Bone remodelling suppressants like the
bisphosphonates reduce bone loss and slow progression of structural decay. As remodelling removes damaged bone, when remodelling suppression is protracted, bone quality may be compromised predisposing to microdamage accumulation and atypical
femoral fractures. The aim of this study was to determine whether
teriparatide therapy assists in fracture healing and improves bone quality in patients with
bisphosphonate associated atypical
femoral fractures. A prospective study was conducted involving 14 consecutive patients presenting during 2 years with atypical
femoral fracture. All patients were offered
teriparatide therapy unless contraindicated. Age and sex matched control subjects without fragility fractures or anti-resorptive treatment were recruited. High resolution peripheral micro-computed tomography (HRpQCT) scans of the distal radius and distal tibia were analysed for their cortical bone tissue mineralisation density using new software (StrAx1.0, StrAxCorp, Australia) at baseline and 6 months after
teriparatide. Administration of 20 μg of
teriparatide subcutaneously daily for 6 months to 5 of the 14 patients was associated with 2-3 fold increase in bone remodelling markers (p=0.01) and fracture healing. At the distal radius, the proportion of less densely mineralised bone increased by 29.5% (p=0.01), and the proportion of older, more densely mineralised bone decreased by 16.2% (p=0.03). Similar observations were made at the distal tibia. Of the nine patients managed conservatively or surgically, seven had poor fracture healing with ongoing
pain, one sustained a contralateral atypical fracture and one had fracture union after 1 year.
Teriparatide may assist in healing of atypical fractures and restoration of bone quality.