Call for emergency medical help. If you suspect you're having a heart attack, don't hesitate. Immediately call 911 or your local emergency number. If you don't have access to emergency medical services, have someone drive you to the nearest hospital.
The most common causes of knee weakness are osteoarthritis, sprain or strain, and chronic knee pain. Other possible causes, such as injury to the knee, are more rare. Osteoarthritis 22. Sprain or strain 17. Chronic knee pain 15. Knee ligament or meniscus tear 8. Fracture of the leg 4. Bursitis 2.
Overuse injury to the knee can lead to inflammation of the tendon below the kneecap (runner's knee or jumper's knee with infrapatellar tendinitis) and bursitis. Diseases that cause knee pain can lead to symptoms and sign such as. 1  swelling, 2  joint redness, 3  warmth of the knee, 4  weakness of the knee,  joint instability,