From the Guidelines
Morton neuroma diagnosis should primarily rely on MRI due to its high sensitivity and specificity, with a sensitivity of 87%, specificity of 100%, accuracy of 89%, PPV of 100%, and NPV of 60% in surgically treated patients 1. When diagnosing Morton's neuroma, it is essential to consider the most effective imaging techniques. The two most commonly used techniques are MRI and US. However, MRI has been shown to have a significant impact on diagnostic and therapeutic decisions made by orthopedic surgeons, increasing their confidence levels and changing treatment plans 1. Some key points to consider when diagnosing Morton's neuroma include:
- MRI is a sensitive and reliable method to evaluate patients with metatarsalgia and Morton's neuroma 1
- MRI can demonstrate increased fluid within the intermetatarsal bursa, suggesting bursitis 1
- The use of gadolinium may not be essential to detect Morton's neuromas but can facilitate detection due to improved soft-tissue contrast 1
- A meta-analysis found that MRI had a pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 93%, 68%, 1.89, and 0.19, respectively 1 Given the high sensitivity and specificity of MRI, it is recommended as the primary imaging technique for diagnosing Morton's neuroma 1.
From the Research
Definition and Causes of Morton's Neuroma
- Morton's neuroma is a common pathology affecting the forefoot, characterized by fibrosis of the nerve, not a true neuroma 2.
- It is caused by pressure or repetitive irritation leading to thickness of the digital nerve, typically located in the third or second intermetatarsal space 2.
Treatment Options
- Treatment options for Morton's neuroma include orthotics, steroid injections, and surgical excision, usually performed through a dorsal approach 2.
- Non-surgical interventions, such as corticosteroid injections, manipulation/mobilisation, and extracorporeal shockwave therapy, have been shown to be effective in reducing pain and improving function 3.
- Sclerosing injections, including 4% ethanol sclerosing injection, have been investigated as a treatment option, with some studies showing promising results 4.
Efficacy of Treatments
- A systematic review found that operative treatment had better outcomes than conservative treatment, but more high-quality studies are needed to confirm these results 5.
- A Cochrane review found low-certainty evidence that corticosteroid and local anaesthetic injection may result in little to no difference in pain and function, but moderate-certainty evidence that ultrasound-guided corticosteroid and local anaesthetic injection probably reduces pain and increases function 6.
- The review also found that plantar incision neurectomy may result in little to no difference in satisfaction and adverse events compared to dorsal incision neurectomy, but the evidence is limited by the small number of studies and low certainty of the evidence 6.
Key Considerations
- Careful clinical examination, patient selection, pre-operative counselling, and surgical technique are key to successful management of Morton's neuroma 2.
- The choice of treatment should be individualized based on the patient's specific condition and needs, and further research is needed to establish the most effective treatment options 3, 6.