Anatomy (see shoulder anatomy)
The shoulder joint is a ball and socket joint. Most shoulder movement occurs where the ball at the top of your arm bone (humerus) fits into the socket (glenoid) which is part of the shoulder blade (scapula). The rotator cuff muscles are a group of muscles whose tendons form a ‘hood’ over the head of the arm bone (humerus). These muscles control the stability of the joint and the finer movements. The lining or sack (capsule) is extremely loose thus allowing much movement between the ball and socket joint.
In frozen shoulder the lining (capsule) of the shoulder becomes scarred, thickened and very much contracted resulting in the joint becoming very stiff. In addition scar tissue forms between the head of the arm bone (humerus) and rotator cuff tendons thus further limiting the movement. This loss of movement is accompanied by marked pain. The reason why this condition occurs, the fact that it is peculiar to the shoulder and the fact that itrecovers of it own accord remains somewhat of an enigma.
The exact cause of a frozen shoulder is not known but it may begin after a minor injury. It is more common in certain conditions:
1. Diabetes – it is very common in diabetics and tends to have a worse prognosis in these patients.
2. Underactice thyroid
3. Ischaemic Heart Disease
4. Previous neck problems
5. Nerve conditions
6. After operations: eg: breast surgery, cardiac surgery and shoulder operations
7. Idiopathic – In most patients, it occurs without any predisposing factor.
Signs of Symptoms
It is more common in women and occurs in the age group from 40 to 60.
The pain of frozen shoulder can be from a minor irritation to severe pain. The pain is often unrelenting and is usually worse at night. It is often felt over the mid part of the arm and not the shoulder itself. Patient usually tolerate the pain during the day but if they do a sudden unexpected movement, the pain is often nauseating but lasts for a couple of minutes only. The night pain is often distressing and patients suffer from chronic fatigue which can result in an element of depression.
One of the classic features of frozen shoulder is severe nauseating pain with sudden movements or jerking of the arm, this makes the patient stop and usually last for seconds or minutes. This is called the ‘JERK PAIN’.
In the initial phase, pain is the main symptom but the patient’s range of movement is normal. It this initial phase it is more difficult to make the diagnosis as it may present just like tendonitis of the rotator cuff. The movement slowly gets worse and the first thing that the patient notices that they cannot do is get their hand behind their back i.e. to do up their bra.
Course or Natural History of Frozen Shoulder
The disease goes through 3 characteristic stages:
Phase 1 – PAINFUL OR FREEZING PHASE
An otherwise healthy person develops slow onset of a generalised aching in the shoulder. Pain is constant, nagging, worse at night and is aggravated by moving the shoulder. Often the only thing that will prevent the pain is keeping the arm still close to their side. A common precipitating event is when the arm is extended and internally rotated ie: reaching into the back seat of the car from the front to lift something. This event is often forgotten. Pain killers and anti-inflammatory tablets do not help the pain much. The length of this phase varies from 4 to 9 months.
Phase 2 – ADHESIVE, FROZEN OR STIFFENING PHASE
The pain settles down and the shoulder remains very stiff. There may be a different pain now which is a muscular pain over the shoulder blade. Because of the stiff joint extra stress is put on the shoulder blade and its muscles thus causing pain. This pain is not as severe as the pain in phase 1. This phase generally lasts from 4 to 12 months.
Phase 3 – RESOLUTION OR THAWING PHASE
During this phase, the pain eases and the stiffness slowly improves. In some patients the improvement is very dramatic ie: patient says ‘it got better overnight‘. This phase may last from 5 to 26 months.
Carter Rowe an eminent American Shoulder Surgeon stated about Frozen Shoulder:
‘ We have all had to claim that the idiopathic frozen shoulder is a self-limited condition and that the majority of patients become pain-free with a full range of motion within a year to 18 months. Our problem has been: How can we shorten the painful period effectively?’.
This will depend on the stage and tailored to the patient’s individual needs.
The effectiveness of these is variable and usually very strong ones are necessary.Initially mild ones will be tried. These will often only be needed at night.
Usually do not help. Celebrex has been advocated in the early phase.
3. Injections into the shoulder
The effect of these is variable, they may only give temporary relief of the pain but insome cases they may hasten the end of the first phase.
4. TENS – Transcutaneous Electrical Neural Stimulation
This can be very effective in some patients and is administered by a physiotherapist.
Pain at night and the inability to sleep is a major problem.
It is more comfortable to sleep in a recliner or propped up in bed. Laying the arm on pillows is helpful. A heating pad can be beneficial.
The use of Amitriptylline (normally an antidepressant) has been shown to be very effective in helping the patient sleep.
Any attempts to stretch the joint to improve movement will just exacerbate the pain.
Local therapy is however very helpful and massage of the periscapular muscles.
It is important to maintain the movement that one has but not to stretch past the limit as this will just exacerbate the pain.
Its use is controversial. It may shorten the frozen phase of the syndrome.
The timing of manipulation is important: if done too early ie: in the freezing phase, it can make the pain worse and lengthen the duration of the freezing phase.
9. Arthroscopy and release
Looking in the shoulder with an arthroscope can better define the stage and then a release can be done. The results of release with the arthroscope and results of manipulation have been shown to be the same.
As with the manipulation, the timing of this is very important. Some surgeons advocate this in all patients but there is no evidence to show that it changes the natural history of the condition.
An arthroscopy and release is done as a last resort in a patient in which no other forms of treatment have been able to control the pain.
Increases vessels seen in the joint capsule or lining in a frozen shoulder.
Different treatments or medication will work for different patients, thus patients must find what works for them and take that treatment till the condition recovers of its own accord.
NO TREATMENT HAS BEEN SHOWN TO EFFECTIVELY ALTER THE NATURAL HISTORY OF FROZEN SHOULDER. IT IS THUS THAT SUPPORTIVE TREATMENT ONLY IS NOW ADVISED.