How to diagnose compartment syndrome in the thigh?

From the Guidelines

Testing for compartment syndrome in the thigh should begin with a thorough physical examination, assessing the 5 P's: pain, pallor, paresthesia, paralysis, and pulselessness, and if diagnosis remains unclear, direct measurement of intracompartmental pressure is indicated, as stated in the 2021 guideline from the Association of Anaesthetists 1. The physical examination should note disproportionate pain that worsens with passive stretching of the affected muscles, and the thigh may appear tense, swollen, and firm to palpation.

• Check for decreased sensation in the distribution of nerves traversing the compartment, particularly the femoral nerve.
• Assess motor function by testing hip and knee movements.
• While pulses are often preserved until late stages, compare with the unaffected limb. The definitive test is compartment pressure measurement using a needle manometer or commercial device inserted into the suspected compartment, with normal compartment pressure below 10-12 mmHg; pressures above 30 mmHg or within 30 mmHg of diastolic blood pressure indicate compartment syndrome requiring immediate fasciotomy, as supported by the 2021 study 1. Continuous monitoring may be necessary in unconscious patients or those with equivocal findings, and early diagnosis is critical as muscle and nerve damage becomes irreversible after 6-8 hours of ischemia, potentially leading to rhabdomyolysis, renal failure, and permanent disability.
• The use of scoring charts, such as that provided by the UK’s Royal College of Nursing, is recommended to help maintain a heightened sense of awareness of this condition among healthcare workers caring for at-risk patients 1.
• It is essential to note that clinical signs alone may not be reliable in diagnosing compartment syndrome, and the presence of multiple signs increases the likelihood of a positive diagnosis, as shown in the 2021 study 1.

From the Research

Diagnosis of Compartment Syndrome

To test for a compartment syndrome in the thigh, the following methods can be used:

• Physical examination alone can often make the diagnosis of acute compartment syndrome (ACS) 2
• Compartment pressure monitors can be a helpful adjunct where the diagnosis is in doubt 3
• Supplemental methods such as:
  • Compartment pressure measurement: ICP higher than 30 mmHg of diastolic blood pressure is significant of compartment syndrome 4
  • Infrared spectroscopy 2
  • Ultrasound 2

Clinical Presentation

The classical description of compartment syndrome is 'pain out of proportion to the injury' 3 Other clinical presentations may include:

• Painful condition caused by the increase interstitial pressure (intracompart-mental pressure - ICP) within a closed osteofascial compartment which impair local circulation 4
• Ischaemic damage may be irreversible within six hours and can result in long-term morbidity and even death 3

Treatment

Initial treatment is with the removal of any constricting dressings or casts, avoiding hypotension and optimizing tissue perfusion by keeping the limb at heart level 3 If symptoms persist, definitive treatment is necessary with timely surgical decompression of all the involved compartments 3, 4 Hyperbaric oxygen therapy can be a useful intervention in the management of compartment syndrome 5, 6