The best non-drug therapies to relieve the pain of knee osteoarthritis

Knee braces and water-based exercise appear to be two of the most effective ways to ease the pain and stiffness caused by knee osteoarthritis. That is according to a review of 12 non-drug therapies, but higher-quality evidence is needed before this guides clinical practice.

The condition is caused by the wear and tear of cartilage that cushions the ends of bones, leading to inflammation, pain and stiffness. Painkillers and anti-inflammatory drugs can relieve these symptoms, but can also have side effects, so clinicians typically recommend physical therapies, such as shoe insoles to relieve knee pressure, supporting the joint with tape or using laser therapy to promote cartilage healing.

However, it is unclear how these methods compare. “A lot of reviews of treatments only look at how well a single therapy works,” says Sarah Kingsbury at the University of Leeds in the UK, who wasn’t involved in the latest research.

To fill this gap, Yuan Luo at the First People’s Hospital of Neijiang in China and colleagues analysed data from 139 randomised controlled trials that collectively assessed 12 approved or experimental physical therapies for knee osteoarthritis. Those trials together involved more than 9600 adults with the condition.

Some of them compared two or three physical therapies, while others tested one therapy against a placebo or no treatment. The participants generally received some form of therapy for several weeks before completing surveys on their symptoms.

Based on this, the researchers found that knee braces appeared to be the most effective at reducing pain and stiffness and improving mobility. This was followed by water-based exercise. “If you walk in a pool, you’re using your muscles, but you’re not putting force [that wears down cartilage] through your joint in the same way as if you were walking down the park,” says Kingsbury.

The order of effectiveness for the remaining tested treatments was: land-based exercise; high-energy laser therapy; firing high-energy sound waves at the knee; low-energy laser therapy; two ways of electrically stimulating nerves in the knee; taping the knee; stimulating the knee with electromagnetic waves; stimulating the knee with ultrasound waves; and wearing insoles.

For various reasons, the results aren’t strong enough that they should influence clinical practice, says Kingsbury. One reason for this is that many of the studies involved fewer than 50 participants and small samples can limit confidence in any findings. What’s more, the treatment period in each study ranged from less than a week to several months, meaning that some therapies may only appear more effective than others because they tended to be used for longer.

Another limitation is that the studies didn’t compare the physical therapies with drug treatments, or test the effectiveness of combining drug and non-drug therapies, says Kingsbury.

Still, ahead of further research, the review offers clues as to what works best, she says. “It is useful and important to have that ranking – maybe we can discount the bottom six or 10 [therapies] and really focus our efforts on improving the evidence around the top few.”