Differential Diagnosis for Post-ACL Surgery Pain

The patient's presentation of severe pain and stiffness localized to the right side following ACL surgery, described as cramping and sharp, radiating from the anterior aspect of the surgical site to the back and buttock region, suggests several potential diagnoses. These can be categorized as follows:

• Single Most Likely Diagnosis

  • Compartment Syndrome: This condition is characterized by increased pressure within a muscle compartment, which can lead to muscle and nerve damage. The use of a tourniquet during surgery, severe pain that is not relieved by analgesics, and pain exacerbated by movement are all consistent with compartment syndrome. The patient's description of cramping pain and the worsening of symptoms since surgery further support this diagnosis.

• Other Likely Diagnoses

  • Nerve Injury or Irritation: Direct trauma to nerves during surgery or from the tourniquet could cause sharp, radiating pain. The sensation of stitches or staples and increased soreness since the procedure could be indicative of nerve involvement.
  • Deep Vein Thrombosis (DVT): Although less common immediately post-op, DVT could cause severe leg pain, especially if it involves the deep veins of the lower extremities. The patient's recent surgery and immobilization increase the risk.
  • Hematoma or Bleeding: Accumulation of blood at the surgical site could cause increased pressure, leading to severe pain that is not relieved by standard pain medications.

• Do Not Miss Diagnoses

  • Infection: Early post-surgical infection can present with increased pain, redness, and swelling at the surgical site. Although the patient does not mention fever or redness, infection must be considered due to its potential severity.
  • Pulmonary Embolism: While the patient's symptoms are localized to the leg, pulmonary embolism (a possible complication of DVT) is a life-threatening condition that must be considered, especially given the recent surgery and potential for immobilization.

• Rare Diagnoses

  • Complex Regional Pain Syndrome (CRPS): This condition is characterized by chronic pain, inflammation, and hypersensitivity following injury or surgery. It is less likely given the early postoperative period but could be considered if other diagnoses are ruled out and symptoms persist or worsen over time.
  • Arterial Injury or Occlusion: Direct injury to arteries during surgery or from the tourniquet could lead to severe ischemic pain. This would be an emergency requiring immediate intervention.

Each of these diagnoses requires careful consideration and potentially urgent evaluation to ensure the patient receives appropriate and timely treatment.