A comparison of intracortical porosity along the length of the human clavicle in an elderly Scottish sample

Cortical bone loss can be the result of an increase in the percentage of pores occupying cortical bone, known as intracortical porosity, and can be affected by factors such as age, sex, biomechanics, and pathology. The aim of this research is to compare intracortical porosity along the length of the clavicle in an elderly Scottish sample exploring the potential impact of sex, age, and intra-skeletal variability. This study included 30 individuals from a Scottish sample (15 males and 15 females; age range: 67-97 years). Cross-sections were cut from the medial, midshaft and lateral clavicular segments producing a total of 90 thin sections. Analysis of photomicrographs was carried out using Pore Extractor 2D software assessing cortical area (CA), total pore number (TPN), mean pore area (MPA), mean pore circularity (MPC) and cortical porosity (CP). Anatomical segments, sexes, and age groups (70s, 80s and 90s) were tested for any existing differences using statistical tests, including but not limited to Independent T-test and Friedman test. Statistically significant differences between clavicular segments were found for TPN and MPA in males, and CA and MPA in females. Statistically significant differences between anatomical segments were found for CP, suggesting some intra-skeletal variation for this parameter. Sex differences were statistically significant between all anatomical segments for CA, with the remaining parameters providing statistically significant results in only some anatomical segments. Differences between age groups were not observed. This research provides further information about intracortical porosity and cortical bone loss in different anatomical segments of the clavicle for advanced age Scottish individuals. The effect of age-related pathologies such as osteoporosis and the hormonal changes between males and females might explain the sex differences observed. Moreover, bone biomechanics, such as biomechanical loading and muscle attachment differences along the length of the clavicle, could justify the reported intra-skeletal variability. An increase in age does not affect intracortical porosity in this sample suggesting no significant change in the later decades of life. This study provides further insight into a population sample which has not yet been explored in terms of intracortical porosity, and further information on bone quality and quantity in an age-group that is underrepresented in literature.