Frozen shoulder

Introduction:
Frozen shoulder is an extremely disabling condition, presenting with and unremitting shoulder pain and stiffness.  This was well defined by Codman in 1934, who described the first and best classical diagnostic criteria still used to this day. 

These were:

1. Global restriction of shoulder movement.
   2. Idiopathic etiology.
   3. Usually painful at the outset.
   4. Normal x-ray.
   5. Limitation of external rotation and elevation.

Frozen shoulder may be either primary idiopathic or secondary to an injury.  This is a distinct pathological condition identified by global limitation of glenohumeral motion, with a loss of compliance of the shoulder capsule, with no specific underlying cause found.

A secondary stiff shoulder or secondary frozen shoulder typically presents after injury or surgery.  There is often an accompanying condition, such as subacromial impingement or a rotator cuff tear. 

Diagnosis:
The diagnosis of a primary Idiopathic frozen shoulder is made on the basis of:

1. No history of injury preceding onset of symptoms of frozen shoulder.
2. Age:  Typically occurring in females more common than males, in the 4th and 5th decade.
3. Pain: The pain is of a constant nature, severe,  maybe affecting sleep.  There is often a toothache pain at rest, with sharp pains with forceful movements.
4. Loss of external rotation: The typical loss of external rotation is such that passive external rotation is less than 30 degrees.

Natural History: 
The natural history of a frozen shoulder has classically been described as passing through 3 stages.  These stages last for approximately 2 years. However, often these distinct phases are not seen and duration may be much longer than 2 years.

Stage:
1. Freezing phrase:  This is associated with pain and loss  of movements for about 3 months.
2. Frozen phase:  This lasts for approximately 3-9 months, with pain at extreme range of movement and marked stiffness.
3. Thawing phase: This last for approximately 9-18 months, usually painless and the stiffness starts to gradual resolve at this stage.

Aetiology:
The frozen shoulder has been found to be more common in association with the following conditions:

1. Diabetes (10-20% association).  There is a 2-4 times increased risk for diabetics of developing frozen shoulder.  Insulin-dependent diabetics have a 36% chance of developing it, 10% bilaterally and the condition is more severe in diabetics.
2. Cardiac/lipid problems.
3.  Epilepsy.
4. Endocrine abnormalities, particularly hypothyroidism.
5. Trauma.
6. Drugs - MMPI.

Treatments:
The natural history of frozen shoulder is not necessarily that of complete resolution as suggested by Codman in 1934.  Many studies have shown frozen shoulder not to be an entirely self limiting condition and most patients still have some restriction of shoulder movement on resolution of the frozen shoulder but no functional disability (Grey JBJSA 1962, Shaffer JBJSA 1992, Bunker JBJSB 1995, Miller Orthopaedics 1996). 

The treatment options range from:
1. Nothing.
2. Physiotherapy.
3. Distention injections.
4. Locally acting steroid injections.
5. Manipulation under anaesthetics.
6. Open/Arthroscopic capsular release.

Non-Operative Treatment:
Studies on non-operative treatments for frozen shoulder have shown that physiotherapy improves range of movement but not necessarily pain relief.  Steroid injections have a benefit for short-term pain relief only but no long-term pain relief (Ryan's Rheumatology 2005, Haslan and Celiker Rheumatol int 2001, Bulgnann Ragum Dis 1984).