Fixation of Trochanteric Osteotomies in Laboratory Beagles with Absorbable Screws of Polylactic Acid

J. E. Räihä; M. Parchman; L. Krook; S. Vainionpää; M. Mero; P. Rokkanen; P. Törmälä

doi:10.1055/s-0038-1636496

Veterinary and Comparative Orthopaedics and Traumatology, Table of Contents

Vet Comp Orthop Traumatol 1990; 03(04): 123-129
DOI: 10.1055/s-0038-1636496

Original Research

Schattauer GmbH

Fixation of Trochanteric Osteotomies in Laboratory Beagles with Absorbable Screws of Polylactic Acid

Authors

J. E. Räihä

¹From the Department of Clinical Sciences, College of Veterinary Medicine, 00580 Helsinki, Finland
M. Parchman

²From the Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
L. Krook

³From the Department of Pathology, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
S. Vainionpää

⁴From the Maria Hospital, 00180 Helsinki, Finland
M. Mero

¹From the Department of Clinical Sciences, College of Veterinary Medicine, 00580 Helsinki, Finland
P. Rokkanen

⁵From the Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, 00260 Helsinki, Finland
P. Törmälä

⁶From the Biomaterials Laboratory, University of Technology, POB 527, 33101 Tampere, Finland

Abstract

Summary

An absorbable, biocompatible 4.5 mm screw, with a matrix of polyright-left-isomeric lactic acid of equal amounts of isomers and fibres of poly-left-isomeric lactic acid comprising a self-reinforced structure, was tested for fixation of a trochanteric osteotomy on six laboratory Beagles. The proximal femurs were harvested two months later and embedded in methylmethacrylate for histological, microradiographic, and fluorescence evaluation. Five specimens showed bony union and one trochanter was ununited. The coarse thread configuration and poor torque strength of the screw required exaggerated tapping of the screw hole resulting in a loose fit for the implant. An improved screw could be clinically appealing and a secondary removal operation would then be omitted.

To test a totally absorbable polylactic acid screw with good initial in vitro strength values a trochanteric osteotomy was fixed with this implant in six laboratory Beagles. Radiographic, microradiographic, fluorescence and histological evaluations indicated healing in five dogs at two months. Nonunion in one dog was attributed to diastasis between the fragments. The strength and strength retention of the screw were considered adequate, but the poor torsional strength made implantation of the screw tedious.

Key words

Absorbable screw - Polylactic acid - Trochanteric osteotomy

Full Text

References

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