My knee got hot and swollen a few days after an injection. Is it infected?

Post-injection flare

• Usually begins within hours to two days of a steroid, hyaluronic acid or PRP injection
• Aching, warmth and some swelling
• Peaks early, then improves day by day
• No fever, and you feel well otherwise
• Eases with rest, ice and simple painkillers

PRP in particular often causes soreness for a few days, which is expected.

Signs that suggest infection

• Pain that keeps getting worse after the second or third day instead of easing
• The knee becomes hotter, redder and more swollen
• You cannot bend it or bear weight
• Fever, chills, sweats or feeling unwell
• Redness spreading up or down the leg, or pus at the injection site

Infection after a knee injection is uncommon when sterile technique is used, but it can happen days to a couple of weeks later. Diabetes, steroids and a weak immune system make it more likely and may hide fever.

What to do

If symptoms fit a flare and are improving, rest, ice for 15 to 20 minutes several times a day and take simple painkillers. Call the clinic that gave the injection if you are unsure. If any infection sign appears, go to an emergency department the same day and tell them which injection you had and when. Do not start antibiotics at home, as fluid from the knee is usually tested first.

Follow-up in Doha

If Dr. Gelber gave your injection at Aman Hospital, contact his team as soon as you are worried. When infection is suspected, the knee is aspirated and the fluid tested. If confirmed, treatment is urgent: antibiotics into a vein and, in most cases, a keyhole washout of the joint.