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The prognostic value of the head-shaft angle on hip displacement in children with cerebral palsy.

van der List JP, Witbreuk MM, Buizer AI, van der Sluijs JA - J Child Orthop (2015)

Bottom Line: II-III) (172° vs. 165°; p < 0.001).The HSA at two years is larger in hips that will displace and larger in children with higher GMFCS levels (IV-V).Prognostic study, level II.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, P.O. Box 7057, 1081 HV, Amsterdam, The Netherlands, jpjvanderlistmd@gmail.com.

ABSTRACT

Background: Hip displacement is the second most common deformity in cerebral palsy (CP). The risk for hip displacement is related to the Gross Motor Function Classification System (GMFCS). Recently, the head-shaft angle (HSA) has been identified as a predictor for hip displacement and the aim of this study is to assess the predictive value of the HSA for hip displacement in CP.

Methods: In this retrospective cohort, we performed radiological measurements in 50 children on both hips. In children with GMFCS level II (30 hips), III (30 hips), IV (20 hips) and V (20 hips), we measured the HSA and migration percentage (MP) in three age intervals: age two years (T1), age four years (T2) and age seven years (T3).

Results: At T1, the HSA was larger (more valgus) in hips that will displace than in hips that will not displace (174° vs. 166°; p = 0.001) and was also larger in higher GMFCS levels (IV-V vs. II-III) (172° vs. 165°; p < 0.001). At T1, GMFCS [odds ratio (OR) 14.7; p = 0.001] and HSA (OR 1.102; p = 0.043) were predictors for hip displacement at T3, but at T2, MP (OR 1.071; p = 0.010) was the only predictor for hip displacement at T3.

Conclusions: The HSA at two years is larger in hips that will displace and larger in children with higher GMFCS levels (IV-V). At age two years, GMFCS and HSA are valuable predictors for hip displacement, but at the age of four years, only MP should be used in the prediction of hip displacement.

Level of evidence: Prognostic study, level II.

No MeSH data available.


Related in: MedlinePlus

AP radiographs of a boy with GMFCS level V cerebral palsy. a At T1 (22 months of age), the patient had a head-shaft angle (HSA) of 169° right and 185° left, with a migration percentage (MP) of 29 % right and 0 % left. b At T3 (95 months of age), the right hip was displaced laterally with a MP of 34 % and the left hip with a MP of 76 %
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Fig4: AP radiographs of a boy with GMFCS level V cerebral palsy. a At T1 (22 months of age), the patient had a head-shaft angle (HSA) of 169° right and 185° left, with a migration percentage (MP) of 29 % right and 0 % left. b At T3 (95 months of age), the right hip was displaced laterally with a MP of 34 % and the left hip with a MP of 76 %

Mentions: Our study presents retrospective longitudinal data on the HSA in CP children aged two to eight years and confirms the prognostic value of the HSA that has only recently been stressed by Hermanson et al. [14]. The HSA at two years is of prognostic value for hip displacement (OR 1.102) when corrected for GMFCS (II–III vs. IV–V), age at T3 and MP at T1. The HSA and GMFCS have a high negative predictive value in this model. This means that, when two hips are compared at age two years with only a 10° difference in the HSA, the hip with the larger HSA has a three times higher risk of hip displacement than the other hip (1.102 raised to the tenth power) (Fig. 4). In this study, we found a clinically relevant threshold of the HSA of 165°, and this means that the risk of hip displacement at T3 is low when the HSA at age two years (T1) is smaller than 165°, regardless of the GMFCS level. Further studies should assess this threshold value in clinical practice. However, it is important to assess that the HSA at T1 seems to play only a minor role compared to GMFCS. The most important predictor of hip displacement is GMFCS and the HSA plays a small additional role in this prediction. There is a correlation between the HSA at T1 and MP at T3 (0.354) and between GMFCS the and HSA at T1 (0.473), but this latter correlation is not as strong as the correlation between GMFCS and MP at T3 (0.581). It is possible that a part of the prognostic value of the HSA is explained by GMFCS. In this study. GMFCS is the most important prognostic factor for hip displacement and the HSA has an additional prognostic factor to GMFCS.Fig. 4


The prognostic value of the head-shaft angle on hip displacement in children with cerebral palsy.

van der List JP, Witbreuk MM, Buizer AI, van der Sluijs JA - J Child Orthop (2015)

AP radiographs of a boy with GMFCS level V cerebral palsy. a At T1 (22 months of age), the patient had a head-shaft angle (HSA) of 169° right and 185° left, with a migration percentage (MP) of 29 % right and 0 % left. b At T3 (95 months of age), the right hip was displaced laterally with a MP of 34 % and the left hip with a MP of 76 %
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig4: AP radiographs of a boy with GMFCS level V cerebral palsy. a At T1 (22 months of age), the patient had a head-shaft angle (HSA) of 169° right and 185° left, with a migration percentage (MP) of 29 % right and 0 % left. b At T3 (95 months of age), the right hip was displaced laterally with a MP of 34 % and the left hip with a MP of 76 %
Mentions: Our study presents retrospective longitudinal data on the HSA in CP children aged two to eight years and confirms the prognostic value of the HSA that has only recently been stressed by Hermanson et al. [14]. The HSA at two years is of prognostic value for hip displacement (OR 1.102) when corrected for GMFCS (II–III vs. IV–V), age at T3 and MP at T1. The HSA and GMFCS have a high negative predictive value in this model. This means that, when two hips are compared at age two years with only a 10° difference in the HSA, the hip with the larger HSA has a three times higher risk of hip displacement than the other hip (1.102 raised to the tenth power) (Fig. 4). In this study, we found a clinically relevant threshold of the HSA of 165°, and this means that the risk of hip displacement at T3 is low when the HSA at age two years (T1) is smaller than 165°, regardless of the GMFCS level. Further studies should assess this threshold value in clinical practice. However, it is important to assess that the HSA at T1 seems to play only a minor role compared to GMFCS. The most important predictor of hip displacement is GMFCS and the HSA plays a small additional role in this prediction. There is a correlation between the HSA at T1 and MP at T3 (0.354) and between GMFCS the and HSA at T1 (0.473), but this latter correlation is not as strong as the correlation between GMFCS and MP at T3 (0.581). It is possible that a part of the prognostic value of the HSA is explained by GMFCS. In this study. GMFCS is the most important prognostic factor for hip displacement and the HSA has an additional prognostic factor to GMFCS.Fig. 4

Bottom Line: II-III) (172° vs. 165°; p < 0.001).The HSA at two years is larger in hips that will displace and larger in children with higher GMFCS levels (IV-V).Prognostic study, level II.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, P.O. Box 7057, 1081 HV, Amsterdam, The Netherlands, jpjvanderlistmd@gmail.com.

ABSTRACT

Background: Hip displacement is the second most common deformity in cerebral palsy (CP). The risk for hip displacement is related to the Gross Motor Function Classification System (GMFCS). Recently, the head-shaft angle (HSA) has been identified as a predictor for hip displacement and the aim of this study is to assess the predictive value of the HSA for hip displacement in CP.

Methods: In this retrospective cohort, we performed radiological measurements in 50 children on both hips. In children with GMFCS level II (30 hips), III (30 hips), IV (20 hips) and V (20 hips), we measured the HSA and migration percentage (MP) in three age intervals: age two years (T1), age four years (T2) and age seven years (T3).

Results: At T1, the HSA was larger (more valgus) in hips that will displace than in hips that will not displace (174° vs. 166°; p = 0.001) and was also larger in higher GMFCS levels (IV-V vs. II-III) (172° vs. 165°; p < 0.001). At T1, GMFCS [odds ratio (OR) 14.7; p = 0.001] and HSA (OR 1.102; p = 0.043) were predictors for hip displacement at T3, but at T2, MP (OR 1.071; p = 0.010) was the only predictor for hip displacement at T3.

Conclusions: The HSA at two years is larger in hips that will displace and larger in children with higher GMFCS levels (IV-V). At age two years, GMFCS and HSA are valuable predictors for hip displacement, but at the age of four years, only MP should be used in the prediction of hip displacement.

Level of evidence: Prognostic study, level II.

No MeSH data available.


Related in: MedlinePlus