Normal joint fluid contains a substance called hyaluronan. It acts like a shock absorber and lubricant in your joint and is needed to help the joint work properly. Hyaluronan is highly viscous, allowing the cartilage surfaces of the bones to glide upon each other smoothly. This leads to decreased symptoms of osteoarthritis.
These drugs can be injected into both knees or just a single knee joint.
Steroid injections, such as cortisone, reduce swelling and ease pain in the joint. The knee can flex more normally. Activity which would have caused pain or been impossible before the injection can be resumed.
An injection of a bio-lubricant can increase flexibility and reduce pain caused by osteoarthritis. The bones are lubricated so there is less grinding on each other.
One of the major benefits of knee injections is they can decrease or eliminate the need for surgery.