Rotator Cuff Calcific Tendinopathy

Rotator cuff calcific tendinopathy is deposition of calcium hydroxyapatite crystals within the rotator cuff tendons, most often supraspinatus, and is the commonest form of hydroxyapatite deposition disease.

It mainly affects women aged 30 to 60. Deposits are also common without symptoms: in one radiographic study they were present in 7.8% of people without shoulder pain and 42.5% of those with subacromial pain.

It differs from degenerative cuff tendinopathy: the deposit follows a biological cycle (the Uhthoff lifecycle) and usually resolves, but the resorptive phase can be severely painful.

Deposits form most often in supraspinatus (over 50% of cases), then infraspinatus and subscapularis; teres minor is rarely involved. The process is cell-mediated rather than wear and tear.

The Uhthoff lifecycle has 3 phases:

• •Pre-calcific (formative): fibrocartilaginous change within the tendon; clinically silent
• •Calcific: formation, then a resting (quiescent) deposit, then resorption, when macrophages and vascular granulation tissue break the deposit down
• •Post-calcific (remodelling): granulation tissue is replaced by organised collagen and symptoms resolve

In the resorptive phase the deposit becomes soft and paste-like under pressure and provokes an inflammatory response, which is thought to explain the acute severe presentation and why anti-inflammatory treatment helps more here than in degenerative tendinopathy.

Risk factors include female sex and age 30 to 60; associations with diabetes, thyroid disease and metabolic syndrome have been reported.