The rotator cuff is the group of four tendons that holds the ball of the shoulder centred in its socket while the arm moves. A tear in one of those tendons is one of the most common causes of shoulder pain, night pain and weakness, and it becomes steadily more common with age.
Rotator cuff tears may be partial thickness or full thickness. They may develop as part of a degenerative process, where the tendon progressively weakens and wears out, or they may be brought on by impingement. They can also occur in relation to an acute injury such as a fall onto the shoulder.
Symptoms of a rotator cuff tear
Symptoms are similar to those of tendonitis, and they are frequently associated with symptoms of bursitis and impingement. Common features include:
- Pain felt down the outer aspect of the arm rather than deep in the joint
- Aching at night, often bad enough to disturb sleep or prevent lying on that side
- A sharp, catching impingement pain as the arm is lifted away from the body, typically at around 90 degrees
- Weakness, and difficulty lifting the arm if the tear is large
- Visible wasting of the muscles around the shoulder blade in longstanding tears
In a small proportion of people, a longstanding untreated rotator cuff tear can progress to arthritis in the shoulder, which may then require joint replacement surgery.
Understanding the terminology
Imaging reports and specialist letters use terms that are not always explained. These are the ones that matter most.
Full thickness tear
This term relates to the vertical depth of the tear at its insertion. It means the tendon is completely detached from its attachment to the humerus. The significance is that a full thickness tear is unlikely to heal back to its insertion, because the tendon and the bone are no longer in contact with each other. Conservative management may relieve symptoms, but it is unlikely to make the tear heal.
Applied to the common anterior supraspinatus tear, full thickness means that if the tear is viewed from inside the joint with an arthroscope, it is possible to see straight out through the tear into the subacromial space.
Partial thickness tear
A partial thickness tear is not at full depth. It may be on the articular (joint) surface, on the bursal surface, or within the substance of the tendon itself. Viewing an articular surface tear from inside the joint, the abnormal tendon is visible but it is not possible to see out into the subacromial space, because part of the thickness of the tendon is still attached.
Because partial thickness tears remain attached at the insertion, healing has classically been thought possible, though the healing potential may not be as great as was long assumed. A rule of thumb used by many surgeons is that where the tear involves less than half the depth of the tendon, a simple debridement is appropriate, removing devitalised tissue to expose healthy, well-supplied tissue, while avoiding the prolonged immobilisation a repair requires. Where more than half the depth is involved, many surgeons will tend to repair the tear, either in situ or by completing it to a full thickness tear and then repairing it.
Complete tear
This usually signifies a full thickness tear in which the whole length of the tendon insertion has detached. Applied to the supraspinatus, it means the tendon has come away from the greater tuberosity along its full width, from its anterior insertion just behind the bicipital groove to its posterior insertion just in front of where the infraspinatus begins.
How a tear is diagnosed
Assessment begins with history and clinical examination, which test the strength and function of each of the four cuff tendons separately. Imaging is then used to confirm the diagnosis and to show the size, location and quality of the tear. An ultrasound is often the first scan arranged. An MRI gives more detail about tendon quality, the degree of retraction and whether the muscle has become fatty, all of which influence whether a repair is likely to be durable.
Treatment
Treatment depends on the type of tear and which tendon is affected. The supraspinatus is the most commonly involved, though tears of the infraspinatus and subscapularis also occur frequently.
Non-surgical treatment
Tears in the rotator cuff are usually treated non-operatively in the first instance, with physiotherapy and in some cases a steroid injection, in an attempt to control symptoms. Partial thickness tears in particular tend to be managed non-operatively before any surgery is considered. For many people, especially those with lower physical demands, this is enough to settle symptoms and restore useful function.
Surgical treatment
For full thickness tears, surgical treatment is often undertaken. Surgery for a minor partial thickness tear will often involve a simple debridement of the tear, trimming the frayed edges back to healthy tissue. Where the tear is substantial, surgery typically involves repairing the tendon back to the bone, and is normally performed in conjunction with an acromioplasty.
Acute full thickness tears in people who are still working or playing sport and wish to continue doing so may need to be repaired surgically before they can return to those activities.
As with any operation, there are risks, including those of the anaesthetic, infection, stiffness, and the possibility that a repaired tendon does not heal. These are discussed individually in consultation before any decision about surgery is made.
Recovery
Recovery after a rotator cuff repair is gradual, because the repaired tendon has to heal back to bone before it can be loaded. A sling is normally worn for a period after surgery, and rehabilitation progresses in stages from passive movement through to active movement and then strengthening, guided by a physiotherapist. The rehabilitation section sets out what to expect week by week.
What to do next
If you have shoulder pain that wakes you at night, or weakness lifting your arm, see your general practitioner. A referral is needed to claim the Medicare rebate for a specialist consultation, and it also means your GP can arrange the right imaging beforehand.
This page is general information and is not a diagnosis. Individual circumstances vary, and the right treatment for you can only be determined after assessment. Any procedure carries risk; these are discussed in consultation.
