Evaluation of Aid to Diagnosis for Congenital Dysplasia of the Hip in General Practice

1. Objectives: * To determine whether the use of a check list for the 6-week hip check can (i) reduce the number of clinically insignificant referrals from primary to secondary care, and (ii) reduce the number of Developmental dysplasia of the hip (DDH) diagnosed beyond the age of 12 weeks. * To determine the cost-effectiveness of this intervention considering a life time horizon. * To conduct an integrated qualitative and quantitative process evaluation in order to: understand the participants' experience with the intervention; identify how the intervention affects general practitioners' capability, opportunity and motivation in relation to the 6-week check; study how the intervention is implemented; and investigate how contextual factors affect uptake of the intervention. 2. Type of trial: Phase III, cluster randomised controlled trial 3. Trial design and methods: This trial incorporates (i) 4-months internal pilot in order to confirm realistic recruitment targets; (ii) process evaluation encompassing qualitative research on changing physician referral behaviour and on normalising the intervention in practice; and (iii) health economic evaluation. 4. Trial duration per participant: 24 months 5. Planned trial sites: 172 GP practices in England. Half will be randomised to the experimental arm (using the diagnostic aid) and half to the control arm (standard of care 6 week hip check) 6. Total number of participants planned: 172 GP practices will be randomised (with an average of 110 infants recruited across the trial period per practice). 7. Main inclusion criteria: * Inclusion: GP practices registered in England and who carry out the 6-week hip check as part of their routine work - these practices must be using either EMIS or System One clinical computer systems