Parathyroidectomy improves bone geometry and microarchitecture in female patients with primary hyperparathyroidism: a one-year prospective controlled study using high-resolution peripheral quantitative computed tomography.

Abstract

Following parathyroidectomy (PTX), bone mineral density (BMD) increases in patients with primary hyperparathyroidism (PHPT), yet information is scarce concerning changes in bone structure and strength following normalization of parathyroid hormone levels postsurgery. In this 1-year prospective controlled study, high-resolution peripheral quantitative computed tomography (HR-pQCT) was used to evaluate changes in bone geometry, volumetric BMD (vBMD), microarchitecture, and estimated strength in female patients with PHPT before and 1 year after PTX, compared to healthy controls. Twenty-seven women successfully treated with PTX (median age 62 years; range, 44-75 years) and 31 controls (median age 63 years; range, 40-76 years) recruited by random sampling from the general population were studied using HR-pQCT of the distal radius and tibia as well as with dual-energy X-ray absorptiometry (DXA) of the forearm, spine, and hip. The two groups were comparable with respect to age, height, weight, and menopausal status. In both radius and tibia, cortical (Ct.) vBMD and Ct. thickness increased or were maintained in patients and decreased in controls (p < 0.01). Radius cancellous bone architecture was improved in patients through increased trabecular number and decreased trabecular spacing compared with changes in controls (p < 0.05). No significant cancellous bone changes were observed in tibia. Estimated bone failure load by finite element modeling increased in patients in radius but declined in controls (p < 0.001). Similar, albeit borderline significant changes in estimated failure load were found in tibia (p = 0.06). This study showed that females with PHPT had improvements in cortical bone geometry and increases in cortical and trabecular vBMD in both radius and tibia along with improvements in cancellous bone architecture and estimated strength in radius 1 year after PTX, reversing or attenuating age-related changes observed in controls.