Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Puncture Wounds of the Foot

Basics
Description
  • Puncture injuries of the foot typically occur on the plantar surface of the forefoot or heel.
  • The injuring object usually is a nail, needle, or pin, but it can be anything that punctures the soft tissue, including thorns, glass, and splinters.
  • Classification:
    • Early presentation: Day of injury
    • Late presentation: At least 3-5 days after puncture, when deep infection develops
General Prevention
Avoid going barefoot outdoors or in areas with debris such as wood fragments or nails.
 
Epidemiology
  • Anecdotally, this injury is more common in children.
  • Males are affected more often than females.
Incidence
  • Puncture wounds of the foot constitute 0.5-1% of all emergency room visits by children.
  • Only 0.6% of children with puncture wounds develop deep infection.
Risk Factors
  • Walking barefoot
  • Construction work
Etiology
  • The penetrating object carries with it organisms from the soil, the skin, or a sock or shoe sole, if these are worn.
    • Pseudomonas and other atypical infections are common.
  • Many times, the flora is polymicrobial.
  • Usually, the site developing infection is a synovial-lined space such as a tendon sheath, joint, plantar bursa, or bone.
Diagnosis
Signs and Symptoms
  • Acute phase:
    • Pain
    • Swelling
    • Bleeding
  • Late presentation:
    • Redness
    • Tenderness
    • Cellulitis
    • Fluctuance or drainage (purulent or serous)
    • Patient may limp, refuse to bear weight, or walk on the heel to avoid pressure on the forefoot.
History
  • Timing of injury
  • Location of injury, degree of environmental contamination
  • Absence or presence of shoe wear at time of puncture wound
Physical Exam
  • Early presentation:
    • Inspect to assess the depth, severity, and contamination of the soft tissue.
    • Palpate the area to determine if any evidence of a retained foreign body is present.
    • Evaluate for joint involvement by proximity of the puncture wound and examination of joint ROM.
    • Examine shoe wear for evidence of penetration.
  • Late presentation:
    • Evaluate for local and systemic evidence of infection.
      • Erythema
      • Swelling
      • Cellulitis
      • Fluctuance
      • Enlargement of lymph nodes (popliteal, inguinal)
    • Check for pain with ROM of the adjacent joints.
      • MTP joint
      • IP joint
      • Midfoot joint
    • Circumferential or dorsal swelling likely indicates a deep infection.
Tests
  • Late presentation:
    • Area of infection (joint, bursa or tendon sheath) may be aspirated to obtain Gram stain and culture to identify an organism, which may guide treatment.
Lab
  • Early presentation: Usually not needed
  • Late presentation (infection suspected): The following can be helpful, although not specific.
    • White blood cell count with differential
    • ESR
    • C-reactive protein
Imaging
  • Plain radiography:
    • To rule out associated fracture, bony involvement, or retained foreign body
    • In late presentations, also may evaluate for osteomyelitis or gas in tissue
  • MRI:
    • May be reserved for difficult cases with deep involvement
    • Can identify abscess, osteomyelitis, and in some cases, retained foreign body
  • Ultrasound:
    • Can diagnose abscess
    • Can identify foreign body retained in foot
  • Nuclear medicine imaging:
    • Alternative to MRI
    • May help differentiate local inflammation from osteomyelitis
Diagnostic Procedures/Surgery
Local wound exploration should be performed to determine the extent of the wound and assess for any contamination.
 
Differential Diagnosis
  • Osteomyelitis
  • Septic arthritis
  • Tenosynovitis
  • Septic bursitis of the foot
  • Cellulitis
Treatment
General Measures
  • Acute presentation:
    • Local irrigation and debridement are indicated.
    • Debate arises whether prophylactic antibiotics are necessary for patients with acute puncture.
    • Tetanus prophylaxis booster should be given.
    • Instruct the patient to return if signs of deep infection develop.
  • Late presentation:
    • Deep infections require surgical irrigation and debridement, and tissue cultures should be obtained.
    • Soft-tissue infections are often Gram-positive Staphylococcus or Streptococcus, but Pseudomonas is not uncommon.
    • If the patient presents with cellulitis, aspiration should be attempted, and the patient should be treated empirically with oral or intravenous therapy for 24 hours with clinical evaluation.
      • If the condition improves, the patient should complete a 5-day course of oral antibiotics.
      • If the condition does not improve, or if Pseudomonas is recovered from the aspirate, surgical drainage is preferred.
    • Areas of fluctuance should be incised and drained.
    • For patients with a small, localized abscess that has been drained adequately with no other evidence of infection:
      • Broad-spectrum oral antibiotic coverage probably is adequate initially, but it should be changed to a culture-specific treatment as soon as possible.
      • Weightbearing activity may be resumed as tenderness resolves.
Medication
  • Acute puncture:
    • Antibiotic treatment remains controversial: It may not be indicated, but a short course may be prudent.
  • Late presentation:
    • After aspiration, administer antibiotics that are effective against Gram-positive organisms.
    • Add an antibiotic effective against Pseudomonas if this organism is recovered from cultures or if symptoms do not resolve.
Surgery
  • If needed, the site of infection should be localized by physical examination or plain radiography.
    • Occasionally, MRI is needed.
  • The approach should be the most direct to the pathologic features and should follow the tract of the puncture wound, if possible.
  • Plantar incisions are acceptable, although they should be positioned to avoid pressure points such as the heel or ball of the foot.
  • Thorough debridement should be performed.
  • Cultures should be sent for identification, including Mycobacterium, if clinically indicated.
Follow-up
Prognosis
  • Generally good
  • Complications include cellulitis, abscess, osteomyelitis, and septic arthritis.
  • The rate of subsequent osteomyelitis is ~0.6-1.8%.
Complications
  • Rate of complications in 1 study was 3.2%.
  • Osteomyelitis (rare)
  • Septic arthritis (rare)
Patient Monitoring
Follow-up examination is performed by a primary care physician or a specialist if symptoms persist.
 
Miscellaneous
Codes
ICD9-CM
  • 682.7 Cellulitis/abscess foot
  • 711.07 Pyogenic arthritis ankle and foot
  • 730.07 Acute osteomyelitis ankle and foot
Patient Teaching
After an acute puncture wound, patients should be instructed about the signs and symptoms of infection and told to return if these occur.
 
FAQ
Q: How should an acute puncture wound be treated?
A: Puncture wounds that present early should be thoroughly cleaned and irrigated. Foreign bodies should be removed. Antibiotics are not necessarily required. Wounds that present late with signs of infection require aggressive irrigation and debridement and antibiotic therapy.
Q: What are the most common pathogens?
A: The most common organisms in infected puncture wounds are skin flora, commonly Gram-positive cocci. Pseudomonas is not an uncommon pathogen and should be suspected in wounds that fail to respond to initial treatment or that show signs typical of this organism (blue-green tinted, foul-smelling, or musty discharge).

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