Calcific tendonitis is a relatively common shoulder condition in which a deposit of calcium forms within one of the rotator cuff tendons. Its peak onset is around the age of 40, and it affects women more often than men. The supraspinatus is the rotator cuff tendon most often involved.
An important point about this condition is that the calcium itself is not usually what hurts. Calcium within the rotator cuff tendons is fairly common, and some studies suggest that between 2% and 20% of people have calcium in these tendons without any symptoms at all. Symptoms arise from the inflammatory reaction that the body mounts against the calcium, which is why the condition can be silent for years and then become acutely painful.
Two theories have been proposed to explain why the calcium forms. The first is that areas of degenerate tendon act as a focus for calcium to be laid down. The second is that calcium is deposited in parts of the tendon that have a poor blood supply and some degree of hypoxia, meaning a reduced oxygen supply. An argument against the first theory is that calcium is more often seen in tendon that looks relatively normal than in tendon with significant tearing.
Stages of calcific tendonitis
The condition passes through recognised stages, and understanding which stage the shoulder is in explains both the symptoms and the treatment options.
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Precalcific stage. An initial change in the fibrocartilage cells of the tendon that allows calcium to be deposited.
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Calcific formative stage. Chalky calcium deposits form within the tendon. This phase is typically chronic and painless.
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Resorptive stage. The body mounts an inflammatory response to the deposit. Macrophages arrive from the bloodstream, react to the calcium and begin to reabsorb it. Enzymes released by the macrophages soften the deposit, so that it takes on a toothpaste-like consistency. The resorptive stage is usually acutely painful.
Symptoms
- Some people with calcium in their rotator cuff tendons have no symptoms whatever.
- Others have mild to moderate chronic pain and discomfort in the shoulder.
- Others again develop acute, severe pain during the resorptive stage.
- Pain is typically felt down the side of the upper arm.
- The shoulder tends to ache at night.
- Pain often occurs when lifting the arm overhead, because the swollen tendon catches under the acromion. This is known as impingement.
Causes
The underlying cause of calcium deposition in the rotator cuff is not fully established, and the two theories described above remain theories. What is clear is that the pain is driven by inflammation rather than by the presence of the calcium alone, and that the severity and pattern of symptoms track the stage the deposit has reached.
Diagnosis
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X-ray. Plain X-rays show calcium deposits very well. Several views are needed to confirm them: neutral rotation, internal rotation and external rotation.
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Ultrasound. Ultrasound is very sensitive to calcium and will almost always demonstrate the deposit.
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MRI. MRI is poor at showing calcium, because the calcium and the surrounding tendon both appear dark, which makes the deposit difficult to distinguish.
Treatment
Non-surgical treatment
Subacromial steroid injections and physiotherapy often relieve symptoms. However, to prevent the problem recurring, the calcium usually needs to be removed from the tendon.
One way of doing this without an operation is needle aspiration. A radiologist inserts a large-bore needle into the deposit under ultrasound guidance. If the deposit is soft it can often be aspirated, and a subacromial steroid injection is given at the same time. Published reports and local experience put the success rate at approximately 50%. Individual results vary.
Success depends mainly on whether the deposit is hard or soft. Needling is less successful for hard, chalky deposits. Hard, chalky deposits are more likely when symptoms have been present for a long time and are mild to moderate. Soft, toothpaste-like deposits are more likely when symptoms have started suddenly, over days to weeks, and are more severe. Whether a particular deposit is hard or soft cannot be known for certain before needling or surgery. Minor discomfort and soreness are expected afterwards.
Surgical treatment
Calcium can be removed arthroscopically, through keyhole incisions. The calcified area is usually identified by an inflamed region of tendon, and its exact location is confirmed by probing with a needle until calcium appears at the needle tip. A small longitudinal incision is then made in the tendon and the calcium is removed with an arthroscopic shaver and a curette. An acromioplasty is often performed at the same time. More detail is on the excision of calcium page.
The operation is carried out under general anaesthetic, and patients stay one night in hospital. A pain pump delivering local anaesthetic is inserted at the time of surgery and remains in place for 48 hours; the catheter is usually removed on day two.
Most people take about 6 weeks to recover, although symptoms may persist for up to 12 weeks after surgery.
The risks include a small risk related to the general anaesthetic, a small risk of infection, and frozen shoulder, which occurs in a small percentage of patients and can be precipitated by the operation. These risks are discussed in consultation.
What to do next
If you have shoulder pain that aches at night and catches when you lift your arm, an assessment with an X-ray or ultrasound will show whether a calcium deposit is responsible and which stage it has reached. Related conditions are covered on the shoulder tendonitis, shoulder impingement and subacromial bursitis pages, and recovery after calcium excision is covered under rehabilitation.
To arrange an assessment, see consultation. The consultation FAQs explain what to bring, and the surgery FAQs answer common questions about having an operation. Other shoulder problems are listed under shoulder injuries and conditions.
This page is general information and is not a diagnosis. Individual circumstances vary, and the right treatment for you can only be determined after assessment. Any procedure carries risk; these are discussed in consultation.
