Impaired geometric properties of tibia in older women with hip fracture history.
This study evaluated side-to-side differences in tibial mineral mass and geometry in women with previous hip fracture sustained on average 3.5 years earlier. Both tibial mineral mass and geometry were found to be reduced in the fractured leg.


BACKGROUND
The purpose of this study was to evaluate side-to-side differences in tibial mineral mass and geometry after hip fracture and to assess the determinants of such differences.


METHODS
Thirty-eight 60- to 85-year-old women with a previous hip fracture and 22 same-aged control women without fractures participated in the study. Bone characteristics of the distal tibia and tibial shaft of both legs were assessed using pQCT in order to compare the side-to-side differences of tibias between the two groups.


RESULTS
The subjects with fracture history had significantly (p < OR = 0.05, analysis of covariance) larger side-to-side differences than the controls in tibial shaft BMC (-4.9% vs. -0.5%), cortical area (-5.2% vs. 0.1%) and polar moment of inertia (I(polar)) (-5.6% vs. -0.8%) and in distal tibia BMC (-5.1% vs. -1.4%) and I(polar) (-7.5% vs. -2.4%). In the fracture patients, the side-to-side differences in muscle characteristics explained 23 to 44% of the variances in the side-to-side differences in bone mass and geometry.


CONCLUSIONS
Hip fracture results in reduced bone mass and impaired bone geometry in the tibia of the affected limb in older women. Muscle-induced loading may have a considerable role in the recovery of bone mineral mass and geometry after hip fracture.
Mikkola
T
T
Department of Health Sciences, University of Jyväskylä, P.O. Box 35, Viveca, 40014 Jyväskylä, Finland. tuija.mikkola@sport.jyu.fi
Sipilä
S
S
Portegijs
E
E
Kallinen
M
M
Alén
M
M
Kiviranta
I
I
Pekkonen
M
M
Heinonen
A
A
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D005260:Female; D005265:Femoral Neck Fractures / Q000473:pathology / Q000503:physiopathology; D005598:Fractures, Spontaneous / Q000473:pathology* / Q000503:physiopathology; D006620:Hip Fractures / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007866:Leg; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000473:pathology; D013977:Tibia / Q000473:pathology* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D016138:Walking / Q000502:physiology