diagnosis

Last reviewed 01/2018

The diagnosis is mainly clinical and further investigations are done as required to rule out other possible causes (1):

  • clinical examination is the mainstay of diagnosis with pain at the intermetatarsal space rather than on the plantar or dorsal aspects of the MTPJs
    • neuroma generally located at the level of and just distal to the metatarsal heads
    • there may be some dorsal MTPJ tenderness due to retraction of the toes as they try to reduce pressure from beneath the ball of the foot
    • compression of the forefoot with pressure at the intermetatarsal space often elicits a click as the nerve is pushed between the metatarsals (termed a Mulder's click) - compression of the forefoot in this manner may or may not be symptomatic
    • there may be a reduction in sensation to the associated web space
  • x-ray - useful in ruling out musculoskeletal pathology (neuromas are not visible) (1)
  • ultrasound (US) and magnetic resonance imaging (MRI) scans are both helpful in the diagnosis and can help to differentiate diagnosis, although sensitivity and specificity can be examiner-dependent
    • US
      • considered by many as the diagnostic test of choice
      • reported to be between 94% and 100%
      • appears as an ovoid, hypoechoic mass just proximal to the metatarsal heads
      • finding a sonographic mass supports the clinical diagnosis but the absence of a mass does not exclude Morton’s neuroma (3)
    • MRI.
      • routine use is not recommended
      • used for atypical presentation and to rule out multiple neuromas (1)

One prospective study which evaluated the accuracy of pre-operative clinical assessment, US and MRI concluded that

  • clinical assessment was the most sensitive and specific modality
  • US and MRI had similar accuracy but was dependent on size
  • accuracy of US was less for small lesions (4)

Reference: