Differential Diagnosis for New Onset Pain at Surgical Site 20 Years After Femur Shortening

• Single Most Likely Diagnosis
  • Aseptic loosening of the prosthetic implant: This is a common complication of joint replacement surgeries, especially after 15-20 years. The new onset pain at the surgical site could be due to the loosening of the implant, which can cause discomfort and instability.
• Other Likely Diagnoses
  • Heterotopic ossification: This is a condition where bone tissue forms outside of the skeleton, often in response to trauma or surgery. It can cause pain and stiffness at the surgical site.
  • Periprosthetic fracture: A fracture that occurs around a prosthetic implant can cause new onset pain at the surgical site.
  • Infection: Although less likely 20 years after surgery, infection is still a possible cause of new onset pain at the surgical site.
• Do Not Miss Diagnoses
  • Osteosarcoma: A type of bone cancer that can occur around a prosthetic implant. Although rare, it is a potentially deadly diagnosis that should not be missed.
  • Deep vein thrombosis (DVT) or pulmonary embolism (PE): These are potential complications of surgery or immobility, and can be life-threatening if not diagnosed and treated promptly.
• Rare Diagnoses
  • Metallosis: A condition caused by the release of metal ions from a prosthetic implant, which can cause pain, swelling, and tissue damage.
  • Chronic regional pain syndrome (CRPS): A condition characterized by chronic pain, inflammation, and sensitivity, which can occur after surgery or trauma.
  • Stress fracture: A fracture that occurs in response to repeated stress or trauma, which can cause pain at the surgical site.