Evaluation of Plasma Sprayed Hydroxyapatite Coated AO Cortical Screws in Equine Third Metacarpal Bone

• Main Author: Durham, Myra Elizabeth
• Other Authors: Sod, Gary
• Format: Others
• Language: en
• Published: LSU 2012
• Subjects: Veterinary Clinical Sciences
• Online Access: http://etd.lsu.edu/docs/available/etd-06052012-192854/

ABSTRACT Objectives - To compare the osteointegration of plasma sprayed hydroxyapatite (HA) coated and uncoated 5.5 mm cortical screws in equine third metacarpal (MC3) bones in combination with a 4.5mm broad dynamic compression plate (DCP). Study design - In vivo study. Animals 6 Adult Thoroughbred horses. Methods For each horse, four HA coated screws were placed unicortically through a 4.5mm broad DCP in the dorsal cortex of a randomly chosen MC3 bone, with 4 uncoated screws placed in an identical manner in the contralateral MC3 bone. All screws were tightened to a torque of 5.4 N-m. Extraction torques were recorded for the screws when removed after 12 weeks. The mean extraction torques for HA coated and uncoated screws were compared to insertion torque using a paired ttest with the statistical significance set at p < 0.05. Results Mean extraction torque of the HA coated screws was significantly (p <0.0002) greater than 5.4 N-m. The mean extraction torque of the uncoated screws was significantly (p < 0.0001) less than 5.4 N-m. The mean extraction torque for the HA coated screws were significantly (p < 0.0001) greater than that of the uncoated screws. Conclusion - The results suggest that osteointegration was occurring for the HA coated screws. The results also suggest that osteointegration did not take place during the 12 weeks period for the uncoated screws. Clinical Relevance - The use of plasma sprayed HA coated screws may provide a means of improving the stability of internal fixation of an equine long bone fractures during the entire healing period by promoting osteointegration.