Mechanical
Comparison of the Youngswick, Sagittal V, and Modified Weil Osteotomies
for Hallux
Rigidus in a Saw Bone Model
Journal
of Foot and Ankle Surgery
in
review
St. John North Shores Hospital, Harrison Twp, MI
and Michigan
State University, East Lansing, MI.
The purpose of this study
was to compare the mechanical properties of three osteotomies often used for
hallux rigidus. Maximum load, failure
energy, stiffness, and fracture pattern were determined for three different
test models as well as a control group.
Twenty-eight first metatarsal polyurethane saw bone models of were
equally divided into four groups. The
osteotomy groups tested consisted of a Youngswick, sagittal V, and a modified
Weil type osteotomy of the first metatarsal.
Each osteotomy was fixated with a
2.7mm cortical screw, all 16 m in length, and a small diameter smooth
wire, both placed perpendicular to the osteotomy. Each model was then loaded to failure in a servo-hydraulic
material testing machine. Results for
maximum load to failure for all 4 constructs showed a mean range of 15.1 to
33.7 N, a mean energy to failure ranging from 0.04 to 0.8 J, and a stiffness
from 1.5 to 3.4 N/mm. Significant
differences in peak load and stiffness (p=0.015 for peak load, p=0.025 for
stiffness) were found between the sagittal V group versus the control and
between the modified Weil and sagittal V group (p=0.037 for peak load, p=0.017
for stiffness). There were no
significant differences in the energy to failure between the 4 groups (p >
0.083). These findings suggest that the
sagittal V osteotomy construct was significantly weaker and less stiff than the
modified Weil.
Orthopaedic Biomechanics Laboratories,
College
of Osteopathic Medicine,
Michigan
State University,
East Lansing,
Michigan 48824
Please address correspondence to:
Roger C. Haut, Ph.D.,
Orthopaedic Biomechanics Laboratory,
College
of Osteopathic Medicine,
A414 East
Fee Hall,
Michigan
State University,
East Lansing,
MI 48824,
Tel: (517)355-0320,
Fax: (517)353-0789,
E-mail:
haut@msu.edu