Therapeutic exercise in osteoarthritis

Physical therapy for osteoarthritis contributes to:

• prevention or elimination of periarticular atrophy of the muscles (for example, the quadriceps of the thigh in patients with gonarthrosis ),
• prevention or elimination of joint instability,
• reduce arthralgia, improve the function of the affected joints,
• slowing the further progression of osteoarthritis,
• weight loss.

Exercises to increase range of motion

Causes of joint stiffness in patients with osteoarthritis can be:

• stretching of the articular capsule, secondary to an increase in the volume of synovial fluid,
• retraction of the articular capsule, periarticular ligaments and tendons,
• fibrous ankylosis of the joint of varying severity due to loss of articular cartilage,
• incongruence of the articular surfaces, the presence of a mechanical block (osteophytes, articular "mice"),
• muscle spasm
• joint pain.

In addition, the attending physician should consider that a decrease in the range of motion in one joint affects the biomechanics of neighboring distal and proximal joints. For example, according to S. Messier and co-authors (1992) and D. Jesevar and co-authors (1993), in elderly patients with gonarthrosis, the range of motion was reduced in all large joints of both lower limbs (hip, knee and ankle) compared with persons control group without joint disease. Violation of the biomechanics of the affected joint leads to a change in the normal movements of the limb, increases the load on the joints, increases the energy consumption during movement, increases pain and instability of the joints. Moreover, limiting the range of motion of the joints of the lower limbs changes the normal kinematics of the gait. For example, in a patient with gonarthrosis, the angular velocity and the volume of movement of the knee joint are reduced, but the angular velocity of the hip joint is compensatory increased compared with control subjects comparable in age, sex and body weight without osteoarthrosis. In addition, in patients with gonarthrosis, an increase in the load on the unaffected limb is observed. At present, it is generally accepted that long-term passive movements have a trophic effect on articular cartilage and can contribute to its repair. Therefore, the restoration of the functional range of motion in the affected joints is an important task of non-drug treatment and rehabilitation of patients with osteoarthritis.

At present, in order to restore the range of motion in the joints, various physical exercises are used:

• passive (joint mobilization is carried out by a methodologist or his assistant),
• semi-active (the patient independently makes movements in the joint, the methodologist / assistant helps to reach the maximum volume only at the end of each movement),
• active (the patient independently performs movements to the fullest extent).

Before a set of exercises, it is possible to conduct a massage or physiotherapy (infrared, shortwave, microwave radiation, ultrasound) to reduce stiffness in the affected joints and facilitate exercise.

[1], [2], [3], [4], [5], [6]

Exercises to strengthen the periarticular muscles

There are many reports in the literature about the connection between osteoarthritis of the knee and weakness / malnutrition of the quadriceps muscle of the thigh. The results of these studies suggest that in patients with gonarthrosis, pain in the joint may be due to weakness of the periarticular muscles and their asymmetric activity, which leads to destabilization of the joint. The load on the unstable joint causes stretching of the innervated tissues and provokes pain, which inhibits the skeletal muscle reflex activity, thereby limiting the function of the limb; thus, the vicious circle is closed. In patients with manifest osteoarthritis of the knee joint, weakness of the quadriceps muscle of the hip is often observed, the immediate cause of which is pain, which limits conscious movement in the joint, which leads to the development of atrophy of the periarticular muscles. This phenomenon is called "arthrogenic muscle depression" (AUM). P. Geborek et al. (1989) reported on the inhibition of muscle function in normal and osteoarthritis affected knee joints with an increase in the volume of the intraarticular fluid and an increase in hydrostatic pressure. In another study, it was found that the maximum isometric strength of the periarticular muscles is significantly reduced in the presence of effusion, and aspiration of excess fluid leads to its increase. At the same time, AUM is observed in patients in the absence of pain and articular effusion, which indicates the presence of other mechanisms of its development. According to histochemical studies, a decrease in the relative number of type II fibrils and the diameter of type I and II fibrils in the gluteus maximus muscle of patients with severe coxarthrosis who are awaiting surgery (arthroplasty), compared with the individuals in the control group. A relative increase in the number of type I fibrils can cause muscle stiffness and contribute to the development of osteoarthritis. It should be noted that in some patients without the hypotrophy of the quadriceps femoris muscle, the weakness of this muscle can be observed. This observation suggests that muscle weakness is not always caused by periarticular muscle atrophy or arthralgia and the presence of articular effusion, and more often by muscular dysfunction. The causes of the latter may be limb deformity, muscle fatigue or changes in proprioceptors. Electromyographic analysis of the quadriceps femoris during an isometric contraction during bending of the knee joint by 30 ° and 60 ° showed significantly greater activity (mainly the rectus femoris) in patients with varus deformity of the knee joint than in healthy individuals. These data explain the higher energy need and rapid fatigue of patients with osteoarthritis with prolonged motor activity.

According to some researchers, the weakness of the quadriceps muscle of the thigh is the primary risk factor for the progression of osteoarthritis of the knee. According to O. Madsen and co-authors (1997), a small increase in muscle strength (by 19% of the average for men and by 27% for women) can lead to a reduction in the risk of progression of osteoarthritis by 20-30%.

The study carried out a quantitative assessment of the movements of the extensor and flexor of the knee joint in patients with gonarthrosis: both isometric and isotonic contraction of the quadriceps femoris was less pronounced in patients with osteoarthritis of the knee joint than in healthy volunteers. According to L. Nordersjo et al. (1983), the contraction activity of the knee flexor was also lower than normal, but to a lesser extent than the extensor. An isokinetic study found that in patients with gonarthrosis, a knee extensor extensor weakness occurs more often than a flexor weakness.

Being natural shock absorbers, the periarticular muscles perform a protective function. Despite the fact that a number of clinical studies have demonstrated the effect of exercises to strengthen the quadriceps femoris on the symptoms of osteoarthritis in patients with gonarthrosis, before starting to perform them it is necessary to stop the pain, swelling of the soft tissues, remove the articular effusion in order to maximally eliminate the AUM phenomenon impeding effective rehabilitation. Moreover, the pressure generated by the activity of the flexor muscle in the knee joint with effusion affects the microcirculation of the joint fluid by squeezing the capillaries.

Exercises to strengthen the periarticular muscles can be divided into three groups:

• isometric (muscle contraction without changing its length): muscle contraction lasts 6 s, followed by relaxation, the exercise is repeated 5-10 times; co-activation of antagonist muscles is also recommended. S. Himeno et al. (1986) found that the load is distributed equally on the TFO surface of the knee joint if the strength of the agonist muscles is balanced by the strength of the antagonist muscles, which in turn reduces the overall load on the joint surface and prevents local damage;
• isotonic (movements of the limb in the joint with or without additional resistance, in which the periarticular muscles are shortened or lengthened); isotonic exercises should be carried out without overcoming the existing range of movements and with submaximal resistance;
• isokinetic (movements in the joint are carried out in full at a constant speed); With the help of an isokinetic dynamometer, resistance varies in such a way that an increase in muscle strength contributes to an increase in resistance, not an increase in speed of movement, and vice versa.

O. Miltner et al. (1997) reported on the effect of isokinetic exercises on oxygen partial pressure (pO ₂ ) in intraarticular tissues in patients with osteoarthrosis: a rate of 60 ° per _second led to a decrease in intra articular pO ₂ below the level observed at rest, then as the speed of 180 ° in 1 s caused the improvement of metabolism in the intra-articular structures. It is known that the pathological decrease in intraarticular pO ₂ has devastating consequences in relation to the metabolism of chondrocytes. However, the most dangerous is tissue reoxygenation following hypoxia. The results of a study conducted by D. Vlake and co-authors (1989) suggest that with lesions of the knee joint (arthritis of different etiologies, including osteoarthritis, complicated synovitis), physical exercise induces damage mediated by active oxygen radicals. The mechanism of synovial ischemia-reperfusion is currently well known. With gonarthrosis, the average pO ₂ value, at rest, is significantly reduced. Exercise in the knee joint with synovitis leads to a pronounced increase in intra-articular pressure, excessive pressure of capillary perfusion, and in some cases an increase in systolic blood pressure, which causes tissue hypoxia. During this period, increased intra-articular pressure decreases the pO _{2 of the} synovial fluid. At rest, intraarticular pressure decreases, reperfusion occurs. The dominant sources of oxygen radicals in the joint, affected osteoarthrosis, resulting from the phenomenon of hypoxia - reoxygenation, are capillary endotheliocytes and chondrocytes. Oxygen radicals induce damage to all components of the cartilage matrix and reduce the viscosity of the synovial fluid. Moreover, hypoxia induces the synthesis and release of endothelial cells of the IL-1 cytokine responsible for the degradation of articular cartilage.

The purpose of stretching exercises is to restore the length of the shortened periarticular muscles. Causes of muscle shortening can be prolonged muscle spasm, skeletal deformity, restriction of movement in the joints. In turn, shortening of the periarticular muscles induces a limitation of the range of motion in the joint. After 4 weeks of stretching and isometric exercises, J. Falconer and co-workers (1992) observed an increase in range of motion and recovery of gait in patients with osteoarthritis. G. Leivseth et al. (1988) studied the effectiveness of passive stretching of the hip abdominal muscle in 6 patients with coxarthrosis. The alternation of stretching (30 s) and pause (10 s) was repeated for 25 minutes 5 days a week for 4 weeks, which led to an increase in the hip abduction volume by an average of 8.3 ° and a decrease in the severity of pain in the joints. Biopsy of muscle tissue revealed hypertrophy of type I and II fibrils and an increase in glycogen content.

Stretching exercises are contraindicated in the presence of effusion in the joint.

[7], [8], [9], [10], [11]

Aerobic exercise

There is some evidence that aerobic exercise programs for osteoarthrosis are needed. It is known that the consumption of oxygen and energy when walking in patients with osteoarthrosis of the knee joints is increased. This is probably due to a change in the normal function of the joints and muscles, which leads to ineffective locomotion. Often, patients with gonarthrosis are overweight, they have a weakness of the periarticular muscles. M. Ries et al. (1995) noted that the severity of gonarthrosis is associated with low maximum oxygen consumption (V ₀ max). This indicates detraining of the cardiovascular system in patients with severe gonarthrosis due to physical inactivity associated with severe pain syndrome and limitation of the function of the affected limb. The results of relatively recent studies have demonstrated an improvement in the physical ability of patients with osteoarthritis (shortening the travel time of a certain distance, etc.) who participated in the aerobic exercise programs.

When developing individual aerobic exercise programs, it is necessary to consider which articular groups are affected by osteoarthritis. For example, cycling (bicycle ergometry) can be recommended for patients with gonarthrosis with a normal amount of flexion in the knee joint and in the absence of significant changes in the PFD joint. Swimming and water exercises effectively reduce the weight load on the joints of the lower extremities during coxarthrosis and gonarthrosis.

However, the methodologist in physiotherapy exercises should take into account that excessive load contributes to the development and progression of osteoarthritis. Although, according to the data of W. Rejeski et al. (1997), high-intensity aerobic exercise improves osteoarthritis symptoms more effectively than moderate-intensity and low-intensity exercises. In any case, when formulating recommendations to the patient, it is necessary to adhere to the basic principle - training should be no more than 3 times a week and last no more than 35-40 minutes.

According to a randomized comparative study of the effectiveness of aerobic exercises and a training program in elderly patients with gonarthrosis, a more significant improvement in motor function and pain in the fitness group are noted compared with the group of patients who participated only in the training program. In another study, it was found that in patients with osteoarthrosis who participated only in aerobic training (aerobic walking, exercise in water) for 12 weeks, a more pronounced increase in aerobic capacity, an increase in walking speed, a decrease in anxiety / depression compared to the control a group of patients who performed only passive exercises to restore range of motion.

[12], [13], [14], [15],