The back of the knee hurts severely due to gout, making it impossible to straighten the leg.

The knee generally refers to the knee joint. In most cases, severe pain at the back of the knee joint that prevents straightening the leg may be caused by factors such as posterior knee injury, soft tissue adhesion, acute gout attack, tophi (gout deposits), or rheumatoid arthritis. Patients are advised to follow medical guidance for symptomatic treatment. Specific analyses are as follows:

1. Posterior Knee Joint Injury

If there is an injury at the back of the knee joint—such as damage to ligaments, soft tissues, or the posterior horn of the meniscus—it can easily cause pain at the back of the knee and prevent leg extension. Arthroscopic surgery may be performed under medical guidance to repair the damage.

2. Soft Tissue Adhesion

Prolonged immobilization and lack of joint movement can lead to adhesion of the posterior soft tissues of the knee, directly affecting the range of motion and causing pain and inability to straighten the leg. This condition can be treated with stretching exercises, acupuncture, massage, or other therapeutic measures.

3. Acute Gout Attack

Gout is primarily caused by purine metabolism disorders, excessive uric acid production, or reduced uric acid excretion, leading to elevated blood uric acid levels. Uric acid crystals may deposit in the synovial membranes of joints, causing symptoms such as knee swelling, pain, and fluid accumulation. Medications such as colchicine tablets or allopurinol tablets may be used under medical supervision.

4. Tophi (Gout Deposits)

As the disease progresses, uric acid salts in the blood may crystallize and deposit in the joint cavity and various body tissues, forming tophi. Patients often experience knee pain and restricted movement, which in severe cases can significantly affect quality of life. Medications such as ibuprofen sustained-release capsules or probenecid tablets may be prescribed under medical guidance.

5. Rheumatoid Arthritis

If rheumatoid arthritis is present, it can damage the knee joint and cartilage, causing inflammatory symptoms such as redness, swelling, heat, and pain. Treatment may include medications like enteric-coated aspirin tablets or prednisone acetate tablets, as directed by a physician.

If patients experience discomfort, they should seek timely medical evaluation and receive targeted treatment to avoid delays in managing their condition.