Pain can be reduced if overweight people shed the pounds, according to new NHS guidance from the UK's National Institute for Health and Care Excellence (Nice).
It advises that aerobic exercise and strength training can ease symptoms and improve quality of life.
Starting exercise programmes may initially make the pain worse, but this should settle down, the guidance suggests.
Nice also gives recommendations on the use of medicines, such as offering non-steroidal anti-inflammatory drugs (NSAIDs) but not offering paracetamol, glucosamine or strong opioids.
It said there was a risk of addiction with strong opioids, while new evidence suggests little or no benefit from some medicines when it comes to quality of life and pain levels.
In the guidance, doctors are told to diagnose osteoarthritis — the most common form of arthritis — themselves, without further investigation in people aged 45 or over who have activity-related joint pain.
Patients should also have no morning joint-related stiffness, or morning stiffness that lasts no longer than 30 minutes, to be diagnosed this way.
Tailored exercise programmes should be offered, with an explanation that “doing regular and consistent exercise, even though this may initially cause discomfort, will be beneficial for their joints”.
Exercising in the long term also increases its benefits, the guidance says.
When it comes to weight loss, people will be told that “any amount of weight loss is likely to be beneficial, but losing 10% of their body weight is likely to be better than 5%.”
Patients can also be referred for hip or knee replacement if their condition cannot be managed in other ways, and referrals should not be held off due to age, sex or obesity.
Dr Paul Chrisp, director of the centre for guidelines at Nice, said: “Osteoarthritis can cause people discomfort and prevent them from undertaking some of their normal daily activities.
“However, there is evidence which shows muscle strengthening and aerobic exercise can have an impact on not just managing the condition, but also providing people with an improved quality of life.
“Beginning that journey can be uncomfortable for some people at first, and they should be supported and provided with enough information to help them to manage their condition over a long period of time.
“Whilst topical and sometimes oral NSAIDs remain an important treatment option for osteoarthritis, we have taken the decision to not recommend some painkillers, such as paracetamol and some opioids, for osteoarthritis.
“This is because new evidence has shown there was little or no benefit to people’s quality of life, pain or psychological distress and particularly in the case of strong opioids, there was evidence that they can cause harm in the longer term, including possible addiction.”
In the UK, more than 10 million people have arthritis or other similar conditions that affect the joints.
The most affected areas are the knees, hips and small hand joints.
Tracey Loftis, head of policy and public affairs at the charity Versus Arthritis, said: “We’ve seen first-hand the benefits that people with osteoarthritis can get in being able to access appropriate physical activity, especially when in a group setting. Something like exercise can improve a person’s mobility, help manage their pain and reduce feelings of isolation.
“But our own research into the support given to people with osteoarthritis showed that far too many do not have their conditions regularly reviewed by healthcare professionals, and even fewer had the opportunity to access physical activity support.
“The lack of alternatives means that, in many cases, many people are stuck on painkillers that are not helping them to live a life free from pain.
“While we welcome the draft Nice guidelines, healthcare professionals need further resources and support to better understand their role in promoting treatment like physical activity for people with osteoarthritis.
“There is clearly a need for people with arthritis to be given a bigger voice so that their health needs are not ignored.”