Weight and knee: Surveying the research and treatments of osteoarthritis

Professor Flavia Cicuttini, AM, is the head of Monash’s Musculoskeletal Unit in the School of Public Health and Preventive Medicine, and also the head of Rheumatology at the Alfred Hospital. This makes her very familiar with the problems faced by patients with diseases of joints, muscles, inflammation, and especially osteoarthritis, which harms the joints, and affects about 600 million people worldwide.

She’s also familiar in a more personal way. After a skiing mishap 20 years ago, Professor Cicuttini tore the anterior cruciate ligament (ACL) in her knee, and a number of other structures – a common but serious sports injury.

She’s so far declined a knee replacement even though, technically, such an injury can lead to earlier osteoarthritis in the joint.

Professor Cicuttini says she intermittently experiences knee pain that limits her activity, but her decision is that she’ll need a knee replacement in the future, not now.

In a newly-published five-yearly review of osteoarthritis (OA) in The Lancet, Professor Cicuttini surveys recent research and treatments for OA, including the modern trend towards surgical replacements in early OA.

With co-authors Professor Margreet Kloppenburg, from the Department of Rheumatology at the Leiden University Medical Center in the Netherlands, and Associate Professor Mosedi Namane, from the University of Cape Town, she’s outlined key messages for The Lancet. They are:

• Every type of osteoarthritis (knee, hip, hand, foot) is different, so a one-size-fits-all approach to management won’t work.

• Targeting obesity and keeping people active is important for OA, but the approaches need to be personalised and start in early to mid-adulthood because OA slowly develops over many years. There is usually a 0.5 to 1kg kilogram weight creep per year in adult years.

• There are many trials currently underway in OA testing new treatments, with promising findings, showing that targeting inflammation is effective in hand OA, but there’s still no drug that halts the disease at the cause. Only symptoms can be treated.

• An area of concern is the growing international trend for knee replacements to be performed for earlier OA, which is fuelling high dissatisfaction rates among patients. Knee replacements cost one billion dollars a year in Australia, the paper explains, and about 20% of patients come away dissatisfied.

No single medication for treatment

Professor Cicuttini says knowledge about the aetiology, or causes, of OA has improved, “with increased understanding of the role of genetic factors, obesity-related inflammation, the microbiome, and the existence of different pain mechanisms”.

But she says while this knowledge is being translated into new drug treatments, there’s still not a single, simple medication that halts the progression of OA.

“A major problem,” she says, “is that OA is a disease that gradually develops over a lifetime, so suddenly targeting treatment in established osteoarthritis means we’re targeting disease too late. The search for much-needed effective treatments that improve both symptoms and the structure of joints, often referred to as disease-modifying osteoarthritis drugs, is ongoing.”

Read more: New research has found an existing drug could help many people with painful hand osteoarthritis

Part of the message of the five-year review is that it’s important to keep joints healthy across a person’s lifetime. Once joints become damaged, this cannot be reversed. This is very similar to what happens in most other chronic diseases.

“For that reason,” she says, “it’s important for a person to develop a treatment plan as soon as the first episodes of joint pain develop. This may be well before a diagnosis of OA is made.

“Many people in the community develop pain in their joints which settles on its own or with over-the-counter medications.

“These early joint pains,” she says, “should be a call to action.”

The pain, in an otherwise well person over the age of 40, is most commonly osteoarthritis or the precursor to OA. In most people, x-rays may be normal.

“Other tests such as magnetic resonance imaging (MRI) are often not helpful. We do MRI in research of OA, but it doesn’t currently guide management of the individual, and may result in unnecessary treatment.”

Tears not the cause of symptoms

Professor Cicuttini says there may also be abnormalities in the joint, such as meniscal tears.

“There can be a temptation to try and fix this problem with knee surgery, such as arthroscopies. However, in most people aged over 40 the tears are just part of the OA process, not the cause of the person’s symptoms. Surgery in this situation is more likely to cause harm than any benefit.”

Her “call to action” includes weight, by honing in on preventing weight gain as the first priority “as well as weight loss when necessary”.

The problem is many people don’t realise that obesity affects joints through two things – loading of the joint, as well as inflammation.

“Therefore, obesity has a double-whammy effect on joints,” she says. “It’s carrying extra weight on a squishy (or inflamed) joint, and damage starts to happen in early life. Once joint damage, such as loss of cartilage, occurs it doesn’t reverse.

“That’s why it’s important to preserve joints and prevent the weight creep that occurs in adult years. This helps joints, and can be achieved with simple lifestyle approaches compared to losing weight.”

Read more: Joining the dots on joint health and heart health

Keeping as active as possible is key. It prevents OA in the first place and maintains healthy joints.

Professor Cicuttini says she would expect her own injured knee to have “moderate” OA, but “I have not imaged the knee as at this stage, as I wouldn’t expect imaging to change my management.”

Episodically, she says, it’s really painful. “Not that often, but episodically really bad. I've got walking poles like hikers use so I can keep active but prevent overloading so I don't keep doing a lot on a sore knee.

“I keep active without stressing it, and – touch wood – until now I've found that I can live a normal life. I do exercise and I focus on preventing weight gain, going to the gym, and all the rest.

“When I get to the point where my knee gets the pain and it persists despite the usual things I try, I try my walking poles, it comes again, and it's interfering with my life, I'll have a knee replacement. Ideally, probably a good time to have it if you need it is around age 70, so hopefully that would see you through.”

Exercise programs can come too late

Supervised exercise programs, which are popular, can be “too little, too late” and “not available to many people in the community because of cost and time pressures, including travelling to appointments.”

Professor Cicuttini’s exercise tips with or without access to supervised classes are:

• Regular physical activity, which is best achieved if it can be integrated into a person’s life.

• Walking is an attractive option that is effective, acceptable and available to people across different socio-economic and cultural groups. It can be done when convenient to the individual.

• If a person has pain, then aids such as walking poles or walking sticks can help, allowing the person to stay active. This helps maintain general muscle strength and protect the painful joint while it’s settling down, but not at the expense of overstressing other joints.

• Preventing joint injuries is an important part of maintaining healthy joints. Injuries such as ACL injuries accelerate the development of OA. Some people call it “old knees in young people”.

In the drug space, there’s excitement about new weight-loss drugs, Professor Cicuttini says, because trials look promising, but “the overall effect in OA is still to be determined. It’s most likely that they will play a role in OA, but not fix the huge problem of obesity-related OA.”

The search for the drug that halts the disease at the cause goes on.

“Each joint is different. For hand OA there’s very promising data showing that targeting inflammation is effective.

“There are currently many different approaches to treatment of OA underway, from the use of stem cells through to testing old, wel- established diabetic medications such as metformin.”

In search of the quick fix

This immediate lack of new treatments is one of the reasons for the trend, in knees, to get a replacement, or a replacement of the replacement, which is called revision surgery, and costs more than the original surgery.

“The evidence is that knee replacements are best when there’s a clear need. I get concerned that sometimes patients may think we’re putting up roadblocks to the best management of OA.”

But people can tend to want quick fixes.

“I think a lot are bailing out and having knee replacements because the idea is always that nothing else works. This is wrong. We almost need a cooling-off period to make sure that a knee replacement is only done if the person has very significant, persistent symptoms, not simply based on the look of an x-ray, because, in fact, most of the time the pain will get better.”

The good news is that signs and symptoms of OA may not be too bad. “For most people, pain may come and go, but it tends to settle,” Professor Cicuttini says. In knee OA data shows that only a small proportion of people have relentless worsening of their pain.

“This is an important message because many people think that if they develop signs and symptoms of OA it is an inevitable downhill spiral. That is not the case.”