Sharp knee pain can be a symptom of something seriously wrong with one of the most important joints in the human body. The sharp pain could indicate any number of issues with the knee, including a torn ligament, arthritis, runner's knee, or the development of a cyst within the joint. Whatever the cause of the pain, the affected person should generally seek immediate medical attention.
One of the most common causes of sharp knee pain is a tear in one of the four ligaments of the knee, which can occur during sports, recreation or other physical activity. Tears occur most often in the anterior cruciate ligament, the posterior cruciate ligament or the medial collateral ligament. Symptoms of a torn ligament include the sudden and strong onset of pain, an inability to use the knee and a sense of instability in the joint.
Other injuries to the soft tissues of the knee can cause sharp pain. These can include tears in the knee cartilage, which can occur in people of all ages. For patients in their teenage and young adult years, the cartilage behind the kneecap can soften due to a condition called chondromalacia patella, which can also lead to knee pain. Resulting from tendinitis of the patellar, or kneecap, tendon, patellar tendinitis can also cause pain around the knee. Other knee injury-related causes of pain are Baker's cyst, which leads to swelling in the back of the knee, and bursitis, which often results in pain right above the kneecap.
So-called runner's knee and gout are the two main causes of sharp knee pain that comes and goes. Gout is a form of arthritis caused by the buildup of uric acid crystals in the joints. Rarely, it affects the knee and leads to the onset of pain. A more common form of temporary knee pain is runner's knee, which is a sharp pain caused by overtraining on hard surfaces leading to the irritation of the iliotibial band. Runners can relieve the pain through rest and by treatment with cold and heat compresses.
Perhaps the most common form of sharp knee pain, especially for older adults, is arthritis of the knee. As an individual gets older, the cartilage in the knee breaks down, removing the knee's cushioning and leaving bone to rub on bone. The pain can be severe enough to slow a person or even prevent them from walking or standing for long periods.