Determination of the Effectiveness of Certain Physical Methods in the Treatment of Knee Osteoarthritis

Osteoarthritis (OA) is a chronic joint disease that involves the entire joint, causing cartilage damage, bone remodeling, osteophyte formation and loss of normal joint function. Knee OA is one of the leading causes of disability in the world and thus represents a major public health problem. Knee OA treatment can be operative and non-operative. Non-operative treatment includes pharmacological treatment, changing life style and physical therapy. The goal of physical therapy in knee OA is to reduce pain and improve knee function through therapeutic exercise, especially by strengthening the quadriceps muscle. In addition to therapeutic exercise, muscle electrical stimulation is often used, and in the literature there is evidence of biofeedback therapy efficacy.

Goal of the study is to investigate whether there is a difference in pain reduction, increase in quadriceps muscle strength, and improvement in knee function in patients who had only kinesitherapy, from those who underwent kinesitherapy and biofeedback, and in patients who received electrical stimulation of quadriceps muscle with kinesitherapy. 93 patients with knee OA according to ACR criteria and Kellgren and Lawrence radiological classification grades 1 and 2 will be included in study. Subjects will complete: Visually Analogous Pain Scale (VAS), Western Ontario Universities Osteoarthritis Index (WOMAC), 36 Item Short Form Health Survey (SF 36), International Classification of Functioning, Disability and Health (ICF) osteoarthritis core set, and quadriceps muscle strength will be measured by EMG biofeedback device.

The research will be conducted in the Department of Orthopedic surgery of the Clinical Hospital Center Zagreb. The research will be prospective, randomized, single blinded. Randomization of patients will be performed before physical therapy using web site www.randomization.com, and the results of the randomization will be known to the physician who will not be directly involved in the treatment or examination of patients.

All patients will sign informed consent before the study begins. Research has been approved by the Ethics Committee of Clinical Hospital Center Zagreb and Ethics committee of the School of Medicine, University of Zagreb.

Inclusion criteria are: patients age 55 years and older who have knee OA according to the American College of Rheumatology criteria (ACR) and knee OA according to Kellgren and Lawrence Radiology Classification Grade 1 and 2, and who report knee pain for at least 3 months. Exclusion criteria are: patients who had surgery on that knee, patients with a pacemaker, and metallic foreign body in the area of muscle stimulation, patients with thrombophlebitis and deep vein thrombosis, patients with skin infection, malignancy, bleeding disorders, patients with neurological disease, patients with inflammatory rheumatological disease, with congenital and acquired knee deformities, with contractures of the hips and ankles, with grade 3 and 4 osteoarthritis according to Kellgren and Lawrence classification, patients who received intraarticular knee injection in the last 3 months and patients with post-traumatic knee osteoarthritis and osteonecrosis.

The investigators will record: age, sex, height, weight, body mass index, leg length and use of orthopedics aids. Clinical examination will be performed on the first day, day 21, after 90 and after 180 days.

At each examination patients will complete following questionnaires: Visually Analog Scale for pain (VAS), Western Ontario Universities Osteoarthritis Index (WOMAC), 36 Item Short Form Health Survey (SF 36) and International Classification of Functioning, Disability and Health (ICF) osteoarthritis core set.

Quadriceps muscle strength will be measured with a Biofeedback therapy device (EMG Biofeedback, Myomed 632, United Kingdom, 2017) .

Patients will be randomisen in three groups. Patients in the first group will be treated with individual kinesitherapy. Patients in the second group will be treated with individual kinesitherapy and biofeedback therapy for strengthening of the quadriceps muscle using EMG Biofeedback device, Myomed 632, United Kingdom, 2017.

Patients in the third group will be treated with individual kinesitherapy together with electrical stimulation of the quadriceps muscle using electrostimulation device (BTL- 4000 Smart, United Kingdom, 2017).

The required sample size was calculated based on pain values data reported in the study by Choi et al. Pain was measured using VAS scale, and sample size was calculated using G Power software package (v3.1.9.4). With the parameter of statistical significance level (alpha) of 0.05 and a test power (1 - beta) of 0.90, based on the data from the Choi et al work, the required final sample size is a total of 93 subjects and 31 subjects for each of the three groups.

The investigators expect to find that kinesitherapy and biofeedback therapy are more efficient compared to kinesitherapy alone or and kinesitherapy and electrical stimulation in reducing pain, improving knee function and strengthening of the quadriceps muscle.

Eligibility Criteria:
Inclusion Criteria:

* radiological evidence of primary OA with Grade 1 and 2 on the Kellgren-Lawrence Scale
* knee pain for 3 months
* knee osteoarthritis defined by American College of Rheumatology Criteria

Exclusion Criteria:

* surgery on that knee
* pacemaker
* metallic foreign body in the area of stimulation
* thrombophlebitis and thrombosis
* skin infection
* malignancy,
* bleeding disorders
* neurological disease
* inflammatory rheumatology disease
* congenital and acquired knee deformities
* contracture of the hips and ankles
* grade 3 and 4 osteoarthritis om the Kellgren and Lawrence classification
* intraarticular injection in the last 3 months
* post-traumatic knee osteoarthritis and osteonecrosis