Gel injections for knee arthritisLubrication for a worn joint.

Hyaluronic acid is a natural part of healthy joint fluid. It helps the joint glide and absorb shock. In arthritis, the joint fluid thins out and loses some of these properties. A gel injection adds hyaluronic acid back into the knee.

Several products are available. Depending on the product, treatment is a single injection or a series of up to five injections over several weeks.

• Knee arthritis, usually mild to moderate, that's still causing pain despite exercise, weight management and medication.
• Patients who didn't get enough relief from a cortisone injection, or who want to limit cortisone.
• Patients who want to delay surgery, or who aren't ready for it.

Results vary more with gel shots than with many other treatments. Some patients get several months of relief; others notice little difference. Large studies show a modest benefit on average, and professional groups disagree about how routinely they should be used.

Many orthopedic surgeons, including Dr. Akhtar, consider them a reasonable option for select patients, especially those who haven't done well with other treatments. Pereira TV, et al. BMJ. 2022;378:e069722.

Dr. Akhtar's approach is practical: if you're a good candidate and you'd like to try it, a gel injection is a low-risk step that can be repeated if it works for you. He also discusses PRP injections, which in research comparisons have outperformed gel shots for knee arthritis.

The injection takes only a few minutes in the office. Image guidance can help place it precisely in the joint. Take it easy for a day or two afterward. Relief, when it comes, usually builds over several weeks.

Side effects are uncommon. Some people have temporary pain or swelling at the injection site. Rarely, a stronger flare of pain and swelling can occur, usually within a day. Call the office if that happens.