What causes sudden knee pain while running, and what should you do about it?

Sudden knee pain during running may be caused by physiological factors, or by pathological conditions such as ligament strain or synovitis. Patients should receive targeted treatment based on the specific cause. The details are as follows:

1. Physiological Factors

If a person has been inactive for a long time, sudden running may cause spasms in underused muscles such as the quadriceps, leading to pain around the knee. This is considered a normal physiological response and generally does not require treatment.

2. Pathological Factors

1) Ligament Strain
Improper running posture or excessive force may lead to ligament strain in the knee, resulting in sudden knee pain. Symptoms can be relieved by elevating the affected limb and applying local cold compresses.

2) Synovitis
For individuals already suffering from this condition, running—due to its relatively large range of motion and intensity—may cause significant swelling of the synovium and joint. This can restrict joint flexion and extension and is often accompanied by pain. Patients may take medications such as celecoxib capsules or diclofenac sodium sustained-release tablets under medical supervision to alleviate symptoms.

Besides the common causes mentioned above, other possible causes include osteoarthritis, meniscus injury, and chondromalacia patellae. Individuals experiencing discomfort should seek timely medical evaluation and treatment to avoid delays in managing their condition.