Thermotherapy (heat treatment) for treating osteoarthritis of the knee

To answer this topic, scientists found and analyzed three studies. Over 170 people with osteoarthritis continue to take their medications but used hot, cold or ice packs/towels with or without massage or no treatment. The studies were not of high quality but this Cochrane review provides the best evidence we have today.

What is thermotherapy and how might it help osteoarthritis of the knee?
Osteoarthritis (OA) is the most common form of arthritis that can affect the hands, hips, shoulders and knees. In OA, the cartilage that protects the ends of the bones breaks down and causes pain and swelling. Thermotherapy involves applying heat or cold to joints to improve the symptoms of osteoarthritis and can be done with packs, towels, wax, etc. Heat may work by improving circulation and relaxing muscles, while cold may numb the pain, decrease swelling, constrict blood vessels and block nerve impulses to the joint. Thermotherapy can be used in rehabilitation programmes or at home.

How well does thermotherapy work?
One study showed that massaging with ice for 20 minutes, 5 days a week for 2 weeks, improved muscle strength in the leg, the range of motion in the knee and decreased time to walk 50 feet compared to no treatment.

Another study showed that ice packs for 3 days a week for three weeks improved pain just as well as no treatment.

Another study showed that cold packs for 20 minutes for 10 periods decreased swelling more than no treatment. Hot packs for the same amount of time had the same effect on swelling as no treatment.

How safe is it?
No side effects were reported in the studies, but in general, studies report that thermotherapy is safe when applied carefully.

What is the bottom line?
Since the studies were small and of low quality firm conclusions cannot be made. There is "silver" level evidence that ice massage could be used to improve
range of motion and strength of the knee and function in people with osteoarthritis of the knee. Cold packs may be used to decrease swelling.

Authors' conclusions: 

Ice massage compared to control had a statistically beneficial effect on ROM, function and knee strength. Cold packs decreased swelling. Hot packs had no beneficial effect on edema compared with placebo or cold application. Ice packs did not affect pain significantly, compared to control, in patients with OA. More well designed studies with a standardized protocol and adequate number of participants are needed to evaluate the effects of thermotherapy in the treatment of OA of the knee.

Read the full abstract...

Osteoarthritis is a degenerative joint disease that affects mostly the weight-bearing joints in the knees and hips. As the affected joint degenerates pain and restriction of movement often occur. Inflammation can also occur sometimes resulting in edema of the joint with OA. Treatment focuses on decreasing pain and improving movement.


To determine the effectiveness of thermotherapy in the treatment of OA of the knee. The outcomes of interest were relief of pain, reduction of edema, and improvement of flexion or range of motion (ROM) and function.

Search strategy: 

Two independent reviewers selected randomized and controlled clinical trials with participants with clinical and/or radiological confirmation of OA of the knee; and interventions using heat or cold therapy compared with standard treatment and/or placebo. Trials comparing head to head therapies, such as two different types of diathermy, were excluded.

Selection criteria: 

Randomized and controlled clinical trials including participants with clinical or radiographical confirmation of OA of the knee and interventions using heat or cold compared to standard treatment or placebo were considered for inclusion.

Data collection and analysis: 

Study results were extracted by two independent reviewers. Outcomes were continuous in nature (pain, strength, improvement) and were analyzed by weighted mean difference using a fixed effects model. Graphical data were used when table data were not available.

Main results: 

Three randomized controlled trials, involving 179 patients, were included in this review. The included trials varied in terms of design, outcomes measured, cryotherapy or thermotherapy treatments and overall methodological quality. In one trial, administration of 20 minutes of ice massage, 5 days per week, for 3 weeks, compared to control demonstrated a clinically important benefit for knee OA on increasing quadriceps strength (29% relative difference). There was also a statistically significant improvement, but no clinical benefit in improving knee flexion ROM (8% relative difference) and functional status (11% relative difference). Another trial showed that cold packs decreased knee edema.