Biceps tendon originates around the shoulder and inserts around the elbow. It is the main flexor of elbow, and accessory supinator of the forearm. This means that not only does the biceps bend the elbow, but is also very important in positioning the hand so that the palmar surface is facing upwards. This movement is very important in manual jobs that involve repetitive rotations like turning the screwdriver, or playing racquet sports like tennis or badminton.
Distal biceps tendon rupture is typically an injury sustained in middle age, and more common in males. It however relatively uncommon in day to-day practice, as a result of which the literature remains scarce, and mostly limited to case series. They are different from proximal long head of biceps tear (I will discuss this in the next blog), which is the smaller of the two origins and relatively insignificant in terms of contributing to the muscle strength. Distally, the biceps muscle inserts as a single tendon and its rupture inevitably leads to loss of strength.
Typically, patients report a ‘pop’ or a sensation of ‘give’ around the elbow or arm when they were trying to lift something heavy. Usually this is followed by severe pain and swelling, but most patients are able to bend their elbow. A bruise may become evident over lower arm and elbow in the coming days. Diagnosis is usually evident by history and clinical examination, but Ultrasound or MRI can be used to confirm if in doubt.
Historically, distal biceps tears used to be treated non-operatively but patients usually end up with a bulge in the arm (popeye sign), and sometimes, cramps in the arm. In a recent paper, Freeman et al. report significantly weaker supination strength (63% of the opposite side). Baker and colleagues reported 30–50% decrease in loss of supination strength and 20% loss of flexion strength with conservative management. Nesterenko et al showied significantly poor peak torque strength in both flexion and supination following nonoperative management of these injuries. Our own publication a few years ago confirmed these findings.
Furthermore, patients can also suffer from cramps and intermittent pain in the arm along with obvious cosmetic disfigurement. As a result, the trend in recent years has moved to operative intervention for these injuries. There are different ways of repairing the tendon, including surgical technique as well as the way it is embedded back into the bone. There are pros and cons of each approach, but outcomes are largely similar with all of them. It is down to surgeon preference as to what approach he/she may prefer.
Timing since injury is critical when repairing the tendon. The tendon should be ideally repaired within 2 weeks to achieve a primary repair and best outcomes. Typically, it retracts and loses elasticity, and it is very difficult to achieve a primary repair after 4 weeks. If a primary repair is not possible, the surgeon may need to perform a reconstruction (using a tissue patch to bridge the gap between native tendon and its anatomical insertion) using tendon graft, which does not fully restore the strength as much a primary repair.
Like any operation, there are certain risks involved with surgery. These include ectopic bone formation leading to stiffness, numbness of a part of the forearm resulting from transient injury to the lateral cutaneous of forearm, failure of repair, and rarely wrist drop etc. The surgeon would go through these risks with you before proceeding with surgery.
There are very few papers quoting the patient-reported outcomes following anatomical repair. In our series quoted above, average postoperative function on Mayo elbow performance score was 93.3 (95% CI, 89.6– 97) signifying excellent result. Overall Oxford Elbow Score was 41.8 out of maximum of 48. Other studies quote similar satisfaction rates, and there is now a good body of evidence supporting early repair of distal biceps tendon unless surgery is contraindicated for any reason. If you see one, or have a patient coming to you with suspected rupture, early referral to your local Orthopaedic surgeon is recommended.