Active monitoring versus immediate abduction as treatment of stable developmental dysplasia of the hip: a systematic review of the literature

OBJECTIVES: This systematic review aims to compare the effects of active monitoring and abduction treatment on the Graf alpha angle, Acetabular Index (AI) and femoral head coverage in infants with stable developmental dysplasia of the hip (DDH). DESIGN: Systematic review reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. DATA SOURCES: A search of the PubMed, Embase, Cochrane and Web of Science databases was performed in January 2020 and updated in January 2021. ELIGIBILITY CRITERIA: (Non-)randomised studies comparing active monitoring with abduction treatment in infants younger than 4 months with stable DDH were included. DATA EXTRACTION AND SYNTHESIS: All eligible articles were methodologically assessed using the Cochrane risk of bias tools. Data were extracted by summarising the study characteristics and results. RESULTS: Of the six included studies, two randomised studies were of low risk and two of some concerns. Two non-randomised studies were of serious risk. In total, 544 dysplastic hips (439 infants) were investigated, of which 307 were observed and 237 were treated. Two studies reported a faster improvement of the alpha angle and average acetabular coverage in treated hips at 3 months. No differences in AI between the treatment and observation group after 3 months were reported. In total, 38 infants (12%) in the observation group switched to the treatment group. At the final radiograph, 21 observed hips and 32 treated hips were dysplastic. CONCLUSIONS: There were no differences in AI between the treatment and observation group after 3 months in infants up to 4 months of age with stable DDH hips. The switch of 38 infants (12%) from the observation to the treatment group corroborates that not all infantile DDH hips will spontaneously progress into normal hips. The small study population sizes and methodological heterogeneity warrant a large randomised controlled trial to study this research question. PROSPERO REGISTRATION NUMBER: CRD4202123300.