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.
Simple causes of knee pain often clear up on their own while you take steps to manage your symptoms. If knee pain is caused by an accident or injury, you should contact your health care provider. If your knee pain has just started and is not severe, you can: Rest and avoid activities that cause pain. Avoid putting weight on your knee.