Femoral neck bone mineral density in ambulatory men with poliomyelitis.

Summary We evaluated bilateral femoral neck bone mineral
densities (FNBMDs) in 32 men with poliomyelitis and
their matched controls. Men with poliomyelitis had significantly
lower FNBMD in both legs, and FNBMD was
lowest in their shorter legs. Knee extensor strength and
regular exercise were important predictive factors associated
with decreased FNBMD.
Introduction People with poliomyelitis (polio) are prone to
leg fractures after mild trauma. The flaccid paralysis,
asymmetric involvement, and underdeveloped growth of
afflicted legs may lead to osteoporosis of either leg,
characterized by different patterns. This study aimed to
measure their femoral FNBMD and to explore the factors
associated with changes in FNBMD in either leg.
Methods We did a prospective study to evaluate bilateral
FNBMD with dual-energy X-ray absorptiometry in 32 men
with polio (age range, 41-57 years; mean, 47 years) and 32
age- and body mass index-matched controls. Measuring the
difference in leg length, we classified the legs of each polio
subject as “longer” or “shorter.” In addition, we chose the
right leg of each control as a reference leg. We then used
the Mann-Whitney U test to compare FNBMD of these
three groups of legs and searched for the factors associated
with FNBMD using stepwise multiple regression analyses.
Results Compared to the reference leg, men with polio had
significantly lower FNBMD in both their longer and shorter
legs, by 13% and 23%, respectively. The difference in
FNBMD between the two legs of polio subjects was
significant. Knee extensor strength and regular exercise
were two important factors associated with bilateral FNBMD
in men with polio.
Conclusions Men with polio had lower bilateral FNBMD.
FNBMD of the shorter leg should be the choice for
predicting the risk of hip fracture in men with polio because
on average, the shorter leg has lower BMD.