SUN-317 Use of PTHrP Analogue for Management of Surgical Non-union

Abstract A. Javed: None. I.M. Bonilla: None. Introduction: Abaloparatide is a synthetic analog of PTHrP that is indicated for osteoporosis treatment in postmenopausal patients. Case reports have documented use of PTH analogues to help with fracture healing, there is less data for PTHrP analogues. We present a case of traumatic non-union humeral shaft fracture healing with use of Abaloparatide. Case Report: A 40-year-old female with no known past medical history presented to Bone Clinic for evaluation of a fracture complicated by non-union. She had sustained a left displaced humeral shaft fracture in a motor vehicle collision (MVC) with no other focal injuries on secondary survey. She had no history of smoking, diabetes, alcohol abuse, osteoporosis, obesity, malnutrition, immunosuppression or malignancy and consumed 1-2 cocktails a week. She was initially treated with closed manipulation and a coaptation splint, x-ray showed marked improvement and acceptable alignment. Patient continued to have pain in the humerus and underwent open reduction internal fixation of left humerus which showed improvement in 6-week follow-up visit. Pain relief was short-lived and at that point MRI was done which ruled out rotator cuff tear but showed concerns for nonunion and she was started on bone stimulator. There was some improvement in range of motion with bone stimulator but no interval increase in healing on x-ray and therefore a second non-union was diagnosed. Of note, she denied any excessive movement at fracture site and there were no local signs of infection to suggest impaired fracture healing. We ordered biochemical work-up that was unremarkable, including PTH, calcium, phosphorous, eGFR, vitamin D, thyroid panel, 24-hour urine chemistry. DEXA scan showed normal Z-scores. Given repeated non-union decision was made to start the patient on anabolic therapy with Abaloparatide. Within 2 months on Abaloparatide patient had excellent healing on x-ray. She completed 3 months of anabolic therapy. Patient had excellent range of motion with good strength, the fracture was well-healed and she was able to do activities as tolerated. Conclusion: Abaloparatide increases bone mineral density and also causes activation of osteoblast function leading to stimulation of bone formation which in turn causes improvement in skeletal microarchitecture. Although indicated for osteoporosis, data from case results show other potential uses for the medication. Further studies are needed to assess its efficacy and safety in patients with fractures complicated by non-union Sunday, June 2, 2024