DETERMINATION OF PROXIMAL FEMORAL EPIPHYSEAL DEPTH FOR REPAIR OF PHYSEAL FRACTURES IN IMMATURE DOGS

Objective-To determine the depth that implants may be safely placed fo r repair of proximal femoral physeal fractures. Study Design-Relations hips were determined between the depth of the proximal femoral epiphys is (PFE) and the contralateral PFE, and the PFE and pubic bone width. Animals or Sample Population-20 immature dog cadavers. Methods-Actual PFE depths were determined at the center of the physeal surface and at four other eccentric points. The contralateral intact PFE depth and t he width of the cranial aspect of the pubic bone were measured from ra diographs. Results-Mean ratios of actual central PFE depth to radiogra phically measured (1) contralateral PFE depth and (2) pubic bone width were 1.04:1 and 1.09:1, and ratios of actual eccentric PFE depths wer e 0.89:1 and 0.93:1. Body weight was not useful in estimating depth of the PFE. Conclusions-For the central epiphysis, pins may safely be pl aced a distance equal to 75% to 80% of the contralateral intact PFE de pth or pubic bone width, measured from a ventrodorsal radiograph, with minimal risk of penetration through the articular surface. Pins place d eccentrically may be safely driven a depth equal to 65% of the radio graphically measured contralateral intact PFE depth or pubic bone widt h. Clinical Relevance-Estimating the safe depth of implant placement i nto the PFE avoids penetration of the articular surface. (C) Copyright 1998 by The American College of Veterinary Surgeons.