What is the anatomy of the biceps tendon and muscle and what is the injury known as a bicep tendon tear?
The bicep muscle is well known to most people as the muscle that forms that shape of the anterior (front) surface of the upper arm and is often the prominent muscle on flexing the elbow. It is more prominent in males because muscle hypertrophy (bulk) is greater in a male’s anatomy due to the level of testosterone, but with the increase in prevalence of weight training in females, the biceps tendon/muscle is easily visualised on the thinner and fitter lady. The muscle starts from two points in the shoulder. The main attachment is the bone known as the coracoid (attached to the front of the shoulder blade) with another attachment (known as the long head of biceps tendon) running through the shoulder joint and starting at the top of the socket of the shoulder (called the supraglenoid tubercle). The 2 muscle tendons then join into the bulk of the muscle and then attach down in the front of the elbow to the proximal (uppermost) radius bone in the forearm.
Most people consider its function to be a flexor of the elbow but in reality, other muscles tend to do this and its main function is to turn the forearm into an upward position (the position which you place the hand in to receive money, also known as supination).
Where can tendon tears occur?
The most common tendon tear is at the long head of biceps proximally (in the shoulder) while the second most common region is distally (where it attaches to the elbow). Muscle belly tears can also occur. The least common is that of coracoid tendon tears, which commonly involves a fragment of bone pulling away with it at the site (a coracoid fracture). We will restrict our discussion to the two most common sites, the long head of biceps or the distal biceps tendon.
Long head of biceps tears (at shoulder)
This is a very common injury, especially with aging when the tendon degenerates. It will often present with several months of increasing pain around the shoulder with a sudden onset of more pain, bruising and then swelling. Often there is development of more prominent biceps but which appears distally (further down the arm) to where the normal biceps muscle appears. People are often concerned by the lump thinking it is something sinister, but it is the bunched up muscle moving further down the arm.
A few weeks after the tendon tears, the pain often improves. The two issues with this condition are:
- Cosmetic, including the deformity of the biceps which leads to a lump distally, known as a Popeye Sign.
- Concern about weakness that the person may develop.
There is a large amount of evidence that weakness is not an issue; there is no evidence that patients who have suffered a long biceps tendon tears are weak. In fact, often after the tear, the pain the patient was experiencing before the tear has reduced. With this, the strength improves.
Whilst proximal bicep tendon tears often result in a cosmetic abnormality, there is no loss of physical function.
One option for treatment is to treat the initial pain, reassure the patient and let the arm settle. The alternative is to repair the biceps tendon. Please note that a long head of biceps tendon repair is not a true repair as it does not involve reattaching it to where it came from (which is through the shoulder joint and at the top of the socket). What one does is tension the biceps tendon and re-attach it either to soft tissue or bone below the shoulder joint, bypassing the shoulder joint.
Indications for the surgery are patients unwilling to accept the cosmetic abnormality or if there are other factors that may warrant surgical intervention to the shoulder. In these cases, consideration will be undertaken to tenodesing (retensioning) the long head of biceps. What this means is that if in the process of the long head of biceps tear occurring the patient is also identified to have significant long standing pathology in their rotator cuff musculature, then in the process of debriding the shoulder and repairing the rotator cuff, then the long head of biceps can also be retensioned if warranted.
The risks of the surgery to retension the bicep includes pain at the site of re-attachment of the biceps from a painful scar. There is also a risk of infection, nerve damage or risks associated with anaesthetic. Whilst Dr Nimon will offer bicep tendon repair if he feels that it is warranted, in many indications we feel this surgical procedure has little merit. Therefore, in providing quality orthopaedic care in the vast majority of cases we feel that this surgery is not required.
Distal bicep tears (at elbow)
Distal bicep tendons are different to the proximal bicep tendons, in that the whole bulk of the muscle attaches distally through one tendon, although it does disperse across some soft tissue called lacertus fibrosis. Most of it attaches to the proximal (part of the radius which is closest to the elbow) at the aspect of the radius which is known as a radial bicipital tuberosity.
Tears of the bicep tendon at this site may suddenly occur after excessive force being placed through the elbow. The story is such that often a patient will go to lift something up, catch something that is falling, be doing a particular exercise or hear something rip in the elbow and they will experience pain. Because the aspect of the tendon that tears is quite deep and because there are other aspects of the tendon that attaches to the soft tissue, the amount of bruising or deformity can be minimal.
In the past, many of these patients would have been missed and treated as having a simple elbow sprain. With the regular availability of ultrasound and MRI scans, these are now more commonly picked up. It is Dr Nimon’s experience that these tendon tears occur on a spectrum from an acute tear in a normal tendon, to one that has been slowly deteriorating over a period of time and has severe degeneration. If the tendon tear is significant, a muscle can contract further up the arm so that they also have a “Popeye Sign” but the Popeye Sign is more proximal (closer to the shoulder).
As in a proximal biceps tear, the issues that arise from the distal bicep tendon tearing are both cosmetic (abnormal appearance in the biceps) and also functional (the possibility of weakness in the elbow). As opposed to the proximal biceps, which has got little evidence to support a functional problem occurring, distal biceps tears have been reported as leading to weakness in the elbow which then justifies a repair. Consequently, most surgeons including Dr Nimon will offer repair. Dr Nimon would hasten to add however that in his experience there have been patients who have declined surgical repair various reasons and have had very good results. In his experience, the actual function or symptoms arising from these tears is less than one would expect.
Repair of the tendon would be recommended in a younger, fit patient, particularly if they are involved in sport or work which requires strength.
Surgery involves an L or S shaped incision in the front of the elbow crease and the tendon is sutured back into bone. It is passed through a hole drilled in the bone and secured with a small metal button and a plastic screw, holding the tendon tight against the bone in a tunnel. Following surgery, the patient will require 6 weeks in a sling or a splint, slowly returning to full range of motion and then a 6 month period avoiding heavy lifting until the tendon is fully healed.
There are some risks involved in the surgery. The surgery involves an incision through the front of the elbow to reach the proximal aspect of the radius, which is deep in the elbow. It involves mobilising the main artery to the forearm out of the way and carefully retracting significant nerves. There is a risk of damaging a nerve, which could lead to either temporary or permanent weakness in the hand. The most important nerve is the post interosseous nerve, which provides extension of the wrist or fingers. There is also the risk of damage to the lateral cutaneous nerve of the forearm, which may develop prior to surgery, secondary to the trauma, and often will lead to some temporary numbness or reduced sensation along the lateral aspect (outside aspect) of the forearm going down to the thumb. The vast majority of will recover but there is a chance that this may not fully recover.
Because of the tightness of the repair the tendon can either re-tear, which is rare, or can lead to tightness and/or stiffness in the elbow. The surgery also requires a general anaesthetic.
The main advantage of the repair is the reduction of long term pain or the increased ability to supinate (place the forearm into a palm upwards position). It is a surgical procedure that is regularly undertaken by Dr Nimon, and as such you can be reassured that you can be offered a balanced approach outlining the risks and benefits of both the surgical procedure and non-operative management, being aware that our aim is to provide quality orthopaedic care, not just an operation.
Glenelg Orthopaedics – Providing Quality Orthopaedic Care