The biceps muscle is located in the front of your upper arm. It is attached to the bones of the shoulder and elbow by tendons — strong cords of fibrous tissue that attach muscles to bones.
Tears of the biceps tendon at the elbow are uncommon. They are most often caused by a sudden injury and tend to result in greater arm weakness than injuries to the biceps tendon at the shoulder.
Once torn, the biceps tendon at the elbow will not grow back to the bone and heal. Other arm muscles make it possible to bend the elbow fairly well without the biceps tendon. However, they cannot fulfill all the functions of the elbow, especially the motion of rotating the forearm from palm down to palm up. This motion is called supination.
To return arm strength to near normal levels, surgery to repair the torn tendon is usually recommended. However, nonsurgical treatment is a reasonable option for patients who may not require full arm function.
The biceps muscle has two tendons that attach the muscle to the shoulder and one tendon that attaches at the elbow. The tendon at the elbow is called the distal biceps tendon. It attaches to a part of the radius bone called the radial tuberosity, a small bump on the bone near your elbow joint.
Biceps tendon tears can be either partial or complete.
Partial tears. These tears damage the soft tissue but do not completely sever the tendon.
Complete tears. A complete tear will detach the tendon completely from its attachment point at the bone.
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.
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 uncommon. It occurs in only three to five people per 100,000 each year, and rarely in women.
The main cause of a distal biceps tendon tear is a sudden injury. These tears are rarely associated with other medical conditions.
Injuries to the biceps tendon at the elbow usually occur when the elbow is forced straight against resistance. It is less common to injure this tendon when the elbow is forcibly bent against a heavy load.
Lifting a heavy box is a good example. Perhaps you grab it without realizing how much it weighs. You strain your biceps muscles and tendons trying to keep your arms bent, but the weight is too much and forces your arms straight. As you struggle, the stress on your biceps increases and the tendon tears away from the bone.
Men, age 30 years or older, are most likely to tear the distal biceps tendon.
Additional risk factors for distal biceps tendon tear include:
Smoking. Nicotine use can affect tendon strength and quality.
Corticosteroid medications. Using corticosteroids has been linked to increased muscle and tendon weakness.
There is often a “pop” at the elbow when the tendon ruptures. Pain is severe at first, but may subside after a week or two. Other symptoms include:
After discussing your symptoms and how the injury occurred, your doctor will examine your elbow. During the physical examination, your doctor will feel the front of your elbow, looking for a gap in the tendon. He or she will test the supination strength of your forearm by asking you to rotate your forearm against resistance. Your doctor will compare the supination strength to the strength of your opposite, uninjured forearm.
In addition to the examination, your doctor may recommend imaging tests to help confirm a diagnosis.
X-rays. Although x-rays cannot show soft tissues like the biceps tendon, they can be useful in ruling out other problems that can cause elbow pain.
Ultrasound. This imaging technique can show the free end of the biceps tendon that has recoiled up in the arm.
Magnetic resonance imaging (MRI). These scans create better images of soft tissues. They can show both partial and complete tears of the biceps tendon.