The biceps muscle acts to bend the elbow (flexion) and to rotate the forearm to turn the palm upwards (supination). It has two attachments at the shoulder and one main attachment at the elbow. While a distal rupture does cause a reduction in strength of the arm, other muscles can compensate meaning that often the reduction in strength does not have a significant functional impact on a person’s activities. However in some people the reduction in strength is not acceptable.
The distal biceps tendon ruptures when the load put through it exceeds its inherent strength. This is most often the case in middle aged men who lift something unexpectedly heavy with a flexed elbow, or if the load they are carrying shifts. The elbow is forced to straight while the biceps is working to maintain a flexed elbow.
There is usually sudden pain in the elbow and the muscle at the front of the arm may cramp and become bunched up. Bruising and swelling may develop over the following days.
In some cases a partial tear may occur which results in pain but no change in the contour of the muscle. A partial tear may become a complete tear with continued activity.
If left, the bruising and swelling settles although the change in contour of the arm will remain. The strength usually recovers as the pain settles but there continues to be a subtle weakness in flexion, while a more pronounced weakness in supination. Supination is the activity used in twisting the top off a jar or using a screwdriver.
Simple painkillers can be useful for the initial pain.
If you rely on strength in your arm, particularly supination work then surgical repair may be recommended. This is best done sooner rather than later following the injury as with time the tendon can retract and become scarred down making surgery more challenging.
A cut is usually made on the front of the arm near the elbow and the tendon secured back to the bone using sutures and bone anchors / metal button / screw which pass into or through the bone.
The mainstay of rehabilitation is prevention of stiffness of the elbow in the initial stages and then to build the strength back once the tendon has had time to heal. Depending on the nature of the injury and the type of repair, movement may commence immediately or your arm may be protected in plaster or a brace for a number of weeks. Your surgeon will be able to advise you of this.
Symptoms tend to settle with either non-surgical or surgical treatment, although the bunching of the biceps will remain with non-surgical treatment. In the younger patient requiring full power in the biceps, surgery is often preferred. People usually have a good outcome with full power following surgery.