My knee pops and catches on the inside when I twist. What is it?

Why twisting brings it on

The meniscus is a C-shaped cushion of cartilage between the thigh bone and shin bone. Twisting on a bent knee grinds it between the two bones. If part of it is torn, the loose edge can get trapped for a moment and then release with a pop. That catch-and-release, with pain on the joint line, is the pattern surgeons recognise.

In younger people this usually follows a sports twist. From middle age, the meniscus becomes more brittle and can tear with ordinary movements such as turning in the kitchen or getting out of a car.

Other possible causes

• Medial plica: a snap at the inner front of the knee as it bends, usually with an ache rather than a sharp catch
• Loose body: a small piece of cartilage or bone floating in the joint, causing unpredictable catching in different positions
• Cartilage flap: damage to the joint surface after an injury or osteochondritis dissecans
• Pes anserine irritation: pain below the joint on the inner shin, usually without true catching

What to do now

Avoid the movements that trigger it: pivoting sports such as padel and football, deep squats and sitting cross-legged. Stay active with straight-line walking, cycling and swimming if they are comfortable. Ice helps after activity, and a short course of anti-inflammatory medicine can help if suitable for you.

Many degenerative meniscus tears settle with a few months of physiotherapy. Tears that keep catching, especially in younger, active people, are more likely to need further treatment.

When to see a knee surgeon

Book an assessment if catching happens repeatedly, the knee swells after activity, or it gives way. Seek same-day care if the knee locks and you cannot straighten it, because a displaced meniscus fragment may need prompt surgery. At Aman Hospital in Doha, Dr. Gelber performs meniscus tests on examination, and an MRI is usually used to show the type and position of a tear before any decision on repair or trimming.