Frozen shoulder, also known as adhesive capsulitis, is an inflammatory condition affecting the shoulder joint capsule. It occurs in about 5% of the population and is more common in females between 40 and 60. Most cases occur without a cause. However, some cases start after a fall onto the shoulder. Other triggers include recent surgery and medical conditions such as diabetes and thyroid disease. Often, we perform a cortisone shot for a frozen shoulder to reduce severe pain and improve movement. What is a frozen shoulder injection, and when should you use it? 

What are the typical findings of frozen shoulder?   

picture showing adhesive capsulitis

A frozen shoulder usually presents with pain and stiffness in the shoulder. Initially, people report increasing pain, followed by shoulder stiffness or restriction of movement. People often find simple movement difficult, such as brushing hair or removing a bra. Sleep also becomes a problem because of intense pain.

How do we diagnose a frozen shoulder? 

Generally, a painful and stiff shoulder is the usual presentation. However, it is essential to rule out other causes of shoulder pain and stiffness, such as arthritis or tendon calcification. This situation is where further investigations such as X-rays are crucial. For more complex cases, imaging such as ultrasound or MRI may be needed.

Will this frozen shoulder get better on its own?

Usually, most cases get better after 18-24 months. However, recent studies suggest some people can have symptoms beyond two years and even ten years.

What are the best treatment options? 

In general, there is a lack of agreement on the best treatments.

Firstly, there is no evidence that tablets such as steroids or anti-inflammatories are effective. Secondly, physiotherapy, such as stretching and strengthening, is an integral part of treatment and is effective in milder cases. However, there is no agreement on the best type of physiotherapy. In severe cases, a cortisone injection for a frozen shoulder can help.

More about frozen shoulder injection

shoulder joint injection under ultrasound

Generally, cortisone injections for frozen shoulder are helpful in the early or freezing stages to reduce pain and stop the progression. We have evidence that an injection can relieve pain for up to 4 months. Injections must be performed with ultrasound to improve the accuracy of the injection.

A frozen shoulder hydrodilatation or injection, also known as shoulder hydrodistension, is a particular type of injection using a high volume of water with a cortisone injection. We think injecting a high volume into the joint leads to a build-up of pressure and a faster ‘thawing’ out of the frozen shoulder.

Also, studies suggest that an injection performed in the early stages of a frozen shoulder is more effective than the latter stages. For example, in this study on injections in frozen shoulder, subjects who received an injection in stage 1 recovered after 2-6 weeks compared to those in stage 2 who resolved after 7-12 weeks. So, early assessment and injection ensure a better effect.

Is a frozen shoulder hydrodilatation better than a simple injection? 

We think so. We have some evidence for hydrodilatation or hydrodistension. Previous high-level studies showed little effect of a frozen shoulder hydrodilatation compared to a simple cortisone injection. However, a recent study says that a frozen shoulder hydrodilatation works much better and improves pain and range of motion than a simple cortisone injection. 

A shoulder hydrodilatation or hydrodistension should be performed with ultrasound to improve accuracy and effectiveness.

PRP injections for frozen shoulder

Platelet-rich plasma or PRP injections are used for various musculoskeletal conditions.

In a study comparing PRP to cortisone injections in frozen shoulder, PRP showed a more significant reduction in pain and improved movement. However, we need more investigations to determine whether PRP is more effective than cortisone in frozen shoulder. Nonetheless, the early results are promising and suggest using PRP as a cortisone replacement.

Is surgery a good option for a Frozen shoulder?

Surgery, also called a capsular release, is only helpful for persistent cases. You must remember that surgery has risks and is not always successful. A recent study suggests that surgery outcomes for frozen shoulder are equal to physiotherapy but have serious adverse effects of 4-5%. Overall, your decision regarding surgery should not be taken lightly.

Other frequently asked questions about a frozen shoulder injection:

Is the volume of fluid injected significant for a successful shoulder hydrodistension?

Potentially yes. We can inject either a moderate volume (20-40mls) or a high volume (over 40mls). Often, high volumes rupture the capsule of the shoulder joint.

We think shoulder hydrodistension with moderate volume stretches the capsule and is better than very high volumes that rupture the capsule. One study found that stretching the capsule is much better for pain and function than rupturing the capsule. 

Is a frozen shoulder injection more effective if done early? 

Yes, we think so. One study found that an injection done in the early stages significantly reduced the time until complete resolution compared to the latter. 

Can an injection cause a frozen shoulder?

Yes. We know that immunisations in the upper arm can trigger a reaction causing a frozen shoulder. During the COVID vaccination program, we saw more cases of frozen shoulder, partly due to increased vaccination. 

Are frozen shoulder injections painful? 

Yes, they can be particularly during the initial freezing stages of this disease. However, we use local anaesthetic, which improves tolerability. 

Can a frozen shoulder show up on an MRI? 

Yes. While a frozen shoulder is a clinical diagnosis, an MRI can help confirm the diagnosis. Often, we see swelling surrounding the biceps tendon and thickening of the capsule at the bottom of the shoulder joint. In addition, MRI can exclude other causes of a stiff and painful shoulder, such as shoulder arthritis or calcific tendonitis. 

Is a multi-site injection better than a one-site injection for a frozen shoulder? 

We are not sure. A recent study found 3-4 injeciton sites are better than one for a frozen shoulder. However, the differences were insignificant. Therefore, until further data becomes available, a frozen shoulder hydrodistension is the preferred first injection option for a frozen shoulder. 

Final word from Sportdoctorlondon about frozen shoulder injection

A combination of treatments for frozen shoulder exists, depending on the stage. In the early phases, we think a frozen shoulder injection is helpful, and a hydrodistension is more effective than a simple cortisone injection. Most cases settle without the need for surgery. The most crucial part of management is ensuring that the diagnosis is correct. Therefore, you should always see a doctor with shoulder expertise and ultrasound injection experience. 

Other common shoulder conditions:

Dr Masci is a specialist sports doctor in London. 

He specialises in muscle, tendon and joint injuries.