Forefoot Fractures - Orthopaedic Trauma - Lecture Slides, Slides of Orthopedics

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Forefoot Fractures

Created March 2004; Revised March 2006

Foot Function

• Hindfoot: Shock absorption, propulsion,

deceleration

• Midfoot: Controls relationship between

hindfoot and forefoot

• Forefoot: Platform for standing and lever for

push off

Forefoot Function

• Platform for weight

bearing

• Lever for propulsion

Anatomy

• First Metatarsal

• Shorter & wider
• Bears 1/3 body weight
• Tendon attachments: (Tibialis Anterior & Peroneus Longus)
• Tibialis Anterior: varus, supination, elevation
• Peroneus Longus: valgus, pronation, depression

Lesser Metatarsals

More mobile medial to lateral Bear 1/6 weight each

Intermetatarsal ligaments (2-3, 3-4, 4-5)

Sesamoids

• Medial (tibial) & Lateral (fibular)
  • Within FHB tendons
• Articulate with 1st MT head
• Weight bearing through sesamoids

Tibial Sesamoid: Tibial FHB Abductor Hallucis

Fibular Sesamoid: Fibular FHB Adductor Hallucis Deep Tverse MT ligament

Phalanges

• Great toe (2)
• Lesser toes (3)
• FDB attaches @ intermediate
• FDL/EDL attaches @ distal

Biomechanics

• Metatarsal heads in contact

with floor 60-80% of stance

phase

• Toes in contact with floor 75%

• of stance phase

Cavanagh, PR, F&A, 1987 Hughes, J, JBJS[Br], 1990

Cross-sectional Geometry of the Human Forefoot

• Griffin & Richmond, Bone, 2005
• Examines the relationship between external loads during walking & running and the geometrical properties of the human forefoot
• Metatarsals 2-4 are the weakest in most cross-sectional geometric properties
• Metatarsal 2 (and 3 to a lesser extent) experience high peak pressures; this may explain the preponderance of stress fractures in these metatarsals

Mechanism

• Industrial accidents

• MVA (airbags)

• Indirect (twisting injuries)

• Other

Physical Examination

• Gross deformity

• Dislocations

• Sensation

• Capillary refill

• Foot

Compartments

Radiographs

• Foot trauma series
• AP/lat/oblique
• Don’t forget oblique
• Sesamoid view
• Tangential view (MT heads)
• Contralateral foot films (comparison)
• CT Scan (occasionally)

Treatment Principles

• Hindfoot: Protect subtalar, ankle and

talonavicular joints

• Midfoot: restore length and alignment of

medial and lateral “columns”

• Forefoot: Even weight distribution

Treatment

• Border Rays

• First metatarsal

• Fifth metatarsal

• Dislocations

• Multiple metatarsal shafts

• Intraarticular fractures

First MT Shaft Fractures

• Nondisplaced
• Consider conservative treatment
• Immobilization with toe plate
• Displaced
• Most require ORIF
• Strong muscle forces (TA, PL)
• Deformity common
• Bears 2/6 body weight

ORIF Plate and screws Anatomically reduce May cross first MTP joint (temp)

First MT Base Fractures

• Articular injuries
• Frequently require ORIF
• Fixation:
• Spans TMT
• Doesn’t span TMT
• Temporarily Spans TMT

Non-displaced Metatarsal Fractures 2-

• Single metatarsal fractures
• Treatment usually nonoperative
• Symptomatic: hard shoe vs AFO vs cast vs

elastic bandage

• Multiple metatarsal fractures
• Usually symptomatic treatment (as above)
• May require ORIF if other associated injuries

Minimally Displaced Lesser Metatarsal Fractures

• Zenios et al, Injury 2005
• Prospective and randomized (n=50)
• Case vs elastic support bandage
• MINIMALLY DISPLACED fractures
• Higher AOFAS mid-foot scores at 3 months and less pain if treated with an elastic support bandage.

Displaced Metatarsal Shaft Fractures

• Sagittal plane displacement & angulation
  • is most important.
• Reestablish length, rotation, & declination
• Dorsal deformity can produce transfer metatarsalgia
• Plantar deformity can produce increased load at affected metatarsal

Treatment Options

Closed Reduction Intramedullary pinning with k-wire (0.054” or 0.062”) Pinning of distal segment to adjacent metatarsal ORIF with dorsal plate fixation

Medullary K-wires in Lesser MTs

• Exit wire distally through

the proximal phalanx

• Plantar wire exit may

produce a hyperextension

deformity of the MTP

Stress Fractures of Metatarsals 2 - 4

• Identify Cause
• First ray hypermobility
• Short first ray
• Tight gastrocnemius
• Long metatarsal
• Treatment
• Treat cause if identifiable
• If overuse, activity restriction
• Reserve ORIF for displaced fractures

Metatarsal Neck Fractures

• Usually displace plantarly

• May require reduction and

fixation:

• Closed reduction and pinning
• Open reduction and pinning
• ORIF (dorsal plate)

Metatarsal Head Fractures

• Unusual

• Articular injuries

• May require ORIF

• (especially if first

MT)

Fifth Metatarsal Fractures

• Mid diaphyseal fractures
• Stress fractures (proximal diaphysis)
• Jones fractures (metadiaphyseal jxn)
• Tuberosity fractures

Proximal Fifth Metatarsal Fractures Dameron, TB, JAAOS, 1995

• Zone 1 cancellous tuberosity
• insertion of PB & plantar fascia
• involve metatarsocuboid joint
• Zone 2 distal to tuberosity
• extend to 4/5 articulation
• Zone 3 distal to proximal ligaments
• usually stress fractures
• extend to diaphysis for 1.5 cm

Proximal Fifth Metatarsal Fractures

Dameron, TB, JAAOS, 1995

• Relative Frequency
  • Zone 1 93%
    • Zone 2 4%
    • Zone 3 3%