Knee pain, especially on top of the kneecap when descending stairs, is a common complaint that can significantly impact daily activities. This discomfort often indicates an issue with the patellofemoral joint, where the kneecap (patella) interacts with the thigh bone (femur). Understanding its causes is key to effective management.
Common Causes
One frequent reason for pain on top of the kneecap is Patellofemoral Pain Syndrome (PFPS), also known as “runner’s knee” or “jumper’s knee.” PFPS can stem from factors like overuse from repetitive activities, muscle imbalances around the hip and knee, or sudden increases in activity levels. The pain is typically a dull ache that worsens with activities such as walking up or down stairs, kneeling, squatting, or sitting with a bent knee for extended periods.
Another related condition is Chondromalacia Patellae, involving the softening and breakdown of cartilage on the underside of the kneecap. While it can be present with PFPS, it’s a distinct condition involving cartilage degeneration. This deterioration can lead to the kneecap rubbing abnormally against the thigh bone, causing irritation, pain, and sometimes a grinding or cracking sensation. It is often an overuse injury, common in young athletes, and can also affect older adults with knee arthritis.
Why Descending Stairs Aggravates Pain
Descending stairs significantly stresses the patellofemoral joint, increasing pain. When walking down stairs, the force on the kneecap can be as high as 3.5 times a person’s body weight. This higher load, compared to walking upstairs (approximately 2.5 times body weight), places considerable pressure on the cartilage beneath the kneecap. This increased compression can exacerbate existing irritation or damage within the joint.
Additionally, descending stairs involves eccentric loading of the quadriceps muscles. Eccentric contraction occurs when a muscle lengthens under tension, such as when the quadriceps control the lowering motion of the body during stair descent. This type of muscle activity demands more from the quadriceps and can increase the forces transmitted through the patellofemoral joint, contributing to pain. Poor alignment of the kneecap, weak hip or ankle muscles, or tightness in the surrounding soft tissues can further alter biomechanics during stair descent, leading to improper tracking of the kneecap and heightened discomfort.
Initial Self-Care
Managing knee pain on top of the kneecap involves several self-care strategies. Resting the affected knee by avoiding pain-triggering activities, such as stair descent, allows inflamed tissues to recover. Applying ice packs for 15 to 20 minutes every few hours can reduce swelling and numb pain. Compression with an elastic bandage minimizes swelling and provides support, while elevating the leg above heart level promotes fluid drainage.
Gentle stretching of the quadriceps, hamstrings, and calf muscles can improve flexibility and muscle balance around the knee. Strengthening exercises for the hips and quadriceps are also beneficial, as these muscles help stabilize the kneecap. Choosing appropriate footwear with good cushioning, arch support, and stability can reduce stress on the knees during daily activities.
When to Seek Professional Help
While self-care measures can provide relief, certain signs indicate the need for professional medical evaluation. If knee pain persists for more than a few weeks despite home remedies, or if it significantly interferes with daily routines, a healthcare provider should be consulted. Immediate medical attention is advisable if the pain results from a forceful impact, or if the knee joint is severely swollen, red, warm, or tender to the touch.
Other concerning symptoms include:
A popping sound at the time of injury
Inability to bear weight on the knee
Buckling or giving way of the knee
A limited range of motion
A doctor can diagnose the pain through physical examination and, if necessary, imaging tests like X-rays, MRI, or ultrasound. Treatment may involve physical therapy, focusing on strengthening and coordination exercises, or other interventions tailored to the specific condition.