Patella fractures are not typically considered osteoporotic fractures. We compared bone mineral density (BMD) and microstructure in elderly women from a multiethnic population-based study in New York City with any history of a patella fracture (n = 27) to those without historical fracture (n = 384) and those with an adult fragility forearm fracture (n = 28) using dual energy x-ray absorptiometry (DXA) and high resolution peripheral quantitative computed tomography (HR-pQCT). Compared to those without fracture, women with patella fracture had 6.5% lower areal BMD (aBMD) by DXA only at the total hip (P=.007), while women with forearm fracture had lower aBMD at multiple sites and lower trabecular bone score (TBS), adjusted for age, body mass index (BMI), race and ethnicity (all P<.05). By HR-pQCT, adjusted radial total and trabecular (Tb) volumetric BMD (vBMD) and Tb number were 10-24% lower while Tb spacing was 12-23% higher (all P<.05) in the fracture groups versus women without fracture. Women with a forearm, but not a patella, fracture also had lower adjusted radial cortical (Ct) area and vBMD and 21.8% (P<.0001) lower stiffness vs. women without fracture. At the tibia, the fracture groups had 9.3-15.7% lower total and Tb vBMD (all P<.05) compared to the non-fracture group. Women with a forearm fracture also had 10.9, and 14.7% lower tibial Ct area and thickness versus those without fracture. Compared to women without fracture, tibial stiffness was 9.9 and 12% lower in the patella and forearm fracture groups, respectively (all P<.05). By HR-pQCT, the patella vs. forearm fracture group had 36% higher radial Tb heterogeneity (P<.05). In summary, women with patella fracture had Tb deterioration by HR-pQCT associated with lower tibial mechanical competence that was similar to those with fragility forearm fracture, a more universally accepted "osteoporotic" fracture. These data suggest patella fractures are associated with skeletal fragility and warrant skeletal evaluation.
Keywords: Forearm; Fracture; Microstructure; Patella; Strength.
Whether patella fractures are associated with skeletal microstructural deterioration is unclear. We used a population-based cohort (n = 439) to compare bone structure in women with history of a patella fracture to those without historical fracture and those with an adult fragility forearm fracture using advanced imaging techniques. By HR-pQCT, women with patella and forearm fractures had trabecular deterioration compared to those without fracture. Women with forearm fractures additionally had cortical bone deficits compared to those without fracture. Compared to women without fracture, tibial stiffness lower in the patella and forearm fracture groups. In summary, women with patella fracture had trabecular deterioration associated with lower tibial mechanical competence that was similar to those with fragility forearm fracture, a more universally accepted “osteoporotic” fracture.
© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.