PRIMARY HEALING OF PHYSEAL SEPARATION UNDER RIGID FIXATION

We observed the healing process under rigid external fixation after Sa lter-Harris type-1 or type-2 physeal separation at the proximal tibia in immature rabbits. Metaphyseal vessels grew across the gap with litt le delay; the site of separation then came to lie in the metaphysis an d was bridged by endochondral ossification. Union was achieved within two days in all rabbits. Progression of endochondral ossification repa ired the separated physis, thus showing 'primary healing of physeal se paration'. This depends on accurate reduction and stable fixation to a llow the survival of vessels across the gap.