Disuse osteopenia following leg fracture in postmenopausal women: Implications for HIP fracture risk and fracture liaison services

Abstract

Introduction: Disuse osteopenia is a known consequence of reduced weight-bearing and has been demonstrated at the hip following leg injury but has not been specifically studied in postmenopausal women.

Method: Bilateral DXA (GE Lunar Prodigy) bone mineral density (BMD) measurements were taken at the neck of femur (NOF), total hip region (TH) and lumbar spine in postmenopausal female groups comprising controls (N = 43), new leg fractures (#<3wks) (N = 9), and participants who had sustained a leg fracture more than one year previously (#>1yr) (N = 24). #>1yr were assessed at a single visit and the remaining groups at intervals over twelve months. Weight-bearing, function, 3-day pedometer readings, and pain levels were also recorded.

Results: The #<3wks demonstrated significant (p < 0.05) losses in ipsilateral TH BMD at 6 weeks from baseline 0.927 ± 0.137 g/cm², to 0.916 ± 0.151 g/cm² improving to 0.946 ± 0.135 g/cm² (n.s) at 12 months following gradual return to normal function and weight-bearing activity. The #>1yr scored significantly below controls in almost all key physical and functional outcomes demonstrating a long-term deficit in hip bone density on the ipsilateral side.

Conclusion: The clinical significance of post-fracture reduction in hip BMD is a potential increased risk of hip fracture for a variable period that may be mitigated after return to normal function and weight-bearing. Improvement at 12 months in #<3wks is not consistent with #>1yr results indicating that long-term impairment in function and bone health may persist for some leg fracture patients. Unilateral bone loss could have implications for Fracture Liaison Services when assessing the requirement for medication post fracture.

Keywords: Activity; Bone mineral density; Disuse osteopenia; Function; Leg fracture; Postmenopausal.