|Classification and external resources|
Calcific tendinitis (also calcific/calcifying/calcified/calcareous tendinitis/tendonitis/tendinopathy, tendinosis calcarea, hydroxyapatite deposition disease (HADD) and calcific periarthritis), a form of tendinitis, is a disorder characterized by deposits of hydroxyapatite (a crystalline calcium phosphate) in any tendon of the body, but most commonly in the tendons of the rotator cuff (shoulder), causing pain and inflammation. The condition is related to and may cause adhesive capsulitis ("frozen shoulder").
Three main theories have emerged in an attempt to explain the mechanisms involved in tendon calcification. The first theory is the theory of reactive calcification and involves an active cell-mediated process, usually followed by spontaneous resorption by phagocytosing multinucleated cells showing a typical osteoclast phenotype. The second theory suggests that calcium deposits are formed by a process resembling endochondral ossification. The mechanism involves regional hypoxia, which transforms tenocytes into chondrocytes. The third theory involves ectopic bone formation from metaplasia of mesenquimal stem cells normally present in tendon tissue into osteogenic cells. As no single theory is satisfactory to explain all cases, calcific tendinopathy is currently believed to be multifactorial.
Presentation and diagnosis
Pain is often aggravated by elevation of the arm above shoulder level or by lying on the shoulder. Pain may awaken the patient from sleep. Other complaints may be stiffness, snapping, catching, or weakness of the shoulder.
The calcific deposits are visible on X-ray as discrete lumps or cloudy areas. The deposits look cloudy on X-ray if they are in the process of re-absorption, and this is also when they cause the most pain. The deposits are crystalline when in their resting phase and like toothpaste in the re-absorptive phase. However, poor correlation exists between the appearance of a calcific deposit on plain x-rays and its consistency on needling. Ultrasound is also useful to depict calcific deposits and closely correlates with the stage of disease.
Dietary calcium restriction
A controversial topic, this conservative treatment can be very effective for some patients, and reports of pain cessation with strict dietary calcium restriction have been documented. Dietary restriction applies to all milk products, nuts that have a high calcium content, calcium-fortified products and high calcium vegetables and snacks. Food nutritional labels are helpful in determining foods to restrict. If no improvement is noted after three months, other treatment modalities should be tried.
It is assumed the body scavenges the pathological calcium deposits when dietary calcium is restricted. Studies are required in this area.
Extracorporeal shock wave therapy
Electroanalgesia, ice therapy, and heat offer symptomatic relief. The benefit of ultrasound in calcific tendinitis is debated; most studies are negative but a study by Ebenbichler et al. (1999) showed resolution of deposits and clinical improvement. Improving the biomechanics of the shoulder will reduce the tension on the fault muscles allowing a decrease in symptoms. Improved biomechanics are thought to reduce the amount of calcification that occurs especially in the case on supraspinatus where it can be caused from repetitive compression against the acromium.
In studies, acetic acid iontophoresis combined with ultrasound provided no better clinical results or shrinkage of the calcific deposits than did no treatment.
Injections, needling, and lavage
Under local anesthetic, the calcific deposits can be mechanically broken up by puncturing them repeatedly with a needle and then aspirating the calcific material with the help of a sluice of saline. About 75% of patients are helped by this procedure. Ultrasound can be used to help localize the deposit and to visualize the needle entering the deposit in real time.
These may be useful when the shoulder is acutely inflamed but otherwise are not generally useful except for the temporary relief of pain.
Removing the deposit/s either with open shoulder surgery or arthroscopic surgery are both difficult operations, but with high success rates (around 90%). About 10% require re-operation. If the deposit is large, then frequently the patient will require a rotator cuff repair to fix the defect left in the tendon when the deposit is removed or to reattach the tendon to the bone if the deposit was at the tendon insertion into the bone.
- Arend CF. Ultrasound of the Shoulder. Master Medical Books, 2013. Free chapter on US evaluation of calcific rotator cuff tendinopathy available at ShoulderUS.com
- Bannuru, RR; Flavin, NE; Vaysbrot, E; Harvey, W; McAlindon, T (Apr 15, 2014). "High-energy extracorporeal shock-wave therapy for treating chronic calcific tendinitis of the shoulder: a systematic review.". Annals of internal medicine 160 (8): 542–9. doi:10.7326/m13-1982. PMID 24733195.
- Ebenbichler GR, Erdogmus CB, Resch KL et al. (May 1999). "Ultrasound therapy for calcific tendinitis of the shoulder". N. Engl. J. Med. 340 (20): 1533–8. doi:10.1056/NEJM199905203402002. PMID 10332014.