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Is It Really Frozen Shoulder?

What is Frozen Shoulder?

The formal name of 'true' frozen shoulder is "adhesive capsulitis". Frozen shoulder is a poorly understood condition characterised by inflammation within the shoulder joint with progressive tightening and thickening joint capsule, giving rise to pain and reduced range of motion. Under the microscope the appearance of shoulder joint capsule is very similar to the tissue which stops the fingers from moving in Dupuytren's contracture, a fairly common condition where the little finger curls into the palm.

How common is it?

Frozen shoulder affects about two percent of the general population. It commonly affects people between the ages of 40 and 60 years, with no clear predisposition based on sex and arm dominance. It is more common in individuals with diabetes. Sometimes it follows an injury.

Natural History

The natural history of frozen shoulder typically goes through three phases:

  • The first is the 'freezing' phase - pain is the main symptom. As pain worsens, the shoulder loses motion. This may last from six weeks to nine months.
  • The second phase is the 'frozen' phase - with time pain becomes less and stiffness becomes a more prominent feature. This generally lasts four months to nine months.
  • The third phase is the 'thawing' phase - resolution of symptoms (both pain and stiffness). This may last five months to two years.
Thus frozen shoulder usually takes at least a year, and often longer, to resolve.
 
Permanent loss of external rotation is common.

How to make the diagnosis?

We diagnose frozen shoulder based on the whole picture: the patient's symptoms and physical examination and the results of imaging and other tests.


Symmetrical external rotation in normal shoulders


Loss of external rotation in left frozen shoulder

 
Examination of shoulder is painful on movement in the early phase, and it may be difficult to differentiate from shoulder impingement syndrome. Later on, stiffness is more prominent and range of motion is reduced in all directions, especially external rotation - the cardinal sign is loss of external rotation.

"The cardinal sign of frozen shoulder is loss of external rotation."


Does MRI help?

X-rays and/or MRI are sometimes used to rule out other causes of shoulder stiffness and pain, because frozen shoulder does not really 'show up' on imaging. X-ray is taken to exclude shoulder joint osteoarthritis. MRI is used to identify other problems, especially rotator cuff tear, which would require repair. Other diagnoses that may be confused, or co-exist, with true frozen shoulder include shoulder impingement syndrome, rotator cuff tear, osteoarthritis of the shoulder joint, infection and tumours and pain referred from the neck.

"Frozen shoulder generally gets better on its own, but it can take years!"

What are the differential diagnoses?

1. shoulder impingement

2. rotator cuff tear 

 
Treatment of Frozen Shoulder

Frozen shoulder generally gets better on its own, but it can take years! The aim of treatment is to reduce pain and restore range of motion.

In the initial phase, the treatment is anti-inflammatory medication and physiotherapy for shoulder stretching exercises. The stretching exercises should be gentle.

If there is no significant improvement, the next step is steroid injection. This is very safe, as the steroid stays in the shoulder. It reduces the inflammation inside the joint and relieves pain, so that stretching exercises can be more effective.

If problems continue, the next step is arthroscopic capsular release. This is 'keyhole surgery'. The capsule is cut with a tiny pair of scissors allowing the shoulder to move normally again. Vigorous post-operative physiotherapy keeps the shoulder movement gained at operation. Most patients have a very quick recovery after arthroscopic release [1-3]. This is a modern version of ‘manipulation under anaesthesia’ where the surgeon moves the shoulder to tear the capsule - it works, but it is pretty sore afterwards, whereas when the capsule is cut instead of torn it is not especially sore.

 

Inflamed joint lining in frozen shoulder looks like soft coral (Arrow)


Arthroscopic capsular release - tiny scissors are used to cut the tight should joint capsule

"Most patients have a very quick recovery after arthroscopic release" 

References

1. Baums MH, Spahn G, Nozaki M, Steckel H, Schultz W, 1. Klinger HM. Functional outcome and general health status in patients after arthroscopic release in adhesive capsulitis. Knee Surg Sports Traumatol Arthrosc. 2007 May;15(5):638-44.

2. Warner JJ, Allen A, Marks PH, Wong P. Arthroscopic Release for Chronic, Refractory Adhesive Capsulitis of the Shoulder. J Bone Joint Surg Am 1996 78: 1808-16.

3. Hannafin JA, Chiaia TA. Adhesive capsulitis. A treatment approach. Clin Orthop Relat Res. 2000 Mar;(372):95-109.

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