This study is a randomised placebo controlled trial designed to investigate the efficacy of intra-articular hyaluronan (Synvisc®) to reduce pain and improve function in people with OA of the first MPJ (hallux limitus). Two studies have previously investigated the efficacy of intra-articular hyaluronan for the treatment of first MPJ OA [13, 14]. However, neither of these studies used a placebo control group. To our knowledge, this is the first randomised controlled trial using intra-articular hyaluronan for OA of the first MPJ.
The use of a placebo control group is essential for studies evaluating the effects of intra-articular therapies as there is likely to be a large placebo response related to the injection procedure and this may inflate the results in uncontrolled evaluations . Indeed, a recent meta-analysis of hyaluronan for knee OA concluded that a placebo effect accounted for 79% of the efficacy of intra-articular hyaluronan .
The study protocol and outcome measures have been developed in accordance of the recommendations of the OARSI Clinical Trials Task Force guidelines . The outcome measures are pain and function subscales of the FHSQ, pain and stiffness at the first MPJ, range of motion (dorsiflexion) of the first MPJ, plantar flexion strength of muscles of the first MPJ, generic health related quality of life (SF-36), patient satisfaction with treatment, consumption of rescue medication as well as frequency and nature of adverse effects. These outcomes will be measured at baseline then at 1, 3 and 6 months after treatment. Previous research suggests that the effects of intra-articular hyaluronan persist for up to 12 months following treatment [9, 38]. Thus, the use of follow-up assessments at 6 month post-treatment will allow us to determine if the effects, if any, of intra-articular hyaluronan persist in the longer term.
Participants will be given the option of a second and final intra-articular injection (of Synvisc® or sterile saline according to the treatment group they are in) on days 30 or 90 if there is no improvement in their symptoms. Although this has the potential to complicate the interpretation of the results of the study, this protocol was included as it is likely to be more reflective of clinical practice , and this is in keeping with the pragmatic nature of this trial.
In summary, this project is the first randomised controlled trial to be conducted to evaluate the efficacy of intra-articular hyaluronan for reducing pain and improving function in people with hallux limitus. The study protocol, including interventions, have been pragmatically designed to ensure that the study findings are generaliseable to clinical practice. Recruitment for the study will commence in June 2008, and we expect final results to be available in mid-2010.