Bone-mineral density in children and adolescents with cerebral palsy : possible predictors of bone fractures

Abstract EN

Background: Long bone fracture is a common problem in non-ambulatory CP children and many of those who sustain a fracture will sustain repeated fractures.

Objective: to evaluate BMD values in a sample of patients who had CP as an indirect indicator of bone fracture and analyze critically the clinical predictors for the fracture of a long bone in those patients.

Methodology : the study population consisted of 30 children and adolescents with CP and 20 age and sex matched control group.

Full history taking with special stress on feeding practice, antiepileptic drug, history of fracture and the physiotherapy programs.

The patients were evaluated according to Gross Motor Functional Classification (GMFC) scale, and those with only scale 3, 4 and 5 were included.

Anthropometric evaluation and musculoskeletal assessments were performed.

Blood samples were obtained from the patients and control groups for measurements of calcium (Ca), phosphorus (Ph), and alkaline phosphatase.

Bone mineral density (BMD) was measured in all patients with CP with dual X-ray absorptiometry (DEXA) at lumber and femur sites.

Results : the mean age of the patients was 9.5 ± 5 years (range 3.25-16 years), 14 (46.7 %) patients were male and 16 (53.3 %) were female.

Eighteen (60 %) patients were ambulatory and 12 were non-ambulatory.

History of fracture was reported by 11 patients with a percentage of (36.7 %).

Although weight, height, skin fold thickness and body-mass index measurements of the study group were lower than those of the control group, yet there were non-significant difference (p > 0.05).

The mean serum levels of calcium, phosphorus and alkaline phosphatase did not differ significantly between the study and the control groups.

Regarding the differences between independent and non-independent CP patients, we found that independent children had significantly better anthropometric parameters than non-independent children.

We have demonstrated a significant association between history of bone fracture and non-ambulation of CP children.

Children with CP had significant lower bone-mineral density (BMD) Z scores values for both, vertebrae and proximal femur than sex-and age-matched children without CP.

BMD Z scores of lumber spine and femur were none significantly lower in GMFC level 5 children than in level 4 children, yet both groups are non–ambulatory.

Furthermore, BMD Z scores were none significantly higher in GMFC level 3 children than in levels 4 and 5 children.

As regards the pattern of involvement, there was a significant reduction in BMD in tetraplegic patients than hemiplegia or diplegia.

BMD Z scores were significantly reduced in patients with history of fracture as well as with unsatisfactory feeding practice.

Ambulation as well as regular physiotherapy correlated with BMD Z scores of femur but not of the lumber spine.

Neither lumber nor femur bone-density Z scores correlate with the use of anticonvulsants.

Using multiple stepwise regression analysis, low BMD of femur ; increase triceps skin fold thickness; immobilization and non-regular physiotherapy were significant independent risk factors predictive of bone fracture in CP children.

Conclusions : the implication of finding from the present study is that regular exercise and nutritional rehabilitation program should be considered as an additional preventive measure to increase bone-mineral density, thus decreasing the risk of fracture in this already vulnerable group of young people with CP.