A 5-7 year in vivo study of high-strength hydroxyapatite/poly(L-lactide) composite rods for the internal fixation of bone fractures.

Abstract

The biocompatibility and biodegradation of hydroxyapatite (HA)/poly(L-lactide) (PLLA) composite bone implant rods were studied using two types of HA particles as reinforcing fillers, uncalcined-HA (u-HA) or calcined-HA (c-HA). Composite rods of u-HA/PLLA and c-HA/PLLA were implanted into the distal femurs of 25 rabbits. Four of these rabbits lived for more than 5 years after implantation, with one living for 7 years 4 months. Samples were retrieved after the rabbits died naturally and specimens were examined by light microscopy and scanning electron microscopy (SEM). For u-HA/PLLA, the shrinkage of the rods progressed further after 4 years, and some were almost completely resorbed. We could not find traces of the rod in some sections from more than 6 years. Remodeled bone encircled the residual material, and trabecular bone bonded directly to the rod was found toward the center. For u-HA/PLLA 30%, results were similar to u-HA/PLLA 40%, and the cross-sectional area had decreased by 4.0% at over 7 years. Most of the PLLA had been released from the rods. Neither obvious osteolytic nor osteoarthritic changes were found after 4 years.

• Authors: Shin Hasegawa, Shinsuke Ishii, Jiro Tamura, Taizo Furukawa, Masashi Neo, Yoshitaka Matsusue, Yasuo Shikinami, Masaki Okuno, Takashi Nakamura
• Journal: Biomaterials (Biomaterials) Vol. 27 Issue 8 Pg. 1327-32 (Mar 2006) ISSN: 0142-9612 [Print] Netherlands
• PMID: 16213581 (Publication Type: Journal Article)

Chemical References

• Bone Substitutes
• Polyesters
• poly(lactide)
• Durapatite

Topics

• Animals
• Bone Substitutes
• Durapatite
• Femoral Fractures (surgery)
• Fracture Fixation, Internal (instrumentation)
• Internal Fixators
• Male
• Polyesters
• Prostheses and Implants
• Rabbits
• Time Factors