A METHOD FOR REPAIRING ZYGOMATIC ARCH FRACTURES USING A HYDROXYAPATITE CEMENT PASTE (BONESOURCE)

A new method has been developed for the closed reduction of minimally displaced, noncomminuted zygomatic arch fractures that is minimally in vasive and precludes the use of nonresorbable materials such as plates and wires in the repair. Twenty rats received simple, minimally displ aced right-sided zygomatic arch fractures under general anesthesia. In 10 animals these fractures were treated with closed reduction through a temporal approach (Gillies method) to reapproximate the fractured s egments. In the second group of 10, immediately after the closed fract ure reduction, 1 mi of hydroxyapatite cement paste (BoneSource, Leibin ger Corp., Dallas, TX) was injected through a 14-gauge needle into and around the fracture site. This paste, which is remodeled into bone ov er time, hardens into a plaster-like substance within 20 minutes of mi xing. The majority of the paste was placed on the medial aspect of the fracture to act as a buttress between the fractured zygoma and the te mporalis muscle lying on the greater wing of the sphenoid. This served to support the fracture by ''casting'' the bone and preventing it fro m collapsing medially. Nine of the 10 fractures treated with the hydro xyapatite paste healed completely without evidence of zygomatic displa cement or malunion. One fracture had mild displacement of the fracture d segment but good bone healing between the fractured sides. No advers e effects were noted in the temporalis muscle of these animals, and ma stication was normal. Five of the 10 treated with closed reduction alo ne also had a good result. Of the remaining 5 fractures, 2 had a mild to moderate bony deformity as a result of improper alignment during fr acture healing. The other 3 did not heal and, therefore, formed a fibr ous nonunion at the fracture site. We concluded that closed reduction of simple zygomatic fractures can be performed if the fracture site is held in place with a stabilizing material such as a hydroxyapatite ce ment paste.