Fracture Risk in Spaceflight and Potential Treatment Options

Abstract

INTRODUCTION: Understanding the effects of microgravity on bone is essential, since humans are now considering long-distance spaceflight missions. It is well known that bone mineral density (BMD) decreases during long-duration spaceflight. While the risk of fracture in a microgravity environment is believed to be low, the potential risk for fracture increases upon re-entering a gravity environment. The objective of this study was to determine skeletal regions of high-risk for fracture after long-duration spaceflight and identify management protocols for those fractures.METHODS: A literature search was conducted on current fracture risk predictive models and suggestions for treatment.RESULTS: Exercise with the Advanced Resistance Exercise Device (ARED), T2 treadmill, and cycle ergometer with vibration isolation and stabilization (CEVIS) on the International Space Station (ISS) is part of a fundamental long-duration spaceflight strategy to mitigate BMD loss. Additionally, studies have shown that bisphosphonates have an additive effect for preventing bone loss. However, if a fracture were to occur, treatments that improve bone healing in space (in addition to standard management modalities such as splinting) include the use of low-intensity pulsed ultrasound, electromagnetic field therapy, and intermittent subcutaneous injections of parathyroid hormone. In the event of a complicated fracture, surgical intervention with a universal external fixation device could be a viable option for management.CONCLUSION: In conclusion, the best strategy for mitigating musculoskeletal injuries for deep-space missions will be a combination of BMD loss reduction coupled with improvements in management protocols for potential fractures.Swaffield TP, Neviaser AS, Lehnhardt K. Fracture risk in spaceflight and potential treatment options. Aerosp Med Hum Perform. 2018; 89(12):1060-1067.