Comparing Observation vs. Bracing in Radiologically Dysplastic, Stable Hips in Infants With Developmental Dysplasia of the hip: A Protocol for a Global Multi-centre Non-inferiority Randomized Trial.
Abstract
Purpose:
Brace treatment is common to address radiological dysplasia in infants with developmental dysplasia of the hip (DDH); however, it is unclear whether bracing provides significant benefit above careful observation by ultrasound. If observation alone is non-inferior to bracing for radiological dysplasia, unnecessary treatment may be avoided. Therefore, the purpose of this study is to determine whether observation is non-inferior to bracing for infants with radiological dysplasia.
Method:
This will be a multi-centre, global, randomized, non-inferiority trial performed under the auspices of a global prospective registry for infants and children diagnosed with DDH. Patients will be included if they present with radiological dysplasia (centred hip, alpha angle 43-60°, percent femoral head coverage (FHC) 35-50% measured on ultrasound) of a clinically stable hip under three months of age. Patients will be excluded if they present with clinical hip instability, have received prior treatment or have known/suspected neuromuscular, collagen, chromosomal or lower-extremity congenital abnormalities or syndromic-associated hip abnormalities. Patients will be enrolled and randomized to undergo observation alone or brace treatment with a Pavlik harness for a minimum of six weeks. Follow up visits will occur at six weeks, one year and two years post-enrollment. The primary outcome will be the acetabular index measured on the two-year radiograph with a three-degree non-inferiority margin. A total of 514 patients will be enrolled in the study. The existing registry has allowed us to pilot the feasibility of the trial’s recruitment, eligibility criteria and treatments. Here we report the results of this pilot data for the trial collected as part of the the registry since 2021.
Results:
Since receiving a POSNA Research Grant for this study in 2021, we have enrolled 309 patients with clinically stable hips into the registry. Two hundred and sixty-five patients were initially braced, 212 with a Pavlik harness, and 42 patients were initially monitored.
Conclusion:
Pilot data demonstrates the feasibility of achieving sufficient recruitment for this trial. However, the observational nature of the registry also highlights the precise need for such a trial: it’s likely many patients were initially braced due to centres not enrolling into the registry until the decision to treat had been made. This rigorous trial will provide definitive evidence for whether patients with radiological dysplasia require treatment. This pilot data collection has also now led to a successful Canadian Institutes of Health Research (CIHR) grant to expand the study into a global trial with per patient remuneration and has spawned a collaboration with a team in the Netherlands executing a similar trial in an older population. The limited existing literature compels a better understanding of the natural history of radiologically dysplastic hips to inform more consistent guidelines backed by the substantial evidence generated by a well-executed, global, multi-centre randomized trial.
Disclosures:
Bryn Zomar
Canadian Institutes for Health Research - co-investigator on funded trial OrthoPediatrics - co-investigator on funded trial
Consultant or employee fees:
I'm a HIPpy Foundation - provides funding to support research in our lab