Look for evidence of systemic disease especially:
- diabetic neuropathy
- inflammatory arthropathy
- neurological disease
- vascular disease
Examination must begin proximally
- any stiffness or deformity (including length discrepancy) which might alter pressures on the forefoot?
- tight Achilles tendon or reduced ankle dorsiflexion, especially if there is fixed equinus (remember to examine in subtalar neutral position)
- pes cavus
- overpronated foot with unstable 1st ray
- peripheral neurological examination
- tenderness or a positive Tinel sign over the major nerve trunks
- hallux deformity or painful 1st MTPJ
- hammer or claw toes - if so, how flexible is the MTPJ. With the MTPJ reduced (if possible) is the fat pad reduced under the metatarsal heads?
- interdigital tenderness, palpable swelling or a positive metatarsal head compression test or Mulder's click
- interdigital corns
- tenderness and/or calluses under the metatarsal heads - check the relationship between the relative positions of heads and calluses. Most calluses are relatively diffuse although there may be increased thickening under the MT heads. However, a very localised callus should raise suspicions of a plantar condylar eminence
- metatarsophalangeal instability or irritability
- it is often possible to assess the relative heights and lengths of metatarsals by palpation
- look for scars of previous surgery
Always screen the patient for diabetes - a urine test is usually enough
This will usually indicate one or more possible factors which may be contibuting to forefoot pain. Differential injections around interdigital nerves and into MTP joints may help distinguish between MTP synovitis and interdigital neuralgia (although at least 10% of patients with each of these conditons also has the other) (Miller 2001). In the end it often requires experience-based judgement to decide which factors should be tackled and in what order.