On Balance Magazine - Issue 20

Frozen shoulder

by Dr John Kagi
Orthopaedic Surgeon, mlcoa

Frozen Shoulder is a term used to describe a shoulder in which both active and passive movement is markedly restricted.

A better term for the pathological process underlying the condition is “adhesive capsulitis of the shoulder”, meaning, a chronic inflammation of the capsule of the shoulder.

Anatomy

• The shoulder joint is a ball (the head of the humerus) and socket (shallow glenoid) joint.
• The ball is held by an almost circumferential fibrous tissue capsule, reinforced by ligaments and muscular extensions, better known as the rotator cuff.
• The rotator cuff strikes a balance between holding the ball against the shallow socket and allowing for the shoulder’s uniquely large range of movement.

Pathology

Several pathological processes can produce the usually mild chronic inflammation in the capsule that causes it to thicken, become less supple and less elastic and eventually hold the humeral head tighter and so restrict movement of the ball joint. By far the most common cause is trauma to the rotator cuff with associated subacromial impingement and bursitis, i.e. inflammation, particularly where there has been operative intervention and subsequent further immobilisation.

The pain from these processes results in voluntary guarding and reduced use of the joint which of itself, if prolonged and particularly in an older person, will quickly result in a stiff shoulder. Other traumatic causes, such as fractures around the joint combined with the resultant immobilisation, may have the same result if mobilisation at the earliest opportunity is not encouraged. Acute calcification of the shoulder (crystal deposition disease) will often result in a frozen shoulder.

Other less common causes are diabetes, myocardial infarction, CVA, neuralgic amyotrophy and surprisingly, having or having had adhesive capsulitis (frozen shoulder) in the other shoulder.

Diagnosis

As usual, a good history is vital and will usually give the cause, as well as the diagnosis.

• Examination will reveal restriction of both active and passive ranges of movement. Restriction of passive external rotation is a reliable indicator of the condition and a way to measure recovery.
• Plain X-ray can reveal chronic rotator cuff disease, disuse osteoporosis, acute calcification or fractures.
• Ultrasound should show an acute rotator cuff tear.
• Arthrography (usually where a tear is suspected) can reveal the diminished joint volume that is the hallmark of a contracted capsule.

Treatment

90% of patients suffering from adhesive capsulitis will respond sufficiently well to conservative treatment, making this the treatment regimen of choice:

• Mobilisation of the joint initially under the supervision of a physiotherapist and with ongoing home exercises for a sufficiently long period (12-18mths), together with;
• Pain relief in the form of non-steroid medication orally or steroid injection into the subacromial region and repeated if necessary, will usually result in a successful outcome.

Of more invasive measures:

• Examination Under Anaesthetic (EUA) may be necessary to confirm the diagnosis, and offers the opportunity for Manipulation Under Anaesthetic (MUA). The latter runs the risk of fracture of an osteoporotic head, or tear of capsule or labrum.
• Hydrodilation under anaesthetic has been used in an endeavour to stretch the capsule.
• ”Open” operative treatment (i.e. cutting open the skin and other tissues so the surgeon has direct access to the joint structures) to release the tight capsule and ligaments, has now been replaced by “arthroscopic” release (i.e. using a thin flexible fiberoptic scope introduced into the joint space).

The subsequent reduction in pain of the arthroscopic procedure is less likely to result in operation failure and often avoids other “open” surgical complications, such as aggravation of the condition it is supposed to alleviate.

Prognosis

• Most patients improve their range of movement with less pain at two years with the conservative regime.
• The prognosis is poorer in: Males, diabetics and where an element of compensation is available.