Use of peripheral quantitative computed tomography to monitor bone healing after radial osteotomy in three-week-old chickens (Gallus domesticus)

Peripheral quantitative Computed tomography (pQCT), a noninvasive method for measuring bone characteristics, was used to evaluate bone healing in 3 white leghorn chickens (Gallus domesticus) after radial osteotomy at 22 days of age. The time sequence for callus formation and mineralization over a 45-day period was examined by performing serial cross-sectional scans of the osteotomized radius of each bird daily from day 2 to day 29 and on days 42 and 45 after surgery. Complete data were available for 2 birds. Formation of a new marrow cavity was apparent by 4 weeks after surgery, and union of the bone ends appeared complete by day 42. Bone mineral content (BMC), bone mineral density (BMD), and cross-sectional area (CSA) were measured at the radial osteotomy site, at 3 mm proximal to it, and at the corresponding areas on the ulna. The radial osteotomy site began to mineralize by day 4, and BMC and CSA increased approximately 100% in both birds between days 5 and 10. In bird 2, BMC and CSA continued to increase (55% and 74%, respectively). Peak radial levels of both BMC and CSA were followed by plateaus lasting approximately 7 days, then both levels decreased during callus resorption. The radial BMD increased during these plateaus, then decreased as the callus was remodeled. Between days 29 and 42, the BMD of the radial osteotomy site increased and approached that of the corresponding ulna. The sequences of changes in BMC, CSA, and BMD after day 10 were similar in each bird. These results indicate that pQCT is a useful tool to monitor postosteomy bone healing in chicks.