Rotator cuff Disease

There is a wide spectrum of disease, from tendinosis, partial tears to complete tears.

Anatomy

• The rotator cuff refers to the tendons of 4 muscles that helps to stabilise the shoulder:
  • Supraspinatus (initial 10-15 deg of abduction; beyond that the deltoid gradually takes over function)
  • Infraspinatus (external rotation)
  • Teres minor (external rotation)
  • Subscapularis (internal rotation)

Note: adduction is done by latissimus dorsi, teres major, and pectoralis major

• Rotator cuff disease frequently involves tear of the supraspinatus tendon. The supraspinatus muscle runs from the supraspinatus fossa and its tendon travels under the acromion and the corocoacromial arch (ligament joining the coracoid process and the acromion). It is in these confines that makes the tendon susceptible to wear and tear.
• Infraspinatus tears are almost always accompanied with supraspinatus tears.
• Subscapularis tears can occur in isolation or with accompanying supraspinatus tears, and can be associated with instability of the long head of biceps.

Epidemiology

• Prevalence of rotator cuff tears increases with age. 
• FT tears are rare before the age of 60, but are present in 50% of population over the age of 70. Most tears are asymptomatic and do not require treatment.
• Tears do not heal with time and is likely to get worse with time.

Pathomechanics

There is a wide spectrum of disease, from tendinosis, partial tears to complete tears. Disease can be acute (usually traumatic tears) or chronic. 

Tendinosis is the accumulation of scar tissue in the affected tendon. Usually caused by 1 or 2 processes:

• Intrinsic overload (generally due to ‘wear and tear’)
• Compression from external structure (eg anatomical variations: tight coracoacromial arch).

A tendinotic tendon does not have the same mechanical property, and  predisposes it to partial and complete tears. It is also thickened and more likely to get impinged in the coracoacromial arch.

Long standing tendon tears also draws the humeral head up against the acromion (due to unopposed action of the deltoid): causing secondary arthropathy.

Presentation

• Patients present with weakness, pain and loss of function. Pain be worse at night. There may be difficulties reaching overhead / back pockets.
• On examination:
  • There may be tenderness at the anterior supraspinatus insertion. In longstanding tears, there may be wasting of the supraspinatus fossae. 
  • There may be features of impingement: due to tendon trapping in the supraspinatus outlet. There may be a painful arc on abduction, restrictions in adduction and forward flexion.
  • External rotation in adduction is generally intact (helps to differentiate this with adhesive capsulitis).
  • Empty can test and Hawkins Kennedy test may be positive.

Imaging

Imaging is not usually required to make the diagnosis, but where indicated:

• XR can show acromial spurring, greater tuberosity changes (cysts/sclerosis/osteophytes), proximal glenoid migration, and GH OA.
• USS can provide a dynamic assessment and show impingement.
• MRI very good for soft tissue and shows degree of tear.

Management

GP

• Acute (traumatic) tendon ruptures with loss of function usually need early surgical referral.
• For chronic disease, non operative management is first line. It may take 6 weeks to show effects; if it does: it should be continued as long as patient shows improvement.
  • Resting; activity modification (avoid repetitive overhead lifting, and lifting away from body); physiotherapy (to help strengthen the intact rotator cuff tendons)
  • Analgesia: oral; subacromial steroid injections (caution: no more than 3 per year)
• Consider surgical referral if there are any diagnostic concerns, or if not responding to conservative management, or acute ruptures (as mentioned above).

Specialist Management

The decision whether or not to perform surgical repairs depends on the patient’s age, cormorbidities, function (including occupation), activity levels, as well as the size of the tear itself.

In general:

• Large traumatic tears usually require surgical intervention.
• Patients less than 60 with symptomatic tears who are otherwise in good health are likely good candidates for surgical repair.
• Partial thickness tears need to be >50% in order to obtain surgical benefit.

Surgery involves reattachment of the torn tendon to its bony attachment +/- acromioplasty +/- surgical correction of other structural problems (eg degenerative LHB tendon, OA etc.)

Following surgery:

• Sling for 6 weeks: no driving
• 10% of patients develop stiffness, usually self resolves by 10 months.
• Patients may continue to improve for 2 years following surgery.