Distal Biceps Tendon Rupture
What is a Distal Biceps Tendon Rupture?
The biceps muscle is found in the front of the upper arm. It helps control the motion of both the shoulder and elbow joint, and is essential to the function of the forearm during lifting. The biceps muscle has 2 tendons (long and short head) that attach the muscle to the bone of the shoulder and one tendon that attaches the muscle to the bone of the elbow. The long head attaches to the glenoid (top of the shoulder socket), while the short head attaches to the top of the scapula (or shoulder blade). The tendon that attaches the biceps muscle to bone at the elbow is called the distal biceps tendon.
A distal biceps rupture occurs when the tendon attaching the bicep muscle to the elbow is torn from the bone (as shown in Figure 2). Injury to the distal biceps is relatively uncommon and represents approximately 3-10% of all biceps ruptures. Far more ruptures of the biceps occur proximally at the shoulder, than distally at the elbow. This injury is also rarely seen in women. Most distal biceps ruptures occur in highly active, middle-aged men in their 40’s and 50’s on their dominant side. Men in labor-intensive jobs are more susceptible to this injury due to the heavy lifting requirements. Often, when the load is heavier than expected or when the load shifts unexpectedly, the elbow is forced to straighten under the weight and the bicep muscle contracts and overcompensates to hold the load. As tension on the bicep muscle reaches its maximum load, the distal bicep tendon completely ruptures or partially tears at the point where the tendon connects to the radius of the forearm.
Signs and Symptoms:
Mechanism of injury is often an acute load to a flexed arm. The patient will often feel an acute pop or tearing sensation. Immediate pain is felt, but subsides quickly with a complete rupture because the tension is immediately taken off of the bicep muscle. A complete rupture usually presents some swelling and bruising in the mid arm and the biceps appears more in the proximal mid forearm. The arm may feel weak with attempts to bend the elbow, lift the shoulder, or supinate (rotate the forearm palm up).
With a partial tear, a pop may not be heard. However, a partial tear will continue to cause pain in the proximal forearm with supination or flexion activities (lifting causing the muscle to engage). The arm may feel weak with movement, similar to a complete rupture.
There isn’t a conservative approach to repair a bicep tendon injury as the bicep will not repair itself with time. Surgery is required to restore maximum strength to the bicep within 2-3 weeks of injury. Restoring arm function with surgery later than 3 weeks is more difficult and may not be possible.
However, biceps repair is not desired by all patients. Non-operative treatment of ruptures can yield acceptable outcomes with modestly reduce strength—especially supination. Non-operative care may be considered for patients who are elderly and inactive, or who have medical conditions that place them at risk for surgery. Some patients choose to live with the injury and to not have the biceps repaired. With this choice, patients must accept the loss of flexion, strength and supination. A distal bicep rupture that is not repaired reduces supination strength (holding item with palm up) by about 50%, although it is possible for the patient to regain up to as much as 80% of their original strength. Nonsurgical treatment may include a sling (to rest the elbow), anti-inflammatory medicines (to ease pain and swelling), and therapy (to gradually strengthen other muscles to help do the work of a normal bicep muscle).
Although patients managed non-operatively can achieve satisfactory results, early operative intervention can greatly improve forearm supination (the ability to rotate forearm palm up) strength, flexion, and function. Biceps repair (reinsertion) is best done within ten days from the initial injury. Whereas delayed presentation, due to patient’s neglect or failure to properly diagnose, is more difficult to successfully treat with surgery. There is a high failure rate associated with surgical delay.
For a complete rupture, the biceps tendon is reinserted back into the radial tuberosity of the proximal radius, either with a single incision technique in the forearm, or a two-incision technique in the forearm; often physician preference. The tendon is reinserted either with suture through drill holes, or through the use of an EndoButton (as shown in Figure 3, 4, & 5). The EndoButton method of fixation has been shown to have the highest ultimate tensile load; however, both the suture and EndoButton techniques do very well. The procedure takes about an hour to an hour and a half and is often done under general anesthetic, but an arm block may be used as well.
Post Operative Rehabilitation:
Dr. McNamara’s Distal Bicep Repair Protocol
Note: These instructions are to serve as guidelines and are subject to Physician discretion. Actual progress may be faster or slower depending on the individual.
Safran, M.R. and Graham, S.M. Distal biceps tendon ruptures: incidence, demographics, and the effect of smoking. Clin Orthop Relat Res. 2002; 404: 275–283