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Pectoralis major rupture

What is it? 

Your pectoral muscles sit on your anterior chest wall.  The larger muscle, the Pectoralis major, is a powerful elevator, internal rotator and adductor (pulls in and internally rotates your arm as well as helping forward flexion).  The muscle has two heads, the sternocostal head (larger) and the clavicular head.  The tendons of your pectoralis major insert into the front of your upper arm (humerus) and the muscle forms the front wall of your armpit. Rupture involves tearing of the tendon normally just by its insertion into the bone. Often, only one of the two heads of your pec major muscle gets ruptured.

Who gets it?

Pec major rupture is fairly rare and almost always occurs in men, mostly those over 30 years old. Normally a heavy-weight gym bench press in the ‘negative’ phase (weight being lowered onto chest) is to blame.  This is because the pec. muscle is being placed under severe eccentric (fibres getting longer as they fire) load during this exercise. 

Some body-builders use steroids or growth hormones to accelerate their muscle gain.  These drugs increase the risk of rupture, as the muscle grows faster than the tendon can, risking overload of the tendon fibres.

How do I know if I’ve ruptured my Pec Major?

Patients typically report a sudden pop, with severe pain and loss of function.  There is often bruising in the armpit and upper arm. There may be alteration of the armpit contour and the nipple on the affected side may drop slightly compared to the uninjured side. Patients may feel weakness in pressing forwards and pulling in with their affected arm.

X-rays are usually normal, but an MRI or Ultrasound scan can confirm the diagnosis.

35yr old athletic male presenting 18 months after right pectoralis major rupture.  Note the subtly altered axillary contour at rest and how this is made obvious with voluntary contraction. Patient was frustrated by weakness on push ups, pull ups, bench-press and aching. 

Does it have to be repaired?

Most patients are keen for surgery to restore both their function and cosmesis.  Studies report excellent functional outcome with surgical repair, with over 95% of normal strength being restored.  These results are significantly better than non-operative treatment, although some patients chose not to have surgery.  Without surgery full strength will not be restored and the anterior armpit fold will remain asymmetrical, although for some this is not a problem.

How is my Pec Major rupture repaired?

If your tear is acute (less than a few weeks old), it is normally feasible to perform a direct repair.  You will have a general anaesthetic and a regional block.  Through an approximately 7cm open incision at the front of your shoulder, your ruptured tendon will be retrieved and re-fixed to your humerus (arm bone) where it belongs.  The fixation uses very strong sutures and metal anchors or buttons fixed within your bone. 

If your tendon has been ruptured for some time (more than a couple of months) the tissue may not be repairable directly as it retracts and scars up.  In this case you may require an allograft (tendon tissue from a donor) to span the gap between your ruptured pec major and your humerus bone.  This works well, but rehab is slower and the cosmetic and power results are less good than a primary repair. 

What is my recovery?

You will go home the same day in a sling. You will need to use this sling for six weeks to protect your repair.  You will be able to do desk-work in your sling after about 2 weeks, but you will not be able to drive for about 6 weeks.  At six weeks you can begin to move your arm more, but you must not do any resistance training until three months.  By six months all restrictions will be lifted.  

What are the potential complications of surgery?

This procedure is generally safe.  However, as with all surgery, there is a small risk of infection, bleeding, shoulder stiffness and nerve injury.  Re-rupture after repair is very rare if you follow the rehabilitation protocol. The risk of anaesthetic is generally low as most patients with pec. major rupture are young and fit.