This open label comparison study examines the hypothesis that teriparatide given immediately following repair of an atypical subtrochanteric or diaphyseal femoral shaft fracture will enhance healing and improve bone mineral density compared to delayed treatment (after six months) with teriparatide or no treatment with teriparatide (patients who refuse therapy or for whom teriparatide is contraindicated). Patients with up-front teriparatide in addition will have greater quality of life measures and less pain compared to those with delayed or no therapy.

Up to 24 postmenopausal women with osteoporosis who have been on bisphosphonate therapy for one year or more at any point prior to fracture and have sustained an atypical subtrochanteric or diaphyseal fracture will be enrolled. Subjects randomized to the two intervention arms will self-administer a daily SQ injection of the study medication for 12 months. The primary objective is to demonstrate greater radiologic evidence of healing at 10 weeks in patients on immediate teriparatide compared to those on delayed teriparatide who receive therapy six months after fracture. Secondary end points include (1) radiologic healing at 2, 6, 24, and 46 weeks; (2) increased bone density at 6 and 12 months as assessed by dual x-ray absorptiometry (DXA) at the spine, contralateral hip, and femoral neck; (3) quality of life improvements at 10 weeks and 6 months as assessed by quality of life questionnaire and pain score; and (4) differences in biochemical markers of bone turnover in patient with upfront therapy compared to patients with delayed therapy and patients who refuse therapy or for whom teriparatide is contraindicated.

Inclusion Criteria:

• postmenopausal women
• with osteoporosis who have been on bisphosphonate therapy for one year or more (all bisphosphonates will be included such as alendronate, risdedronate, ibandronate, or zoledronic acid).
• Patients will also be included if they are on glucocorticoids or other medications known to affect bone mineral metabolism as these are often found in patients with these types of fractures.
• sustain an atypical subtrochanteric or diaphyseal femoral shaft fracture as defined by the the 2010 ASBMR task force. An atypical fracture must include all of the following: (1) a location in the femur distal to lesser trochanter; (2) no trauma or minimal trauma as a fall; (3) transverse or short oblique configuration; (4) noncomminuted; and (5) complete fracture extends through both cortices and may be associated with a medial spike; incomplete fractures involve only the lateral cortex. Patients who have an incomplete fracture can be included if they fall into the 2010 ASBMR task force definition.

Exclusion Criteria:

• men
• children
• those who have had radiation therapy
• Paget's disease
• treatment with teriparatide for two year in the past
• metastatic bone disease
• active cancer
• hypercalcemia
• hyperparathyroidism
• metabolic disease other than osteoporosis