Knee Injections

A straightforward guide for patients

What are Knee Injections?

Knee injections are commonly used to treat pain and inflammation caused by conditions such as osteoarthritis, tendon irritation, ligament strain, and general joint inflammation. These injections help reduce swelling inside the joint, improve mobility, and make daily activities easier. Knee injections are a safe, minimally invasive, non-surgical treatment option.

Goal of the Injection

The purpose of a knee injection is to deliver medication directly into the joint space or surrounding tissues to:

  • Reduce inflammation
  • Relieve pain
  • Improve the ability to walk, bend, and use the knee
  • Delay or prevent progression of chronic knee pain

Depending on your symptoms, the injection may include:

  • Corticosteroid (steroid) — reduces inflammation
  • Viscosupplement (gel injections such as hyaluronic acid) — improves lubrication and cushioning
  • Local anesthetic — provides temporary numbness
  • Orthobiologics like PRP

Your provider will decide which type is most appropriate based on your diagnosis and imaging.

The Procedure

  • You will be brought into a sterile procedure room and positioned for comfort.
  • The skin around the knee is cleaned well to reduce infection risk.
  • Local anesthetic is applied to numb the area.
  • Using anatomical landmarks or ultrasound guidance (if needed), the needle is placed into the knee joint or surrounding tissue.
  • Medication is injected slowly.
  • A small bandage is applied afterward.
    The entire process usually takes only a few minutes.

After the Procedure

Follow the instructions given to you at discharge:

  • Resume activities as tolerated, but avoid strenuous exercise for 24 hours.
  • You may shower, but avoid baths, hot tubs, or swimming for 24 hours.
  • Mild soreness at the injection site is normal.
  • Ice may be used for comfort.
  • Steroid injections may take 2–7 days to provide full benefit.
  • If you received a viscosupplement (“gel injection”), improvement may take 1–3 weeks.
  • You may receive a follow-up call or appointment to assess your response.

Seek medical attention if you develop severe pain, redness, swelling, or fever.

If Your Procedure Includes Sedation

(Some knee injections are performed without sedation; this section applies only if sedation is used.)

  • No solid foods 8 hours before the procedure
  • Clear liquids allowed until 2 hours before (water, broth, pulp-free juice, tea or coffee without cream; no carbonated beverages)
  • No gum, candy, or lozenges for 2 hours
  • The care team will review your medications prior to the procedure

Failure to follow these steps may result in rescheduling.

Potential Risks

Knee injections are generally very safe. Rare but possible risks include:

  • Pain or bruising at the injection site
  • Temporary increase in soreness
  • Infection (very rare)
  • Bleeding, especially in patients on blood thinners
  • Allergic reaction to medication
  • Nerve or tissue irritation
  • No improvement in symptoms
  • Post-injection flare (temporary increase in pain within the first 48 hours)

Let your provider know if you take any blood-thinning medications such as:

Warfarin, Plavix, Aspirin, Xarelto, Eliquis, Lovenox, Heparin, or others.

When to Expect Results

  • Steroid injections: relief typically starts within 2–7 days
  • Viscosupplement (gel) injections: improvement may take 1–3 weeks
  • Platelet Rich Plasma (PRP) can give substantial improvement in 4-6 weeks
  • Some patients may require a series of injections or a combination of therapies
  • If one type of injection does not help, your provider may recommend a different option based on your response

Insurance Requirements

Insurance companies may require:

  • Recent X-rays or MRI
  • Documentation showing limited improvement with medications, rest, or physical therapy
  • A trial of conservative management before authorizing certain types of knee injections (especially viscosupplementation)