Treatment of Clinical Instability
Limited evidence supports either immediate or delayed (2-9 weeks) brace treatment for hips with a positive instability exam.

Rationale

For infants with a positive hip instability exam, there is conflicting evidence about whether a period of observation or immediate brace treatment leads to a difference in later dysplasia or persistent hip instability leading to later brace treatment. One moderate strength and three low strength studies looked at radiographic differences between an early versus late brace treatment group (Gardiner, 1990, Gardiner, 1992, Molto, 2002, Paton, 2004, Wilkinson, 2002). None of these studies differentiate dislocated from dislocatable hips.

Gardiner (1992) found a significant difference in the radiographic appearance of the femoral capital epiphysis and delayed iliac indentation at 6 months for a no treatment group compared to a brace group. Twenty-nine percent of the non-treatment group had cross-over and were treated at two weeks. Limitations were not defining the femoral capital epiphyseal ossification subcategories and iliac indentation and not explaining the relevance of either.

Molto (2002) compared von Rosen splinting immediately after birth to splinting after two weeks. The outcome criterion was acetabular index. They noted a significant improvement in the acetabular index at 15 months in the immediate treatment group (76 patients) as compared to the 27 patients in the second group treated after two weeks.

Paton (2004) reported on 75 hips in 2 groups, including 37 patients (59 hips) in the early splint treatment group versus 11 patients (16 hips) in the late splint treatment group. Outcome measures included continued instability that required late splint treatment after six weeks, radiographic abnormality, AVN, or surgical intervention at walking age. Authors noted no significant differences when treatment started at less than one week in the early treatment group versus nine weeks on average in the delayed treatment group. This study included both dislocatable and dislocated hips with outcome measures not specifically correlated to the nature of the instability.

RISKS AND HARMS
The risks/harms of this recommendation are overtreatment and the potential complications and burden of care.

2022 UPDATE ADDITIONAL EVIDENCE
1. Bruras, K. R., Aukland, S. M., Markestad, T., Sera, F., Dezateux, C., Rosendahl, K. Newborns with sonographically dysplastic and potentially unstable hips: 6-Year follow-up of an RCT. Pediatrics 2011; 3: e661-e666.

2. Cook, K. A., Schmitt, M., Ingram, M., Larson, J. E., Burgess, J., Janicki, J. A. Pavlik Harness initiation on Barlow positive hips: Can we wait? J Orthop 2019; 5: 378-381.

3. Larson, J. E., Patel, A. R., Weatherford, B., Janicki, J. A. Timing of Pavlik Harness Initiation: Can We Wait?. J Pediatr Orthop 2019; 7: 335-338.