Background The primary complaints of patients suffering from osteoarthritis of the knee are pain, stiffness, instability, and loss of function. In early disease, pain will be intermittent and mostly associated with joint use. For many people, symptomatic disease progresses and the pain become more chronic and may also be present at rest and during the night. The joint will feel stiff, resulting in typical pain and difficulty when initiating movement after a period of rest.

Objective This report is based on two existing systematic reviews (from the Netherlands and Canada) and guidelines from "The Philadelphia Panel", in addition to an updated systematic review on studies published from 1998 to January 2004. The objective was to evaluate the effectiveness of physical therapy, restricted to electrotherapy and exercise, for osteoarthritis of the knee. The clinical endpoints were pain, physical function, sickness days and quality of life.

Search strategy Relevant databases that were searched were The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE), International Network of Agencies of Health Technology assessment (INAHTA) database, The Physiotherapy Evidence Database (PEDro), National Guidelines Clearinghouse, Medline, Embase, OHE Economic Evaluations Database and NHS Economic Evaluation Database.

The literature search for primary literature identified 770 abstracts that were reviewed. 180 possibly relevant studies were assessed, and 36 studies included in the report. Ten systematic reviews were also included.

Results / Conclusions Both home based exercise and exercise led by a physical therapist improved pain, function and quality of life in patients with osteoarthritis of the knee. The exercise programs must last for a minimum of eight weeks to give significant effects.

Most studies on exercise concentrate on strength training of the quadriceps and used 2-4 repetitions each week.

Both laser and TENS gave significant effects on pain relief at the end of treatment (2-4 weeks). However, the evidence for the effect by laser is weaker than for TENS.

There is a lack of evidence regarding effect on osteoarthritis of the knee after treatments including ultrasound and pulsed electromagnetic fields.

The effect of physiotherapy (exercise, laser and TENS) persist for 1-3 months after the end of treatment.

The conclusions regarding cost-effectiveness of physiotherapy on osteoarthritis of the knee are uncertain since no reliable data are available on this subject.