My knee swelled up overnight after a twist, but I can walk. Could it still be an ACL tear?

Why you can walk on a torn ACL

The ACL works hardest when the knee rotates or the shin bone is pushed forward, as in cutting, pivoting and landing. Walking on flat ground places little demand on it, and the surrounding muscles take over much of the job. That is why many people limp for a few days and then walk almost normally, even with a complete tear.

The absence of severe pain can be misleading too. Once the first swelling settles, an ACL tear is often surprisingly comfortable at rest.

What the timing of the swelling tells us

• Swelling within a few hours usually means blood in the joint, which most often comes from an ACL tear, a kneecap dislocation or a fracture
• Swelling that builds slowly over a day or two is more typical of a meniscus tear or irritation of the joint lining
• Swelling on the outside of the knee, rather than within the joint, may be bruising or bursitis

These patterns are clues, not a diagnosis, but they help decide how soon you should be examined.

What you can do while the swelling settles

Use ice for 15 to 20 minutes a few times a day, raise the leg when sitting, and use a compression sleeve if it is comfortable. Keep bending and straightening the knee gently so it does not stiffen. Simple painkillers can help; check with a pharmacist or doctor if you have other medical conditions.

Avoid sport, running and stairs taken at speed until the knee has been assessed.

When to book a knee assessment in Doha

Book an appointment if swelling came on quickly after a twist, if the knee feels unstable, or if it has not settled within a week or two. Go to urgent care if you cannot bear weight, the knee is locked, or the calf becomes painful and swollen.

At Aman Hospital, Dr. Gelber examines the ligaments, menisci and kneecap and decides whether an MRI is needed. Draining the knee is sometimes considered when it is very tense and painful.