Detection and Nonoperative Management of Pediatric Developmental Dysplasia of the Hip in Infants up to Six Months of Age
Moderate evidence supports not performing universal ultrasound screening of newborn infants.There is moderate evidence to not do universal screening of all infants for DDH. Two moderate strength studies showed no statistical difference between universal and selective ultrasound screening of the infant hip for diagnosis of late presenting DDH.1,2 Holen augmented clinical screening with either universal or selective (risk) ultrasound. The rate of late cases in Holen’s study was 0.13/1000 with universal ultrasound screening and 0.65/1000 with selective (risk) screening. The difference in late detection was not statistically significant. Rosendahl used three matched study groups: general ultrasound screening, risk factor screening and only clinical screening. Late cases identified by group were 0.3/1000, 0.7/1000 and 1.3/1000 respectively and these differences were not statistically significant.
Screening of all infants with ultrasound has the potential to lead to over-treatment. Rosendahl’s study found that general ultrasound screening resulted in a higher treatment rate (3.4%) than either selective ultrasound screening (2.0%) or clinical screening (1.8%). The higher rate with universal screening is statistically significant. Universal ultrasound screening requires considerable diagnostic and therapeutic effort and these studies which involve large numbers of newborns indicate that such a commitment of resources will not significantly impact the prevalence of late cases. Risks and Harms of Recommendation There is a potential to miss a case of DDH in an infant with a normal clinical examination and no risk factors. This could lead to a late diagnosis with concerns for a potential of higher rate of treatment complications as a result of late diagnosis.
Risks and Harms of Recommendation
There is a potential to miss a case of DDH in an infant with a normal clinical examination and no risk factors. This could lead to a late diagnosis with concerns for a potential of higher rate of treatment complications as a result of late diagnosis.
Moderate evidence supports performing an imaging study before 6 months of age in infants with one or more of the following risk factors: breech presentation, family history, or history of clinical instability.If the risk factors of family and/or breech presentation are present, there is moderate evidence to support selective ultrasound screening between 2-6 weeks of age for infants who otherwise have a normal clinical hip examination or an AP radiograph at 4 months of age. There were two studies of moderate strength that confirm significance for selective prospective screening by ultrasound in infants with history of possible clinical instability and/or risk factors: breech and family history to prevent late dislocations and need for surgery.16, 17
Of the 10 studies of low strength the various risk factors included were: breech, family history, sex, combination of sex and breech, combination of sex and family history, hip click, first born, swaddling, and talipes.
Breech literature included six studies all of low study strength. The results of these studies were meta-analyzed and the meta-analysis overwhelmingly supported breech presentation as a risk factor for neonatal instability. The literature terminology on breech is: breech at birth, breech delivery, and breech position at the third trimester; there is no literature to substantiate a particular duration of breech positioning as a risk factor.
Family history: four articles of low strength all showing statistical significance for family history as a risk factor for DDH. 4, 5, 13, 18 There was one study which showed no statistical significance. 3
One study compared treatment for dislocatable hips (at age less than one week) with no treatment for stable hips with positive family history. 8 The outcome was residual dysplasia at five months and was noted to be significant for the no treatment category. The authors further treated these patients from the no treatment category at age five months and compared them with the original cohort of Barlow positive patients treated at age less than one week. This time around, the outcome parameter was residual dysplasia at two years and was again noted to be significant. Other outcome measures included AVN at two years, which was not significant, and treatment failure, which was noted to be significant. This study did not have a true comparative group for analysis. There was a combination of dislocated and dislocatable hips in the Barlow positive category, which confounds the analysis.
The literature definitions of family history of DDH range from unspecified hip disorders to hip dislocation and from first degree relative (parents and siblings), to any relative (even if distant or vague) with hip problems or DDH (all other articles). Three articles listed family history, but did not specify the relationships or specific hip problems.3, 5, 7
One study compared ultrasound screening in infants who had risk factors alone with those who had “doubtful” clinical instability.17 Rate of detection of dislocation as confirmed by ultrasound was 13/1000 (7 to 24) vs 87/ 1000 (57 to 126/1000) respectively.
There is no substantiation in the literature of the optimal age for imaging studies in these infants with risk factors.8 One study performed hip radiographs at 4 months of age. Two studies14, 15 performed ultrasound between 2-6 weeks of age.
Examination of other quoted risk factors was done. Evidence was not found to include foot abnormalities, gender, oligohydramnios, and torticollis as risk factors for DDH.
Risks and Harms
There is a potential risk of over diagnosis and treatment.
Limited evidence supports that the practitioner might obtain an ultrasound in infants less than 6 weeks of age with a positive instability examination to guide the decision to initiate brace treatment.If faced with an unstable hip examination, there is limited evidence to support the use of sequential ultrasound to aid in determining when to initiate brace treatment for infants up to 8 weeks of age. Fewer children may undergo brace treatment with no difference in the occurrence of late dysplasia. One moderate strength study showed fewer children in the ultrasound group had abduction splinting in the first two years than did those in the no ultrasound group (0•78; 0•65–0•94; p=0•01). 19 The primary outcome was the appearance on hip radiographs by two years. Secondary outcomes included surgical treatment, abduction splinting, level of mobility, resource use, and costs. Analysis was by intention to treat. Protocol compliance was high, and radiographic information was available for 91% of children by 12–14 months and 85% by 2 years. By age 2 years, subluxation, dislocation, or acetabular dysplasia were identified by radiography on one or both hips of 21 children in each of the groups (relative risk 1•00; 95% CI 0•56–1•80).
Surgical treatment was required by 21 infants in the ultrasound group (6•7%) and 25 (7•9%) in the no-ultrasound group (0•84; 0•48–1•47). One child from the ultrasound group and four from the no-ultrasound group were not walking by 2 years (0•25; 0•03–2•53; p=0•37). Initially this study was graded as high strength, but was downgraded to moderate strength because the rate of splint treatment was not the primary outcome. Additionally, it is unclear that all subjects were normal infants with DDH and no confounding diagnoses.
In this study infants with hips that had minor instability were not immediately treated. Experienced doctors performed the clinical examinations. Even though there is even distribution between the groups in terms of number of history of instability, subgroup analysis of dislocated versus dysplastic hip results were not available.
There is a potential delay of necessary treatment.
Limited evidence supports the use of an AP pelvis radiograph instead of an ultrasound to assess DDH in infants beginning at 4 months of age.There is limited evidence that an AP pelvis radiograph is preferred to the use of ultrasound to assess for DDH in infants from 4-6 months of age. This evidence does not distinguish between children with normal or abnormal physical examinations or between children with and without risk factors for DDH. One moderate-strength study investigated the radiographic assessment of every ultrasound positive hip in children four to six months of age. 20 Seventy-four infants with ultrasound positive hips for acetabular dysplasia who met criteria for treatment received an AP pelvis radiograph. Of these 74 infants, 30 were found to have satisfactory acetabular indices and did not receive treatment.
Limitations of this study include the lack of long-term follow-up of the infants to determine if the radiographic assessment altered outcome and failed to address the optimal time of conversion from ultrasound to radiographic assessment in infants with DDH.
Risks and Harms of Recommendation:
Radiographs involve exposure to ionizing radiation.
Limited evidence supports that a practitioner re-examine infants previously screened as having a normal hip examination on subsequent visits prior to 6 months of age.If faced with a child who has a normal physical examination, there is limited evidence that performing subsequent hip physical examination screening of children up to 6 months of age will detect additional children with DDH. The reviewed literature does not include the screening of children up to walking age when other examination findings such as gait abnormalities may allow for detection of additional children with DDH. One low strength study presented evidence that repeated studies at three months were productive in identifying late diagnosed DDH. 22 Another low strength study noted that exams at eight months of age had a high rate of false positives, but no yield of true positives.21
There is no literature to define the optimal frequency or duration of follow-up surveillance.
Risks and Harms
There is a potential risk of over diagnosis and treatment.
Limited evidence supports observation without a brace for infants with a clinically stable hip with morphologic ultrasound imaging abnormalities.For an infant with a normal physical examination and ultrasound abnormalities, there is limited evidence to support observation without treatment of that infant with serial ultrasound evaluation up to 6 weeks of age. One low-strength study evaluated a group of at-risk patients who were evaluated by ultrasound between two and six weeks of age with clinically stable hips showing ultrasonographic abnormalities that were randomized to treatment with Pavlik harness or observation.23The two primary outcome measures were the acetabular coverage on ultrasound and acetabular index on radiograph. While acetabular coverage, measured ultrasonographically, improved in both groups, and was statistically better in the splinted group at the final, three month follow-up, there was no difference in acetabular index.
Risks and Harms
The risk of implementing this recommendation is that necessary treatment could be delayed.
Limited evidence supports either immediate or delayed (2-9 weeks) brace treatment for hips with a positive instability exam.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. 24, 25(follow-up), 26, 27, 28 None of these studies differentiate dislocated from dislocatable hips.
Gardiner 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.25 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 compared Von Rosen splinting immediately after birth to splinting after two weeks. 26 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 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.27 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.
The risks/harms of this recommendation are overtreatment and the potential complications and burden of care.
Limited evidence supports use of the von Rosen splint over Pavlik, Craig, or Frejka splints for initial treatment of an unstable hip.There are no high quality comparative effectiveness studies between different types of braces for the treatment of DDH. Limited evidence suggests that rigid braces may have higher rates of resolution of hip dysplasia than non-rigid braces. Two low strength studies compared rigid bracing to soft bracing for initial treatment of unstable hips in infants. 29, 30 Heikkila compared the Frejka pillow with the von Rosen splint.29There were 920 patients treated with Frejka pillow and 180 patients treated with von Rosen splint. Fifty-five of 920 from the Frejka pillow group had treatment failure, while 1 out of 180 from the von Rosen splint group failed treatment. These differences were significant. A limitation of this study is that it was a historical comparative study of two cohorts over two time periods. AVN rates were inadequately reported. The authors did not differentiate between dislocated and dislocatable hips.
Three splints were compared in the Wilkinson study: Craig, Pavlik, and von Rosen.30 Four of 28 in the Craig splint group, 13 of 43 in the Pavlik group, and 0 of 26 in the von Rosen group required further treatment in the form of plaster or operation.
This recommendation is based on the braces that were studied, but other similar fixed-position braces may or may not work as well as the braces mentioned in the evidence.
Risks and Harms
Nineteen percent of the patients in the rigid brace group experienced skin irritation29. There is a potential risk of AVN with all bracing; the relative risk is unknown between rigid and soft bracing.
Limited evidence supports that the practitioner perform serial physical examinations and periodic imaging assessments (ultrasound or radiograph based on age) during management for unstable infant hips.If brace treatment is initiated, there is limited evidence that episodic serial physical and imaging reassessments during the treatment cycle can lead to changes or duration of the treatment plan. Two low strength studies report monitoring of brace treatment using physical exam, ultrasound, and radiography following the appearance of the ossific nucleus.31, 32 Both studies identified failure of reduction or persistent dysplasia in patients undergoing brace treatment. These findings necessitated a change in treatment plan or duration. No parameters for optimal timing or frequency of imaging were established by research protocol.
Risks and Harms:
Radiographs involve exposure to ionizing radiation.
Guideline Work Group:
Kishore Mulpuri, MBBS, MS (Orth), MHSc (Epi), Chair
Kit M. Song, MD, MHA, Vice-Chair
Richard Henry Gross, MD
Gary B. Tebor, MD
Norman Yoshinobu Otsuka, MD
John P. Lubicky, MD, FAAOS, FAAP
Elizabeth Ann Szalay, MD
H. Theodore Harcke, MD
Bonnie Zehr, MD, FAAP
Andrew Spooner, MD
Charlotte Henningsen, MS
Doug Campos-Outcalt, MD, MPA
AAOS Guidelines Oversight Chairs:
Michael Goldberg, MD
W. Timothy Brox, MD
AAOS Clinical Practice Guidelines Section Leader:
Kevin Shea, MD
AAOS Council on Research and Quality Chair:
Kevin J. Bozic, MD, MBA
William Shaffer, MD, AAOS Medical Director
Deborah Cummins, PhD, Director of Research and Scientific Affairs
Jayson N. Murray, MA, Manager, Clinical Practice Guidelines
Peter Shores, MPH, Statistician
Mukarram Mohiuddin, MPH, Lead Research Analyst
Anne Woznica, MLS, Medical Librarian
Yasseline Martinez, Administrative Coordinator
Kaitlyn Sevarino, Evidence-Based Quality and Value Coordinator
Former AAOS Staff:
William Robert Martin III, MD, AAOS Medical Director