8-12 h). Metrics included daily maximum flexion and flexion during stance/swing phases of gait. Maximum flexion was equal between cohorts at all time points. Contrastingly, patient stance and swing flexion were reduced pre-TKA, yet improved post-TKA. Specifically, patient stance and swing flexion were reduced below control/pre-TKA values during post-TKA week 1. Stance flexion exceeded pre-TKA and equaled control levels after week 2. However, swing flexion only exceeded pre-TKA and equaled control levels at 1-year post-TKA. This novel method improves upon the accuracy/portability of current methods (e.g. goniometry). Interestingly, surgery did not impact maximum ROM, yet improved the ability to flex during gait allowing more efficient and safe ambulation. This is the first study continuously monitoring long-term flexion before/after TKA. The results offer richer information than clinical measures about expected TKA rehabilitation.
全膝关节置换术（TKA）是美国最常见的关节置换术。运动范围（ROM）监测包括理想化的临床测量（例如，被动 ROM 时的测角法），这些测量可能无法准确反映膝关节的功能。因此，开发、验证并实施了一种新颖的、便携式的基于惯性测量单元（IMU）的 ROM 测量方法。通过两个 IMU 之间的相对运动计算膝关节屈曲，并通过光学运动捕捉进行验证（p>0.05）。对 10 名健康个体（5 名男性，50±19 岁）和 20 名接受 TKA 的患者（3 名失访，10 名男性，65±6 岁）进行了前瞻性分析。对照组佩戴 IMU 一周。患者在 TKA 前佩戴 IMU 一周，TKA 后立即佩戴 6 周，TKA 后 1 年佩戴 1 周。每天连续计算屈曲度（8-12 小时）。指标包括每天最大屈曲度和步态站立/摆动阶段的屈曲度。在所有时间点，两组的最大屈曲度都相等。相比之下，患者在 TKA 前的站立和摆动屈曲度都降低了，但在 TKA 后有所改善。具体来说，患者在 TKA 后第 1 周的站立和摆动屈曲度低于对照组/TKA 前的值。站立时的屈曲度在第 2 周后超过 TKA 前和对照组水平。然而，摆动屈曲度仅在 TKA 后 1 年超过 TKA 前和对照组水平。这种新方法提高了当前方法（如测角法）的准确性/便携性。有趣的是，手术并没有影响最大 ROM，但改善了在步态中屈曲的能力，从而使步行更加高效和安全。这是第一项连续监测 TKA 前后长期屈曲的研究。研究结果提供了比临床测量更丰富的关于 TKA 康复的信息。
