Case: Patient is a 46-year-old woman who presented to the emergency department with ankle pain. Just prior to arrival, she fell down a flight of stairs and inverted her right ankle. She immediately had severe pain of the right ankle, and was unable to ambulate or bear any weight at the scene. She denied numbness weakness or tingling in the leg or foot.
On exam, the patient was found to have severe tenderness to palpation involving the anterior-lateral midfoot, severe pain with range of motion (dorsiflexion and plantar flexion of the ankle), and was unable to bear any weight on the affected limb in the emergency department.
Pain control (ketorolac) was administered, and X-rays of the ankle were obtained.
Radiograph Impression: Normal, no fracture or dislocation.
Reassessment: Pain had not improved with pain medication and the patient remained unable to bear any weight on the affected limb. A CT of the ankle was then obtained.
CT Impression: Nondisplaced linear fracture through the anterior process of the calcaneal bone.
Disposition: A post-mold splint was applied, the patient was kept non weight bearing on the affected limb, and crutches were provided. An orthopedic follow up appointment was arranged.
Why it Matters: Fractures of the anterior process of the calcaneus are often misdiagnosed as ankle sprains due to similarities in mechanism and physical exam and difficulty in diagnosis via plain radiographs. Delayed diagnosis can lead to morbidity and longer lengths of disability. Significant swelling and ecchymosis of the lateral foot with point tenderness over the cuboid-calcaneus joint (approximately 2 cm anterior to the tip of the lateral malleolus) may serve to increase suspicion of a fracture of the anterior process of the calcaneus. As these fractures are often occult on plain radiographs, CT imaging should be considered in cases with high suspicion despite negative X-rays.
Written by:
William Haufe, MD
PGY-2
Emergency Department
Cook County Hospital
Reviewed by:
Scott Sherman, MD
Associate Program Director
Emergency Department
Cook County Hospital
References:
Judd, Daniel, and David Kim. "Foot Fractures That Are Frequently Misdiagnosed As Ankle Sprains." American family physician 66, no. 5 (2002): 785.
Dhinsa, Baljinder S., Ahmed Latif, Roland Walker, Ali Abbasian, Diane Back, and Sam Singh. "Fractures of the anterior process of the calcaneum; a review and proposed treatment algorithm." Foot and Ankle Surgery 25, no. 3 (2019): 258-263.
Renfrew, Donald L., and Georges Y. El-Khoury. "Anterior process fractures of the calcaneus." Skeletal radiology 14, no. 2 (1985): 121-125.