Causes and Risk Factors of Tendinopathy

Causes/Risk Factors of Tendinopathy:

Rotator cuff tendinosis has many possible causes that may act alone or in combination to result in tendon degeneration. The causes are listed as follows:

Age: as we age, our tendons and ligaments lose strength and their internal
capacity for tissue repair and healing decreases. Thus, they are equally more
prone to injury and less likely to recover quickly.

Overuse: repetitive use of the arms, especially at or above shoulder level may cause fatigue and damage to the rotator cuff tendons. If the rate of tissue
breakdown exceeds the rate of tissue healing, tendon degeneration may occur.
This may be know as Repetitive Strain Injury (RSI). Giving the damaged tissue
sufficient time to heal is essential to recovery. Continued pain during activity is an
indicator of internal tissue damage and should not be ignored. Efforts to .work
through. The pain will likely only result in further injury.

Poor Posture: forward slumping of the shoulders causes the shoulder blade to tilt
forward and down. This narrows the space available for the rotator cuff tendons
and may cause abrasion of the tendon’s surface. In addition, excess pressure from
the downward sloping acromion bone may wring out. The tendon’s blood supply
resulting in tissue breakdown.

Weakness: many people who engage in repetitive motion activities, whether
through work, sport or recreation, develop fatigue in the rotator cuff muscles. If
the muscles are not allowed sufficient time to rest, recover and remodel, fatigue
can lead internal damage to the muscle and tendon. In addition, fatigue promotes
faulty mechanics in the ball and socket mechanism that accelerate this damage.

Bursa Stiffness: injury to the shoulder, whether from a
single incident or from repetitive overuse, often causes
the capsule surrounding the ball and socket joint to
contract and tighten. This is particularly true for the
posterior capsule of the shoulder. Posterior capsule
tightness causes the ball to slide upwards on the socket
during many activities such as reaching and lifting. This
abnormal movement of the ball on the socket results in
abrasion of the rotator cuff on the acromion bone and
coracoacromial ligament which form the roof above the
tendons.

Instability: some people are born with particularly elastic connective tissue and
may have shoulder joints that are very lax (wide range of motion). Such
hyperlaxity may predispose some people to develop subtle shoulder instability
whereby the ball does not stay properly centered in the shoulder socket during
shoulder movement. This condition may be associated with impingement of the
rotator cuff on the acromion bone and coracoacromial ligament.

Smoking: as with many other tissues in the body, the connective tissues of the
musculoskeletal system are adversely affected by smoking. Specifically, smoking
damages the circulation to tendons and bones. This not only places these tissues
at risk for injury but also slows or prevents their healing during a recovery period.

Additional Information on the Risk of Tendinitis:
Tendinitis is more common in males, and Achilles tendon tears occur 4 to 7 times more frequently in males than females (Maffulli). Middle-aged individuals are more likely to develop tendinitis (Steele) since tendons deteriorate with age. Work-related factors that increase the risk for tendinitis and tendinosis include vibration, cold temperatures, intense and sustained exertion, and maintaining awkward postures.

The use of certain broad-spectrum antibiotics, known as fluoroquinolones, is associated with increased risk of tendinitis. Individuals who use steroids or have decreased kidney function (renal insufficiency) are at higher risk of developing fluoroquinolone-associated tendinitis. Fluoroquinolone-associated tendinitis often occurs bilaterally in the Achilles tendons and also has been reported in the shoulders and hands, whereas overuse tendinitis usually occurs on one side only.

Calcific tendinitis usually occurs in individuals between the ages of 30 to 40, and is more common in diabetics (Cluett).

Additional Information on Risk Factors For Tendinosis

Tendinosis is a chronic degenerative tendon injury that is usually brought on by repetitive motion. The repetitive motion is often associated with activities in the workplace or with sports. Microinjuries gradually accumulate faster than they can heal until the area eventually becomes painful. The severity of the injury is influenced by many factors, including
• the amount of overuse and lack of recovery time (for example hours of typing per day, per week, and per month as well as number of breaks per day)
• the person's genetics (for example anything that makes the tendons more prone to injury, such as a higher initial Type III/Type I collagen ratio in the tendons)
• the ergonomics associated with the repetitive motion activity (such as awkward position, tools that cause vibration, improperly fitted tools or sports equipment, or poor technique)
• the person's age, level of fitness, and general health (chronic tendon degeneration is more common with age, and poor fitness makes sports injuries much more common)
• the length of time the condition persists before the person seeks help and limits the activities that cause pain (this is often influenced by the person's awareness of RSI and the pressure the person feels to continue the injurious activity)
• the quality of medical care/advice that is received

Why swimmers are prone to getting Tendinopathy

Neer and Welsh described a classification system for shoulder tendinitis7. Stage I, mostly seen before the age of 25, consists of oedema and haemorrhage of the supraspinatus and biceps tendons from overuse. Stage II consists of fibrosis and tendinitis, and usually occurs in those older than 25 years. In Stage III, seen mostly after 40 years of age, there is degeneration and rupture of the tendons, as well as changes in the bony structure.
Impingement tendinopathy comes about through overwork, subacromial loading and hypovascularity8. The shoulder is a relatively unstable joint, conferring a high degree of mobility and significantly relying on the rotator cuff muscles for stability. When competitive swimmers make repeated overhead movements, the muscles fatigue, superior migration of the humeral head occurs and subacromial loading is increased, contributing to tendinopathy.
The blood supply to the tendon of supraspinatus and long head of biceps is another factor. When the arm is held in adduction and internal rotation, the two tendons are stretched over the humeral head, reducing the blood supply near the musculo-tendinous junction, which predisposes to tendinopathy8.
Finally, the passage of the tendons under the coraco-acromial arch makes them vulnerable. When the arm is abducted, flexed and internally rotated during entry and the beginning of the pull phase, the tendons are impinged upon as the head of the humerus is forced superiorly8. This in turn leads to degenerative changes and tendinopathy.