The effect of anti-gravity treadmill training for knee osteoarthritis rehabilitation on joint pain, gait, and EMG: Case report

Abstract

Introduction: To date, the anti-gravity treadmill (AlterG), as a representative method of Lower body positive pressure (LBPP) treadmills, has been rarely reported for knee osteoarthritis (KOA) rehabilitation. The purpose of this case study was to setup the clinical protocol example for AlterG intervention on KOA and evaluate treatment effectiveness by 3D gait analysis combined with free EMG to explore the kinematic gait parameter changes.

Patient concerns: A 65-year-old female patient (BMI = 26, mild obesity) undergoing "more than 7 years of KOA." The activity of the right knee joint was obviously limited and she suffered from severe pain over the past month.

Diagnosis: Due to the patient's symptoms and radiographic findings, she was diagnosed with acute attack of KOA.

Interventions: The patient has performed clinical function evaluation and gait analysis combined at pretreatment, post-treatment, and 4 months follow-up assessment. AlterG training was performed 6 days/week for 2 weeks, with up to 30 min of training per session. The training protocol included two major parts, walking and squatting in AlterG.

Outcomes: After 2 weeks of AlterG intervention, the 10-m walking test (10 MWT) and Timed-up-and-go (TUG) test improved significantly post-treatment, whereas the Visual Analog Scale (VAS) score decreased post-treatment. The Modified Barthel Index improved post-treatment and the patient restored basic community walk after treatment. The temporal parameter results showed that stride length (%height), mean velocity (%height), and cadence gradually increased before treatment, after treatment, and at 4-month follow-up. The right range of motion (ROM) of knee flexion-extension were gradually increased. Meanwhile, the synchronized EMG data showed that the RMS (root means square) values of the rectus femoris, semitendinosus, and biceps femoris at post-treatment were improved to different degrees than at pretreatment.

Conclusion: We found that for this patient with KOA, AlterG relieved pain, and was also effective at improving spatio-temporal parameters, knee flexion/extension gait pattern, and corresponding muscle strength, thereby restoring certain community activities.

Conflict of interest statement

The authors declare that there is no competing interest regarding the publication of this article.

Figures

Figure 1

Diagram of AlterG setting up (A) and AlterG intervention protocol (B). (A) The AlterG setting up and the patient training on the anti-gravity treadmill. (B) The AlterG protocol consisting of warm-up phase (5 min), walking phase (15 min), cooling down phase (5 min), and squatting phase (5 min). BW = body weight, min = minute, mph = miles per hour.

Figure 2

The MR image of the right knee. The sagittal view (A and B) and the coronal view (C) of right knee show roughened and thinning cartilage, osteophyte, and effusion (white arrows). MR = magnetic resonance, R = right.

Figure 3

BTS gait analysis system setting up. (A) and (B) show marker positioning based on Davis protocol. (C) The BTS software interface of data acquisition. asis = anterior superior iliac spines, c7 = cervical 7, eRHS = R heel strike, which means right foot initial ground contact (at least two events must be defined), mall = malleolus, met = metatarsus, l = left, r = right.

Figure 4

The spatio-temporal parameters of the patient with KOA at pre-, post-treatment and 4 month follow-up. (A) The percentage of right stand phase (dark green) versus swing phase (light green) in gait cycle. (B) The percentage of left stand phase (dark red) versus swing phase (light red) in gait cycle. (C) The stride length (% height) of right side (green) versus left side (red). (D), (E) and (F) show mean velocity (% height/s), step width and cadence respectively. m = meter, min = minute, Pre = pre-treatment, post = post-treatment, post 4M = 4 months after treatment; s = second.

Figure 5

The right ROM of knee flex-extension in gait cycle and the synchronized EMG activity of the patient with KOA at pre-, post-treatment and 4 month follow-up. (A) The knee flex-extension of the patient and (B) shows the synchronized EMG activity of the patient with KOA in gait cycle at pre- (yellow), post-treatment (blue) and 4 month follow up (red). The knee flex-extension reference of normal subject was also showed in (A) (grey). deg = degree, Ext = extension, Flex = flexion, mV = microvolt, pre = pre-treatment, post = post-treatment, post 4M= 4 months after treatment, R = right, RMS = root mean square, s = second.