Box 1.

Summary of the Arthritis Research UK Osteoarthritis and Crystal Diseases Clinical Studies Group recommendations

For clinical efficacy studies:

Carefully define the phenotype and ensure its relevance to the intervention being tested

Randomization is critical

Where mechanisms of action of the intervention are understood, the comparator intervention should be defined in terms of action in order to control for these mechanisms as much as possible

Where mechanisms are not understood or a comparator is not feasible, a non-intervention arm should be considered

Should the intervention need to be customized, the investigator is encouraged to define a standard operating procedure for the customization

Other design considerations include a run-in phase, within-patient controls, cross-over designs and increased patient and public involvement

In efficacy studies, the duration of the trial may be short (6–12 weeks) in order to maximize adherence and minimize loss of follow-up

Trials should include assessments of the use of the device and measures of compliance

Trials should include a blinded assessor and should use one or more objective measures to assess the primary effect

Trial design and analysis should take into account adverse events, including pain in other joints