Bone mineral density of the hip and knee in children with spinal cord injury.
OBJECTIVE
To report on the bone mineral density (BMD) of the hip, distal femur, and proximal tibia in children with spinal cord injury (SCI) of at least 1-year duration and before skeletal maturity.


METHODS
BMD values were measured in 28 children (age, 9.6 +/- 2.5 years; range, 5-13 years) using dual-energy x-ray absorptiometry (DEXA) and were analyzed based on sex, injury, and time since injury. The hip values were compared with reported age- and sex-matched values in children without disability. No comparison was made at the knee because normative data were not available.


RESULTS
Average BMD values were 0.48 +/- 0.17 g/cm2 for the total hip, 0.48 +/- 0.17 g/cm2 at the femoral neck, 0.41 +/- 0.17 g/cm2 at the greater trochanter, 0.47 +/- 0.17 g/cm2 at Ward's triangle, 0.38 +/- 0.10 g/ cm2 at the distal femur, and 0.37 +/- 0.07 g/cm2 at the proximal tibia. Trends were observed with respect to sex, level of injury, and time since injury. Z-scores for the femoral neck, greater trochanter, and Ward's triangle were -1.65 +/- 1.02, -1.83 +/- 1.30, and -1.78 +/- 0.78, respectively, representing a 40% lower BMD in comparison with children without disability.


CONCLUSIONS
Children with a SCI seem to have a substantially lower BMD at the hip and knee in comparison with children without disability, placing them at the same risk for lower extremity fractures as adults with SCI, with potentially higher risks as they age given the lack of activity in a period of their life where exercise is essential for optimal bone health.
Lauer
Richard
R
Research Department, Shriners Hospitals for Children, 3551 North Broad Street, Philadelphia, PA 19140, USA. rlauer@shrinenet.org
Johnston
Therese E
TE
Smith
Brian T
BT
Mulcahey
Mary Jane
MJ
Betz
Randal R
RR
Maurer
Alan H
AH
D015502:Absorptiometry, Photon / Q000379:methods; D000293:Adolescent; D000367:Age Factors; D015519:Bone Density; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006615:Hip / Q000503:physiopathology*; D006801:Humans; D007717:Knee / Q000503:physiopathology*; D008297:Male; D012737:Sex Factors; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000503:physiopathology