Lateral femoral scan: an alternative method for assessing bone mineral density in children with cerebral palsy

Abstract

Background: Children with cerebral palsy (CP), often nonambulatory and/or on anticonvulsants, are at increased risk for fractures. Bone mineral density (BMD) measured by the conventional techniques of dual-energy X-ray absorptiometry (DXA) often cannot be reliably or easily measured in these patients.

Objective: To find an alternative site to whole body, spine and hip that can be conveniently used to measure BMD in CP patients.

Materials and methods: Having observed that CP patients prefer to lie on their sides, we explored measuring BMD at the distal femur in the lateral projection. A total of 92 scans were performed without sedation in 34 children and adolescents with CP, aged 4-19 years. Four femoral shaft subregions were created: two trabecular and two cortical.

Results: The coefficients of variation (CV %) were generally higher for opposite-side comparisons (n = 12 patients) than for same-side comparisons (n = 16 patients). For intra- and interobserver analyses, CV % were higher for cortical regions than for trabecular regions. Overall, the CV % were similar to those for hip and spine.

Conclusion: This peripheral site in the femur should be considered as an alternative for patients with CP when whole-body, hip and spine DXA are not practical.