Metatarsalgia

definition

· pain in the forefoot in the region of the metatarsal heads

aetiology

Great toe

· hallux valgus

· hallux rigidus

· sesmoiditis

Lesser toes

· transfer metatarsalgia

· interdigital neuroma

· March fracture

· Frieberg’s disease

· intractible plantar keratosis

· plantar wart

Interdigital neuroma

· syn. Morton’s neuroma

epidemiology

· usually presents in middle age (peak 55 yrs)

· affects women more than men

· most commonly in 3rd-4th interspace

pathology

· degenerative change in plantar nerve

· immediately proximal to bifurcation

· adjacent to distal part of transverse intermetatarsal ligament

· nerve develops fusiform swelling

· not true neuroma

· contains degenerating and regenerating nerurones

· most likely due to ischaemia

clinical features

History

· acute burning pain on plantar aspect of forefoot into toes

· may be associated parasthesiae

· related to weight-bearing

· aggravated by high heels

Examination

· acute tenderness when pressure exerted in affected web space on plantar aspect

· pain on laterally squeezing foot and compressing metatarsal heads together

· may be decreased sensation in affected cleft

treatment

Nonoperative

· appropriate shoes

· domed metatarsal insole

Operative

· usually required

· plantar or dorsal incision

· plantar incision

· protect digital vessels

· dorsal incision

· divide intermetatarsal ligament

· resect nerve sufficiently proximally to prevent development of stump neuroma

March fracture

epidemiology

· usually of 2nd or 3rd metatarsal shaft

· occurs in

· adults after unaccustomed activity

· women with postmenopausal osteoporosis

clinical features

History

· pain after walking and then with walking

· swelling after activity

Examination

· tender swelling along metatarsal shaft

Radiology

X-ray

· initially normal

· later shows callus around fine transverse fracture

Bone scan

· shows increased activity before x-ray changes

treatment

· symptomatic

· rest for 3-4 weeks

· may need strapping or cast

Freiburg’s disease

definition

· osteochondritis of metatarsal head

· usually 2nd

· may be 3rd

epidemiology

· usually young females

· peak age 15 yrs

· F:M = 3:1

clinical features

· pain under metatarsal head on exercise

· palpable tender bony lump

· pain on forced dorsiflexion

radiology

· flattened enlarged metatarsal head

· increased joint space

treatment

Nonoperative

· metatarsal insole

Operative

· cheilectomy

· removal of dorsal osteophytes

· remove at least 1/3 of dorsal MT head

· extension osteotomy of MT neck

· to increase dorsiflexion range

Sesamoiditis

· present with acute pain in region of sesamoids on weight-bearing

· well-localised tenderness of one or other sesamoid

· x-ray may show

· nothing

· multipartite sesamoid

· increased density

· relieved by excision of troublesome sesamoid

Hyperkeratotic disorders

definition

· syn. corn, callus, callosity, heloma, clavus

· localised keratosis caused by abnormal pressure

· pressure may be

· intrinsic (from bony prominences)

· etxernal (from shoewear)

pathology

· hypertropy of stratum corneum

· central keratotic plug

Hard corn

· occurs on exposed surfaces of toes

· esp. on dorsolateral aspect of PIP jt of 5th toe

· occurs with lesser toe deformities

· usually on dorsum of PIP jt

Soft corn

· usually interdigital

· forms over phalangeal condyle

· most common between 4th and 5th toes

· where head of 5th proximal phalanx abuts base of 4th proximal phalanx

· similar to hard corn but overlying tissue becomes macerated

plantar corn

· syn. plantar keratosis

· forms over bony prominences

· most commonly on plantar surfaces under MT head

· if fibular condyle of MT prominent

· if MTP joint subluxed

· may be

· focal (under one MT head)

· diffuse (under multiple MT heads)

· may be confused with plantar wart

· differentiation from plantar wart

· callus painful to direct pressure (cf. side-to-side pressure)

· skin markings radiate into and through callus (cf. stop at edge)

· avascular (cf. punctate bleeding with paring)

Treatment

Nonoperative

· paring of callus

· extra depth shoes with metatarsal support

Operative

· indicated in focal keratosis not responding to nonoperative treatment

· metatarsal osteotomy

· dorsal closing wedge

· sliding with internal fixation

Plantar wart

· caused by virus of Papillovirus group

· enters unrecognised breach in skin

· common site is on plantar aspect of metatarsal heads

· presents as round or oval lesion

· may be mistaken for callosity

· may be multiple and may coalesce

· treated by

· salicylic acid

· curettage and cauterisation of wall

· wide excision if resistant