FAQS on Joint Injections – Hip, Knee, Shoulder

 

A joint injection is used to alleviate the pain and stiffness associated with joint inflammation and loss of synovial fluid. Common joints injected include the knee, hip, and shoulder. The main cause of joint pain is osteoarthritis, but other types of arthritis can lead to joint problems.

What conditions respond to joint injections?

Other than osteoarthritis, joint injections treat:

  • Rheumatoid arthritis
  • Gout
  • Inflammatory arthritis
  • Bursitis

What are the types of joint injections?

Several types of joint injections are used to alleviate pain, improve function, and improve joint abilities. These include:

  • Corticosteroid injection – Triamcinolone, dexamethasone, and methyl-prednisolone are steroidal agents used in joint injections. These substances decrease the inflammatory response that is caused by arthritis.
  • Hyaluronic acid (HA) – Orthovisc, Synvisc, and Hyalgan are all forms of hyaluronic acid that is used to replace lost synovial fluid inside the joint space.
  • Platelet-rich plasma (PRP) – This involves drawing a sample of the patient’s blood, processing the blood in a centrifuge machine, and injecting the concentrated platelets into the joint knee.

What happens during the joint injection procedure?

The doctor will inject the joint in the medical office under local anesthesia. After the joint region is cleaned with an antiseptic, the skin and deeper tissues is numbed using an anesthetic. The needle is guided into the joint space using real-time x-ray to assure correct placement. After the solution is instilled, the needle is removed.

When will I notice pain relief after a joint injection?

If an anesthetic is injected into the joint, you will have immediate pain relief. When a corticosteroid is used alone, pain does not improve for 3-6 days after the injection. With PRP injections, the joint will be tender and inflamed for a few days right after the injection, as the solution causes a temporary inflammatory response. The PRP starts to work in around 1-2 months. When hyaluronic acid is used, it takes a few days before symptoms improve.

Do hyaluronic acid and corticosteroid joint injections work?

In a study of 500 patients with chronic arthritis knee pain in the U.S., researchers separated them into two groups. The study was blinded, so the patients did not know what was injected. One group got hyaluronic acid and the other group got saline solution. The pain relief was most noticeable among the hyaluronic acid group. In a study evaluating corticosteroid joint injections, results showed that waling pain scores were significantly reduced after the injections, and synovial hypertrophy was reduced 75% in the hips that were injected.

Which joint injection is best?

A study comparing corticosteroid injections to hyaluronic acid injections fund that both groups at significant pain reduction at the 3 month follow up, and at 12 months, 34% of the patients in the HA group still had pain relief, which was compared to only 8% in the steroid group. In addition, functional improvement was higher in the HA group.

How long does the joint injection results last?

After hyaluronic acid joint injections, patients typical have relief of pain for 14-26 weeks. The doctor may choose to do a series of injections spaced 4 weeks apart.  Osteoarthritis is not curable, so repeat treatments are often required. Some patients receive hyaluronic acid injections every six months.

Resources

Micu MC, BogdanGD, & Fodor D (2010). Steroid injection for hip osteoarthritis: efficacy under ultrasound guidance. Rheumatology, 49(8), 1490-1494.

Trueba DCA, Trueba VC, Navarette AJM et al. (2014). Clinical efficacy of intraarticular injections in knee osteoarthritis: a prospective randomized study comparing hyaluronic acid and betamethasone. Rheumatology, 7, 9-18.