Elsevier

The Journal of Pediatrics

Volume 147, Issue 6, December 2005, Pages 791-796
The Journal of Pediatrics

Original Article
Bone Measurements by Peripheral Quantitative Computed Tomography (pQCT) in Children with Cerebral Palsy

https://doi.org/10.1016/j.jpeds.2005.07.014Get rights and content

Objective

To use peripheral quantitative computed tomography (pQCT) to determine bone measurements in patients with cerebral palsy (CP) age 3 to 20 years and compare them with control subjects.

Study design

A total of 13 (5 male) patients with CP, along with 2 sex- and age-matched controls for each, were included in a mixed-model analysis with matched pairs as random effects for pQCT bone measurements of the 20% distal tibia.

Results

Tibia length was similar in the CP and control groups (P = .57). Weight was marginally higher in the control group (P = .06). Cortical bone mineral content (BMC), area, thickness, polar strength-strain index (pSSI), and periosteal and endosteal circumferences were greater in the control group (P < .05 for all). Relationships between bone measurements and weight showed that cortical BMC, area, periosteal circumference, and pSSI were greater at higher weights in the control group (group-by-weight interaction, P < .05 for all). Cortical thickness was greater in the control group and was correlated with weight. Cortical volumetric bone mineral density (vBMD) was greater with higher weights in the CP group (group-by-weight interaction, P = .03).

Conclusions

Bone strength, as indicated by pSSI, is compromised in children with CP due to smaller and thinner bones, not due to lower cortical bone density.

Section snippets

Methods

Participants were recruited from a long-term residential care facility. Two sex- and age-matched (± 6 months) control subjects for each case were randomly selected from an existing database of healthy children obtained from the same geographic region. The protocol was approved by the institutional review boards at South Dakota State University and the University of South Dakota. Informed consent was signed by a parent if the child was not of adult age and also if the child was of adult age but

Results

Means and standard deviations for anthropometric and bone measurements by group and P values from matched-pairs analysis are given in Table. Cortical BMC, cortical area, cortical thickness, periosteal circumference, endosteal circumference, and pSSI differed by group (all P < .05), whereas tibia length and cortical vBMD did not differ. Weight was marginally greater in the control group than in the CP group. Group-by-weight interactions were significant (P ≤ .05) in mixed models for cortical

Discussion

In patients with CP, standard measurements for bone density and geometric bone measurements are limited because of joint contractures, bony deformities from fractures or surgical procedures, metallic implants, positioning confines, and uncontrollable movements that invalidate the scans. pQCT methods are not immune to these challenges. In general, pQCT imaging can be used to measure peripheral bones and obtain trabecular bone measurements at an ultra-distal site while cortical bone measurements

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