Overuse injuries to the muscle tendon unit are common occurrences in the work place. Tendons connect muscles to bones and are responsible for the movement of bones and joints. Collagen is the main component of tendons. When a tendon and its covering (sheath) becomes inflamed, it is commonly referred to as TENDINITIS.

Workers in high force, high repetition jobs have a greater incidence of tendinitis than low force, low repetition. This may be especially true if the worker is unaccustomed to the task. High repetition and forces over a prolonged period of time may result in micro tears, chronic inflammation and degeneration of tendons, often leading to tendon ruptures. With age, the strength of tendons begins to decrease, thus older workers starting a new task may be more susceptible to tendon injuries. Training results in increased tensile strength and collagen content in tendons, therefore, a slow, steady increase in workload is necessary to avoid inflammation of the tendon and its sheath.

Acute problems will often present with pain with movement of the body part. A crackling sensation may be felt with movement of the inflamed tendon. Occasionally swelling will develop over the inflamed area. The area will always be very tender to light touch.

Chronic injuries develop when acute problems are not addressed. Often the injured area will be stiff with early movements and as blood goes to the area, the injured part may slightly improve. With repetitive stress to the area, pain will develop and if chronic stresses are not addressed, pain will be present at all times, even with movement of the body part at rest.

The best treatment is always prevention. Identifying why the worker was injured is of primary importance. Was it the type of job, repetitive force, amount of force that caused the injury, or was it the wrong person for the job? Did the worker assume the task too abruptly without slowly increasing the activity or did an acute injury take place?

When an inflammatory condition to a tendon occurs, the worker must immediately stop the action that caused it and rest the injured area. Other tasks may be substituted that will not stress the injured tendon. Once a diagnosis has been made, physical therapy is ideally suited to reduce the inflammation. Splinting the injured area will also assist in diminishing daily stress to the area, thus allowing the inflammation to subside. Once the inflammation is decreased to a tolerable level, slowly increasing the range of motion to the inured area, followed by increasing strength to the muscle tendon unit will limit recurrences. Occasionally, anti-inflammatories may be used to assist in healing the injured tendon. If unresponsive to physical therapy and anti-inflammatories, placing the patient in a fiberglass cast will often put the tendon to complete rest and allow healing to take place. This will be followed by therapy to restore range of motion and to improve muscle strength.

When a tendon is extended beyond its point of elasticity, over stretching and rupture of some or all of the tendon fibers occurs. Sudden application of a stretching force to a tendon, is the most common mechanism causing tendon rupture. Disease processes (i.e. chronic tendinitis) in tendons predisposes to this spontaneous rupture, often from only slight strain.

Several causative factors have been suggested to contribute to tendon rupture. Advanced age, peripheral vascular disease, corticosteriod use, arthritis, and tendinitis may weaken the tendon enough to allow rupture from minimal trauma.

Identifying workers who may be predisposed to tendon ruptures avoids the pain and suffering these injuries cause and limits the economic exposure to the employer.

Most ruptures need to be repaired surgically on an emergency basis.

Tendons may be lacerated (severed or cut) from sharp objects or from crushing type injuries. Lacerated tendons may be accompanied by a simple cut in the skin or may be associated with crushed wounds with or without skin loss. Other vital structures may be injured in the wound including nerves and bones. Injured structures must be identified and treatment initiated on an emergency basis. Surgical cleansing of the wound and repair of vital structures must be performed. Clean wounds should be repaired within six hours. Contaminated or crushed wounds should be cleansed in the operating room to remove devitalized tissue. A secondary repair may be performed if the wound is clean within three to five days.