2017 ISAKOS Biennial Congress ePoster #1225

 

Safety and Feasibility of Robot Suit-Assisted Knee-Function Improvement Therapy During the Early Postoperative Period after Total Knee Arthroplasty

Tomokazu Yoshioka, MD, PhD, Noda, Chiba JAPAN
Naoya Kikuchi, MD, Tsukuba, Ibaraki JAPAN
Shigeki Kubota, PhD, Tsukuba, Ibaraki JAPAN
Hisashi Sugaya, MD, PhD, Tsukuba, Ibaraki JAPAN
Yu Taniguchi, MD, PhD, Tsukuba, Ibaraki JAPAN
Norihito Arai, Tsukuba, Ibaraki JAPAN
Kojiro Hyodo, Tsukuba, Ibaraki JAPAN
Akihiro Kanamori, MD, PhD, Tsukuba, Ibaraki JAPAN
Masashi Yamazaki, MD, PhD, Tsukuba, Ibaraki JAPAN

University of Tsukuba, Tsukuba, Ibaraki, JAPAN

FDA Status Not Applicable

Summary

Knee extension exercise with a wearable robot suit, hybrid assistive limb-single joint (HAL-SJ), performed as part of the acute phase of post-TKA rehabilitation, and resulted in immediate improvements in extension lag without increased knee pain. HAL-SJ-based knee-function improvement therapy could be used as a novel post-TKA rehabilitation modality.

Abstract

Purpose

Reduced knee range of motion (ROM) after total knee arthroplasty (TKA) is associated with a decrease in patient-based functional evaluation score. Suggested reasons for reduced ROM soon after surgery include pain associated with surgical invasion and dysfunctional quadriceps. Therefore there is a need to develop new methods of treatment for pain reduction and rapid recovery of quadriceps function after surgery. The objective of this study was to evaluate the safety and feasibility of using a robot suit to improve joint function after TKA.

Methods

We performed a prospective study of patients who underwent TKA for treatment of knee osteoarthritis at our department from April 2015. TKA was performed using a longitudinal incision, a medial parapatellar approach, and the modified gap technique. Patients were allowed to bear full weight beginning the first day after surgery. Rehabilitation was carried out by a physiotherapist for 40 minutes, five days/week. ROM exercise by means of continuous passive motion (CPM) was performed for 1 hour each day. The use of a wearable robot suit (single-joint HAL®, CYBERDYNE, Japan) was initiated on postoperative day 8, with knee extension exercises (10 times/set × 5) being performed twice a week for the duration of hospitalization. We carried out statistical analysis of changes in vital signs, impaired surgical wound healing, number and duration of exercise sessions, and changes in knee pain before and after intervention, as assessed by visual analog scale (VAS) (mm) and extension lag (º).

Results

Thirteen patients were enrolled this study up to May 2016, and 9 underwent robot suit assisted-knee extension exercises, with 4 patients being excluded from the study owing to the diagnosis of postoperative deep venous thrombosis (DVT). The patient population comprised 3 men and 6 women, with the mean age 71.1 years. None of the patients exhibited changes in vital signs or impaired surgical wound healing that would have required exercise to be discontinued. The mean number of exercise sessions was 2.9, with a mean duration of 20.1 minutes. After the first three interventions, VAS improved from 15.5 to 12.5, 20.4 to 11.1, and 17.8 to 12.1, respectively; however, these differences were not found to be significant. Extension lag improved from 9.6 to 8.2, 9.2 to 5.9, and 9.0 to 4.9, respectively, with significant improvement appreciated after the second and third interventions.

Discussion

The absence of any serious adverse events indicated the safety of the robot suit; its feasibility was confirmed by reducing knee pain and the duration of the exercises. Extension lag improved significantly after the second and third sessions; however, further studies are required to verify its efficacy.

Conclusion

The robot suit could be used safely to improve knee function during the early postoperative period after TKA.