What to expect from PRP injection for knee osteoarthritis

Osteoarthritis changes the joint surfaces and may cause pain, stiffness, swelling, or reduced confidence with walking. PRP is made by processing a small blood sample and injecting the platelet-rich portion into the knee, sometimes with imaging guidance. It may help modify the local inflammatory environment and support symptom management, but it does not reverse osteoarthritis or restore a worn joint to its original state.

The knee may feel tender or fuller before it feels better. Your clinician will judge the response by changes in walking, stairs, sleep, stiffness, and daily activities, not by an immediate sensation after the injection. Results vary with joint changes, strength, movement habits, and other health factors.

Tell the clinician about blood-thinning medicines, bleeding conditions, infection, allergies, diabetes, and previous knee procedures. Clarify which medicines to take on the day and how to manage discomfort. Plan a quieter period after the appointment and wear clothing that allows the knee to be examined easily.

Use relative rest at first: avoid impact, heavy resistance, and long periods of kneeling until advised otherwise. Keep the knee moving gently if permitted, then follow a physiotherapy programme that builds quadriceps and hip strength, joint control, and tolerance for walking or stairs. Weight management, footwear, and activity pacing may also reduce load on the knee. Review the plan if pain remains limiting.

Call the clinic if the knee becomes progressively more swollen, hot, red, or painful, or if the puncture site leaks fluid. Fever or feeling acutely unwell needs prompt medical advice. Urgent assessment is appropriate for severe sudden pain, inability to use the leg, new calf swelling, chest pain, or breathlessness.

Ask how advanced your osteoarthritis is, what goal the injection is meant to support, when you can drive or return to work, how physiotherapy will be adjusted, and what alternatives are available if symptoms continue. Ask specifically about medicines and activities that could interfere with the aftercare plan.