Differential Diagnosis for Ankle Injury

The patient presents with a suspected high ankle sprain, tenderness over the bone, and edema around the ankle, but is able to bear weight and declines an X-ray for assessment. Here is a differential diagnosis organized into categories:

• Single Most Likely Diagnosis

  • High Ankle Sprain: This is the most likely diagnosis given the patient's presentation of tenderness in areas consistent with a high ankle sprain, edema, and the ability to bear weight. High ankle sprains involve the ligaments above the ankle joint and can present with similar symptoms.

• Other Likely Diagnoses

  • Lateral Ankle Sprain: Although the patient appears to have a high ankle sprain, a lateral ankle sprain is also possible and common. It involves the ligaments on the outside of the ankle and can present with similar symptoms of pain, edema, and tenderness.
  • Medial Ankle Sprain: Less common than lateral ankle sprains, medial ankle sprains involve the ligaments on the inside of the ankle. The presence of tenderness over the bone and edema could also suggest a medial sprain.
  • Ankle Contusion: A contusion or bruise around the ankle could also explain the patient's symptoms, especially if there was a direct blow to the area.

• Do Not Miss Diagnoses

  • Fracture (e.g., Maisonneuve Fracture): Although the patient is able to bear weight and declines an X-ray, it's crucial not to miss a fracture, especially a Maisonneuve fracture, which is a type of ankle fracture that involves the fibula and can be associated with a high ankle sprain. Missing this diagnosis could lead to improper healing and long-term disability.
  • Osteochondral Lesion: An injury to the cartilage and bone of the ankle joint, which could occur with a severe sprain. This condition might not be immediately apparent without imaging.
  • Syndesmotic Injury: An injury to the syndesmosis, the ligaments that connect the two bones of the lower leg (tibia and fibula) above the ankle. This type of injury can be associated with high ankle sprains and requires proper diagnosis for appropriate treatment.

• Rare Diagnoses

  • Peroneal Tendon Subluxation: A condition where the peroneal tendons, which run along the outside of the ankle, slip out of their normal position. This could cause pain and instability in the ankle.
  • Ankle Ligament Avulsion: A condition where a piece of bone is pulled off with the ligament, which could require surgical intervention.
  • Stress Fracture: A small crack in one of the bones in the ankle, which might not be immediately apparent without imaging and could worsen with continued weight-bearing activity.