Calcifying Tendonitis

Updated: Sep 10, 2019
  • Author: Anthony H Woodward, MD; Chief Editor: Herbert S Diamond, MD  more...
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Overview

Practice Essentials

Calcific tendinitis is a painful shoulder disorder characterised by either single or multiple deposits in the rotator cuff tendon or subacromial bursa.  The disease subsides spontaneously in the majority of cases and can be managed with conservative therapy, but some patients continue to have a painful shoulder for an extended period of time with the deposits not showing any signs of resolution. The cause of calcifying tendinitis is not known, but it is generally agreed that it is not caused by trauma, and it is only rarely associated with systemic disease. 

The diagnosis of calcifying tendinitis is made from standard radiographs because they allow localisation and assessment of the texture and morphology of the deposits. Deposits are most commonly located in the supraspinatus and infraspinatus. Less commonly, deposits are located in the teres minor and the subscapularis (3%). [1]

This article addresses only calcifying tendinitis as it occurs in the shoulder. (See also the Medscape Reference article Rotator Cuff Disease.) For excellent patient education resources, see eMedicineHealth's patient education article Tendinitis.

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Pathophysiology

The pathophysiology of calcifying tendinitis is controversial. The early hypothesis was that the calcification is a consequence of age-related tendon degeneration; however, the peak incidence of calcifying tendinitis occurs at an earlier age than that of degeneration. Calcifying tendinitis, in contrast to degenerative tendinopathy, may resolve, and the tendon heals spontaneously. Calcifying tendinitis is rarely associated with tears of the rotator cuff. 

The chemical composition of the calcium salts in degenerate tendons is different. The calcific deposit of calcifying tendinitis consists of poorly crystallized hydroxyapatite. Calcifying tendinitis appears to occur in viable, not necrotic, tissue, whereas dystrophic calcification appears to occur in necrotic tissue.

Uhthoff and Loehr proposed that calcifying tendinitis is a disease that progresses through correlating pathologic and clinical stages, as follows [2] :

  • Formative phase: As a consequence of an unknown trigger, a portion of the tendon undergoes fibrocartilaginous transformation, and calcification occurs in the transformed tissue. The deposit enlarges; the calcific deposit resembles chalk.

  • Resting phase: Once formed, the calcific deposit enters a resting period. The calcific deposit may or may not be painful. If large enough, the deposit may cause mechanical symptoms.

  • Resorptive phase: After a variable period, an inflammatory reaction may ensue. Vascular tissue develops at the periphery of the deposit. Macrophages and multinuclear giant cells absorb the deposit during this phase. The calcific deposit resembles toothpaste and occasionally leaks into the subacromial bursa, which may result in very painful symptoms.

  • Postcalcific phase: Once the calcific deposit has been resorbed, fibroblasts reconstitute the collagen pattern of the tendon. 

The correlation between increased incidence of thyroid disorders or diabetes and risk of developing cacifying tendonitis remains unclear; similarly, the associations with genetic mutations needs further study. It has been speculated that patients with theses predisposing factors may be at greater risk of developing cacifying tendonitis. [1]

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Epidemiology

The incidence of rotator cuff calcification without shoulder symptoms in the general population is 3-20% according to different reports. The highest incidence is in adults aged 30-50 years. [3]  

Women are affected slightly more frequently than are men (housewives and clerical workers account for most cases), and the right shoulder is affected slightly more often than the left. [1]  

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Prognosis

In general, it appears that the acute severe symptoms of calcifying tendinitis are likely to resolve spontaneously within 3 weeks. Chronic symptoms also tend to resolve over a period of months to a few years, although some have been reported to persist up to 15 years. Initially, asymptomatic shoulders with calcific deposits have been reported to become painful. This tendency for spontaneous recovery means that the effectiveness of any treatment can be established only with controlled trials.

A 2-year follow-up of 24 patients treated by arthroscopic subacromial decompression who had calcific deposits demonstrated that in 19 patients (79%), the calcific deposits became smaller, although they had not been touched. [4]  The postoperative clinical results of these patients were indistinguishable from those of matched patients without calcific deposits who underwent similar decompressions.

Calcification can recur following surgical treatment. Rupp et al reported a 16% incidence of recurrence, [3]  and Wittenberg et al reported an 18% incidence. [5]

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