Evaluation of Cortical Bone by Peripheral Quantitative Computed Tomography in Renal Transplant Recipients

• Published in: Transplantation proceedings Vol. 37; no. 2; pp. 1020 - 1022
• Main Authors: Negri, A.L., Lombas, C., Cuevas, C., Schiavelli, R., Bogado, C.E., Zanchetta, J.R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY Elsevier Inc 01.03.2005; Elsevier Science
• Subjects: Adult; Biological and medical sciences; Bone and Bones - diagnostic imaging; Female; Fractures, Bone - epidemiology; Fractures, Bone - prevention & control; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Kidney Failure, Chronic - surgery; Kidney Failure, Chronic - therapy; Kidney Transplantation - adverse effects; Kidney Transplantation - physiology; Male; Medical sciences; Middle Aged; Reference Values; Renal Dialysis; Risk Factors; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Tissue, organ and graft immunology; Tomography, X-Ray Computed - methods; Evaluation; Radiodiagnosis; Transplantation; Homotransplantation; Kidney; Medicine; Treatment; Urinary system; Surgery; Medical imagery; Graft; Computerized axial tomography; Cortical bone; Quantitative analysis
• ISSN: 0041-1345; 1873-2623
• DOI: 10.1016/j.transproceed.2004.12.056

The absolute risk of fractures in renal transplant patients is 3 times that of matched controls. Most of the symptomatic fractures are peripheral, suggesting a greater compromise of cortical bone. Peripheral quantitative computed tomography (pQCT) is a new imaging technique that allows separate noninvasive evaluations of cortical and trabecular bones. We investigated cortical bone by pQCT in 12 renal transplant patients (seven men and five women) for comparison with 27 normal controls. pQCT (XCT 960, Stratec, Pforheim, Germany) was performed upon the distal radius of the nondominant forearm (15% the length of the ulna, proximal from the radius end plate). We evaluated total and cortical bone mineral density (TBMD, cBMD), total (cross-sectional) and cortical area (TA, cA), cortical thickness (cThk), endosteal and periosteal circumferences, and the buckling ratio ( r/cThK). Compared with normal controls transplant patients as a whole showed a significant increase in TA, in endosteal circumference ( P < .001), and in the buckling ratio ( P < .001) with a significant reduction in cThK ( P < .001). Female patients had a marked decrease in cA (51.4 vs 69.3 [pixel n]; P < .0001) and cThK (2.08 vs 2.78 mm; P < .0001). Male patients also had a decrease in cThK (2.54 vs 3.30 mm; P = .0001) and an increase in endosteal perimeter (31.2 vs 26.4 mm; P < .0001). Total time on dialysis prior to renal graft correlated negatively with cortical thickness ( r = .62; P < .01). Our results suggest that a marked thinning of cortical bone may explain the increased incidence of peripheral fractures among renal transplant patients.