Calcifying Tendinitis

Updated: Apr 14, 2020
  • Author: Anthony H Woodward, MD; Chief Editor: Herbert S Diamond, MD  more...
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Overview

Practice Essentials

Calcifying or calcific tendinitis is a painful shoulder disorder characterized by calcific deposits in the rotator cuff tendon or subacromial bursa. The disease may subside spontaneously. The majority of cases can be managed with conservative therapy. However, some patients continue to have a painful shoulder for an extended period of time with the deposits not showing any signs of resolution, in which case surgical removal of the deposits is an option. 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, which allow assessment of the morphology and location of the deposits. Deposits are most commonly located in the supraspinatus and infraspinatus tendons. Less commonly, deposits are located in the teres minor and the subscapularis tendons (3%). [1]

This article addresses only calcifying tendinitis as it occurs in the shoulder. (See also the Medscape article Rotator Cuff Disease.) For patient education information, see the Tendinitis Directory.

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Pathophysiology

The calcific deposit consists of amorphous calcium phosphate and poorly crystallized hydroxyapatite.{ref 28} During the acute phase, the macroscopic appearance of the calcific deposit resembles a milky emulsion like toothpaste; during the chronic phase, it resembled a granular conglomerate or an amorphous mass composed of many small round or ovoid bodies.

Calcification of the tendon usually progresses through the following series of chronological phases [2, 3] :

  • 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. 
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Epidemiology

Calcifying tendinitis has been reported in 3%, 7%, and 8% of x-rays of asymptomatic persons and in 7% and 43% of patients with shoulder complaints according to different authors. [3, 4] Women are affected slightly more frequently than are men. [1] Approximately 80% of calcific deposits occur in the supraspinatus tendon, 6% in the subscapularis tendon. The condition is bilateral in 10-20% of cases. [5]  Calcifying tendinitis is associated with kidney stones in 32% of patients. [6]   

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Prognosis

Spontaneous resolution can occur. Resolution of the calcific deposit ocurs within 3 years in 9% of cases. On average, symptoms persist for about 4 years.

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. [7]  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. [8]

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