Calcific Tendinitis: The Shoulder Pain That Arrives Overnight

A shoulder can go from normal to almost unusable in a day or two, with no fall, no lifting and nothing to point at. Calcific tendinitis is one of the few problems that behaves this way.

Here is what the deposit is, why the timing of the pain makes sense once you know the phases, and which treatments have real evidence behind them.

What is actually in the tendon

Calcific tendinopathy is a build-up of calcium crystals inside living tendon tissue. The StatPearls review of ultrasound-guided barbotage describes it as a multifocal, cell-mediated calcification of living tissue, and notes that in tendons the clinical entity is hydroxyapatite crystal deposition disease.

The important words there are cell-mediated and living. This is an active biological process in tissue that is alive and responding, rather than a passive lump of debris that has settled somewhere. That is why the deposit can change over months, and why it can disappear.

The majority of cases affect the supraspinatus and infraspinatus tendons, the two rotator cuff tendons that run across the top and back of the shoulder. Hip and spine follow after the shoulder. It often affects middle-aged adults.

A 2025 review of ultrasound-guided percutaneous lavage for supraspinatus calcific tendinopathy puts numbers on how common it is. Prevalence in the general population ranges from 2.7 percent to 22 percent, and it has been identified in 6.8 percent of shoulder pain cases. It primarily affects people between the ages of 30 and 50, with a higher incidence in women than men. Roughly 10 to 20 percent of patients have deposits in both shoulders.

That range in prevalence is wide because many deposits cause no symptoms at all. They get found on an X-ray taken for another reason and never cause trouble.

The four phases, and why the worst one is progress

The most useful thing to understand about this condition is that the deposit is not static. The StatPearls review sets out the Uhthoff phases.

The pre-calcific phase involves metaplasia of tendon collagen fibres into fibrocartilage, which means the tendon tissue changes character. The formative phase involves chondrocyte development and crystal formation, followed by a resting state where the crystalline deposits simply sit there. The resorptive phase is characterised by inflammation. The post-calcific phase involves capillary and collagen formation as the tendon reorganises itself.

Now match those phases to the pain. The 2025 lavage review states that pain is frequently associated with the resorption phase, probably due to an inflammatory response. Someone can carry a deposit through the formative and resting phases with a mildly irritable shoulder or no symptoms at all. When the body starts dismantling it, the inflammation that comes with the clearing process is what drives the severe pain.

This changes the conversation in the clinic. A patient who cannot lift their arm and has not slept for two nights usually assumes something has torn. Explaining that the pain is tied to a clearing process, rather than to new damage, is often the single most useful thing said in the first appointment. It does not make the pain smaller. It does change what the person expects to happen next.

We deliberately avoid quoting a fixed length for the resorptive phase, because the figures given in different sources vary and we would rather not hand you a number that sets the wrong expectation.

How it gets separated from other shoulder problems

Several shoulder problems produce pain over the outside of the arm and trouble lifting overhead, so the history matters.

Onset is the first question. A shoulder that became severe over one or two nights with no mechanism behaves differently from one that built up over months of overhead work. Gradual onset with a clear activity link points more toward the patterns covered in our comparison of shoulder bursitis and tendinopathy.

Stiffness pattern is the second. A shoulder that has lost movement in every direction, including when someone else moves it for you, suggests a capsular problem rather than a tendon deposit. That distinction is covered in our guide to frozen shoulder versus rotator cuff problems.

Imaging settles it. Calcium deposits show up on plain X-ray and on ultrasound, which is why this is one of the shoulder conditions where imaging genuinely adds information rather than just confirming what the examination already found. Ultrasound also guides the needle-based treatments, since the practitioner needs to see the deposit to reach it.

Treatment options that have evidence behind them

The StatPearls review lists the options used in practice: oral pain medication, corticosteroid injection, ultrasound-guided barbotage, extracorporeal shockwave therapy, and surgery.

Barbotage, also called percutaneous lavage, uses a needle under ultrasound guidance to break up and wash out the deposit. The 2025 review reports that Farin and colleagues found 73 percent excellent results with a reduction in the size of the calcifications. It is a procedure performed by a physician or radiologist rather than a physiotherapist, and it needs the deposit to be in a state where it can be aspirated.

Shockwave therapy is the option most relevant to a physiotherapy clinic, and it has been studied carefully. A systematic review by Bannuru and colleagues, published in Annals of Internal Medicine in 2014 and summarised on the NCBI Bookshelf, pooled 28 randomised controlled trials with 1,745 participants. The average age was 51 years, with a range of 47 to 56 across the trials, and 58 percent of participants were female.

Their findings were specific about energy. High-energy shockwave therapy is defined as an energy flux density of 0.28 mJ per square millimetre or above. High-energy treatment reduced shoulder pain or improved function significantly compared with placebo. Compared with low-energy treatment, high-energy was superior in most trials for function but not for pain, and appeared more efficient at reducing the calcification itself.

The trade-off is tolerability. The review reported more adverse events with high-energy treatment than with low-energy or placebo, though no serious adverse events were recorded. Anyone considering this should expect the session to be uncomfortable and should discuss the energy setting beforehand.

We use shockwave in the clinic for several tendon problems, and the treatment itself works the same way regardless of the target, as described in our article on shockwave therapy for plantar fasciitis. What differs is the evidence base for each condition and the settings used.

Where physiotherapy fits alongside the procedures

The deposit is one part of the picture. The shoulder that has been guarding, avoiding and compensating for weeks is the other part, and that part does not resolve when the calcium does.

During the painful phase, the practical work is keeping the joint moving within what it tolerates, keeping the neck and upper back from stiffening up, and protecting sleep as far as possible. Loading the tendon hard through severe pain achieves nothing useful.

As pain settles, the work shifts to restoring range and rebuilding rotator cuff and scapular control, since the shoulder has usually lost both. That progression follows the same principles as any rotator cuff rehabilitation programme, and the decision points are similar to those covered in our article on rotator cuff pain, exercise and surgery.

Expectations should be set honestly. Some deposits resolve, some shrink and stop causing symptoms, and some persist while the shoulder becomes comfortable anyway. The goal is a shoulder that works, and that goal does not always require the X-ray to come back clean.

When to get it looked at, and what needs a physician

Sudden severe shoulder pain with no injury is worth having assessed, particularly if you cannot lift the arm or sleep on that side. So is shoulder pain that has been building for more than a few weeks without settling.

One situation needs urgent medical assessment rather than a physiotherapy booking. The StatPearls review notes that acute presentations of calcific tendinitis may include pain, swelling, warmth and fever. Those same signs can indicate an infected joint, which is a medical emergency. If your shoulder is hot and swollen and you have a fever, contact your physician the same day or go to Lions Gate Hospital. Do not wait for a physiotherapy appointment to sort it out.

Other reasons to see a physician first include severe pain following a fall, an arm that has lost strength suddenly, or a shoulder that looks visibly out of shape.

If your shoulder became painful without warning and nobody has explained why, book a 30-minute assessment and we will work out what is driving it and what treatment fits. You can see what we treat or reach the clinic here.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Sources

• Ultrasound-Guided Barbotage, StatPearls, NCBI Bookshelf
• Ultrasound-Guided Percutaneous Lavage for the Treatment of Calcific Tendinopathy of the Supraspinatus
• Bannuru RR, Flavin NE, Vaysbrot E, Harvey W, McAlindon T. High-energy extracorporeal shock-wave therapy for treating chronic calcific tendinitis of the shoulder: a systematic review. Annals of Internal Medicine 2014;160(8):542-549, summarised on NCBI Bookshelf
• College of Health and Care Professionals of BC public registry

This article is for general information only and does not constitute medical advice, diagnosis, or treatment. Individual presentations vary, and assessment findings and treatment plans differ from person to person. If you are experiencing severe symptoms, neurological changes (numbness, weakness, bowel or bladder changes), or a significant trauma, contact your physician or emergency services. Care at Medstar Sport Physio & Health is provided by practitioners registered with their respective British Columbia regulatory colleges.