1 SHOULDER IMPINGEMENT SYNDROME

This is a very common condition with many interchangeable names, b ut they all refer to some part of the same condition. Some of terms used include: • Painful arc syndrome (see picture for representation) • Subacromial impingement • Subacromial • / tendinosis Different elements of these terms describe different parts of what is happening, and some words are obviously more patient friendly than others.

What is subacromial impingement? The simplest way of describing the problem is that one or more of the rotator cuff tendons become trapped and pinched under the during movement. With all overhead movements the rotator cuff tendons slide under the acromion and there is a bursa which facilitates this gliding motion. Acromial The bursa is a normal fluid filled sac which reduces spur friction between the rotator cuff and the acromion during movement. Problems occur when the rotator cuff tendons stop gliding seamlessly in this space, because they are sprained or overused, or mechanically not working as they are supposed to. This leads to them impinging (being pinched) under the acromion and/or the adjacent acromio-clavicular joint (ACJ). This results in the bursa becoming swollen and inflamed (subacromial bursitis), resulting in even less space for the rotator cuff tendon.

What are the rotator cuff tendons? The rotator cuff is made up of 4 muscle/tendon units: i. Supraspinatus (the upper most tendon in the and the tendon most commonly involved in impingement) ii. Infraspinatus (towards the back of the shoulder joint) iii. Subscapularis (in front of the shoulder joint) iv. Teres Minor (the smallest and least significant of the four) These tendons control very precisely the complex shoulder movements, especially elevation and rotation – hence the inclusion of ‘rotator’ in their name. Furthermore, these muscles and tendons form a continuous sleeve over and around the shoulder joint – hence the ‘cuff’ description.

What causes the problem? There are several reasons why impingement may occur: 1. Repetitive strain to the tendon Repeated pressure and use (e.g. heavy overhead manual work or overuse in the gym) can cause of the rotator cuff tendon (known as tendinopathy – explained more below); this causes the tendon to swell, which leads to the tendon catching and impinging through movement. 2. The rotator cuff tendon may weaken because of reduced blood supply (this occurs silently as we all get older), and this can lead to a partial thickness. or even, full thickness tears. A torn tendon leads to a weaker shoulder, which in turn causes impingement.

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk 2 SHOULDER IMPINGEMENT SYNDROME

3. Low-lying Acromion A low lying or hooked acromion can decrease the space underneath the acromion and cause impingement of the rotator cuff tendons. Historically this was considered the most common cause of impingement, but this problem is now thought to be a lot less significant. 4. of the Acromioclavicular joint (ACJ) Wear and tear within the AC joint leads in time to thickening and enlargement of the joint (termed hypertrophy). Sometimes there can be bone spurs associated with this. Together these decrease the space under the joint and can cause impingement. Most AC joint arthritis is caused by wear and tear of the joint over several decades. Typically people with manual or labouring jobs are at risk, as are weight-lifters and sports people (tennis, rugby, boxing are all common). 5. Bursitis Many of the conditions above are associated with subacromial bursitis (where the bursal sac gets swollen and inflamed); this results in further loss of space for the rotator cuff tendon, which in turn perpetuates and contributes to impingement. 6. Poor Posture

Poor posture brings the shoulders forwards, as well as rotating the shoulder blade; these together close down the subacromial space, leading to impingement.

What is rotator cuff tendinopathy? One of the most common reasons for impingement is a rotator cuff tendinopathy. This can occur as a result of either an acute or an overuse injury to the tendon, or a more chronic problem, and on occasion it can be due to a combination of all three of these. It is reasonably easy to understand why an overuse tendon injury e.g. repeated unaccustomed overhead use, such as racket sports, or maybe painting a wall or a ceiling, causes internal damage to the tendon (tendinopathy), but a chronic tendinopathy is comparatively harder to understand. Ironically in chronic tendinopathy no inflammation occurs in the tendon, which explains why some rotator cuff tears can occur silently. However, if these tendon changes affect the mechanics of the shoulder, the tendon then does begins to catch/impinge on and pain will be present from inflammation within the (subacromial bursitis). Chronic tendinopathy occurs in people typically from middle age onwards, and is actually the result of natural wear and tear. As part of the natural ageing process the internal structure of the tendon becomes disorganised or deconditioned (tendinosis), leading to thinning and weakening of the tendon, and making it more prone to developing tears. A good analogy for this tendon disorganisation is the effect water has on a paperback book – the pages inside the book soak up the water and when it dries the pages wrinkle and the book gets fatter and is more difficult to put back on a bookshelf.

What investigations are useful? Investigations are not always required as the diagnosis is often clear from just the story and the examination, but they do have a role:

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk 3 SHOULDER IMPINGEMENT SYNDROME

X- ray: Useful to exclude arthritis of the shoulder/acromio-clavicular joint and to rule out calcific tendonitis; not so useful ironically for seeing ‘spurs’. : This is the same type of scan as used during pregnancy. It is very useful at diagnosing problems and can be used in impingement for guided injections into the subacromial bursa. MRI scan: This is undoubtably the most comprehensive investigation. It is used specifically to look for a rotator cuff tear, the log head of biceps, for inflammation of the AC joint, or if the diagnosis maybe is in doubt.

What treatment options are there? Activity modification Avoiding doing any type of overhead activity or sports which may be causing the problem, will help. Medications An anti-inflammatory medication is one of the most common forms of treatment for this condition; these help reduce swelling and pain in the affected area, but these should not be taken long term, and they should be avoided in anyone with high blood pressure, heart disease, liver cirrhosis, kidney disease, or asthma and anyone with a history of stomach problems, including heartburn and peptic ulceration. Physical therapists, osteopaths, chiropractors and sports therapists focus their attention on restoring normal movement to the shoulder, ensuring good postural control and scapular control exercises. exercises for improving range of movement can also prove extremely helpful e.g. if there is stiffness reaching behind your back, which signifies tightness in the posterior capsule of the shoulder. Using specific stretching exercises for the posterior capsule can be quite effective in relieving shoulder pain. As the pain improves, the therapist will move towards a strengthening program for the rotator cuff. Patience is a virtue when it comes to physiotherapy – improvement takes time and full recovery can take between 3 and 6 months. Steroid Injections If medications, rest and physical therapy aren't relieving pain, an injection of local anaesthetic & steroid might prove beneficial. Cortisone is an extremely effective anti- inflammatory medication. By injecting it into the bursa (+/- the ACJ) it can reduce the inflammation in the subacromial bursa which helps reduce pain and improve range of movement; this will make then make it easier to undertake the physiotherapy exercises necessary to resolve the problem in the longer term. Subacromial injection A steroid injection in isolation is often not enough! Surgery Where all else fails and symptoms have been present for many months a keyhole operation can be performed; this operation is termed an Arthroscopic Subacromial Decompression (ASD), and it makes more space in the subacromial bursa. Sometimes removal of the adjacent Acromio-Clavicular joint (ACJ) will also be required, if it appears to be contributing to the pain.

What is the long-term prognosis? A full resolution of your symptoms should be possible.

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk