I fell on my knee and now my kneecap has a sharp pain. Is it broken?

The one test that matters most

Lie or sit with the leg out straight and try to lift the whole leg off the bed, keeping the knee straight. This is the straight-leg raise. If you can do it, even with pain, the mechanism that straightens the knee is working.

If you cannot lift it, or the knee buckles when you try to stand, the kneecap, the quadriceps tendon above it or the patellar tendon below it may be broken or torn. That needs same-day assessment and usually an X-ray.

Likely causes

• Bone bruise or soft tissue bruise: tender, sore to kneel on, sometimes with a bruise colour over days, but you can walk and lift the leg
• Prepatellar bursitis: a soft swelling over the kneecap appearing hours to days after the knock
• Kneecap fracture: severe pain, rapid swelling, sometimes a gap you can feel, difficulty straightening
• Kneecap dislocation: after a twist rather than a direct blow, the kneecap shifts to the outside, often with a visible deformity that may pop back
• Cartilage damage behind the kneecap from the impact, which may cause ongoing pain and swelling weeks later

First aid

If you can lift the leg and walk, use a cold pack wrapped in a cloth for 15 to 20 minutes several times a day for the first two days, rest from kneeling and sport, and elevate the leg. Simple pain relief may help. Keep gently bending and straightening to avoid stiffness.

If you cannot straighten the leg, keep it supported in a straight position and do not try to walk it off. In football, padel or a fall on a hard court, stop playing.

When to go and where

Go to an emergency department the same day if you cannot do a straight-leg raise, cannot bear weight, the knee looks deformed, swells within a few hours, or there is a wound over the kneecap.

If you are walking but the pain has not settled after two weeks, or swelling and clicking appear later, book an assessment. At Aman Hospital in Doha, Dr. Gelber examines the extensor mechanism and kneecap, reviews X-rays and decides whether an MRI is needed to look at cartilage. Displaced fractures and tendon tears are usually treated surgically, ideally soon after the injury.