According to the American Academy of Family Physicians, tendons are composed of collagen fibers, elastin, proteoglycans and lipids, and are surrounded or sheathed by epitenon, which contains the tendon's blood vessels and nerve supply. Tendons link muscles with bones, and although overuse injuries may occur anywhere along the tendon, the osteotendinous junction--where the tendons insert into bone--is the most common site. Common tendon issues include tendonitis, tendinosis and avulsion fractures.
Tendinitis
The Mayo Clinic states that tendinitis is inflammation or irritation of a tendon, and that it causes pain and tenderness near a joint. Tendinitis can manifest in any of the body's tendons, although it commonly occurs around the shoulders, elbows, wrists and heels.
Common names for different tendinitis problems include tennis elbow, golfer's elbow, pitcher's shoulder, swimmer's shoulder and jumper's knee. Typical signs and symptoms of tendinitis are a dull, achy pain at the point where a tendon inserts into a bone, tenderness and mild swelling.
According to Tendonitis.net, tendinitis symptoms may range from achy pain and stiffness around the tendon's insertion point to a burning sensation that envelops the entire joint. Tendinitis symptoms typically are most acute during and after activity, and the affected tendon may become stiff the day after vigorous activity.
Tendinosis
According to the Podiatry Today website, tendinosis involves damage to a tendon at the cellular level that results in a fraying or scarring of tendon tissues. The micro-tears in the connective tissue in and surrounding the tendon cause an up-regulation in the number of tendon repair cells, which begin laying down scar tissue throughout the injured tendon.
The Podiatry Today website notes that the scar tissue may be palpable or microscopic, bulbous or diffuse, depending on the injury. Tendinosis may cause reduced tensile strength in the tendon, which heightens the possibility of a tendon rupture.
Like tendinitis, tendinosis can produce achy pain and stiffness around the tendon's insertion point or a burning sensation that surrounds the entire joint, and tendinosis symptoms often are worse during and after activity. The affected tendon may develop stiffness the day after activity, due to swelling that limits the affected tendon's movement.
Avulsion Fractures
Although relatively rare, one of the most serious tendon issues is an avulsion fracture. According to the Mayo Clinic, an avulsion fracture occurs when a tendon--or a ligament--pulls a fragment away from the bone into which it inserts. Avulsion fractures involving tendons occur when the muscular contraction acting on a bone is greater than the forces keeping the bone together.
The Mayo Clinic states that many avulsion fractures heal well without surgery, although injuries involving significant tendon damage, in conjunction with an avulsion fracture, may require surgery to re-approximate the bone fragment.
Less severe avulsion fractures may be treated conservatively, using ice to reduce swelling and inflammation, and resting the involved segment or body part. Although it may be seen on X-ray, small avulsion fractures often are asymptomatic after the injury resolves.
