Bram 2021.

Study characteristics
Methods	Design: retrospective (matched) Unit of randomization: baby
Participants	Location/Setting: two tertiary care children's hospitals; USA Sample size: 53 babies (64 hips) Number of withdrawals/dropouts: not stated Sex: 46 girls, 7 boys Mean age: 16.6 (SD 11), range 5‐56 days in the not weaned group, 15.7 (SD 14.7), range 3‐65 days in the weaned group Graf: not reported Inclusion criteria: pretreatment ultrasound (US) in whom the harness was initiated under 3 months of age and with radiographic follow‐up at ~12 months of age. For all criteria, uncorrected, chronological ages were used. Exclusion criteria: babies in whom the harness failed for any reason and subsequently required a rigid brace or surgical treatment. Reduced/dislocatable hips (e.g. Barlow positive) were also excluded as these hips are less common and, therefore, harder to match between institutions.
Interventions	Intervention (sample size): weaned (n = 27) Control (sample size): not weaned (n = 26)
Outcomes	Primary outcome(s): acetabular index at one year Secondary outcome(s): duration of harness treatment to US normalization Timing of outcome assessment: one year
Notes	Study start date: not stated Study end date: not stated Funding source: none Conflicts of interest: the authors declare no conflicts of interest. Comment(s): hips were matched but the analysis does not appear to take matching into account