Calcific Tendonitis is a relatively common shoulder condition. It has a peak onset age of 40 years of age. It affects women more commonly than men. The most commonly affected of the rotator cuff tendons is the supraspinatus tendon.
THEORIES ON CAUSES
It seems that the presence of calcium in the rotator cuff tendons is relatively common. Some studies have suggested that between 2 to 20% of people may have calcium present in their rotator cuff tendons without symptoms. The shoulder becomes symptomatic when an inflammatory reaction occurs in relation to the calcium within the rotator cuff tendon. It is the inflammatory reaction rather than the presence of the calcium that causes the symptoms.
There are two theories as to how calcium is deposited in the tendon. One theory suggests that degenerate areas of tendon act as a focus for the calcium to form within the tendon. The other theory claims that calcium is deposited within areas of tendon with low blood flow and a degree of hypoxia.
The argument against the degenerate tendon theory is that calcium is in fact more commonly seen in more normal looking tendon rather than tendons with significant tears.
Several stages of calcific tendonitis are described. There appears to be some initial change in the fibrocartilage cells within the tendon that allows calcium to be deposited within the tendon. This precalcific stage is followed by a calcific formative stage in which chalky calcium deposits form. This stage tends to be a chronic, painless stage. This is different to the resorptive stage, in which the body mounts an inflammatory reaction to the calcium. Macrophages from the blood stream react to the calcium and start to reabsorb the calcium deposit. The calcium lump becomes soft and toothpaste like due to the enzymes released by the macrophages. This stage is usually acutely painful.
Patients with calcium in their rotator cuff tendons may be entirely asymptomatic. They may present with mild to moderate chronic pain and discomfort in their shoulder or they may develop acute severe pain in the shoulder related to the inflammatory reaction against the calcium deposit as the body tries to reabsorb it.
Pain is typically felt down the side of the upper arm. The shoulder tends to ache at night time. Pain is often felt as the arm is lifted overhead with the swollen area of tendon catching on the under surface of the acromion and impinging.
X-Rays shows the deposited calcium very well. However, several views will need to be taken to be certain to demonstrate it. X-Rays need to be taken with the arm in neutral rotation and in internal and external rotation.
Ultrasound is particularly sensitive to calcium and will invariably demonstrate it.
A MRI examination is not very good at demonstrating calcium deposits because the calcium shows up dark on the scans, as does the tendon in which the calcium is sitting in. So, it is often hard to distinguish the calcium lump within the tendon because both appear dark on the MRI scans.
Steroid injections to the subacromial space and some physiotherapy are often very helpful in relieving the symptoms. However, to prevent the symptoms recurring it is usually necessary to remove the calcium from the rotator cuff tendon.
The calcium can be removed by needle aspiration. A large bore needle is inserted into the calcium deposit under ultrasound guidance by a radiologist and if the deposit is soft it is often possible to aspirate it. A steroid injection is given at the same time into the subacromial space. Needle aspiration tends to be successful in about 50% of cases. However, the results depend most on whether the lump of calcium is hard or soft. This technique is not particularly successful if the calcific deposit is a hard-chalky deposit. The calcium is more likely to be hard and chalky if the symptoms have been present for a long period of time and are of a mild to moderate severity. Calcium deposits are more likely to be soft and toothpaste like in nature if the symptoms have been present for a short period of time such as days to weeks and if they have started fairly suddenly and are more severe. There is no way to be certain prior to needling or surgery whether the deposit is hard or soft.
Minor discomfort and soreness can be expected in the shoulder following a needle aspiration.
The calcium can also be removed surgically. This is done arthroscopically with keyhole surgery. The region of tendon with the calcium inside it can usually be identified by the visualisation of an inflamed area of tendon. The location can be confirmed by probing the tendon with a needle until calcium is seen in the tip of the needle. Once the calcium is located, a small longitudinal incision is made in the tendon and the calcium removed with an arthroscopic shaver and curette. Often an acromioplasty is performed as well.
Recovery following surgery is straightforward. Most people take about 6 weeks to recover following the surgery although symptoms may persist until 12 weeks postoperative. Patients spend a night in hospital following the surgery, which is performed under a general anaesthetic. A pain pump will be inserted at the time of surgery and will stay in for 48 hours following the procedure to assist with post-operative pain. The pain pump contains local anaesthetic which is infused into the operative site by the canula. Generally, the patient will remove the catheter on day two following the operation.
As with any operation, there is always the possibility of a complication occurring. There is a small risk related to the general anaesthetic. There is a small risk of an infection developing. Frozen shoulder occurs in a small percentage of patients and is precipitated by the operation.