TKR Rehabilitation Through the Immersive Virtual Reality in Aquatic Scenarios

This study is a multicenter non-randomized single-blind controlled trial, aimed at investigating the feasibility and efficacy of hydrotherapy based on IVR, for the patients with TKR(Total Knee Replacement), on the function, gait performance, postural balance control, and knee edema reduction. The protocol was draft according to the Consolidated Standards of Reporting Trials (CONSORT ) checklists.

A total of 96patients with total knee prosthesis will be recruited and divided into three groups, to receive a traditional rehabilitation (TR) program, traditional hydrotherapy (TH)or hydrotherapy through immersive virtual reality (HIVR) using Bts-Nirvana. Assessments will be performed at baseline and at the end of treatment.

For the study, inpatients will be taken into consideration. A maximum of 17 treatment sessions will be conducted, divided from 3 to 5 training sessions per week. The treatments will be carried out in groups consisting of 3 patients.

All patients included in the study will perform 45 minutes of traditional rehabilitation treatments, consisted in:

* passive mobilization for the recovery of the complete articular range;
* active work on cycle ergometer;
* muscle strengthening with isometric and isotonic exercises;
* proprioceptive exercises in standing position for load balancing and balance control;
* step training with progressive reduction of walking aids;
* recovery of autonomy in the ascent and descent from the stairs;
* recovery of autonomy in daily life activities. In addition to this common program, specific knee therapy will be performed as provided in the three groups.

Traditional Rehabilitation (TR): the TR group exercises will be performed in the gym with a physiotherapist. In particular, patients will perform:

* exercises with a patient sitting on a chair (3 minutes per exercise):
* flexion-extension of the knee;
* leg and hip circling;
* flexion-extension of the ankle;
* triple flexion;
* walking (with and without aids).

Traditional Hydrotherapy (TH): the TH group exercises will be performed in a swimming pool suitable for hydrotherapy treatments. In particular, patients will perform:

* exercises with patients sitting on the swimming pool edge with lower limb immersed in the water;
* flexion-extension of the knee;
* leg and hip circling;
* flexion-extension of the ankle;
* triple flexion;
* water walking exercises.

Hydrotherapy through Immersive Virtual Reality (HIVR): the HIVR exercises will be performed using Nirvana system, a medical device based on virtual reality specifically designed to support motor rehabilitation, by projecting aquatic scenarios on the floor that simulates the movement and the noise of the water due to the motor exercise execution by the patient. In particular, the following virtual reality scenarios will be used:

* "Swimming pool": the environment represents a swimming pool (water and edge). The patient must perform exercises by moving the lower limbs while sitting on a chair. The virtual environment gives the sensation of having the lower limbs immersed in water above the knees;
* "Water metal": the environment gives the feeling of being immersed in water up to the waist. The subject interacts with the virtual water performing walking exercises and receiving visual and auditory biofeedback.

Eligibility Criteria:
The inclusion criteria are:

* Aged ≤ 85;
* Capacity to consent and to perform the exercises of the specific protocol;
* Patients with total knee prosthesis.

The exclusion criteria are:

* Failure to meet the inclusion criteria;
* Concomitant participation in other studies;
* Unicompartmental knee prostheses;
* Surgery without drainage;
* Wound complications;
* Cognitive disorders;
* Diagnosis of epilepsy;
* Lack of written informed consent;