Tendinopathy: a review of treatment methods

Tendinopathy of the Patellar Ligament The term tendinopathy is a general designation for clinical conditions associated with excessive stress on the tendons and surrounding tissues. Histologically, this condition is characterized by random proliferation of tenocytes, destruction of collagen fibers and subsequent increase in non-collagenous matrix.

Clinically Relevant Anatomy

Healthy tendons are shiny white in color and have a fibroelastic structure. Tenoblasts and tenocytes make up 90%-95% of the cellular elements of tendons. The remaining 5%-10% of cellular elements include chondrocytes, tendon sheath synovial cells, capillary endothelial cells, and arteriole smooth muscle cells.

Oxygen consumption by tendons and ligaments is 7.5 times lower than that of skeletal muscles. A low metabolic rate and a well-developed anaerobic energy capacity are necessary to tolerate loads and maintain tension over long periods of time, reducing the risk of ischemia and subsequent necrosis. However, a low metabolic rate leads to slow healing after injury.

Epidemiology/Etiology

An injured tendon has a higher rate of matrix remodeling, resulting in mechanical instability and increased susceptibility to injury. The results of histological studies of samples taken from patients with established tendinopathy show either no or minimal significant inflammation. Typically, they indicate proliferation, loss of collagen fiber density, increased proteoglycan content, and neovascularization. Inflammation appears to play a role only in the initiation, but not in the spread and progression of the pathological process.

Previously, it was believed that failure to heal and the resulting tendinopathy of the tendon was associated with chronic overload, but subsequently the same histopathological characteristics were described in tendons that were not overloaded. Lack of load on the tendon is accompanied by the same changes in cells and matrix as in the case of an overloaded tendon. This also leads to a decrease in its mechanical strength.

Causes of tendinopathy

Tendinopathy can affect people of any age, but is more common in athletes. Older people are also susceptible to this condition because as they age, tendons tend to lose elasticity and become weaker. This means that the joint is no longer able to move and move freely. Age-related changes also occur in the blood vessels surrounding the tendons. This aggravates the severity of the disease.

Tendinopathy is classified into inflammation of the knee, shoulder, hip, wrist, and Achilles tendons (which connect the calf muscle to the heel bone). The patient experiences discomfort that makes it difficult to do basic things like putting on clothes. The disease requires early diagnosis, given the similarity of symptoms with manifestations of arthritis and inflammation of the ligaments. Making a preliminary diagnosis is quite difficult, and the inflammatory process becomes chronic.

The main reasons for the development of the disease:

Rheumatoid arthritis.
Excessive load on the muscle.
Previous injuries (bruises, tendon rupture).
Diseases of an immune nature.
Metabolic disorders (obesity) or problems of endocrine origin (diabetes mellitus).
Infectious processes affecting connective tissue.
Inflammation, wear and tear of joints.

Predisposing factors also include thermal damage to the tendon - thermal injury. Climbers, rock climbers and tourists encounter this type of damage. Most cases affect the areas of the hands, wrists, ankles and feet.

Anatomical features are a rare cause of tendinopathy. If the tendons do not have a smooth surface, they become vulnerable and become inflamed and irritated quite easily. In this situation, surgery is often necessary to solve the problem.

Clinical picture

The main manifestations of tendinopathy are pain and decreased functional activity. The pain is usually associated with exertion. At an early stage, pain appears only at the beginning of physical activity and disappears during its process. Usually the patient is able to localize the painful area quite clearly. In the early stages, the pain is described as “severe” or “sharp,” and sometimes as “dull,” especially if the pain persists for several weeks.

Examples of tendinopathy include the following conditions: rotator cuff tendinopathy, lateral and medial epicondylitis, patellar ligament and Achilles tendinopathy.

Types of tendinopathy

There are several types of tendinopathy: the classification is based on the location of the lesion.

Lateral epicondylitis (“tennis elbow”) causes pain on the outside of the elbow joint.

Medial epicondylitis (golfer's elbow) is a condition that causes pain on the inside of the elbow. It occurs in people with occupations that require repetitive movements of the elbow (for example, construction work).

Knee tendinopathy involves the tendon located at the inferior edge of the patella or the quadriceps tendon at the top of the kneecap. This is a common type of injury, especially in basketball players and long-distance runners.

Wrist tendinopathy most often presents as de Quervain's disease, a condition that causes pain in the back of the wrist at the base of the thumb. Sometimes the pathological condition develops during pregnancy.

Rotator cuff tendinopathy causes dull, aching pain that is not localized to just one area. It often radiates to the upper arm and chest projection. The pain intensifies at night, making it difficult to sleep.

Achilles tendinopathy is rarely caused by diseases such as ankylosing spondylitis, reactive arthritis, gout, or rheumatoid arthritis. The development of pathology is preceded by prolonged flexion and extension of the foot or wearing ill-fitting shoes. The pain is felt in the back of the heel or a few centimeters above it.

Physical examination

The examination includes examination for muscle atrophy, asymmetry, edema and erythema. Atrophy is often present in chronic conditions and is an important clue to the duration of tendinopathy. Also, when examining pathological tendons, swelling, erythema and asymmetry may be observed. Range of motion testing is often limited on the symptomatic side.

The physical examination should include tests that load the tendon to simulate pain and other stress tests that assess the condition of adjacent structures.

Symptoms of an ACL tear

Pain in the area of injury, the intensity of which depends on the severity of the rupture.
Increased pain when trying to perform passive and active movements in the knee.
Swelling of the soft tissues of the knee area, provoked by the development of an inflammatory reaction and the release of blood plasma from the blood vessels into the intercellular substance.
Limitation of passive and active movements in the knee joint due to its instability and pain.
Instability of the knee joint, accompanied by posterior displacement of the tibia in relation to the femur.

The severity of these manifestations depends on the degree of violation of the integrity of the ligament, as well as in combination with damage to other structures of the knee. The maximum severity of clinical symptoms is determined at grade 3 rupture.

Physical therapy

The use of eccentric exercises has been proposed to accelerate tendon remodeling through the formation of interfiber bonds. What causes tendon healing in the eccentric mode is not known for certain, but it is assumed that the forces generated during eccentric loading are greater than during concentric exercises.

It is possible that eccentric exercise not only has a beneficial mechanical effect on the tendons, but also acts on pain mediators, reducing their presence in the affected tissues. In any case, the positive effects of eccentric exercise are evidenced by studies conducted on athletes and people leading a sedentary lifestyle.

However, there are many questions regarding what variables can influence the outcome of training: should the training be painful, how long should it be, what method of progression should be chosen, etc.

To date, three basic principles have been formulated for the eccentric training regime:

Tendon length - if the tendon is pre-stretched, its length at rest will be greater, and the tension during movement should be less.
Load – by gradually increasing the load on the tendon, we can expect an increase in its strength.
Speed – Increasing the speed of contraction requires more force.

However, more research is needed to confirm these conditions.

Shock wave therapy

Extracorporeal shock wave therapy is an intervention based on the use of high-energy electromagnetic waves, which has recently become popular for the treatment of various diseases of the musculoskeletal system. It is most often used to treat tendinopathies.

ESWT is of interest to clinicians for two reasons. First, it stimulates the metabolic activity of the target cells, which promotes tissue healing. Secondly, it is assumed that ESWT has an effect on localized nociceptors, which leads to a decrease in pain intensity.

Acoustic shock wave signal transduction is converted into a biological signal, which leads to cell proliferation and/or differentiation. Most research regarding ESWT has focused on better understanding the mechanisms that lead to mechanosensitive feedback between acoustic impulses and specifically stimulated cells. However, the mechanisms that allow tissues to recognize and convert the intensity, frequency, amplitude and duration of an acoustic signal into a biological response are still not fully understood.

The effect of ESWT on pain intensity has also not been fully studied. It is believed that the mechanical effect is focused on the primary afferent nociceptive C-fibers, which are responsible for the sensitization of the affected tissues.

The rationale for the clinical use of ECVT remains the stimulation of soft tissue healing and the inhibition of pain receptors (nociceptors). There is no consensus regarding the use of low-energy extracorporeal shock wave therapy, which does not require local anesthesia, as opposed to the use of high-energy extracorporeal shock wave therapy, which requires local or regional anesthesia.

Although ESWT is popular in the rehabilitation world, the scientific rationale for treating specific pathologies, including tendinopathies, is still evolving. There are conflicting opinions in the literature in favor of the use of ESWT for tendon injuries.

Low Level Laser Therapy

There is no consensus regarding the use of low-level laser treatment for tendinopathies. There are also a number of unresolved problems associated with the use of low-level laser therapy in combination with other interventions, especially exercises, mainly in the tendon remodeling phase.

Iontophoresis and phonophoresis

Iontophoresis and phonophoresis involve the use of ionizing current or ultrasound to deliver drugs locally. Typically, corticosteroids and non-steroidal anti-inflammatory drugs are used for this purpose. Both methods are widely used, but all randomized controlled trials have failed to provide reliable evidence of their effectiveness.

Friction massage

There is currently little evidence to support the use of this method in the treatment of tendinopathies. In particular, a Cochrane review suggests that friction massage is not superior to other treatments for tendinopathies.

Ultrasound

Therapeutic ultrasound is widely used in the treatment of tendinopathies. Despite this, there are few clinical studies demonstrating the effectiveness of ultrasound in promoting tendon healing.

Most in vivo studies have confirmed the effectiveness of ultrasound treatment. However, in the era of evidence-based medicine, further research, especially randomized control trials, is needed to determine how effective ultrasound is in the treatment of tendinopathies.

There are only two pathologies in the treatment of which ultrasound has shown good results. These are lateral epicondylitis and calcific supraspinatus tendinopathy.

Hyperthermia

Early data on hyperthermia are encouraging but remain preliminary. Only two randomized clinical trials have been published that evaluated hyperthermia versus therapeutic ultrasound in the treatment of tendinopathies. These studies reported a decrease in pain intensity and improved well-being of patients in the hyperthermia group compared to the ultrasound group.

Diagnostics

Arthroscopy is a diagnostic technique in which a special optical device, an arthroscope with a camera and lighting, is inserted into the joint cavity, allowing the doctor to conduct a thorough examination of its internal walls.
Ultrasound examination of the knee.
Radiography is a visualization technique that makes it possible to determine gross damage.
Computed tomography or magnetic resonance imaging, which are high-resolution techniques that allow visualization of even small violations of the integrity of the knee structures.

Using diagnostic arthroscopy using microinstruments, the doctor can perform minor surgical procedures aimed at restoring the integrity of the connective tissue fibers of the ligaments.