Osteo-enhancement procedures in hip fracture prevention: definition and local interventions

Abstract

Fragility hip fractures are associated with increased morbidity and mortality in elderly patients and place a large medical and economic burden on affected individuals, families, and healthcare systems. Furthermore, in patients with a recent hip fracture, the risk of a second contralateral hip fracture is doubled at 1 year, and increases to 9–20% after 5 years. Mortality can be up to three times higher following a contralateral hip fracture. Currently available pharmaceutical treatments to improve bone mineral density in fragility fracture of the proximal femur can take up to 18 months to significantly reduce the risk of fracture, and have patient compliance issues. Thus, given the limitations of existing methods, there is a significant need for new approaches to reduce hip fractures through so-called surgical osteo-enhancement. “Osteo-enhancement” might be defined as any procedure in which a new material is surgically introduced with the aim of strengthening the proximal femur, increasing the resistance of the femoral neck to compression and distraction forces acting on it, and thereby preventing fall-related fractures. In the past decade, several groups have presented various prophylactic augmentation approaches for the osteoporotic proximal femur and evaluated them by means of experimental biomechanical testing; however, none of them met the ideal requirements for in vivo application. Ideally, a surgical procedure should be minimally invasive and safe. The intervention must not increase the immediate risk of hip fracture, must provide long-term fracture risk reduction, and, if a subsequent fracture does occur, the intervention should not interfere with a standard approach for fracture repair. More recently, to address local osteoporotic bone loss, a resorbable implant material named AGN1 was introduced as a new device for strengthening the proximal femur. The implant material sets in situ and is designed to be resorbed and replaced with new bone to improve femoral strength and reduce hip fracture risk in osteoporotic patients.