Effects of recombinant human parathyroid hormone on the anabolic window and acceleration of lower extremity stress fracture healing

Abstract

BACKGROUND: Stress fractures are one of the more severe overuse injuries and occur more frequently in women than men. Location and severity of stress fractures vary according to the sport and intensity of physical activity and most commonly involve the lower extremities. The treatment period may extend beyond 12 weeks based on the severity of the stress fracture and physical activity of the patient. Although data are sparse, there is an evolving interest in using systemic medical interventions to potentially improve or accelerate stress fracture repair. Intermittent administration of human recombinant parathyroid hormone (PTH) (1-34) (Teriparatide) is a FDA-approved anabolic treatment used to treat osteoporosis in men and women and reduce fracture risk in postmenopausal women. Although there may be potential benefits of systemic teriparatide therapy to hasten the healing of fractures, there only a few randomized, controlled studies at present. OBJECTIVES: To determine in this randomized, placebo-controlled study whether teriparatide can increase the anabolic window in premenopausal women with lower extremity stress fractures and can hasten the healing process, as assessed by Magnetic Resonance Imaging (MRI). Specifically, we will evaluate: 1) Whether bone formation markers increases more rapidly than resorption markers in response to daily teriparatide (20 μg) at 4 and 8 weeks and of the anabolic window, using the area under the curve between percent changes in biomarkers of formation over resorption over time, and 2) whether there is acceleration of the stress fracture healing, as assessed by MRI images. [TRUNCATED]