Differential Diagnosis for Bilateral Knee Pain
Single Most Likely Diagnosis
- Osteoarthritis: This is the most common cause of bilateral knee pain in adults, especially in those over 50. The lack of deformity, erythema, or swelling does not rule out osteoarthritis, as these symptoms can be absent in early or mild cases.
Other Likely Diagnoses
- Overuse or Repetitive Strain Injury: Individuals who engage in activities that involve frequent knee bending, jumping, or running are prone to overuse injuries, which can cause bilateral knee pain without significant swelling or erythema.
- Patellofemoral Pain Syndrome: This condition, often related to tracking issues of the patella, can cause pain around or behind the patella, typically without significant swelling or deformity.
- Meniscal Degeneration: As people age, the menisci can degenerate, leading to pain, especially with activities that involve twisting or bending. Early stages might not present with significant swelling or erythema.
Do Not Miss Diagnoses
- Septic Arthritis: Although less likely given the absence of erythema, swelling, or systemic symptoms, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. It can present subtly, especially in immunocompromised patients or those with a history of joint surgery.
- Osteonecrosis: This condition, which can be caused by various factors including steroid use, alcohol abuse, or sickle cell disease, might not initially present with significant swelling or erythema but can lead to severe joint damage if not addressed.
- Rheumatologic Conditions (e.g., Rheumatoid Arthritis, Lupus): These conditions can cause bilateral knee pain and might not always present with significant swelling or erythema, especially in early stages.
Rare Diagnoses
- Hemochromatosis: A genetic disorder leading to iron overload, which can cause arthropathy similar to osteoarthritis but is much less common.
- Wilson's Disease: A rare genetic disorder that leads to copper accumulation, which can cause liver disease, neurological symptoms, and sometimes arthropathy.
- Gaucher's Disease: A genetic disorder that can lead to avascular necrosis and bone pain, including in the knees, though it is quite rare.