The fixation properties of carbon fiber-reinforced liquid crystalline polymer implant in bone: An experimental study in rabbits

Abstract

A novel composite material with ultra-high strength and a low elastic modulus called carbon fiber-reinforced liquid crystalline polymer (LCP/CF) has been developed. We studied the fixation properties of an intramedullary LCP/CF rod in rabbit bone. The medullary canals of both femora were reamed with a drill 3.2 mm in diameter starting from the trochanteric fossa in eleven New Zealand White rabbits weighing on average 4.8 kg. A smooth LCP/CF rod 3.2 mm in diameter and 50 mm in length was introduced into the medullary canal of both femora. The follow-up intervals were 0, 6, 12, and 52 weeks. The upper part of the harvested femora was cut into two pieces, each 25 mm in length. A mechanical push-out test was performed within 48 h to determine bone-implant interface attachment strength in the proximal (cancellous) and distal (cortical) locations. The mean push-out strength values at 0, 6, 12, and 52 weeks were 61, 250, 382, and 612 KPa in the cancellous location and 0, 32, 41, and 68 KPa in the cortical location, respectively. The strength of the bone/implant interface appeared to be quite low, similar to other uncoated or nonporous implants, but it was found to increase with time.