The effect of Abduction therapy on stable developmental dysplasia of the hip (DDH) between the age of 3 and 6 months.

DDH is treated at a young age to prevent hip dysplasia in adult life with a
subsequent increased risk on arthrosis, pain and invalidity. This increased
risk is documented in the literature (1,2,9). In the Netherlands, stable hip
dysplasia (Graf 2b en 2 c) is treated as of 3 months of age. In many other
European countries, stable DDH is treated as of the first month of age often in
relation to the screening program of that country. The abduction treatment
should improve the relationship between femoral head and acetabulum and
increase the development of the acetabulum. However, the effect of abduction
treatment is never proved in children of 3 months old with stable DDH.
The only study on the natural history of stable hip dysplasia has showed a
surprisingly result (78% normalisation at the age of 18 years). RCT is
abduction treatment below the age of 3 months has not showed any effect and the
natural history shows normalisation in the majority of cases. The discussion
on the indication of abduction treatment in children with stable DH remains
because of the risk on avascular necrosis with subsequent growth disturbance of
the femoral head.
Treatment and follow-up with ultrasound (US) or rontgenographs (X-rays) is done
by medical specialists. Dor US or X-ray investigations, the classifications
respectively according to Graf (tabel 1) and Tonnis (table 2) are used.

Classification Graf, Table 1
Type Graf Alpha / Beta angle age Classification
Ia *60 / *55 any age Normal
Ib *60 / >50 0-3 months(mos) Normal
IIa 50-60 / 55-70 * 3 mos Immature
IIb 50-60 / 55-70 > 3 mos Stable dysplasia
IIc 43-50 / 70-77 any age Severe dysplasia
D 43-50 / >77 any age Decentered
III <43 / >77 any age Subluxation
IV no angle/ >77 any age Dislocation

Alpha angle is the angle between the line along the bony part of the acetabulum
and the reference line paralel to the lateral aspect of the os ilium. Beta
angle is the angle between the line through the labrum (cartilage roof) and the
bony rim (turning point concavity-convexity).


Classification Tõnnis en Brunken, Table 2


Grade I normal
Grade II mild pathology
Grade III severe pathology
Grade IV extreme pathology

age mean I II
III IV
3-4 mos 25 < 30 30-34 35-39 * 40
5-24 mos 20 < 25 25-29 30-34 * 35
2-3 years 18 < 23 23-27 28-32 * 33
3-7 years 15 < 20 20-24 25-29 * 30
7-14 years 10 < 15 15-19 20-24 * 25

The AC-angle is the angle between the line along the acetabulum and to a
horizontal line through the centers of the triradiate cartilages on an AP X-ray
of the pelvis. (Fig 2)

1. Dezateux C, Rosendahl K. Developmental dysplasia of the hip. Lancet.
2007;5:369:1541-52. Review.
2. Lehmann HP, Hinton R, Morello P, Santoli J. Developmental dysplasia of the
hip practice guideline: technical report. Committee on Quality Improvement, and
Subcommittee on Developmental Dysplasia of the Hip. Pediatrics. 2000;105:E57
3. Pratt WB, Freiberger RH, Arnold WB. Untreated congenital hip dysplasia in
the Navajo. Clin Orthop Rel Res 1982;162:69-77
4. Roovers EA, Boere-Boonekamp MM, Mostert AK, Castelein RM, Zielhuis GA,
Kerkhoff TH. Ultrasonographic screening for developmental dysplasia of the hip.
Reproducibility of assessments made by the radiographers. J Bone Joint Surg
2003;85:726-730
5. Roovers EA. Post-neonatal ultrasound screening for developmental dysplasia
of the hip. A study of cost-effectiveness in the Netherlands [PhD thesis]
Enschede, The Netherlands: University of Twente 2004
6. Roovers EA, Boere-Boonekamp MM, Mostert AK, Castelein RM, Zielhuis GA,
Kerkhoff TH. The natural history of developmental dysplasia of the hip:
sonographic findings in infants of 1-3 months of age. J Pediatr Orthop B.
2005;14:325-30
7. Sampath JS, Deakin S, Paton RW. Splintage in developmental dysplasia of the
hip: how low can we go? J Pediatr Orthop 2003;23:352-5
8. Shipman SA, Helfand M, Moyer VA, Yawn BP. Screening for developmental
dysplasia of the hip: a systematic literature review for the US Preventive
Services Task Force. Pediatrics. 2006;117:e557-76. Review
9. US Preventive Services Task Force. Screening for developmental dysplasia of
the hip: Recommendation Statement. Pediatrics. 2006;117:e898-902
10. Wood MK, Conboy V, Benson MK. Does early treatment by abduction splintage
improve the development of dysplastic but stable neonatal hips? J Pediatr
Orthop 2000;20:302-5

The purpose of this study is to show no difference in the outcome with
abduction treatment versus no treatment in stable hip dysplasia between the age
of 3 and 6 months.

Open prospective multi-center randomised trial. One half of the study group
will have the regular treatment with the Pavlik harness, the other half will
have supervised neglect. The choice of treatment for the individual child will
be made with randomisation lists generated by the computer. We expect no
relevant differences in sex after randomisation.
To maximize equality in group comparison, type IIb en type IIc will be
randomised.


Patient numbers
In all 5 participating hospitals, patients will be included recording the
inclusion criteria. Based on an estimated national incidence of 2% of
hipsdysplasia type IIb en IIC, we expect to include 20 patients a year for each
center.
After one year, the number of patients included should be 100.


Treatment in one half of the study group will consist of Pavlik harness
according to standard treatment protocol, compared to supervised neglect in the
other half of the study group.
The parents will be asked to register the contacts with the hospital.
US follow up will be after 6 weeks en 3 months.

In case of worsening of the type of dysplasia to Graf D after 6 weeks follow-up
and in case of persisting DDH at 3 months follow-up, regular treatment will be
started.
All children who have normal US after 3 months of follow-up will be considered
as good and no treatment will be given at this point.
Further follow-up will be done by US at 6 months and an x-ray of the pelvis at
9 months follow-up.
complications will be registrated on a separate form.

supervised neglect versus regular treatment with Pavlik harness

extension of period of abduction treatment.