Ankle pain

This page is for adult patients. For pediatric patients, see: Ankle pain (peds).

Background

Ankle anatomy: left ankle, anterior-lateral view.
Ankle anatomy: left ankle, anterior-medial view.
Ankle anatomy

Clinical Features

  • Ankle pain

Differential Diagnosis

Other Ankle Injuries

Distal Leg Fractures

Foot and Toe Fractures

Hindfoot

Midfoot

Forefoot

Foot diagnoses

Acute

Subacute/Chronic

Evaluation

Workup

Acute traumatic

  • Consider x-rays

Atraumatic / Subacute

Diagnosis

Acute traumatic

  • Typically determined by imaging

Atraumatic / Subacute

  • See following for analysis of synovial fluid, if indicated

Arthrocentesis of synoval fluid

Synovium Normal Noninflammatory Inflammatory Septic
Clarity Transparent Transparent Cloudy Cloudy
Color Clear Yellow Yellow Yellow
WBC <200 <200-2000 200-50,000

>1,100 (prosthetic joint)

>25,000; LR=2.9

>50,000; LR=7.7

>100,000; LR=28

PMN <25% <25% >50%

>64% (prosthetic joint)

>90%

Culture Neg Neg Neg >50% positive
Lactate <5.6 mmol/L <5.6 mmol/L <5.6 mmol/L >5.6 mmol/L
LDH <250 <250 <250 >250
Crystals None None Multiple or none None
  • Viscosity of synovial fluid may actually be decreased in inflammatory or infectious etiologies, as hyaluronic acid concentrations decrease
  • The presence of crystals does not rule out septic arthritis; however, the diagnosis is highly unlikely with synovial WBC < 50,000[1]

Management

Disposition

  • Depends on specific diagnosis
    • Most closed and distally neurovascularly intact traumatic injuries are treated as an outpatient
    • Ortho referral for significant fractures/dislocations
    • Septic joint should be admitted

See Also

  • Shah K, Spear J, Nathanson LA, Mccauley J, Edlow JA. Does the presence of crystal arthritis rule out septic arthritis?. J Emerg Med. 2007;32(1):23-6.