Differential Diagnosis for Knee Replacement Stiffness and Burning
Single most likely diagnosis
- Loosening of the prosthetic component: This is a common cause of stiffness and pain in a knee replacement, especially if it occurs suddenly. The loosening can cause micro-motion, leading to inflammation and stiffness.
Other Likely diagnoses
- Polyethylene wear: As the polyethylene liner wears down, it can cause stiffness, pain, and a burning sensation due to the debris generated by the wear.
- Infection (low-grade): Although there's no redness, a low-grade infection can still cause stiffness, warmth, and a burning sensation without the typical signs of infection like redness or swelling.
- Heterotopic ossification: This is the formation of bone in soft tissues, which can cause stiffness and limited range of motion.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Deep vein thrombosis (DVT): Although less likely one year post-surgery, DVT can cause warmth and stiffness in the affected leg and is a medical emergency if not treated promptly.
- Septic loosening: An infected loosening of the prosthetic component, which is a serious condition requiring urgent medical attention.
- Neurovascular compromise: Any condition affecting the nerves or blood vessels around the knee, which could lead to serious complications if not addressed.
Rare diagnoses
- Complex regional pain syndrome (CRPS): A rare condition characterized by burning pain, stiffness, and changes in skin temperature and color, which can occur after surgery.
- Metallosis: A rare condition caused by the release of metal debris from the prosthetic components, leading to an inflammatory response and tissue damage.
- Tumor or cyst formation: Rarely, a tumor or cyst can form around the prosthetic component, causing stiffness, pain, and limited range of motion.