Effect of corticosteroid injection for trochanter pain syndrome: design of a randomised clinical trial in general practice

BACKGROUND Regional pain in the hip in adults is a common cause of a general practitioner visit. A considerable part of patients suffer from (greater) trochanteric pain syndrome or trochanteric bursitis. Local corticosteroid injections is one of the treatment options. Although clear evidence is lacking, small observational studies suggest that this treatment is effective in the short-term follow-up. So far, there are no randomised controlled trials available evaluating the efficacy of injection therapy. This study will investigate the efficacy of local corticosteroid injections in the trochanter syndrome in the general practice, using a randomised controlled trial design. The cost effectiveness of the corticosteroid injection therapy will also be assessed. Secondly, the role of co-morbidity in relation to the efficacy of local corticosteroid injections will be investigated. METHODS/DESIGN This study is a pragmatic, open label randomised trial. A total of 150 patients (age 18-80 years) visiting the general practitioner with complaints suggestive of trochanteric pain syndrome will be allocated to receive local corticosteroid injections or to receive usual care. Usual care consists of analgesics as needed. The randomisation is stratified for yes or no co-morbidity of low back pain, osteoarthritis of the hip, or both. The treatment will be evaluated by means of questionnaires at several time points within one year, with the 3 month and 1 year evaluation of pain and recovery as primary outcome. Analyses of primary and secondary outcomes will be made according to the intention-to-treat principle. Direct and indirect costs will be assessed by questionnaires. The cost effectiveness will be estimated using the following ratio: CE ratio = (cost of injection therapy minus cost of usual care)/(effect of injection therapy minus effect of usual care). DISCUSSION This study design is appropriate to estimate effectiveness and cost-effectiveness of the injection therapy. We choose to use a pragmatic study design and are thus not able to study specific effects of the injection with corticosteroids. A distinction between placebo effect of the injection and specific effects of the corticosteroids is therefore not possible.