The first geniculate artery embolization (GAE) to take place in the UK to treat osteoarthritis pain in the knee has been performed by Mark Little at the Royal Berkshire Hospital in Reading, UK. Little is the lead investigator in the GENESIS study, investigating the use of GAE in UK patients.
A previous Japanese study found a 75% reduction in pain over a four-year period. Yuji Okuno (Tokyo, Japan) and colleagues found that, in a small cohort of patients, GAE for mild to moderate knee osteoarthritis was feasible, rapidly relieved resistant pain, and restored knee function.
Currently in Europe, osteoarthritic patients are given painkillers, and knee-replacement surgery is conducted in severe cases. GAE is therefore posited as a potential minimally invasive alternative for patients with mild-to-moderate osteoarthritis pain for whom painkillers have not worked.
Little, who is leading the study, comments: “If the results of this study and future studies confirm the Japanese data, then geniculate artery embolization is a potential game changer for the treatment of osteoarthritis. Performed under only local anaesthetic, the procedure takes about one hour and patients go home the same day. It is truly minimally invasive. If you can get patients off high-dose painkillers who are struggling with mobility and unable to work, it has a massive impact on their health and quality of life.”
Speaking to Interventional News, Little elaborates about the ideal GAE patient: “Osteoarthritis of the knee is a hugely common problem. Whilst knee replacement is a good treatment, it is not a perfect treatment, and talking to orthopaedic surgeons, they do not want to operate on the patients who are 40 to 55 because they are young. Some of these patients have conservative treatment (physiotherapy, joint injections), and some will benefit from that for a period of time, but some will not. There is this real middle band of patients that have got significant symptoms from their knee osteoarthritis that are severe enough to affect their quality of life, but which are not severe enough to merit having knee replacement surgery. I think that is where GAE has a massive role to play, if it is proven long-term. As a scientist and as an interventional radiologist, I think we have to get together as a community and study this treatment, as we have done with prostatic artery embolization (PAE), and as we have done with uterine fibroid embolization (UFE). We need good quality data so we can say with decisiveness that this is a good option for our patients.”
Against the backdrop of the current opioid epidemic, in both Europe and North America, Little further emphasises the positive role GAE may play in these patients’ lives by calling the procedure a “big opportunity” to lessen the dependence on painkillers. Whilst deliberate in not over-stating the present role of GAE in this regard, Little does say that “GAE has the potential to be game-changing”. More data are needed to confirm this hope.
Through his work on GAE, Little has been working with orthopaedic surgeons. Of this experience, he says: “The multidisciplinary collaboration is very good. As these patients have failed conservative treatment, but are not suitable candidates for joint replacement, the orthopaedic surgeons are delighted to refer these patients. To be able to offer a potential new treatment for these patients is really very beneficial. There is a huge demand for a treatment in this space—that is why we are having no trouble at all with referrals for the GENESIS study.”
The GENESIS study has nearly completed enrolment, with 38 of 50 anticipated patients currently on board. Little reports a high patient referral rate for this study, and tells Interventional News that he anticipates enrolment to be complete within a few weeks of this newspaper going to press. Preliminary data will be presented at the annual meeting of the Cardiovascular and Interventional Radiological Society of Europe (CIRSE; 1–10 September, Barcelona, Spain), and Little says that though this will be based on “incomplete data”, and therefore will not provide “the full story”, he believes that “we will still be able to draw some early meaningful conclusions, as we have a number of patients already with up to six months’ follow-up”.
The GENESIS study, which will follow all patients up to two years, is being conducted in collaboration with the University of Reading, UK. It has funding from Merit Medical and support from the National Institute for Health Research (NIHR). An additional multicentre, randomised controlled trial investigating GAE against a sham procedure has been submitted by Little and collaborators for approvals in the UK through the Health Technologies Assessment (HTA) process, and an “ambitious international project” focusing on the procedure is underway.
Enthusing about the potential of this work, Little comments: “Interventional radiologists are great innovators, and we need to combine that creativity with performing very good, high calibre research. By doing that, musculoskeletal embolization and image-guided intervention may have a huge role to play in the future. There are certainly lots of patients out there, so we just need to prove that it works.”
The first GAE case in the UK: The patient response
The 65-year-old patient, Linda Skilton, underwent the procedure on 29 January, and reported positive results. Quoted in a press release from the Royal Berkshire NHS Foundation Trust, she says that before the procedure “I was having problems with my left knee; a lot of swelling, a lot of fluid, limited mobility.
“I was given cortisone injections, which made it settle for a while, but it flared up again a year later when I was using some equipment in the gym. For the past couple of years, I have not been able stand for too long because it got so sore and swollen and I could not keep it bent or straight for any length of time either, which made sleeping difficult.
She continues to describe the procedure: “I only felt the initial cut to get to the artery, which was no worse than a paper cut. I was expecting some feeling of pushing and pulling, but I did not feel anything at all.
“Since the procedure, I can feel day-to-day that my knee is improving. I can easily walk up the stairs for the first time in years. I am delighted with the outcome.”
Commenting specifically on this patient’s response to the procedure, Little says “Linda is clearly very active and if we can keep her playing golf, then that will have a profound impact on her social interactions with friends, improve her happiness, and well-being, and give her back her independence.”
However, while he hopes that every patient has a reaction as positive as this, Little stresses that “n=1 does not mean that this is going to be the panacea. I will reserve getting carried away until we have data up to two years. Hopefully, we get consistently good results, but we need to take an analytical approach and compare all of our results before we can be categorical in our conclusions.”
You can read an article on this topic authored by Sandeep Bagla (The Vascular Institute of Virginia, Woodbridge, USA), the first to perform this procedure in the USA, here.
The patient is treated as a day case procedure. They have a pre-procedural contrast-enhanced MRI scan, where Little says the radiologist is “looking for synovitis and capsular enhancement”.
During the procedure, in the majority of patients the interventional radiologist performs an antegrade puncture in the common femoral artery. The interventionalist then navigates the catheter under X-ray guidance down the affected leg into the geniculate arteries.
Little says “We are looking for an abnormal contrast blush in the region of the degenerative change that correlates with the pre-procedural MRI scans”. Next, the IR uses angiography to select the vessels that correspond to those areas with abnormal vascularity. “Once we are in there,” Little says, “we will confirm through an on-table cone beam CT, and then once we are happy with everything, we will embolize the geniculate arteries. We use diluted Embosphere (Merit Medical) particles to embolize the abnormal regions”.