CAUSES
. Abnormal pressure distribution plantar to the metatarsal heads
. General
. Excessive or repetitive stress - high heels, ballet dancers, competitive athletes
. Soft tissue dysfunction - intrinsic muscle weakness, laxity of the Lisfranc ligament
. Abnormal foot posture - forefoot varus or valgus, cavus or equinus deformities, loss of the metatarsal arch, splay foot, pronated foot
. Dermatologic - warts, callus
. Great toe
. Hallux valgus (bunion), varus or rigidus
. Lesser metatarsals
. Freibergs infraction (aseptic necrosis of the metatarsal head usually in adolescents who jump or sprint)
. Hammertoe or claw toe
. Morton syndrome (long second metatarsal)
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DIFFERENTIAL DIAGNOSIS
β’ Stress fracture (most commonly 2nd metatarsal)
β’ Morton neuroma (interdigital neuroma)
β’ Sesamoiditis or sesamoid fracture
β’ Arthritis (rheumatoid, inflammatory, osteoarthritis, septic)
β’ Infection (cellulitis, diabetic foot, Lyme disease, leprosy)
β’ Bone tumors (rare)
β’ Ganglion cyst
β’ Foreign body
β’ Vasculitis (diabetes)
LABORATORY Only if diagnosis is in question:
ESR, RF, HLA Ag, VDRL, uric acid, glucose, CBC with differential.
IMAGING
β’ Weight-bearing films AP, lateral and oblique views. Occasionally metatarsal or sesamoid axial films (to r/o sesamoid fracture), or skyline view of the metatarsal heads - obtained with the metatarsophalangeal joints in dorsiflexion (to evaluate alignment).
β’ Bone scan if high index of suspicion of stress fracture