One side of the knee joint space is wider than the other.

Under normal circumstances, uneven joint space in the knee—wider on one side and narrower on the other—may be caused by factors such as trauma, meniscus injury, anterior cruciate ligament (ACL) injury, osteoarthritis, or knee arthritis. Treatment should be based on the specific cause. Detailed analysis is as follows:

1. Trauma

When the knee joint suffers external impact, it may lead to fractures or dislocations, which in turn can cause narrowing of the knee joint space. Patients can receive treatment under medical guidance using external plaster immobilization, or undergo open reduction and internal fixation surgery if necessary.

2. Meniscus Injury

The meniscus is cartilage that connects the femur and tibia. Once injured, it may result in uneven knee joint space, causing the aforementioned issues. In severe cases, patients should go directly to the hospital and, according to medical advice, take medications such as nimesulide capsules or diclofenac sodium sustained-release tablets to relieve symptoms.

3. Anterior Cruciate Ligament (ACL) Injury

ACL injury may also lead to uneven knee joint space. Patients can follow medical instructions to use non-steroidal anti-inflammatory drugs (NSAIDs) to alleviate symptoms, such as acetaminophen tablets or ibuprofen sustained-release capsules.

4. Osteoarthritis

Osteoarthritis is one of the most common joint diseases and causes damage and deformation of joint cartilage. When osteoarthritis affects the knee joint, it leads to uneven bone loss on the medial and lateral sides, resulting in a narrowed gap on one side and a widened gap on the other. For mild symptoms, patients may take medications such as celecoxib capsules or aceclofenac tablets as directed by a physician. For more severe cases, surgical intervention at a hospital may be required.

5. Knee Arthritis

This condition may be caused by advanced age, excessive obesity, or other factors. Patients commonly experience knee pain, stiffness, and in some cases, even knee joint deformity. Under medical guidance, patients may relieve symptoms through heat therapy, massage, and similar methods. If necessary, they may undergo total knee arthroplasty (artificial knee joint replacement) at a qualified hospital.

In addition, this condition may also be related to conditions such as collapse-type cartilage injury or knee synovitis. It is recommended that patients seek timely evaluation at a reputable medical facility upon noticing these symptoms and receive appropriate treatment to prevent worsening of the condition.