Understanding rotator cuff injuries: from anatomy to treatment

Your shoulder joint is one of the most complex joints in your body and the rotator cuff is vital to its stability and movement. Any injury to the rotator cuff can therefore cause significant discomfort, pain and movement problems. To understand what can go wrong with your rotator cuff, it helps to first understand what makes up your shoulder joint. 

The anatomy of your shoulder joint

Your shoulder joint actually comprises two joints — the glenohumeral joint and the acromioclavicular joint. Your glenohumeral joint forms the main part of your shoulder joint; it is a ball and socket joint, where the socket is formed by your shoulder blade (scapula) and the ball is formed by the top of your upper arm bone (humerus).

Over the glenohumeral joint sits a bony canopy formed by the outer part of your collarbone and a specific part of your scapula called the acromion — this is your acromioclavicular joint.

If you think of your shoulder joint as a house, your glenohumeral joint forms the main part of the house while your acromioclavicular joint forms the attic roof. Your rotator cuff sits inside the attic, above your glenohumeral joint and beneath your acromioclavicular joint.

This cuff consists of four different tendons that all attach to your humerus, holding the bone in the socket of your scapula and allowing the surrounding muscles to smoothly move your shoulder joint. Your rotator cuff can become damaged as a result of direct trauma at any age, or due to wear and tear over the years, which usually becomes apparent in older individuals.

Risk factors for rotator cuff injuries

Although your rotator cuff can be injured at any age due to direct trauma eg breaking a fall with an outstretched arm, rotator cuff injuries are more common with age due to wear and tear of the tendons over time. Rotator cuff injuries are also more common in women and in those who perform repetitive overhead movements for work or leisure eg playing tennis or painting walls. 

Symptoms of rotator cuff injury

The most common rotator cuff injury is a tear. Traumatic tears can occur as a result of a fall and can be easily missed. This is because an X-ray of your shoulder in the immediate aftermath of your accident will not always pick up damage to the soft tissues, such as your rotator cuff. If you, therefore, have persistent pain in your shoulder after an accident, you should see your doctor as you may have a rotator cuff tear. 

Rotator cuff tears can also develop over time, causing persistent discomfort, pain, weakness and/or reduced mobility. You may also find that your shoulder pain worsens at night making sleep difficult. However, not all tears cause pain. In fact, around 30% of individuals aged 60 or over will have a rotator cuff tear without any symptoms; this increases to around 50–60% in those aged over 80. 

If you have persistent shoulder pain, it is important to see your doctor as treatment can relieve your pain but also reduce your risk of developing more serious shoulder problems in the future, such as cuff tear arthropathy, which is a type of shoulder arthritis. 

Treating rotator cuff tears

Rotator cuff tears do not heal by themselves and usually need treatment of some kind. The type of treatment depends on the size and depth of your tear. 

For small tears, treatment may be as simple as resting your shoulder, taking over-the-counter anti-inflammatory medication (eg ibuprofen), applying an ice pack several times a day and performing regular physiotherapy exercises. However, more severe rotator cuff tears, such as full-thickness tears, may need surgery. 

Your orthopaedic surgeon will discuss the risks and benefits of surgery with you, so you can make an informed decision. Surgery to repair a rotator cuff is usually performed as a day case, so you can return home on the same day as your surgery. 

What to expect from rotator cuff surgery

In most cases, your surgery will be performed under general anaesthesia, so you will not be awake. However, if after discussion with your surgeon and anaesthetist, you decide that you do not want to have a general anaesthetic, it is possible to have sedation instead, where you will be awake but relaxed and drowsy. 

Whether or not you have a general anaesthetic, you will be given a regional anaesthetic called a shoulder block. This involves injecting a local anaesthetic into the group of nerves supplying your shoulder in order to provide complete pain relief in this area for up to 24 hours. 

Surgery for a full-thickness rotator cuff tear involves re-attaching your torn tendon to the humerus, either through open surgery or keyhole surgery (arthroscopy). If the tendon is badly damaged you may also need a graft to replace the damaged area; the graft may be taken from elsewhere in your body or may be synthetic. 

After your surgery, once the shoulder block wears off, you can take over-the-counter painkillers or prescribed painkillers. You may need to wear a sling for up to five weeks after your surgery depending on the tear pattern but will still need to perform regular physiotherapy exercises as part of your rehabilitation programme to strengthen your shoulder and gradually improve its mobility. 

Most people recover full range of movement after surgery to repair a rotator cuff tear. However, in a minority of cases, there may be some lingering stiffness — this is more likely if your tear wasn’t treated for a long time, causing your muscles to weaken. 

The risk of recurrent rotator cuff injuries

There is always a risk of re-tearing your rotator cuff, especially if you have sustained a large tear. Your risk is also dependent on the types of activities you perform eg if you play certain sports where repetitive overhead shoulder movements are involved. This risk can be reduced by performing exercises to improve your core stability and strengthen your shoulder joint.

Advances in rotator cuff repair

Arthroscopy to repair rotator cuffs has improved dramatically in the last two decades, with advances in the cameras, instruments, anchors and stitches used. There has also been progress in graft materials, with the advent of biological scaffolds ie synthetic grafts containing human stem cells. As the technology has improved, rotator cuff surgery has become faster and recovery times shorter.

Research into what is happening at the molecular level, that is, inside tendon cells and with enzyme levels, has also improved our understanding of why some people are more prone to tears. This may help in both the treatment and prevention of rotator cuff tears in the future.