Effect of Strengthening the Hip Abductor in Patients With Knee Osteoarthritis: Randomized Controlled Trial

Osteoarthritis (OA) is a prevalent disease associated with significant morbidity and is one of the most common causes of joint pain. Characterized by their chronicity, slow and progressive evolution. The overall prevalence of symptomatic knee osteoarthritis is estimated at 3.8%, with peak prevalence in the population with an average age of 50 years. The main objectives of interventions in patients with knee OA are reduced pain and improved functional capacity and exercises are widely recommended. The literature shows a lack of clinical trials verifying the effect of strengthening the hip muscles in patients with knee osteoarthritis. Thus, the aim of this study is to assess the effect of strengthening the hip abductor muscles versus hip adductor muscles in patients with symptomatic OA of the knee.

The physical therapy sessions will average duration of one hour, often twice a week for six weeks. The exercise intensity will be monitored by the physiotherapist as determined by the participant's ability to complete 10 repetitions for a particular exercise and its difficulty of execution perceived by the modified Borg scale (CR-10). The exercises are performed with load between 60-80% of their capacity, the load will be increased from 2 to 10% when the patient can perform 14 full repetitions in the last series (76). It will be set to 30 seconds of rest between reps and 2 minutes between sets of exercise.

Both groups will perform prior heating exercises exercise bike for 10 minutes with moderate intensity with the Borg scale. Then there will be two stretches repetitions held for 30 seconds of muscle groups: hamstrings, quadriceps, abductors, adductors and gastrocnemius. Manual therapy for patellofemoral and tibiofemoral joint will be held after the completion of stretching. Recent clinical guidelines on knee OA strongly recommend the use of strengthening exercises of the lower limbs, both in closed kinetic chain and open. Thus, they will be performed strengthening exercises in extension and knee flexion in open kinetic chain, squat up and down a step and exercises to sural triceps. For symptom control during exercise in CKC will be used the numeric scale of pain before and after its execution.

The GABQ add the hip abduction exercises in lateral decubitus, exercise "Clam" and pelvic elevation. Studies prior point out that these exercises are among those with higher electromyographic activity of the gluteus medius muscle.

The GADQ add the adduction exercises hip in lateral recumbency, bilateral adduction with a ball between the legs and functional diagonal leg.

The exercises will be carried out to load 60-80% of 1 repetition maximum 8-12 reps, 1-3 sets and 2-3 times a week. All exercises are performed without worsening pain and intensity of exercise will be controlled according to the perceived exertion scale of Borg.

Eligibility Criteria:
Inclusion Criteria:

* OA knee radiograph grades 2 - 4 according to the Kellgren-Lawrence scale;
* Reporting knee pain with minimum intensity of 3 on Numerical Pain Scale;
* Complaints of pain and functional reduction in the last three months;
* Meet at least one of the American College of Rheumatology classification criteria;
* Deambulation independent;
* Absence of prostheses or orthoses
* Predominant pain in the medial aspect of the knee.

Exclusion Criteria:

* Contraindications for physical exercises evaluated by the Physical Activity Readiness Questionnaire (PAR-Q);
* Diabetes type I or decompensated;
* Hypertension decompensated;
* Cardiac pacemaker;
* Cancer History
* Neurological deficits (sensory or motor)
* Body mass index above 40 kg / m2
* Hip symptomatic osteoarthriti
* Orthopedic surgery of the lower limbs
* Systemic inflammatory disease
* Can not walk.