High Cortico-Trabecular Transitional Zone Porosity and Reduced Trabecular Density in Men and Women with Stress Fractures.

Afrodite Zendeli,Lukas Fischer,Ali Ghasem-Zadeh,Minh Bui,Wolfgang Schima,Ego Seeman

doi:10.3390/jcm10051123

Abstract

To determine whether stress fractures are associated with bone microstructural deterioration we quantified distal radial and the unfractured distal tibia using high resolution peripheral quantitative computed tomography in 26 cases with lower limb stress fractures (15 males, 11 females; mean age 37.1 ± 3.1 years) and 62 age-matched healthy controls (24 males, 38 females; mean age 35.0 ± 1.6 years). Relative to controls, in men, at the distal radius, cases had smaller cortical cross sectional area (CSA) (p = 0.012), higher porosity of the outer transitional zone (OTZ) (p = 0.006), inner transitional zone (ITZ) (p = 0.043) and the compact-appearing cortex (CC) (p = 0.023) while trabecular vBMD was lower (p = 0.002). At the distal tibia, cases also had a smaller cortical CSA (p = 0.008). Cortical porosity was not higher, but trabecular vBMD was lower (p = 0.001). Relative to controls, in women, cases had higher distal radial porosity of the OTZ (p = 0.028), ITZ (p = 0.030) not CC (p = 0.054). Trabecular vBMD was lower (p = 0.041). Distal tibial porosity was higher in the OTZ (p = 0.035), ITZ (p = 0.009), not CC. Stress fractures are associated with compromised cortical and trabecular microstructure.

Highlights

Stress fractures are commonly the result of repetitive loading and are seen in athletes, military recruits and professional dancers, but stress fractures occur in recreational athletic individuals as vigorous exercise increases the risk for injuries [1,2,3,4,5]
A region composed virtually exclusively of cortical bone, growth in size and mass occurs by periosteal apposition with concurrent endocortical resorptive modeling producing a radial ‘modeling drift’ so the cortex becomes thinner relative to its increasing total cross-sectional area (CSA) [18,19]
The cortico-trabecular transitional region so formed between the cortical bone and the more centrally placed trabecular bone is composed of mineralized bone matrix that transitions from the more compact cortical configuration to a more open spongy trabecular configuration with more void volume [20]

Summary

Introduction

Stress fractures are commonly the result of repetitive loading and are seen in athletes, military recruits and professional dancers, but stress fractures occur in recreational athletic individuals as vigorous exercise increases the risk for injuries [1,2,3,4,5]. These fractures exist across a spectrum from low-grade stress reactions, bone marrow edema to complete fractures visible radiologically [6,7,8]. The cortico-trabecular transitional region so formed between the cortical bone and the more centrally placed trabecular bone is composed of mineralized bone matrix that transitions from the more compact cortical configuration to a more open spongy trabecular configuration with more void volume (porosity) [20]

Objectives

Methods

Findings

Conclusion