Osteoarthritis: This is the most common cause of knee pain and is not directly related to uric acid levels. It involves wear and tear of the joint cartilage and underlying bone, leading to pain and stiffness, especially in older adults.

Meniscal Tear: A tear in the cartilage of the knee joint can cause pain, especially with twisting motions. Uric acid levels are not relevant to this diagnosis.
Ligament Sprain: Sprains of the ligaments around the knee can cause pain and are common in individuals who participate in sports or activities that involve running, jumping, or quick changes of direction.
Tendinitis: Inflammation of the tendons around the knee, such as the patellar tendon, can cause knee pain and is often related to overuse or repetitive strain.
Bursitis: Inflammation of the fluid-filled sacs (bursae) that cushion the knee joint can cause pain and swelling, often due to repetitive motion or direct pressure on the knee.

Septic Arthritis: Although less common, an infection within the knee joint can cause severe pain, redness, and swelling. It is a medical emergency that requires prompt treatment, regardless of uric acid levels.
Osteonecrosis: A condition where the bone tissue dies due to lack of blood supply, which can cause knee pain. Early diagnosis and treatment are crucial to prevent further damage.
Tumor: Both benign and malignant tumors can cause knee pain. While rare, missing a diagnosis of a tumor could have significant consequences.

Hemochromatosis: A genetic disorder that leads to iron overload, which can cause joint pain, including knee pain, due to iron deposition in the joints.
Wilson's Disease: A rare genetic disorder that leads to copper accumulation in the body, which can cause joint pain among other symptoms.
Pseudogout (Calcium Pyrophosphate Deposition Disease, CPPD): A type of arthritis that causes sudden, severe joint pain, often in the knee. It is associated with the deposition of calcium pyrophosphate dihydrate crystals within the joint, and uric acid levels may not be elevated.