Calcifying Tendinitis

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. 

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]   

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]

Calcifying tendinitis can be asymptomatic, discovered serendipitously by an imaging study. Symptomatic calcifying tendinitis may present in the following 3 ways:

1. Chronic, relatively mild pain with intermittent flares

2. Mechanical symptoms may arise from a large calcific deposit, which may block elevation of the shoulder.

3. More severe acute pain is attributed to the inflammatory response of the resorptive phase.

The pain commonly radiates from the point of the shoulder to the deltoid insertion and, less frequently, to the neck or elbow. It is often aggravated by elevation of the arm above shoulder level or by lying on the shoulder. Pain may waken the patient from sleep. Other possible complaints are stiffness, snapping, catching, or weakness of the shoulder.

Patients with chronic or subacute symptoms may demonstrate loss of range of motion, a painful arc of motion from 70-110º of forward elevation, or impingement signs. Catching or crepitus may be noted. In the acute phase, the pain may be so severe that only little movement is allowed, and the tenderness is very marked.

Complications of calcifying tendinitis include the following: 

• Secondary frozen shoulder: Limited range of shoulder motion, which can be treated with manual therapies, nonsteroidal anti-inflammatory drugs (NSAIDs), and intra-articular steroid injections.[9]

  2. Rotator cuff tear: In one review full-thickness tears were found in 4% of patients at an average of 9 years after treatment; however, the tears could be due just to the passage of years.[4]

The diagnosis of calcifying tendinitis is made from standard shoulder radiographs—anterior-posterior (AP), outlet, and axillary views. Laboratory studies are not required.

Plain x-rays

Plain x-rays demonstrate calcific deposits. Routine shoulder views, true anteroposterior (AP) and lateral views, AP views with the shoulder in internal and external rotation, axillary views, and supraspinatus outlet views should be sufficient to demonstrate calcification in any rotator cuff tendon. The sensitivity of plain x-rays for detecting calcific deposits is 0.90 (when using ultrasonography as the standard).

The calcific deposit can be characterized radiologically as follows:

• Location: Lateral or medial
• Size: Large (>1.5 cm), medium, or small. Large deposits may be more likely to be symptomatic.
• Morphology: Two systems have been proposed for classifying the morphology of calcific deposits: one by Gärtner and Heyer, ^[10]  another by the Société française d'arthroscopie (SFR: French Society of Arthroscopy). ^[4]

Gärtner and Heyer classify calcific deposits into the following three types:

• Type I (formative phase): Dense calcifications with well-defined border; frequency, 37%; pain, mild
• Type II (resting phase): Dense calcifications with Indefinite border; frequency, 32%; pain,  moderate to severe
• Type III (resorptive phase): Translucent calcifications with indistinct border; frequency, 31: pain, severe

However, Kappa values for interobserver and intraobserver agreement indicate that the Gärtner and Heyer system is unreliable.{ref28[4, 11, 12]        

The SFA classification comprises four types, with the appearance and frequency as follows[4] (French Society of Arthroscopy)

• Type A: Dense, well defined, circumscribed calcifications; 17%
• Type B: Dense, well defined, Segmented calcifications; 19%
• Type C: Transparent and nonhomogeneous calcifications; 45%
• Type D: Dystrophic deposit at tendon origin; 19%

 Magnetic resonance imaging (MRI)

MRI is not necessary to detect calcifying tendinitis, although its accuracy for finding calcification is more than 95%. It is most useful in cases of chronic calcifying tendinitis, which may be associated with rotator cuff tears, adhesive capsulitis or osteolysis of the tuberosity.[1]  

The calcific deposit causes decreased signal intensity on T1-weighted images.[13, 14]  If edema is present around the calcific deposit, as might occur in the resorptive phase, increased signal intensity around the calcific deposits may be present on T2-weighted images.[13] Do not misinterpret this increased area of signal intensity that is due to edema as a rotator cuff tear.

Ultrasonography

High-resolution ultrasonography (US) shows the presence of deposits and also defines their locations in the tendon, plus their size and texture. In the resting phase, the deposits appear hyperechoic and arc shaped, whereas they appear non-arc shaped (fragmented/punctate, cystic, nodular) in the resolving phase. These appearances can also be correlated with the symptomatic and asymptomatic phases of the disease. US examination during the nodular or cystic phase shows increased vascularity around the deposits.[1]

Ultrasonography does not expose the patient to radiation but accuracy of results depends heavily on the skill of the technologists and the interpreting radiologist. In experienced hands, ultrasonography is more sensitive than plain x-rays.[11, 15]

Computed tomography (CT)

CT has excellent resolution to detect calcium deposits. However, cost and radiation exposure limit its use.[15]

Conservative management is the first line of treatment. This includes analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), transcutaneous electrical nerve stimulation (TENS), corticosteroid injection, physical therapy, ultrasound-guided needling (UGN), and extracorporeal shock wave therapy (ESWT).

If conservative treatment modalities fail, surgical removal of the deposits is the remaining option. Failure of nonoperative therapy has been defined as persistence of symptomatic calcific tendinitis after a minimum of 6 months of nonoperative treatment.[16]  

Conservative care

Symptomatic management may include analgesics of the appropriate strength (NSAIDs are often prescribed), physical therapy using cold or heat,  exercises to maintain or restore the patient's shoulder range of motion and all muscle strength, and corticosteroid injections. 

Ultrasound-guided needling is safe but has not been proven to be more effective than an ultrasound-guided subacromial corticosteroid injection. Yoo et al combined needle decompression with corticosteroid injection and reported that 25 of 35 shoulders showed improvement after 6 months. A poor result was associated with persistence of the calcific deposit.[17]

In one study of 125 patients treated nonoperatively, approximately 50% had obtained good clinical results after 6 months.[18]  A prospective study in 420 patients with chronic calcifying tendinitis found that 27% had persistent symptoms after conservative treatment consisting of physical therapy, analgesics, NSAIDs, and corticosteroid injections. Higher failure rates correlated with bilateral disease, medial location of deposits, and larger deposits.[16]

A retrospective review of 159 patients determined that over 49 months, 70% of patients obtained good results after four different conservative treatment modalities. After an average of 9 years, 82% of calcific deposits were no longer visible on ultrasonography.[19]    

Extracorporeal shock wave therapy

ESWT uses sound waves that are focused to a point within the target tissue. The results of one study demonstrated that positioning the shoulder in hyperextension and internal rotation during ESWT may be a useful technique to achieve resorption of calcific deposits.[20]  ESWT with three-dimensional, computer-assisted navigation to localize calcific deposits provides significantly better results, compared with localization through patient-to-therapist feedback.[21]

The advantages of ESWT are its noninvasiveness and low complication rates, although hematomas develop in most patients (80% for all musculoskeletal areas). An assessment of minimally invasive treatments concluded that ESWT is safe and effective.[22] ​ In a single-blind randomized study comparing ESWT with simulated treatment in 70 patients, ESWT provided a significant decrease in pain, while patients receiving sham treatments received no benefit. Complete resorption of the calcific deposit occurred in 31% of patients who received ESWT.[23]  Earlier recovery makes ESWT 5-7 times more cost-effective than surgery. 

ESWT is painful, however, and the use of high-energy shock may require anesthesia. Nevertheless, high-energy ESWT is the most thoroughly investigated minimally invasive treatment option. In the short term to midterm it has proved to be safe and effective.[22]

ESWT can use low energy (< 0.08 mJ/mm2) or high energy (> 0.28 mJ/mm2). Better results have been reported with high-energy therapy. In a randomized trial in 80 patients, symptoms were significantly improved with high-energy ESWT, whereas low-energy ESWT had no significant effect.[24]  A meta-analysis of 5 randomized controlled trials concluded that high-energy ESWT provided better clinical and radiologic results than low-energy ESWT.[25]

ESWT compared with other treatments:

• TENS treatment: In a randomized trial comparing ESWT treatment in 33 shoulders with TENS treatment in 30 shoulders, both groups improved but ESWT was more effective. ^[26]
• Surgery: In a prospective study that compared surgical extirpation in 29 patients with ESWT in 50 patients, at 12 months good or excellent results were reported in 75% of operated patients versus 60% of those receiving ESWT. At 24 months, 90% of surgical patients had good or excellent results compared with 64% of those receiving ESWT. ^[27]  In a retrospective comparison of arthroscopic extirpation in 22 cases and ESWT (0.10 to 0.13 mJ/mm ²) in 24 cases, University of California Los Angeles (UCLA) rating system scores and patient reports of excellent or good outcomes showed no significant differences at 24 months ( P = 0.38). ^[28]

• Kinesio taping: In a randomized controlled trial, ESWT followed by application of kinesio tape provided better improvement than ESWT alone at 12 weeks follow-up.[29]

• Needling: A prospective randomized controlled trial in 80 patients demonstrated greater symptomatic improvement with ultrasound-guided needling in combination with high-energy ESWT than with ESWT alone, after a mean of 4 months, with disappearance of the calcific deposit occurring in 60% versus 33% of shoulders, respectively.[30]  A randomized controlled trial in 81 patients determined that ESWT and ultrasound-guided needling combined with subacromial corticosteroid injection were equally successful in relieving symptoms at 1-year follow-up, but calcification size decreased more after needling than after ESWT.[31]  

• Ultrasound-guided percutaneous lavage: A meta-analysis of 8 randomized controlled trials with 617 cases provided limited evidence that lavage was superior to ESWT.[32]

Injections

Subacromial corticosteroid injections are often given for calcifying tendinitis. Yoo et al reported that 6 months after ultrasound-guided needle decompression and subacromial corticosteroid injection, 25 of 35 shoulders showed improvement. A poor result was associated with persistence of the calcific deposit.[17]

In a study by Cacchio et al that used injection of disodium ethylenediaminetetraacetic acid (EDTA) by phonophoresis in 40 patients, the visual analog scale (VAS) pain score fell from 7 pretreatment to 3 at 1 week; in the 40 patients who received a sham injectino, the VAS score remained at 7. At 1 year, the VAS score was 2 in the treatment group and still 7 in the control group. Calcification disappeared completely in 63% of the treatment group but in 0% of controls.[33]

Needling

Needling involves breaking up the calcific deposits by repeatedly puncturing them with a needle. The deposit can be localized by fluoroscopy or by ultrasonography. A systemic review of the efficacy of ultrasound-guided needling (UGN) concluded that, due to the variation in studies and the low quality of evidence, the efficacy of UGN could not be firmly established.[34]

In a prospective observational study, 86 patients were treated by ultrasound-guided percutaneous needling followed by corticosteroid injection. They were then advised to follow a specific rehabilitation protocol that focused on mobility, strength, and function. Subjects who performed exercises regularly after the procedure had a better result than those who were less compliant.[35]  

Barbotage

Barbotage is a procedure in which saline is repeatedly injected then aspirated from the subacromial space in an attempt to wash out the calcific deposit. A meta-analysis of eight randomized controlled trials involving 617 cases indicated that ultrasound-guided percutaneous lavage provided better pain relief and clearance of the calcific deposit than ESWT.[32]  In a case series by Pfister and Gerber, barbotage was completed successfully in 76% of 62 shoulders and produced significant improvement, with reduced pain intensity  at 2- and 6-months follow-up.[36]

Farin et al reported on treatment of 61 shoulders by multiple punctures of the calcific deposit followed by lavage. One year later, clinical results were excellent in 74% and calcification had disappeared or decreased in size in 74%.[37]  

Serafini et al reported reported a significant decrease in symptoms for 1 year after barbotage.in 219 patients, compared with 68 controls. At 5 years and 10 years, however, there was no difference between the two groups.[38]

An open or an arthroscopic approach may be used for surgical treatment.[39, 40, 41, 42]  Although favorable results have been described with open removal of calcific deposits, arthroscopy has become the preferred technique, yielding results similar to open surgery but with less morbidity.[1]  

A study that compared arthroscopic needling with complete removal of the calcium deposit and tendon repair found both techniques effective in treating pain and in improving function in chronic calcifying tendinitis recalcitrant to conservative treatment.[43]  

A systematic review of six studies involving 294 operated shoulders found no difference in outcome following acromioplasty with removal of calcific deposit, acromioplasty alone, or isolated removal of the calcific deposit.[44]

A study comparing 28 patients treated by arthroscopy with aspiration and lavage of deposits with 12 patients treated with arthroscopic complete excision and tendon repair found no difference between the two groups at 6 months and 12 months. Only a few patients had residual calcification—all of which was less than 10 mm—and there was no correlation between residual calcification of the tendon and Constant shoulder scores.[43]  

In a retrospective review, 14 patients treated by arthroscopic curettage (eight had additional subacromial decompression) were followed for an average of 41 months. All patients improved; the average UCLA score postoperatively was 34, which is in the good/excellent category. Analysis of the results showed no difference with or without subacromial decompression.[45]

In a retrospective case series, 30 patients were followed on average for 3 years after arthroscopic removal of the calcific deposit. Pain decreased significantly, with mean VAS scores falling from 8.7 to 0.8.[46]

Maier et al followed 93 patients for a mean of 3 years after arthroscopic removal of a calcific deposit. An excellent clinical result was achieved in 90% of patients. Complete removal of the calcific deposit was achieved in 83%.[47]

A review by Porcellini et al of arthroscopic treatment in 95 shoulders of 63 patients found that at 24 months, outcome strongly correlated with the presence of residual calcium deposits; consequently, these authors recommend complete removal of residual calcium deposits in the tendon.[48]  Other studies have found that the presence of some residual calcium deposits does not affect the clinical result.[47, 49]

Yoo et al treated 35 patients by complete removal of the calcific deposits. In 18 this resulted in a complete tear of the very rotator cuff tendon which was repaired with a suture anchor technique. Pain relief was achieved within six months for 30 patients. 10 patients developed secondary frozen shoulder.[50]

In a retrospective case series, 23 of 24 athletes treated with arthroscopic excision of the calcific deposit returned to sports at a mean of 5 months after their operation, all but one to competition at the same level.[51]  When 54 of 58 patients treated by arthroscopic removal of calcific deposits were followed at intervals, maximum pain relief was achieved at 3 months by 31%, at 6 months by another 17%, at 9 months by another 20% and at 12 months by another 28%; 78% returned to work within 6 weeks.[41]

Arthroscopy compared to conservative treatment: Wittenberg et al.[8] in a study of 100 patients treated with surgery or conservative measures reported better outcome in patients treated with surgery. This study also showed that surgery group of patients treated surgically have earlier recovery - within 5 months average for ADLS in contrast with 20 months for patients treated conservatively.

Factors affecting surgical outcome include the following:

• Complete removal: most studies report better results with more complete removal of the calcific deposit.
• Subacromial decompression does not seem to be required.
•  Excision of the calcific deposits may leave a defect in the rotator cuff that requires repair, and that may be followed by stiffness and slower recovery.