Saturday, November 9, 2013

How is the diagnosis of shoulder arthritis made?

Glenohumeral arthritis is diagnosed by taking a complete history, performing a physical examination, and obtaining high quality plain x-rays. On occasion other tests are helpful.

A. History and Presenting Symptoms – progressive loss of comfort and function of the shoulder. While shoulder may be comfortable at rest, sleep and activities of the shoulder become increasingly difficult. Often the patient's biggest problem is loss of shoulder motion (stiffness). Another cause of stiffness is a frozen shoulder, but in frozen shoulder, the x-rays show no evidence of arthritis or damage to the surfaces of the joint.  See also Effect of posterior capsular tightnessFrozen shoulderFrozen shoulder and diabetes.

B. Physical Exam – limitation of glenohumeral movement: flexion, internal rotation in abduction, reach up the back, cross body adduction, and external rotation. When the range of motion of the humerus is examined in reference to the thorax, scapulothoracic motion may conceal the extent of loss of glenohumeral motion. Strength of deltoid and rotator cuff are typically preserved. See also Is the shoulder stiff? and The stiff shoulder

C. Plain Radiographs – Proper x-ray technique is important. Two well-taken x-ray views are usually sufficient.  Joint space narrowing, often most evident on a true axillary view. It is important that the x-rays be of good quality so that the pathoanatomy is revealed. One of the important characteristics is the type of the glenoid, as originally described by Walch. Another is the amount of posterior humeral subluxation on the glenoid. Again, a properly done axillary view reveals most of what is needed to confirm the diagnosis and plan surgery.  A few simple measurements can characterize the important pathoanatomical features. Links to typical x-rays for the different types of arthritis are shown below

1 Primary osteoarthritis (primary degenerative joint disease)
2. Post-traumatic arthritis
3. Capsulorrhaphy arthropathy
4. Chondrolysis
5. Inflammatory arthritis/rheumatoid arthritis
6. Avascular necrosis
7. Dysplasia
8. Rotator cuff tear arthropathy

X-rays can reveal the severity of the joint damage from arthritis, a particularly severe form is known as the bad arthritic triad.

More information about x-rays in shoulder arthritis can be found at this link.

D. Special Imaging – CT scans and MRIs are unnecessary to make the diagnosis or plan treatment in the majority of cases. A CT scan is useful in assessing post-traumatic deformities or when there is a question about the status of the tuberosities or the adequacy of glenoid bone stock. An MRI is useful when the integrity of the rotator cuff is in question.

E. Additional tests – EMGs are considered in shoulders having had prior surgery where there is a question about the integrity of the axillary and suprascapular nerves.


**To see more of the Shoulder Arthritis Book, click here.**

Additional relevant posts
Anatomy of the arthritic glenoid