Based on the patient’s history and mechanism of injury, several foot structures are likely involved in the ankle pain. These structures include ligaments, tendons, muscles, bones, and joints. The “pop” sound the patient heard suggests a possible ligament tear.
In addition to pain, other symptoms that need to be explored include swelling, bruising, stiffness, and difficulty moving the ankle joint. Differential diagnoses for ankle pain may include ligament sprains, fractures, tendonitis, arthritis, and nerve impingement.
During the physical examination, the healthcare provider should inspect the ankle for swelling, bruising, and any deformity. The provider should also perform range of motion testing to assess the patient’s ability to move the ankle joint. Special maneuvers such as the anterior drawer test can be performed to assess the stability of the ankle joint.
The Ottawa ankle rules can be applied to determine if additional testing is required. These rules state that an X-ray is necessary if there is pain in the malleolar zone (the medial or lateral malleolus), and any of the following:
- Inability to bear weight for four steps both immediately and in the emergency department
- Tenderness at the posterior edge or tip of the lateral malleolus
- Tenderness at the posterior edge or tip of the medial malleolus
- Tenderness over the navicular bone
- Tenderness over the base of the fifth metatarsal
If the patient does not meet any of the above criteria, X-ray imaging may not be necessary. However, additional testing such as MRI or ultrasound may be indicated based on the results of the physical examination and the suspected diagnosis.