Acute Compartment Syndrome, leg

Acute compartment syndrome occurs when there is an increased pressure within the closed osteofascial compartment which results in impaired circulation within a few hours of the inciting event. Richard von Volkmann, a German surgeon, was the first person to describe compartment syndrome and did so in 1881.

Etiology

• Ischemia
• Trauma
  • Crush injuries
  • Severely comminuted or segmental fractures → tibial fractures (most common)
  • Widely displaced joint or fracture pieces
  • High-energy injuries with impaired sensation
• Burn injuries
• Tight dressing or cast

Pathogenesis

• Inciting event (i.e., ischemia, trauma, burn injury) occurs and causes a decreased intracompartmental space and increased intracompartmental fluid volume due to the inability of the fascia to expand
• No equilibrium between venous outflow and arterial inflow is permitted
• Venous pressure and venous capillary pressure increases which leads to the intracompartmental pressure to increase
• Decreased oxygenation of tissues occurs as a result of decreased arterial inflow and venous outflow, leading to ischemia
• Usually manifests within a few hours, but can be up to 48 hours later

History

• Tense, tender leg muscles
• Leg numbness
• Dysesthesias

Physical Exam

• Tense, tender muscles → “wood-like” feeling
• Pain on passive motion (early)
• Impaired motor function
• Pain out of proportion
• Intracompartmental pressure > 30 mmHg (normal pressure is < 10 mmHg)
• Pulses may be present! Presence or absence of a pulse isn’t definitive.
• 5Ps: pain, pulselessness, paresthesia, paralysis, pallor

Labs

• CPK (creatinine phosphokinase): may be elevated; suggestive of muscle breakdown from ischemia, damage, or rhabdomyolysis

Imaging

• Radiograph if fracture is present
• Intracompartmental pressure
• Delta pressure: difference between diastolic blood pressure and intracompartmental pressure

Treatment

• Surgical emergency!
• Flow restoration
  • Thrombectomy
  • Embolectomy
  • Bypass
  • Thrombolytic therapy
• Lower extremity fasciotomy
  • If intra-compartmental pressure is > 30 mmHg

Relevant Information

• Fascia
  • Thin, inelastic connective tissue 
  • Surrounds muscle compartments and has a limited capacity for expansion
• Compartment syndrome is most likely to occur in the lower extremity, likely as a result of ischemia or restoration of flow after a period of ischemia
• Superficial branch of the peroneal nerve: lies adjacent to the intermuscular septum between anterior and lateral compartments 
• Compartments of the leg
  • Anterior → most common location for compartment syndrome
    • Tibialis anterior
    • Peroneus tertius
    • Extensor hallucis longus
    • Extensor digitorum longus 
  • Lateral
    • Peroneus longus
    • Peroneus tertius
  • Superficial posterior
    • Gastrocnemius
    • Soleus
    • Plantaris
  • Deep posterior
    • Tibialis posterior
    • Popliteus 
    • Flexor hallucis longus
    • Flexor digitorum longus

Complications

• Contractures
• Pain
• Rhabdomyolysis
• Nerve damage, associated numbness/weakness
• Infection
• Renal failure
• Death

Differential Diagnoses

• Deep vein thrombosis
• Cellulitis
• Gas gangrene
• Rhabdomyolysis
• Peripheral vascular injuries