Tendons and Rotator Cuff Tendinopathy in Active Sports
Tendons are biological tissues connecting the skeletal muscles to the bone in a system that transmit the force of muscular contraction to aid movement. Microscopically these delicate structures appear as a hypocellular structure composed of elongated fibroblasts –cells that synthesize matrix and collagen for animal tissues –interspersed in a network of the protein matrix. At its smallest functional unit, tendons are made of multiple units of fibrils. The macroscopic structure varies in size and shape and can present as short, thick structures originating from powerful bundles of muscle groups.
In a healthy tendon, the extracellular matrix is made of collagen –65 – 80% dry weight, elastin –1 – 2%, and ground substance, which consists of 60 – 80% water, proteoglycans ad glycoproteins. In sports, injury to the tendon reportedly accounts for over 30% of all injuries in active athletes. Since athletes are required to train harder, longer, and beyond the physical limits, the tendon is consistently exposed to mechanical stress that can lead to injuries. Many studies have linked a healthy tendon to heightened athletic performance, especially in sports that require fine maneuvers.
Tendinopathy is a generic term that describes the ongoing process of degeneration and fails healing of the tendon extracellular matrix in response to acute or chronic injury. Tendinopathies are not necessarily caused by tendon overuse; however, in all cases, the affected tendon has a disorganized structure with separation of the collagen fibrils and an increase in ground substance composition. Tendon injuries are generally classified as tendonitis –characterized by inflammation and tendinosis characterized by degeneration in the normal tendon structure. The tendons most susceptible to tendinopathies include the Achilles and patellar tendons, the rotator cuff tendons, and extensor carpi radialis brevis tendons. Rotator cuff tendinopathy can be treated with Prolotherapy.
Rotator Cuff Tendinopathies: Overview and Epidemiology
Rotator cuff tendinopathy (RCT) is reported as the third most common musculoskeletal complaint in athletes. To better understand the pathophysiology and clinical presentation of these conditions, clinicians many times coin terms that directly describe the extent of damage to the rotator cuff tendon. A partial rotator cuff tear is defined as tears involving less than 50% of the rotator cuff tendon. If more, a full rotator cuff tear s diagnosed. In 2017, Sage Journal published an article describing the incidence of the rotator cuff in the general population. Results from this study suggest that the incidence of rotator cuff tendinopathy ranges from 0.3% to 5.5%, with an annual prevalence of 0.5% to 7.4%.
In the United States alone, an estimate of 75,000 surgical repairs of the rotator cuff tendon is performed annually. The incidence of rotator cuff tendinopathies is increased in athletes and individuals engaged in repetitive overhead activities, including sports such as baseball and occupation such as carpentry and painting. There are also different clinical studies linking the onset of tendon injury and fatigue to aging in humans. The occupational risk factors for rotator cuff tendinopathy include strenuous static postures, direct load-bearing, and repetitive arm movements. Risk factors for rotator cuff tendinopathy with a medical basis include adiposity, metabolic disorders, decreased flexibility, and tissue aging.
Pathophysiology and Etiology
The causes of rotator cuff injury appear to be multifactorial. Functionally, tendons repeatedly transmit forces between the muscles and the bone. This action makes the tendon susceptible to acute and chronic injury. If acute stress overload or laceration occurs, the tendon might rupture. In addition to tendon injury caused by stress overload, repetitive micro-trauma might increase the risk of inflammation and painful sensation in the affected tendon. A combination of these effects can consistently damage the tendon structure before a normal cycle of tendon healing is completed. Other widely studied causes of rotator cuff tendinopathy include a compromised microvascular supply, pathologic tendon degeneration, and age-related tendon wear.
Clinical Presentation and Diagnosis
On presentation, a detailed history of musculoskeletal health is needed for an accurate diagnosis of rotator cuff tendinopathy. This is also important to rule out conditions that present with the same clinical symptoms. Symptoms presented are examined if related to a specific localized injury at the shoulder or liked to a repetitive movement of the shoulder in a consistent overhead movement. Suppose an athlete or patient presents with associated symptoms, including instability, inflammation, restricted movement, and pain. Pain felt with rotator cuff tendinopathy radiates over the shoulder and becomes worst with a forced overhead movement. The symptoms associated with rotator cuff tendinopathies in aged patients are confusing, especially when there are no specific injuries.
They are accurately diagnosing rotator cuff tendinopathy involving medical tests that directly evaluate the integrity of the rotator cuff tendon in movement and fine maneuvers. Strength testing, Drop-arm tests, Neer Impinging test, Relocation test, and the Apprehension tests are popular clinical methods of diagnosis a possible rotator cuff tear. In the Drop-arm test, the affected shoulder is abducted at 90 degrees, and the patient is asked to lower the arm deliberately to the side in the same arc of movement. In a positive test, the patients experience severe tearing pain as the arm slowly returns to the side.
Treatment of rotator cuff tendinopathy is aimed at restoring normal tendon function and eliminating all forms of presenting symptoms. The selected treatment approach depends on the severity of tendon degeneration, tendon use history, and the potential physical demands of the affected shoulder. Non-surgical treatment methods involved the use of medications and exercises. Non-steroidal anti-inflammatory drugs (NSAIDs) remain the mainstay medication therapy for tendon tears. By blocking the production of prostaglandins –biological lipid molecule involved in inflammation, these classes of medications effectively reduced the associating painful sensation linked with rotator cuff tear. Corticosteroids and nitric oxide are also prescribed.
Eccentric exercises are also prescribed as conservative therapy for tendon tears. With these exercises, the tendon lengthens under tension and reportedly hastens the production of type 1 collagen that subsequently increases the density of the subunit collagen fibrils. Imaging reports and biochemical analysis suggest that eccentric exercises improve the outcomes of treatment and help the tendon heal faster. Platelet-rich plasma injections have been proposed for the treatment of rotator cuff tendinopathies. These injections are autologous blood products containing an enriched concentration of platelets. When injected locally into the tear, PRP reportedly delivers an abundant amount of growth factors and cytokines known to enhance tissue healing.
The surgical options available for the treatment of rotator cuff tendinopathy remove the degenerated tendon, fix the tear, or restart the healing process. The most popular surgical procedures for a rotator cuff tendinopathy include Percutaneous longitudinal tenotomy and Percutaneous ultrasonic microanatomy. The prognosis of rotator cuff tendinopathy improves with early diagnosis and quick initiation of therapy. Athletes and individuals with heightened occupational risk factors remain the most susceptible group to any form of tendon tear.