Therapeutic ultrasound for osteoarthritis of the knee

Background

Therapeutic ultrasound is one of several physical therapy modalities suggested for the management of pain and loss of function due to osteoarthritis (OA).

Objectives

To assess the effectiveness of therapeutic ultrasound therapy for treating OA.

Search strategy

We searched the Cochrane Musculoskeletal Group register and MEDLINE (to December 2000) using the sensitive search strategy developed by the Cochrane Collaboration. The search was complemented with bibliography searches of the reference list of the trials retrieved from the electronic search. Key experts in the area were contacted for further published and unpublished articles.

Selection criteria

All randomized controlled trials (RCTs) and controlled clinical trials (CCTs) in people with OA comparing therapeutic ultrasound against placebo or another active intervention were selected.

Data collection and analysis

Two reviewers determined the studies to be included based on inclusion and exclusion criteria. Data were independently extracted by two reviewers and checked by a third reviewer. using an adapted form from the OA subgroup of the Cochrane Musculoskeletal Group.

The same two reviewers independently assessed the methodological quality of the RCTs and CCTs using a validated scale. Outcome measures for OA were extracted from the publications. The pooled analyses were performed using weighted mean differences (WMDs) for joint counts, pain, and global and functional assessments. A chi-square test was used to assess heterogeneity among trials. Fixed effects models were used throughout and random effects models used for outcomes showing heterogeneity.

Main results

Three trials including 294 participants with hip or knee OA were included. Only one trial (n of 74), where n is the number of participants, compared therapeutic ultrasound to placebo. This trial showed no difference in range of motion, pain or gait velocity after four weeks of therapeutic ultrasound. Two trials compared therapeutic ultrasound to an active therapy (n of 220). These trials showed no statistical difference between ultrasound, galvanic current or short wave diathermy for the outcomes of pain and participant assessed improvement.

Authors' conclusions

Ultrasound therapy appears to have no benefit over placebo or short wave diathermy for people with hip or knee OA. These conclusions are limited by the poor reporting of the characteristics of the device, the population, the stage of OA, therapeutic application of the ultrasound and overall low methodological quality of the trials included. No conclusions can be drawn about the use of ultrasound in smaller joints such as the wrist or hands.