Tendons are bundles or bands of strong fibres that attach muscles to bones. Tendons transfer force from the muscle to the bone to produce the movement of joints.

Tendon disorders are medical conditions that result in the tendons not functioning normally. These disorders occur in two types of tendons: tendons without sheaths (Figure 1), and tendons with sheaths (Figure 2). Tendinitis is a disorder of tendons without sheaths and tenosynovitis is a disorder of tendons with sheaths.

Figure 1

Figure 2

What is tendinitis?

Tendinitis (also called tendonitis) is the term used to describe an inflammation of tendons. Tendons are rope-like structures made of strong, smooth, shiny fibers. With repetitive or prolonged activities, forceful exertion, awkward and static postures, vibration, and localized mechanical stress, the tendons fibers can tear apart in much the same way a rope becomes frayed.

These tendon changes trigger an inflammatory response. Inflammation is a localized response of tissue to injury. Over time, inflamed tendons become thickened, bumpy, and irregular. Without rest and time for the tissue to heal, tendons can become permanently weakened. What is tenosynovitis?

Tenosynovitis is an inflammation of the tendon sheath. The inner walls of the sheath produce a slippery fluid, called synovial fluid, which lubricates the tendon. With repetitive or prolonged activities, forceful exertion, awkward and static posture, vibration, and localized mechanical stress, the lubrication system may malfunction. It may not produce enough fluid, or it may produce a fluid with poor lubricating qualities. Friction between the tendon and its sheath results when the lubricating system fails. This leads to inflammation and swelling of the tendon sheath. Repeated episodes of inflammation cause fibrous tissue to form that thickens the tendon sheath and hinders tendon movement.

The most common sites for tendon disorders are (Figure 3):

Figure 3

• Shoulder

• Bicipital tendinitis - inflammation of the tendon to the biceps.
• Rotator cuff tendinitis - inflammation of the tendons that rotate the humerus [upper arm bone] and help raise the arm.

• Elbow

Lateral epicondylitis or tennis elbow - inflammation of the tendon that attaches some forearm muscles to a "bump" or projection [lateral epicondyle] on the side of the humerus, just above the elbow.

• Hand and Wrist
• Flexor tendinitis - inflammation of the tendons in the palm side of the wrist and hand.
• Extensor tendinitis - inflammation of the tendons in the back of the hand and wrist.
• Flexor tenosynovitis - inflammation of the tendon sheaths in the palm side of the wrist and hand.
• Extensor tenosynovitis - inflammation of the tendons in the back of the hand and wrist.
• De Quervain's disease - inflammation of the tendon sheaths at the base of the thumb.
• Dupuytren's contracture - in this condition, the tissues (fascia) under the skin on the palm of the hand thicken and shorten enough that the tendons connected to the fingers cannot move freely; this leads to a non-inflammatory degeneration of the tendons of the palmaris muscle in the hand.

Shoulder tendinitis

The most common tendon disorders of the shoulder are bicipital tendinitis and rotator cuff tendinitis. The latter is also known as supraspinatus tendinitis, subdeltoid bursitis, subacromial bursitis or partial tear of the rotator cuff.

Tendon disorders of the shoulder are seen among workers exposed to high repetitive movements requiring a significant use of force. Workers doing jobs requiring awkward postures such as overhead work, arm elevation, and specific postures relative to the degree of arm bending and arm elevation.

Elbow tendinitis

Tendinitis of the elbow also known as tennis elbow or lateral epicondylitis is associated with jobs that require repeated or forceful movements of the fingers, wrist, and forearm. Specific movements associated with the development of tendinitis of the elbow include simultaneous rotation of the forearm and bending of the wrist; stressful gripping of objects with inward or outward movement of the forearm; jerky, throwing motions. For more information please refer to our OSH Answers document on Tennis Elbow.

Hand and wrist tendinitis

Tendinitis of the hand and wrist include a variety of diagnoses such as tenosynovitis, tendinitis, De Quervain's disease, and Dupuytren's contracture.

High risk occupation and activities associated with hand and wrist tendinitis include assembly line work, meat processing, manufacturing, knitting, typing, and piano playing.

There is some evidence that workers exposed to risk factors such as high force and high repetition are at increased risk for hand and wrist tendinitis. What are the symptoms?

The clinical presentation of tendon disorders is characterized by the presence of pain on the site of injury. Specific physical findings on examination include tenderness when the area over the affected tendon is touched and may be associated with swelling, redness, and restriction of movement.

Treatment of tendon disorders is of a conservative nature and rarely requires surgery.

Workplace interventions are essential to promote effective treatment.

Avoiding those activities that caused or aggravated the disorder will prevent the condition from persisting or recurring. The use of non-steroidal anti-inflammatory drugs (NSAIDs) is usually effective for pain relieve. Application of ice or heat, friction massage, stretching and strengthening exercises, transcutaneous [through the skin] electrical nerve stimulation (TENS), ultrasound, and iontophoresis are also used. Iontophoresis is a method of delivering certain water-soluble drugs through the skin to localized tissue areas by applying a small electrical current to a solution of the drug. However, the efficacy of some of these methods has not been fully evaluated. How can we prevent tendon disorders?

Tendon disorders have been associated with repetitive or prolonged activities, forceful exertion, awkward and static posture, vibration, and localized mechanical stress. The prevention of tendon disorders should include identifying and remedying these risk factors

Good design of work practices and equipment should aim at reducing repetitive movements, awkward postures and static posture (periods spent in one position). Job design should also aim at minimizing the need to use forceful exertion and making sure that rest and work breaks are properly used.