What’s Causing My Knee Pain?

Knee pain is one of the most common reasons people look for help. Two people can point to the same spot on their knee and have completely different problems.

At Innovative Nerve & Joint Centers, we help patients understand the causes of knee pain so treatment targets the source. Below are the causes we see most often outside of arthritis and meniscus tears, which have their own guides.

What Is Runner’s Knee (Patellofemoral Pain Syndrome)?

Runner’s knee, or patellofemoral pain syndrome, is pain around or behind the kneecap. It often hurts with stairs, squatting, kneeling, or sitting for long periods with the knees bent.

Despite the name, it is not limited to runners. It frequently develops when the kneecap does not glide smoothly in its groove, often because of weak hip and thigh muscles or a sudden increase in activity.

Strengthening the hips and thighs and improving how the knee tracks during movement are usually the foundation of care.

What Causes Knee Tendonitis?

Knee tendonitis is irritation of a tendon from repeated stress. Patellar tendonitis, sometimes called jumper’s knee, causes pain just below the kneecap. Quadriceps tendonitis causes pain just above it.

It often follows jumping, running, or a quick increase in training. Pain is usually felt right at the tendon at the start of activity, may ease as you warm up, then return afterward.

Tendonitis is sometimes confused with arthritis. Tendon pain is usually pinpointed at the tendon and tied to loading, while arthritis tends to bring joint stiffness and swelling. Tendons generally respond well to a gradual, guided strengthening program.

What Is Knee Bursitis?

Bursae are small fluid-filled sacs that reduce friction around the knee. When one becomes irritated, it can swell and become painful.

Prepatellar bursitis causes swelling over the front of the kneecap and is common in people who kneel often. Pes anserine bursitis causes pain on the inner side of the knee, just below the joint, and is often seen alongside knee arthritis.

A bursa that is red, hot, and very swollen can be infected and needs prompt medical attention.

How Do Ligament Injuries Cause Knee Pain?

Four main ligaments hold the knee together: the ACL, PCL, MCL, and LCL. Injuries usually happen with a twist, a sudden stop, or a blow to the knee.

An ACL injury often comes with a pop, rapid swelling, and a knee that feels unstable. MCL injuries usually cause pain along the inner knee after a blow to the outside of the leg.

Mild sprains often recover with conservative care. More serious tears may need a surgical opinion, which is why a thorough exam matters after any injury that causes significant swelling or instability.

Can Muscle Imbalances Cause Knee Pain?

Yes. The knee sits between the hip and ankle, and it often pays the price when either one is not doing its job. Weak hip muscles can let the knee drift inward during walking, squatting, and stairs, which increases stress on the joint.

Stiff ankles and tight thigh muscles can have a similar effect. These imbalances rarely show up on imaging, but they often appear clearly during a movement assessment.

Correcting them is one of the most effective ways to reduce knee pain and keep it from coming back.

How Do Inflammation and Body Weight Affect Knee Pain?

Body weight and knee load are closely linked. Research has found that each pound of weight lost removes about four pounds of load from the knee with every step.

Body fat also produces inflammatory substances that may contribute to joint pain and arthritis. That helps explain why even modest weight loss often reduces knee symptoms.

Inflammation from injury, overuse, or arthritis can make the knee swollen, stiff, and sensitive. Calming it is often an early goal of care.

Frequently Asked Questions About the Causes of Knee Pain