THE INDUCTION OF OSTEOGENESIS IN DEEP FROZEN ALLOGRAFTS BY DRILLING -COMPARATIVE HISTOLOGY AND RADIOGRAPHY OF DRILLED AND UNDRILLED ALLOGRAFTS IN SHEEP

Incorporation of massive cortical bone allografts in the human is slow and remains incomplete. Late biopsies of implanted allografts or hist ological studies of explanted allografts always show the partial subst itution of necrotic bone by new bone from the host. The aim of the pre sent study was to evaluate the value of drilling the massive deep-froz en cortical allografts in order to induce osteogenesis. Thirteen sheep were operated on and a standard segment of the proximal ulna was remo ved and the gap filled either by an unperforated allograft or by a per forated one. Based on histological and microradiographic examination, a complete substitution of the perforated allografts was observed but in this model no statistically significant difference was observed bet ween perforated and unperforated allografts. Further study is needed t o assess the effect of the perforations.