Hyaluronic acid (HA) is a naturally occurring substance in our bodies. It makes up parts of our skin, eyes, intervertebral discs and joints. HA is very hydrophilic, attracting water and one of the main functions of HA in our joint is to act as a joint lubricant helping to nourish the joint cartilage and to act as a shock absorber.
One of the signs of arthritis in our joints is that we start to have less synovial fluid within the joint making the joint stiff and achy. HA can be injected into the joint to help to replace this joint fluid and help to preserve joint cartilage. Injecting HA into arthritic knee joints has been shown to improve function and reduce pain for up to 6 to 12 months. There are many different products on the market such as Ostenil, Durolane, Synvisc or Cingal. Depending on which product is used you require between one and three injections into the effected joint over the course of a few weeks.
Numerous clinical trials have shown that HA is both effective and safe for intra-articular injections, such the knee joint, the shoulder, or the hip joint. It is believed that HA has a multitude of affects when it has been injected into a painful joint. This includes having an anti-inflammatory effect by inhibiting immune cells which break down cartilage and reducing inflammatory mediators within the joint. HA helps to restore joint homoeostasis by stimulating the joint to produce more of the body’s own HA. It has a painkilling affect by modulating and inhibiting pain receptors within the joint. It also has a protective effect on the cartilage itself forming a mesh light network over the joint surface and it has also been shown to delay a breakdown of cartilage within the joint that happens with osteoarthritis.
HA can also be injected into tendon sheaths and around painful tendons, as well as injected into a painful bursa such as the subacromial Bursa in the shoulder. HA has an anti-inflammatory effect within these tissues helping to calm down pain and inflammation and restore function.
At Wandsworth physiotherapy and Osteopathy we can perform intra articular hyaluronic acid injections into knee, shoulder, and hip joint using ultrasound guidance. We can also use a product called Cingal, which is a combination of 88mg of HA combined with triamcinolone, a corticosteroid. This can be injected into the knee joint to calm the pain of knee joint arthritis. We can inject hyaluronic acid into the shoulder bursa as an alternative to corticosteroid injections as the HA has a powerful anti-inflammatory effect, without the side effects of tendon damage that accompanies steroid injections.