Biofeedback-assisted exercise in the rehabilitation of patients after total knee arthroplasty – effects on functional outcomes and quality of life

Intervention includes 21 day of inpatient postoperative rehabilitation after TKA according to standard protocol which consists of daily sessions of land-based exercise therapy, application of physical agents (interferential current therapy and electrostimulation), group aquatic exercise and individual education. Each of 21 days of rehabilitation follows the same protocol, except Sundays when patients do not receive physiotherapy (there are three Sundays during the patients' stay at the hospital). There are 18 days of rehabilitation consisting of: 50 minutes of land-based exercise, 30 minutes of aquatic exercise, 10 minutes of interferential current therapy, and 10 minutes of electrostimulation. All interventions are performed on a daily basis, except individual education. Programme of land-based exercise consists of 20 exercises. Patients perform 7 variations of isometric exercises for thigh muscles and 13 dynamic exercises for lower limb which include active straight leg raise (upward and combined upward and into hip abduction) from long-sitting position with and without elastic band, hip abduction straight leg raise (and in combination with hip flexion and extension), hip flexion in long-sitting position, leg extension in sitting position with elastic band, hip abduction from sitting position, hip flexion from sitting position, hip flexion and leg exstension exercise on a Swiss ball, and pelvic lift exercise. Isometric exercise is performed in sets of 1, 5 repetitions with maximal efort lasting 5 seconds. Dynamic exercise is performed in 1-2 sets, 10 repetitions. Progression of dynamic exercise is achieved with elastic band and during the last 6 days of rehabilitation ankle weights (1kg) are included. Interferential current therapy is provided using Myomed 632 device (Enraf-Nonius B. V., Rotterdam, The Netherlands) in duration of 10 minutes using symetrical waves, phase duration of 100 µs, phase interval 0 µs, impulse frequency 80 Hz, modulation frequency 0 Hz, modulation programme 1/1 sec, with intensity in mA according to patient's tolerance. Electrostimulation is provided using Myomed 632 device (Enraf-Nonius B. V., Rotterdam, The Netherlands) in duration of 10 minutes using symetrical waves, phase duration of 500 µs, phase interval 0 µs, impulse frequency 1Hz, modulation frequency 0 Hz, modulation programme 1/1 sec, with intensity in mA according to patient's tolerance. Group aquatic exercise include 13 exercises for range of motion and strength (standing toe raise, standing heel raise, semi-squats, hip flexion, extension and abduction in standing position and while floating in water, knee flexion and extension in standing position and while floating in water). Individual education is mainly targeted to long-term care of the prosthesis regarding how to return to activities of daily life, recommended and non-recommended activities, coping with postoperative pain and prevention of blod clots by regular physical activity. It is provided by physiotherapists before and after exercise session, orally. Education is provided once, at the start of the rehabilitation, with additional explaining as necessary (if patients has questions). A portion of land-based exercise therapy will be biofeedback-asissted (Myomed 632, Enraf-Nonius B. V., Rotterdam, The Netherlands), with individually adjusted targets for muscular isometric contraction, according to manufacturer's instruction. Biofeedack is provided by superficial electromyography (EMG) unit, e. g. electrical activitiy of a muscle is registered and passed on as quantitative information (feedback) to the patient and the physiotherapist in real time, during exercise. That way, the patient is able to monitor the strength of the contraction on screen and try to achieve adequate intensity of the muscular isometric contraction. The device is attached to the patient via three electrodes, two EMG electrodes, and one reference electrode. The EMG electrodes are placed at ¼ th of the muscle belly of the anterior portion of the m. quadriceps femoris. The reference electrode is placed on the anterior portion of the tibia of the opposite leg. At the beginning of the biofeedback-assisted exercise the patient will perform maximal isometric contraction of the m. quadriceps femoris to establish the treshold, e.g. the target intensity of the muscular contraction. Sensitivity of the EMG signal is set to 200 µV to achieve good visibility to a patient, e.g. to achieve good graphical representation of the muscle's electrical activity on the screen of the device. After the patient performed maximal isometric contraction this is recored by the device. The pyhsiotherapist in charge will set the treshold which will be the value of the muscular contraction the patient should acomplish during his exercise, e.g. during periods of active muscular contraction. The patient should contract the muscle above the treshold which is visible on the screen. The treshold is set to 80% of the maximal isometric contraction achieved at the start of the session. Biofeedback-assisted exercise consists of isometric contractions of the m. quadriceps femoris for 15 minutes (10 seconds periods of contraction and 10 seconds periods of relaxation between contractions). Intervention will be provided once per day, face to face, by physiotherapist in a special hospital for rehabilitation. Adherence to the treatment will be monitored by physiotherapist in charge.