Knee osteoarthritis is one of the most common forms of arthritis, with a incidence of of 10 to 15% in adults over 60 years of age in the western world (Ozen et al. 2019).

It would seem obvious that the ultimate way of treating knee osteoarthritis is joint replacement. However, long before joint replacement is a viable option the patient will have symptoms ranging from mild to significant such as chronic joint pain, muscle weakness and loss of function. In recent years there has been a significant movement towards ‘making the knee last as long as possible’ before surgery. Therefore patients often require conservative and medical treatment long before surgical intervention would be considered. Pulsed shortwave is a way to ‘bridge the gap’ between those requiring surgery and those in need of symptom management in the earlier stages.

In a review article in 2016 Wang et al. concluded:

Short-wave therapy is beneficial for relieving pain caused by knee osteoarthritis (the pulse modality seems superior to the continuous modality)

They found that pain decreased significantly and extensor strength (quads) increased (isokinetic tests) however function did not improve significantly:

Recommendation: 

• Single Head =
  • Pulsed better than continuous
  • Stay between 4w and 15w
  • Use less pulses
  • Frequency = 3x week down to 1x per week
  • 20 mins
  • For 3-6 weeks
  • Combine with exercises for best results

In a randomised control trial in 2005 Laufer et al. tried using both low (1.8w) and high (18w) doses of pulsed shortwave and did not see differences between a sham group and the 2 treatment groups. Based upon this earlier study it does appear the effects of pulsed shortwave are dose dependent with upper and lower boundaries.

Later in a multi center trial Fukuda et al. (2011), found that 14w of treatment was effective for pain relief and improvement of function (Knee Osteoarthritis Outcome Score) both in the short term and at 12 months following treatment. Of interest they tried using a longer treatment time (38 mins) as well as the more standard 19 mins The shorter treatment offered better results at 12 months.

It would appear the treatment is not changing the inflammation in the joint. In a study by Callaghan et al. in 2005 they found no changes in the radioleucoscintigraphy (inflammation) between a treated and placebo group.

So if inflammation is not being reduced but symptoms are improving can we use continuous shortwave?

Ozen et al. (2019) found that both pulsed and continuous shortwave reduced symptoms in OA so the answer appears to be yes.

Overall it would seem that pulsed shortwave is a viable option for symptom management for patients who have earlier OA symptoms although the Osteoarthritis Research Society International guideline for the non-surgical management of KOA does not include shortwave pulsed or otherwise (McAlindon et al. 2014).