Ultrasound-Guided Cortisone Injections for Morton's Neuroma

 

Introduction

Morton’s neuroma is a painful condition affecting the nerves in the forefoot, most commonly between the third and fourth toes. It occurs due to thickening or irritation of the interdigital nerve, leading to symptoms such as burning pain, numbness, and a sensation of walking on a pebble. This condition is often caused by repetitive stress, improper footwear, or biomechanical abnormalities.

At Alton Pain Clinic, ultrasound-guided cortisone injections may be considered as a targeted approach for reducing inflammation and pain in Morton’s neuroma. This blog provides a detailed overview of Morton’s neuroma, including anatomy, pathology, causes, symptoms, diagnosis, and treatment options, with a focus on how cortisone injections work and their mechanism of action.

Anatomy of the Foot and Morton’s Neuroma

The foot is composed of bones, muscles, ligaments, and nerves that work together to provide support and mobility.

Key Anatomical Structures Involved in Morton’s Neuroma

✔ Interdigital Nerves — Small nerve branches that run between the metatarsal bones, providing sensation to the toes.
✔ Metatarsal Heads — The rounded ends of the long bones in the foot, which bear weight during walking.
✔ Transverse Metatarsal Ligament — A fibrous band that stabilises the forefoot but may contribute to nerve compression.

When excessive pressure or repetitive stress affects the interdigital nerve, it may cause thickening of the nerve tissue, leading to pain and discomfort associated with Morton’s neuroma.

Pathology of Morton’s Neuroma

Morton’s neuroma is not a true tumour but rather a fibrotic thickening of the interdigital nerve due to chronic irritation. Key pathological changes include:

✔ Perineural Fibrosis — The nerve sheath develops scar-like tissue, causing irritation and compression.
✔ Nerve Inflammation — Constant mechanical stress leads to swelling and pain in the affected area.
✔ Widening of the Nerve — The nerve may become thickened, increasing sensitivity to pressure.
✔ Compression by the Transverse Metatarsal Ligament — This ligament can press against the nerve, exacerbating symptoms.

Causes of Morton’s Neuroma

Morton’s neuroma is commonly caused by repetitive trauma or pressure on the foot.

1. Improper Footwear

• Tight shoes, high heels, or narrow toe boxes can squeeze the metatarsals together, compressing the interdigital nerve.

2. Biomechanical Abnormalities

• Flat feet, high arches, or excessive pronation can alter weight distribution, increasing pressure on the forefoot.

3. High-Impact Activities

• Sports such as running, tennis, and basketball place repetitive stress on the forefoot, contributing to nerve irritation.

4. Repetitive Trauma

• Frequent walking on hard surfaces or engaging in weight-bearing activities can lead to chronic nerve compression.

Symptoms of Morton’s Neuroma

✔ Burning pain in the ball of the foot — Often worsens with activity.
✔ Tingling or numbness — Typically affects the third and fourth toes.
✔ A sensation of walking on a pebble or lump — Common when weight is applied to the foot.
✔ Pain relief when removing footwear or massaging the foot — Suggests nerve compression.
✔ Radiating discomfort — Pain may spread to adjacent toes or up the foot.

Symptoms often progress over time, becoming more persistent if left untreated.

Diagnosis of Morton’s Neuroma

Clinical Assessment at Alton Pain Clinic

A clinician will evaluate the foot using:

✔ Medical History — Discussing symptoms, footwear choices, and activity level.
✔ Physical Examination — Applying pressure to the affected area to reproduce symptoms (Mulder’s sign).

Imaging Studies

1. Ultrasound Scan — A high-resolution scan to assess nerve thickening and inflammation.

Treatment Options for Morton’s Neuroma

Conservative Management

✔ Footwear Modifications — Wide-toe shoes and cushioned insoles can reduce pressure on the forefoot.
✔ Orthotic Inserts — Custom insoles help redistribute weight and reduce nerve compression.

Ultrasound-Guided Cortisone Injections for Morton’s Neuroma

For persistent pain and inflammation, ultrasound-guided cortisone injections may be considered.

Mechanism of Action of Cortisone Injections

Cortisone injections contain corticosteroids, which:
✔ Reduce inflammation — Suppressing the release of inflammatory mediators within the nerve sheath.
✔ Alleviate nerve irritation — Minimising swelling and pressure on the interdigital nerve.
✔ Provide temporary pain relief — Allowing improved mobility and function.

Why Use Ultrasound Guidance?

At Alton Pain Clinic, ultrasound guidance ensures:
✔ Accurate placement of medication around the affected nerve.
✔ Reduced risk of complications by avoiding nearby structures.
✔ Optimised treatment effectiveness.

Procedure Overview

1. Preparation — The foot is cleaned, and a local anaesthetic is applied.
2. Ultrasound Imaging — The affected nerve is visualised to ensure precise targeting.
3. Injection — Corticosteroid medication is delivered to the inflamed area.
4. Post-Injection Care — Patients are advised to limit high-impact activities for 24–48 hours.

Why Choose Alton Pain Clinic for Morton’s Neuroma Treatment?

✔ Experienced clinicians specialising in musculoskeletal conditions.
✔ Advanced ultrasound-guided injection techniques.
✔ Comprehensive, patient-centred approach tailored to individual needs.

Conclusion

Morton’s neuroma is a common cause of forefoot pain, often resulting from nerve compression between the metatarsal heads. While conservative measures such as footwear modifications and physiotherapy may help, ultrasound-guided cortisone injections can provide targeted relief by reducing inflammation and nerve irritation.

At Alton Pain Clinic, we offer expert musculoskeletal care, ensuring precise and effective treatment to help patients regain comfort and mobility.