Predicting developmental dysplasia of the hip in at-risk newborns

Table 2 Simple regression analysis of candidate predictors in 1953 infants who had outcomes ascertained (DDH was defined as α < 55° at age > 42 days, or α < 50 at age < 42 days). All values are numbers (percentages) unless otherwise stated

Candidate Predictor	All infants (N= 1953)	Infants with DDH (N = 77)	Odds ratio (95% confidence interval)	P
Female sex	1037 (53.1)	65 (77)	5.04 (2.70, 9.39)	< 0.001
First degree family history of DDH	184 (9.4)	15 (9)	2.44 (1.36, 4.39)	0.003
Vaginal delivery	892 (45.7)	42(58)	1.59 (0.99, 2.55)	0.06
Birth weight in kg (mean ± SD)	3.22 ± 0.58	3.40 ± 0.52	1.81 (1.14, 2.87)	0.01
Foot deformity warranting followup ^c	51 (2.6)	5 (8)	2.76 (1.07, 7.16)	0.04
First born child	1108 (56.7)	46 (66)	1.35 (0.82, 2.23)	0.24
Multiple birth (twin pregnancy)	257 (13.2)	6 (9)	0.61 (0.26, 1.41)	0.25
Breech at presentation	586 (30.0)	20 (39)	0.81 (0.48, 1.36)	0.43
Oligohydramnios	39 (2.0)	0 (0)	NA^a	NA^a
Torticollis	10 (0.5)	1 (1)	NA^b	NA^b
Abnormal hip examination ^d	86 (4.4)	43 (56)	53.91 (31.35, 92.71)	< 0.001
Ortolani positive	14 (0.7)	11 (14)	NA^b	NA^b
Barlow positive	20 (1.0)	14 (18)	NA^b	NA^b
Galeazzi positive (leg length discrepancy)	16 (0.8)	11 (14)	NA^b	NA^b
Hip instability	25 (1.3)	7 (9)	NA^b	NA^b
Asymmetry in hip abduction	36 (1.8)	21 (27)	NA^b	NA^b

SD standard deviation
^aNot possible to estimate because no DDH cases had oligohydramnios
^bNot applicable (NA) for risk model due to low prevalence
^cFoot deformity receiving orthopedic or physiotherapy follow-up
^dThis variable includes hips with at least one of the following criteria present: leg length discrepancy, asymmetry of hip abduction, Barlow positive, Ortolani positive, hip instability. The latter 3 were mutually exclusive. This variable thus indicates hips that showed an abnormal physical examination

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