Pioneering an alternative to surgery for knee osteoarthritis

After years of research, Professor Little has pioneered the use of GAE in the treatment of mild to moderate osteoarthritis of the knee. Professor Little often sees patients in their 50s or 60s who are prevented from enjoying an active lifestyle due to their knee pain. These patients have tried conservative therapies like steroid injections or physiotherapy and haven’t received the benefits they hoped for. They also aren’t good surgical candidates, or they may not want surgery, which leaves them few treatment options. Other patients opting for GAE also include younger patients in their 40s with early-onset knee osteoarthritis who want to avoid joint replacement surgery at that age. “Aside from increasing their pain relief, these patients don’t have many options,” Professor Little explains.

What the procedure involves

The aim of GAE is to identify abnormal blood vessels around the knee joint, which research has shown release factors that cause inflammation and pain, and block them off. Before the procedure, patients first have a contrast MRI to identify inflammation of the lining of the knee join and confirm their diagnosis of osteoarthritis. 

The procedure itself takes about an hour and is performed under local anaesthetic in the angiography suite of The Princess Grace Hospital’s interventional radiology department. A very small incision is made in the skin of the groin, through which a small needle is used to gain access to the common femoral artery. “It’s a very common access point for angiograms,” Professor Little explains. “When talking about angiograms, patients often think about the heart. It’s a very similar procedure, but rather than going up to the heart, we go down to the knee.”

Guided by X-rays, a catheter is navigated through the femoral artery to the very small arteries (the genicular arteries) surrounding the knee joint. Once it reaches this point, tiny embolisation particles are released from the catheter to selectively block the abnormal blood vessels. The catheter is then removed, and as the incision made is so small, the hole where the catheter was inserted is just pressed for 10 minutes until it closes, like after an injection – no stitches are required. And as GAE is a day-case procedure, the patient is able to return home after just a couple of hours of recovery.

The benefits of GAE

As GAE is minimally-invasive, it has a number of benefits – it helps to reduce pain with less post-procedure discomfort, fewer complications and much faster recover times. After around 10 days post-procedure procedure, most patients who had GAE have reduced knee pain and can start to return to their normal activities.

Long-term research into GAE, looking at data for up to two years post-procedure, has shown that around 70% of osteoarthritis patients will have a sustained benefit of reduced knee pain and improved function. But to Professor Little, the definition of success is dependent on the initial indication and the patient’s goals. “If you’re a 60-year-old patient who’s able to get back to tennis, that’s a great win,” says Professor Little. “For an 80-year-old patient, it may just be getting up the stairs more easily. You have to set your treatment strategy on your patient’s expectations and their physical health at baseline.” 

The success of GAE also depends on a collaborative approach to post-procedure care. “Breaking the cycle of pain is one thing,” explains Professor Little, “but people with chronic pain often alter the way they walk, so they will need formal retraining.” To tackle this, Professor Little collaborates with physiotherapists and orthotists to support his patients’ recovery. The success of this support relies on first addressing the source of pain, highlighting the importance of a multidisciplinary approach to ensuring successful patient outcomes. “Addressing the pain is just one aspect, and improving overall function is the next step,” says Professor Little, “and this is where the physiotherapy team comes into play.”

Ongoing research

The benefits of GAE for osteoarthritis patients have been demonstrated in both clinical trials and now in practice. But research is ongoing into the potential placebo effect. This effect has been explored in three randomised sham-controlled trials to date, where half of patients had GAE and the other half had a sham procedure. While all trials showed GAE resulted in a benefit for patients, one didn’t show a significant benefit of GAE over the placebo. “These studies highlight the difficulties of measuring pain and considering the placebo effect, particularly when using an invasive intervention,” says Professor Little. “Further trials will continue to investigate this.” The trial Professor Little is currently running is the largest randomised sham-controlled GAE trial in the world and is looking to further elucidate the benefits of the treatment over a placebo. But GAE is still a very promising non-surgical intervention for osteoarthritis, and Professor Little’s research will help further our understanding of the treatment. Above all, it’s important that patients are offered appropriate treatments for them and that they’re able to make an informed treatment decision with a full understanding of benefits and risks. “Patient selection is key,” says Professor Little, “and so is informing patients where we are with the research.” 

Read more about GAE as a treatment for osteoarthritis.