Knee pain can significantly affect your mobility, and walking up or down stairs is often particularly problematic. Pain at the front of the knee -- also known as anterior knee pain -- is frequently related to a problem with the patellofemoral joint, where the kneecap moves atop the lower end of the thighbone. Stair climbing increases compression at this joint. Possible causes of anterior knee pain include patellofemoral pain syndrome, tendon irritation, arthritis and bursitis, among others.
Patellofemoral Pain Syndrome
Patellofemoral pain syndrome (PFPS) is the leading cause of anterior knee pain. It most commonly occurs in young, physically active people and women are affected more often than men. Typical symptoms include achy kneecap pain that is characteristically aggravated by walking up or down stairs, squatting, running and prolonged sitting with the knees bent. People with PFPS have no structural abnormality of the knee joint or no underlying disease process affecting the knee. One or more factors are thought to contribute to the development of PFPS, all of which can put excess stress on the patellofemoral joint. Contributing factors may include:
-- overuse, especially running and jumping
-- weakness or imbalance of the hip muscles
-- misalignment between the hip and ankle
-- inappropriate footwear or improper training technique
Patellar Tendon Injury
Frontal knee pain while climbing stairs can be caused by irritation of the patellar tendon, which attaches the kneecap to the shinbone. The top of the kneecap is attached to the quadriceps muscles in the front on the thigh. These muscles straighten the knee and keep it from bending too quickly during high-impact activities. Both jumping and landing stress the patellar tendon, potentially irritating it with short- or long-term overuse. Short-term overuse frequently causes inflammation of the tendon, known as patellar tendinitis. This condition often occurs in military recruits and people who dramatically increase their physical training over a short period. Long-term, excessive stress on the patellar tendon can damage and weaken the tissue, a disorder called patellar tendinopathy. Both knees are commonly affected, although the pain is often more severe in one knee. Pain associated with a patellar tendon injury often intensifies with activity and decreases with rest.
Cartilage provides padding between bone surfaces in joints. Patellofemoral arthritis involves wearing away or breakdown of the cartilage on the underside of the kneecap. Patellofemoral arthritis is common, particular among older adults. The most frequent symptom is anterior knee pain, which is characteristically aggravated by walking up or down stairs, squatting and kneeling. Joint stiffness also typically occurs with patellofemoral arthritis, particularly after a period of inactivity. Osteoarthritis, also known as degenerative arthritis, is the most common type of patellofemoral arthritis. This condition develops gradually over time due to age-related wear and tear. Prior injury to the knee and overuse can predispose to the early development of osteoarthritis of the patellofemoral joint.
Bursae are small fluid-filled sacs in or around joints. These structures cushion pressure points and reduce friction. There are 4 bursae around the kneecap that can become inflamed. This condition, known as knee bursitis, typically develops in response to direct injury or prolonged irritation, such as occurs in people who frequently kneel or squat due to their occupation. Typical symptoms of knee bursitis include swelling, tenderness over the site of the inflamed bursa and pain. The pain tends to be more constant and intense compared to that experienced with other causes of anterior knee pain. Walking up or down stairs characteristically provokes sharp pain in people with knee bursitis. The severity of the pain may make walking up or down stairs virtually impossible.
Other Considerations and Next Steps
Other, less common conditions not previously discussed can potentially cause frontal knee pain provoked by walking up stairs, including a joint infection or a tumor. Additional diseases and conditions also warrant consideration when this symptom occurs in a child or adolescent.
Given the lengthy list of possible causes, it's important to see your doctor as soon as possible if you experience frequent, persistent or worsening anterior knee pain. An accurate diagnosis is necessary so you can begin appropriate treatment and get back to the activities you enjoy. Seek immediate medical care if your knee pain developed in association with a traumatic injury, or if you cannot bear weight on the affected leg.
Reviewed and revised by: Tina M. St. John, M.D.