Natural history of hip instability in infants (without subluxation or dislocation): a three year follow-up

Examining the Short-Term Natural History of Developmental Dysplasia of the Hip in Infancy: A Systematic Review

BACKGROUND

This study was an update on the AAOS clinical practice guideline's analysis of the natural history of developmental dysplasia of the hip (DDH). The objective was to delineate the natural history of clinical instability or radiologic abnormalities of the hip in infants by identifying the proportion of cases that resolved without treatment compared to cases that progressed and/or required treatment.

METHODS

We performed a literature search of PUBMED to identify studies which evaluated the natural history of DDH. We used the same search strategy as that utilized in the previous AAOS guidelines, updated to include articles published between September 2013 and May 2021. We assessed the quality of included articles using the Oxford Centre for Evidence-Based Medicine level of evidence and reported study demographics and outcomes using summary statistics.

RESULTS

Twenty-four articles met our eligibility criteria. Most included studies were retrospective (14/24), investigated either the incidence of DDH (8/24) or assessed screening programs (7/24). The most prevalent study population followed were Graf 2A hips (7/24). Most studies were low quality with level of evidence 3 (13/24) or 4 (7/24). Sample sizes ranged from 9 to 3251. Twenty studies reported the number of cases resolved over the follow-up period with a mean rate of 84.3% (95% confidence interval 76.1, 92.6).

CONCLUSION

We found most mild-to-moderate DDH can resolve without treatment in early infancy, especially in physiologically immature (Graf 2A) hips. More high-quality evidence is needed to properly assess the natural history of DDH as only one included study was a randomized trial.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00510-6.

Abduction treatment in stable hip dysplasia does not alter the acetabular growth: results of a randomized clinical trial

Background The effect of bracing over natural history of stable dysplastic hips is not well known. This multicenter randomized trial aimed at objectifying the effect of abduction treatment versus active surveillance in infants of 3 to 4 months of age. Methods Patients were randomized to either Pavlik harness or active surveillance group. Ultrasound was repeated at 6 and 12 weeks post randomization. The primary outcome was the degree of dysplasia using the Graf α-angle at 6 months of age. The measurement of the acetabular index (AI) on plain pelvis X-rays was used to identify persistent dysplasia after 9 months and walking age (after 18 months). Findings The Pavlik harness group (n = 55) and active surveillance group (n = 49) were comparable for predictors of outcome. At 12 weeks follow-up the mean α-angle was 60.5° ± 3.8° in the Pavlik harness group and 60.0° ± 5.6° in the active surveillance group. (p = 0.30). Analysis of secondary outcomes (standard of care) showed no treatment differences for acetabular index at age 10 months (p = 0.82) and walking age (p = 0.35). Interpretation Pavlik harness treatment of stable but sonographic dysplastic hips has no effect on acetabular development. Eighty percent of the patients will have a normal development of the hip after twelve weeks. Therefore, we recommend observation rather than treatment for stable dysplastic hips.

Neonatal hip ultrasound: tangent to lateral roof angle correlates better with stability than alpha angle according to Graf or percentage femoral head coverage

The aim of this study was to determine the relationship of tangent to the lateral roof angle (TLRA), Graf's alpha angle and percentage femoral head cover (PHC) and to observed stability, and to establish intraobserver and interobserver errors for measurement of alpha angle and TLRA. In total, 2235 babies referred to the hip review clinic over a period of 8  years. Intraobserver and interobserver errors were calculated from readings of 383 hip images by an experienced paediatric radiologist and a trainee. Taking TLRA <70° as abnormal resulted in sensitivity for unstable right hips of 88% compared with 77% for alpha angle <60° (P  =  0.002) and 81% for PHC <60% (P  =  0.028) and specificity of TLRA 89%, alpha angle 90% (P  =  0.07) and PHC 83% (P  <  0.001). Corresponding figures for left hips are sensitivity of TLRA 99%, alpha angle 91% (P  <  0.001) and PHC 96% (P  =  0.013), and specificity TLRA 86%, alpha angle 83% (P  =  0.001) and PHC 67% (P  <  0.001). Mean intraobserver errors for alpha angle were 1.85° and 1.81° for consultant and trainee compared to 2.54 and 2.55 for TLRA. Mean interobserver errors were 2.22 for alpha angle and 3.42 for TLRA. TLRA, a new parameter, correlated better with observed stability with significant improvement in sensitivity in both hips and specificity in left hips compared with Graf's alpha angle, and significantly improved sensitivity and specificity in both hips compared with percentage femoral head cover.