Differential Diagnosis for 56yo Male with L Ankle Pain

Single Most Likely Diagnosis

• Ankle Osteoarthritis: Given the patient's age and symptoms of pain, tenderness, and crepitus with passive range of motion, ankle osteoarthritis is a highly plausible diagnosis. Osteoarthritis can cause pain and stiffness in the affected joint, and crepitus is a common finding due to the degeneration of cartilage.

Other Likely Diagnoses

• Tibialis Posterior Tendinopathy: This condition affects the tendon that supports the medial arch of the foot and can cause pain and tenderness along the medial aspect of the ankle, consistent with the patient's symptoms.
• Deltoid Ligament Sprain: A sprain of the deltoid ligament, which is located on the medial (inner) aspect of the ankle, could explain the pain and tenderness in this area, especially if there was a recent injury.
• Medial Ankle Impingement: This condition occurs when there is abnormal contact between the bones of the medial ankle, leading to pain and tenderness, particularly with activities that involve dorsiflexion of the foot.

Do Not Miss Diagnoses

• Osteonecrosis of the Talus: Although less common, osteonecrosis (avascular necrosis) of the talus can present with ankle pain and should be considered, especially if there's a history of trauma or steroid use. Missing this diagnosis could lead to significant morbidity.
• Infection (Septic Arthritis): Ankle pain, especially with signs of inflammation or systemic illness, could indicate a septic joint, which is a medical emergency requiring prompt diagnosis and treatment.
• Tumor: Although rare, a tumor in the ankle region could cause pain and should be considered, particularly if the pain is persistent and unexplained by other diagnoses.

Rare Diagnoses

• Gout or Pseudogout: These are forms of arthritis that can cause sudden, severe pain in the ankle, although they are less common in this joint compared to others like the big toe.
• Tarsal Coalition: An abnormal connection between two of the bones in the foot (tarsal bones) can cause pain and stiffness, particularly in the ankle and foot.
• Ankle Stress Fracture: A stress fracture in one of the bones around the ankle could cause pain, especially with weight-bearing activities, and might be considered if other diagnoses are ruled out and the patient has a history of increased activity or stress on the ankle.