Splinting for the non-operative management of developmental dysplasia of the hip (DDH) in children under six months of age

Splinting for dislocated and shallow hips in babies

What are dislocated or shallow hips?

Dislocated or shallow hips occur when the ball and socket at the end of the thighbone do not fit together. The medical term is ‘developmental dysplasia of the hip' (DDH). Shallow hips occur in 10 out of 1000 newborn babies, though dislocated hips are rarer, occurring in 1 in every 1000 newborns. Hips can be ‘dislocated’, unstable (i.e. easily fall out of the socket during examination) or ‘stable’ (i.e. located in the joint throughout examination).

How are these hips treated?

Shallow and dislocated hips are commonly treated with hip splints. Splints control the movement of the legs to guide the hips into the socket, allowing the hip to improve naturally. Splints can either fix the legs in position, called ‘static splints’, or allow the legs some freedom to move, called ‘dynamic splints’. Occasionally, clinicians may recommend the use of double nappies (double diapers), which are bulky, and gently push the legs apart to act as a type of splint.

What did we want to find out?

We wanted to know how successful splinting was, and if there were any groups of babies for whom the best treatment may differ. We focused on the development of the socket, the need for further surgery, and any complications up to two years after treatment. We were also interested in factors that parents told us were important, such as the ability to breastfeed and the bond between the parent and baby.

What did we do?

We searched for studies that investigated splinting for shallow and dislocated hips amongst babies under six months of age. We were interested in studies that compared the success of one type of splint to another splint, or a splint compared to no treatment. We included studies that assigned babies into different treatment groups using a process called randomization and studies that did not assign babies at random. In the studies that did not use randomization, babies were usually allocated to the different groups based on the choice of the clinician. Whilst studies without randomization contributed to the discussion, our conclusions are based largely on the results of the studies that used randomization.

We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and study size.

What did we find?

We found six studies that used randomization and included 576 babies and 16 studies that did not use randomization and included 8237 babies.

Five studies had non-commercial funding, three studies stated that there was no funding and 14 studies did not state the funding source.

Main results

Comparing immediate dynamic splinting to delayed dynamic or no splinting

Four studies compared dynamic splinting at first diagnosis with a strategy of waiting up to 12 weeks after diagnosis before starting treatment. Two studies looked at stable shallow hips, one at unstable shallow hips and one at a combination of both. None of the studies considered dislocated hips.

Amongst hips that were not dislocated, two studies showed no clear evidence of a difference in the development of the socket at one year by delaying the initial treatment. Furthermore, two studies of stable hips showed that the development of the socket was no different at two years by delaying the initial treatment. No studies reported results at five years after treatment.

Delaying the start of treatment did not increase the number of complications or the rates of later surgery in three studies. One study identified two babies who required surgery in the dynamic splinting group.

Two studies looked at an important complication called 'avascular necrosis', where the blood supply to the hip is damaged. No hips were affected by this in either study.

Comparing immediate static splinting to delayed static splinting or no splinting

No randomized studies compared these treatments.

Comparing double nappies to single nappies

One study compared double nappies with single nappies but did not report any outcomes of interest.

Comparing dynamic to static splinting

One study reported no occurrences of avascular necrosis with either treatment.

Comparing immediate removal of splint at the end of treatment to gradual removal (weaning)

No randomized studies compared these treatments.

Overall summary

Only 576 babies have been involved in randomized studies to find the best treatments in DDH. Amongst stable hips, there was no clear evidence to support treatment with splints at any time point. For unstable hips, a delay in treatment of up to six weeks had similar results at one year, with fewer hips requiring treatment.

Results from studies without randomization supported the findings from the studies with randomization, without offering any additional clarity.

What are the limitations of the evidence?

We were not confident in the evidence because we found only a few studies, which were small, with few babies randomly placed into treatment groups. In addition, studies were done in different types of babies and not all studies provided data about everything we wanted to know.

How up to date is the evidence?

The evidence is up to date to November 2021.

Read the full review on the Cochrane Library, here

Images by Londenp, CC BY-SA 3.0, commons.wikimedia.org/wiki/File:Pavlik.jpg and commons.wikimedia.org/w/index.php?curid=1804587