Differential Diagnosis for the 19-year-old Amateur Ballet Dancer
- Single most likely diagnosis: + Ankle sprain: The patient's mechanism of injury, which involved inversion of the foot, and the location of tenderness over the anterior part of the lateral malleolus, are consistent with an ankle sprain. The fact that radiological investigations did not reveal any fracture and the patient complains of a "giving way" sensation in her ankle three months post-injury, suggests chronic ankle instability, a common sequela of ankle sprains.
- Other Likely diagnoses: + Peroneal tendon injury: The peroneal tendons run along the lateral aspect of the ankle and can be injured with inversion mechanisms. Tenderness over the lateral malleolus could be consistent with this diagnosis. + Anterior talofibular ligament (ATFL) injury: The ATFL is the most commonly injured ligament in ankle sprains. The patient's symptoms and examination findings are consistent with an ATFL injury. + Chronic ankle instability: This condition is characterized by recurrent ankle sprains and a feeling of instability or "giving way" in the ankle, which aligns with the patient's complaints three months post-injury.
- Do Not Miss diagnoses: + Osteochondral lesion of the talus: Although radiographs did not show a fracture, an osteochondral lesion (a piece of cartilage and bone that has been damaged) could have been missed. This condition can cause chronic pain and instability. + Syndesmotic injury: A high ankle sprain involving the syndesmosis (the ligaments connecting the tibia and fibula) can present with similar symptoms and must be considered to avoid missing a potentially serious injury.
- Rare diagnoses: + Peroneal nerve injury: While less common, a peroneal nerve injury could occur with severe ankle sprains, especially if there was significant force involved. + Ankle impingement syndrome: This condition, characterized by pain and limited mobility due to soft tissue or bony impingement in the ankle joint, is less likely but could be considered if other diagnoses are ruled out.