What should you know about a transient dislocation of the patella?

The kneecap normally tracks in a groove at the front of the thighbone. A sudden twist, change of direction, direct impact, or instability can move it sideways. After it returns, the knee may remain swollen, tender, or feel unreliable. A transient event can still injure cartilage or the soft tissues that help hold the kneecap in place, so a normal-looking knee does not rule out damage.

Stop sport and avoid twisting or loaded bending until the knee has been assessed. Keep the leg supported, use a wrapped cold pack for comfort, and elevate it if swollen. Do not force the kneecap back or repeatedly test whether it will slip. A clinician may recommend a knee brace for a period, followed by physiotherapy to restore movement, strength, balance, and confidence. Repeated instability may prompt discussion of MPFL reconstruction or another stabilising option.

Get urgent medical help if the kneecap remains out of place, the knee is visibly deformed, you cannot bear weight, pain is severe, swelling develops quickly, or the foot becomes cold, pale, numb, or weak. Arrange prompt assessment even if the kneecap relocated by itself, particularly after an impact or a first episode. Ongoing knee giving way or kneecap pain needs review.

Could cartilage or a stabilising ligament be injured? Do I need imaging? How long should I use a brace? Which physiotherapy exercises are safe? When would surgery be considered?