Robot-based Wrist Rehabilitation in Orthopaedics: Efficacy and Comparison With Traditional Methods

The present randomized clinical trial addresses the issue about the application of robot-based rehabilitation programs in orthopedic conditions. The aim of the study is to test the efficacy of a robot-based rehabilitative protocol to recover wrist functionality after traumatic injuries.

Thirty patients with work related wrist injuries resulting in wrist joint dysfunction are enrolled in an open randomized controlled trial over a 24 months period. Each participant is randomly allocated to experimental or control group and receives a 3-week rehabilitation program including both assessment and rehabilitative sessions. While patients in the control group undergo a traditional rehabilitative protocol, the experimental group is treated replacing traditional exercises with robot-aided ones performed with WRISTBOT, a 3 Degrees of Freedom (DoFs) robotic exoskeleton. WRISTBOT allows for passive, active and assisted range-of-motion (ROM) exercises, isotonic and elastic tasks, proprioceptive and perturbation training. All subjects perform the same sessions of assessment, which include two evaluations through the robotic system and clinical measures at the beginning (Tb) and at the end (Te) of the rehabilitative training, and a follow-up through phone call, three months after the end of the treatment (Tf). The assessment sessions include a robot-based evaluation (measurement of ROM, exerted forces, dexterity, and wrist position sense acuity) and clinical measures (Patient Rated Wrist Evaluation, Jebsen-Taylor and Jamar Test). Subjects' level of satisfaction about treatment is asked at the end of the rehabilitative treatment (Te). The primary objective is to evaluate the results of a robot-based rehabilitative approach on wrist functionality after work-related trauma, comparing the effects of robotic therapy with those achieved through a conventional therapy.

Adult, Humans, Middle aged, Robotics / instrumentation*, Wrist Injuries / physiopathology, Wrist Injuries / rehabilitation*

The patients in the "WRISTBOT Group" underwent to following interventions: 1. General Rehabilitation 2. Specific wrist rehabilitation by WRISTBOT device

The patients in the Control Group underwent to following interventions: 1. General Rehabilitation 2. Specific wrist rehabilitation performed by physiotherapist.

The WRISTBOT is a fully backdrivable manipulandum that allows for movements along its 3 Degrees of Freedom (DoFs) in a human-like Range Of Motion (ROM) of the wrist: 62° flexion/extension (FE), -40°/+45° in ulnar/radial deviation (RUD), and 60° pronation/supination (PS). In addition, the robot permits motions along planes that involve combined multi-DoFs movements. Mechanically, the robot was developed to have low values of inertia, emulating the fluency of natural movements. Each DOF is measured by high resolution incremental encoders and actuated by one brushless motor or two in case of the RUD planes, providing both gravity compensation and continuous torque values necessary to manipulate the human wrist joints. Depending on the torques exerted, the device can be used in either active or assistive/passive modality. The system is integrated with a Virtual Reality environment (VR), useful to provide a visual feedback to the user while he/she is requested to complete the tasks.

Exercise with elastic bands or weights, exercise of manipulation and dexterity, simulation of daily life activities supervised by the physiotherapist

Using a hand dynamometer, subjects perform three trials to evaluate the mean static palmar force exerted in kg

Consist of six items, its aim is to evaluate dexterity in terms of fine motor skills, weighted functional tasks and non-weighted functional tasks. Each item is scored according to the time taken to complete the task

A questionnaire composed of a pain (PRWE-P) and a function (PRWE-F) subscale. Each subsection has a maximum score of 50 and a minimum of 0, where less score points out a better performance

Change from 3th week (Te) Patient Rated Wrist/Hand Evaluation (PRWE) at the follow-up assessment after 3 months (Tf)

A questionnaire composed of a pain (PRWE-P) and a function (PRWE-F) subscale. Each subsection has a maximum score of 50 and a minimum of 0, where less score points out a better performance

Starting from the neutral position (0° along each DoF), the device moves the wrist of the subject along different directions until subject's maximum tolerance, notified by himself/herself pushing a button with the not injured hand. Target directions are 8 equally distributed in the Flexion-Extension/Radial-Ulnar Deviation (FE/RUD) space, and 2 along Pronation-Supination. Outcome measures consist in the maximum ROM in degrees achieved along each direction.

From the initial neutral position, subjects move actively the device as far as they could, along the same directions of the Passive ROM assessment. Any assistive force is applied, but the weight of the device is compensated during active motions. The outcome measure is the maximum active ROM in degrees achieved along each direction.

While the device keeps subjects on the wrist neutral position, they are requested to perform a maximal contraction toward different directions. While subjects push towards each target direction, the device resisted to the imposed force, such that no motion is performed. The outcome measure is maximal peak force in Newton measured along each direction (same directions as in ROM assessment).

Subjects have to follow a target moving on a first order Lissajous trajectory, showed on the screen two-dimensional space. Subjects perform two laps, actively moving in two different directions of rotation (counter and clockwise) across the space described by combinations of FE/RUD motions. The size of the figure is determined by the 75% of the smallest assessed ROM in each direction. The resulting outcome measure is the mean figural error in degrees, i.e. the average angular distance between target and end-effector trajectory in each sampled point.

While the subject is blindfolded, the device moves his/her wrist in a defined direction, until the 75% of the subject's ROM along that direction. After 3 seconds, the wrist is passively brought back to the neutral position. Then, maintaining the blindfolded condition, the subject is asked to reproduce the joint configuration previously assumed passively. Target directions corresponded to the same directions along which the ROM has been assessed. Performance is measured in terms of matching error, i.e. the Euclidean distance between target and matched points. Matching error is measured in degrees.

Subjects were asked to indicate their approval rating of the rehabilitation program through a Numerical Rating Scale (NRS) from 0 (least satisfied) to 10 (most satisfied)

Inclusion Criteria: Functional and spatial limitations of the wrist joint, following an injury occurred at workplace Post-immobilization phase Temporal distance from the acute event not exceeding 6 months Signed informed consent acquisition Exclusion Criteria: Non-compliance with study requirements Pregnancy or breast feeding; Current or prior history of malignancy Open skin at the level of the patient-device interface Sensory deficit at the level of the patient-device interface Acute inflammatory arthritis of the wrist Contraindications to passive movements

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