I hit my knee on the dashboard in a car accident and the back of it hurts. What could it be?

Why the dashboard injures the PCL

The PCL stops the shin bone from sliding backwards under the thigh bone. When the knee is bent and the upper shin hits a hard surface, the tibia is driven backwards and the PCL can stretch or tear. The same mechanism happens in motorcycle falls and when someone falls hard onto a bent knee.

Unlike an ACL tear, a PCL injury often causes less dramatic swelling and some people can walk afterwards, so it is easy to miss in the emergency department when other injuries take priority.

Symptoms people notice

• Aching or tightness at the back of the knee
• Bruising or a graze just below the kneecap, where the shin struck
• Mild to moderate swelling over the first day or two
• Discomfort walking downstairs, slowing down or kneeling
• A vague feeling that the knee is not solid, especially when tired

Red flags that need urgent care

High-energy accidents can injure several ligaments at once, and in some cases the knee briefly dislocates. Go to emergency care straight away if the foot is cold, pale or numb, if the calf is very painful or tense, if the knee looks deformed, or if you cannot move or bear weight on the leg. These can be signs of injury to the artery or nerve behind the knee and are time-critical.

Getting it checked in Doha

If emergency care has ruled out a fracture and serious injury, book a knee assessment within the first few weeks. Dr. Gelber examines the PCL with the posterior drawer and sag tests, checks the other ligaments, and usually arranges an MRI. Bring any emergency X-rays and reports from the accident.