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Interdigital Bursitis

Interdigital bursitis is very often confused with Morton's Neuroma as the symptoms can be identical. It is caused by a pocket of fluid building up between the metatarsal heads and compressing the nerve.

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A person holding their right forefoot with both hands. The forefoot has been made red to indicate it is painful.

About Interdigital Bursitis

Each toe shares a nerve with the toe next to it, and the nerve effectively 'splits' in two parts when it passes the knuckle joints. 

For those with an interdigital bursa, the body may identify that increased amount of compression occur at this point and create a 'bursa' (fluid cushion) to protect the nerve.

Symptoms of Interdigital Bursitis

Symptoms of an interdigital bursa are consistent with those for any nerve entrapment, like Morton's Neuroma:

  • Numbness

  • Burning

  • Tingling

  • Shooting pains or electric shocks

Although, because the bursa affects the nerve on the bottom of the foot, it can also create feelings like:

  • A rucked-up sock under the foot/toes

  • A pebble in your shoe

When a bursa gets particularly large, it can also create a 'Churchill sign', which is where it causes the toes either side to splay; however, this is more likely to be the result of plantar plate injuries than Interdigital Neuromas.

A collage showing a photo of Winston Churchill (with a cigar) making the 'peace' sign (two fingers up, palm facing forward) and a lady's foot where the toes have separated slightly forming something known as 'Churchill's sign'.
A graphic showing the anatomy of the bottom of the foot, including the muscles and tendons.

What else could it be?

Despite the relatively small amount of space at the front of the foot, there is quite a lot going on, especially due to the amount of force that goes through this region. Other differential diagnoses for interdigital bursitis include:

  • Morton's Neuroma

  • Capsulitis

  • Stress Fractures

  • Plantar plate injuries

  • Flexor tendinitis

  • Tarsal tunnel syndrome

How is interdigital bursitis diagnosed?

Interdigital bursitis and Morton's Neuroma are notoriously difficult to differentiate, and in most instances, their differentiation is not important to the clinical outcome. If diagnosis is important for the patient, then imaging is the only way to differentiate the two.

Imaging that can be used for Morton's Neuroma:

  • Ultrasound scans (particularly dynamic)

  • MRI Scans (may often miss neuromas if 'slices' taken are too widely spaced.

  • X-rays can be used to rule out other issues, like fractures, however, unless the X-ray is a standing X-ray, it provides very little useful information that may assist with the diagnosis of a neuroma.

A sagittal plane MRI of a foot showing a type of imaging that might sometimes be used to identify a space occupying lesion.
A podiatrist about to inject the bottom of a foot.

How is interdigital bursitis treated?

Interdigital bursitis, like Morton's Neuromas, are typically caused by biomechanical factors, and so the way to treat them is often to alter biomechanics. This being said, analgesics can also be helpful. 

Some of the treatments that are recommended include:

  • Stretching the calf muscles

  • Changing footwear

  • Use of anti-inflammatories

  • Orthotics and insoles

  • Manipulation and mobilisation of joints

  • Shockwave therapy

  • Steroid injections

Ready to start being pain free?

How long does it take to cure Interdigital Bursitis?

Unlike Morton's Neuroma, Interdigital Bursitis can resolve! If the biomechanical issues are changed, then the bursa (fluid filled sac) can disappear or shrink. Due to the clinical difficulties in differentiating the two conditions though, the timescales are quite similar. 

Generally speaking, symptoms can be improved by 30-50% within a week of starting insole therapy. 

If combined with changes in footwear, an improvement of 70-80% can often be enjoyed. 

Very few patients, after 6-8 weeks of treatment, will 

be considering surgery. 

A man running with his dog.
Ready to say goodbye to your pain?

At Keep On Your Feet, we openly acknowledge that we cannot guarantee a cure for things: but we will work as hard as we can with you to help you reach your goals. 

If your symptoms fit the above, you will need to book a 'Foot Pain' consultation. This will be £95 and lasts approximately 60 minutes usually. If you need insoles, we'll give you some basic ones to try out (or some fancier ones and reduce their price!). 

This is a picture of Jeremy Ousey, director and podiatrist of Keep On Your Feet.

About the Author

Jeremy Ousey is the owner at Swansea's podiatry clinic: Keep On Your Feet. All the information found on this page was written by him (there's no AI or Chat-GPT here!), and has been carefully chosen to provide you with the information that you need to know about the condition. Jeremy has a Bachelor of Science in Podiatry, with honours, a Post-Graduate Certificate in Podiatric Sports Medicine, a Post-Graduate Diploma in Medical Ultrasound, and two Master's of Science degrees in the Theory of Podiatric Surgery, and Sports & Exercise Medicine. If you would like to know more about Jeremy, please click here.

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