Fractures of the Fifth Metatarsal Anna Quinn Harrelson

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Fractures of the Fifth Metatarsal

• Anna Quinn Harrelson
• Radiology-USC-SOM

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Varieties

• Proximal
• -Acute fx of the tuberosity (metaphysis) aka
  dancers fx
• Jones Fx (classic)
• Stress Fx of the proximal diaphysis
• Acute on chronic diaphyseal fxs
• Distal

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Clinical Common Signs and Symptoms

•    -Taking a good history is key to diagnosis and
  treatment.
• Sharp pain, especially with standing or walking
     -Tenderness, swelling, and later bruising of
  the foot    -Numbness or paralysis from swelling
  in the foot, causing pressure on the blood
  vessels or nerves (uncommon)
• then of course- physical exam is always crucial.

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Anatomy
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Avulsion Fracture

• This is the most common- You Will See It!
• Sometimes also called a Dancers Fractures (fx at
  the base of the 5th metatarsal)
• HP sudden onset of pain at the base of the 5th
  metatarsal, usually after forced inversion with
  the foot and ankle in plantar flexion.
  Tenderness, ecchymosis and swelling at the site
  may be present.
• Dont forget to fully evaluate the distal fibula
  and lateral ligaments for other injuries.

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Tuberosity avulsion fracture Note that the
radiolucency is perpendicular to the long axis of
the fifth metatarsal. Intra-articular involvement
is not present in this example.
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Avulsion Fracture

• Differential Apophysis (normal in age 9-14)
  Apophysitis (Iselins Dz), Accessory Ossicles
• Treatment Nondisplaced conservative (elastic
  wrapping, ankle splints, low-profile walking
  boots and casts), weight-bearing as tolerated,
  3-6 wks until sxs abate
• Comminuted fxs and those involving more than 30
  of the cubometatarsal articulation surface
  should be referred.

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Apophysis (arrow) of the base of the fifth
metatarsal, common in girls nine to 11 years of
age and in boys 11 to 14 years of age. Note the
oblique orientation with the radiolucency aligned
in parallel to the fifth metatarsal diaphysis.
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Tuberosity avulsion fracture with intra-articular
involvement. This example involves greater than
30 percent of the cubo-metatarsal articulation
with displacement. These characteristics help
define indications for surgical consultation.
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Jones Fracture

• Important Not To Miss!
• Within 1.5 cm of the tuberosity
• HP sudden pain at the base of the 5th
  metatarsal, with difficulty bearing weight on the
  foot. Often bruising and swelling will be
  present.
• Mechanism is described as a laterally directed
  force on the forefoot during plantar flexion of
  the ankle (ex pivot-shifting in football or
  basketball with the heel off the ground)

Lateral radiograph of the foot. A patient
stepped off a curb and sustained a fracture of
the proximal aspect of the fifth metatarsal.
According to Greenspan, this would be termed a
"true Jones fracture." 
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Some people have all the luck!
1902Sir Robert Jones Injured himself while
dancing around a Maypole at a Military Garden
Party
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Classification/Radiographic Appearance
Torgs Classification

• Type I no intramedullary sclerosis, a sharp,
  well-delineated fx line and minimal cortical
  hypertrophy
• Type II(delayed unions) have a fx line that
  involves both cortices with associated periosteal
  new bone, a widened fx line with adjacent
  radiolucency related to bone resorption and
  evidence of intramedullary sclerosis
• Type III (nonunions) wide fx line with
  periosteal new bone and radiolucency and complete
  obliteration of the medullary canal at the
  fracture site by sclerotic bone

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Fracture of the fifth metatarsal shaft within 1.5
cm of the tuberosity, type II. This type II
fracture includes intramedullary sclerosis,
widening of the fracture line and cortical
hypertrophy. The history is critical in
distinguishing acute type II fractures (delayed
unions) from stress-type fractures (see Table 1).
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Why bother with the classification???

• Prior to the system- there were HIGH rates of
  nonunion due to disruption of the vascular supply
  which enter the bone at the metaphyseal-diaphyseal
  region.
• Proper classification of Type I or II can be
  initially treated conservatively in all but
  athletes or pts who opt for surgery
• Anyone with a displaced fx should be referred

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Treatment of Jones Fracture

• Type I non-weight-bearing short leg cast for 6-8
  wks with progressive ambulation after cast
  removal
• Type II same cast worn longer to allow union- if
  athlete- surgery (medullary curettage and inlay
  bone grafting or intramedullary screw fixation)
• Type III operateof course there may certainly
  be complications

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Oblique radiograph of the foot. Two years later
the patient returns for continued pain. A
radiograph reveals nonunion of the fracture, a
frequent complication of the Jones fracture. 
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Stress Fracture

• A stress fracture is a break in a bone cause by
  repetitive stress. There is often no recollection
  of injury. The patient may simply develop a
  painful forefoot after some activity, such a
  walking, sports, or stooping down onto the ball
  of the foot.
• Without proper treatment, this may progress to a
  overt fracture of the bone. Metatarsal stress
  fracture may not become apparent on x-rays until
  a few weeks after the injury.
• HP Occurs predominantly in younger patients and
  athletes. Athletes present early in the training
  season. Patients usually have prodromal pain for
  weeks to months before presentation.
• Sharp pain in the forefoot, aggravated by walking
  Tenderness to pressure on the top surface of a
  metatarsal bone. Diffuse swelling of the skin
  over the forefoot.

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Stress fxs

• Causes Decreased density of the bones (eg.
  osteoporosis) Unusual stress on a metatarsal due
  to malposition or another forefoot deformity (eg.
  bunion) Abnormal foot structure or mechanics
  (eg. flatfoot) Increased levels of activity,
  especially without proper conditioning Obesity
• Treatment stress fxs within 1.5cm of the
  tuberosity of the 5th metatarsal may require up
  to 20 wks of non-weight bearing immobilization
  and may still result in nonunion, muscle atrophy
  or persistent pain.
• Tx Type II and III stress fxs like acute Jones
  fxs

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Diagnosis

• Radiography is the first and often the only
  investigation required for the diagnosis of
  fractures. X-Ray can be used diagnose all acute
  fractures, dislocations, and established stress
  fractures.
• Bone scanning is more sensitive than plain
  radiography and indicated when a stress or acute
  fracture is suspected and radiographs are
  negative. Bone scanning is not a specific
  investigation.

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Diagnosis

• Although MRI is more sensitive than radiography
  and bone scanning, it is used only for the
  assessment of soft tissue structures and
  ligamentous injuries. MRI is the most sensitive
  technique for imaging stress fractures of the
  foot and can depict bone marrow edema even before
  increased uptake is seen on bone scans.
• CT scanning is useful for finding avulsion
  fractures and comminuted fractures to assess for
  intra-articular extension.

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Limitations of Techniques

• Small avulsions can be missed on radiographs. In
  the early stages of stress fracture, radiographs
  can be normal, or they may show only subtle
  periosteal reaction, which can be easily missed.
• Radiography cannot be used to assess soft-tissue
  and ligamentous disruption.
• Although CT and MRI are more sensitive than
  radiography, they are not cost-effective and not
  indicated for the diagnosis of fractures.
• Although bone scanning is sensitive, it can still
  miss some stress fractures in the early stages.

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Treatment

• Based on Fracture Type and Classification
• Most Injuries respond to Conservative management.
• Make sure you know when to refer and what you can
  treat yourself.

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foot notes

• http//www.emedicine.com/radio/topic850.htm
• http//www.physsportsmed.com/issues/1998/02feb/sha
  piro.htm
• Duke Orthopaedics Wheeless Textbook of
  Orthopaedics www.wheelessonline.com
• www.aafp.org