Biceps tendon tears can be either partial or complete and affect the shoulder or the elbow areas.
Partial tears. These tears do not completely sever the tendon.
Complete tears. A complete tear will split the tendon into two pieces.
In most cases, tears of the distal biceps tendon are complete. This means that the entire muscle is detached from the bone and pulled toward the shoulder. Distal biceps tendon rupture is equally likely in the dominant and non-dominant arm.
Other arm muscles can substitute for the injured tendon, usually resulting in full motion and reasonable function. Left without surgical repair, however, the injured arm will have a 30% to 40% decrease in strength, mainly in twisting the forearm (supination).
Rupture of the biceps tendon at the elbow is unusual. It occurs in only one to two people per 100,000 each year, and rarely in women.