Why does it hurt when going downstairs but not when going upstairs?

Generally, pain when going downstairs but not when going upstairs may be related to factors such as meniscus injury, posterior cruciate ligament (PCL) injury, osteoarthritis, fat pad inflammation, and osteophytosis. Patients are advised to follow medical guidance for symptomatic treatment. Specific analyses are as follows:

1. Meniscus Injury

When the meniscus in the knee joint is injured, the external force exerted during ascending stairs is relatively small, so pain typically does not occur. However, descending stairs increases stress on the knee joint, leading to localized pain. Patients can take medications such as ibuprofen sustained-release capsules or indomethacin tablets under medical supervision.

2. Posterior Cruciate Ligament (PCL) Injury

If the knee suffers trauma, the posterior cruciate ligament is prone to injury. When descending stairs, the damaged ligament is stretched, causing varying degrees of pain. However, when ascending stairs, the ligament remains relaxed and usually does not cause pain. After injury, immobilization with plaster or a brace is recommended. If necessary, patients may take medications such as diclofenac sodium sustained-release tablets or etoricoxib tablets as directed by a physician, which help relieve pain and reduce inflammation.

3. Osteoarthritis

This condition is usually caused by overuse or long-term wear and tear, resulting in narrowing of the joint space or degeneration of articular cartilage, leading to symptoms such as knee swelling and pain—particularly exacerbated when descending stairs. Patients can be treated under medical guidance with medications such as glucosamine hydrochloride tablets or Kebigu Tai capsules to control disease progression.

4. Fat Pad Inflammation

Due to impact or chronic strain on the front of the knee joint, the infrapatellar fat pad beneath the kneecap becomes inflamed, causing pain when descending stairs. However, since there is no compression during stair climbing, pain generally does not occur. Patients may use medications such as Sanqi tablets or Shujin Huoxue tablets under medical supervision.

5. Osteophytosis (Bone Spur Formation)

When the knee is subjected to prolonged excessive load beyond its capacity, bone spurs may develop. Pain while walking is often mild, but discomfort occurs when going up or down stairs. Some patients may also experience lower back pain. Treatment options include taking glucosamine sulfate capsules or chondroitin sulfate tablets under medical supervision.

In addition, similar symptoms may also be associated with patellar chondromalacia or knee joint degeneration. If patients experience any discomfort, they should seek timely medical evaluation at a hospital to avoid delays in diagnosis and treatment.