Table 2.

Conclusions and recommendations.

Guideline question	Conclusions	Recommendations1	GRADE
(i) Reduction with Pavlik harness vs other abduction devices	There were no significant differences reported comparing the Pavlik harness to the Frejka pillow, Craig splint, and Von Rosen splint, with regard to successful reduction (around 90%), complication rates, secondary procedures, and residual dysplasia. (Zidka et al. 2019, Wilkinson et al. 2002, Atar et al. 1993). The great majority of literature on abduction devices is on the Pavlik harness, and it is by far the most applied device in the Netherlands. It can be applied for all grades of DDH.	Use the Pavlik Harness as the first step in treatment for (sub)luxated DDH hips in babies under the age of 1 year. Follow-up with ultrasound is recommended at 3–4 and 6–8 weeks.	Very low1
(ii) Unsuccessful Pavlik treatment → closed reduction restricted by limited hip abduction – traction vs adductor tenotomy	In 1 comparative study, no significant differences were reported for successful reduction, residual dysplasia, secondary procedures, AVN, or other complications. (Carney et al. 2005). In 4 non-comparative studies, 39–79% of patients still had an indication for adductor tenotomy after traction (Brougham et al. 1990, Burgos-Flores et al. 1993, Forlin et al. 1992, Gogus et al. 1997).	Perform adductor tenotomy, and not traction, if closed reduction is restricted by limited hip abduction.	Very low1
(iii) Unsuccessful closed reduction → surgical reduction through a medial or anterior approach vs other surgical approaches	No significant differences were reported for successful reduction, functional outcome, secondary procedures, AVN or other complications, blood loss, and operative time between approaches. (Duman et al. 2019, Yorgancigil et al. 2016, Hoelwarth et al. 2015, Holman et al. 2012, Tarasolli et al. 2014, Matsushita et al. 1999). The scientific evidence and general clinical experience for arthroscopic procedures or the wide-exposure method are highly limited, in contrast to the anterior and medial approaches.	Use either the anterior, anterolateral, or medial approach, based on surgical preference and experience.	Very low1
(iv) After successful surgical reduction (closed or open): short period of spica cast treatment compared vs longer period	No significant differences were found with regard to to successful reduction and residual dysplasia (Emara et al. 2019) comparing 4 weeks of spica cast and a 11–13 months weaning regime with an abduction splint, compared to a spica cast for 12 weeks.	The recommended duration of spica cast treatment after closed or open reduction is 12 weeks.	Very low1
(v) Preferable method of diagnostic assessment during follow-up in spica cast	No comparative studies were found.	Use transinguinal ultrasound for the evaluation of the hip after reduction and during follow-up in spica cast. When not available, an arthrogram is advisable after reduction, followed by standard radiographs during follow-up. When in doubt, MRI or low-dose CT can be applied.	Not applicable
(vi) Subsequent abduction device after spica cast treatment – yes or no	No comparative studies were found.	(Additional) Treatment with an abduction device after spica cast treatment is advised under the age of 1 year old, in cases with severe residual dysplasia.	Not applicable

Recommendations are based on the literature conclusions, as well as the clinical considerations as described in the text.

¹GRADE Level of evidence was downgraded by one level because of study limitations, including bias by indication, no adjustment for confounding, or low numbers of patients (imprecision).

DDH, developmental dysplasia of the hip; GRADE, grading recommendations assessment, development, and evaluation (Guyatt et al. 2008).