Objective—To compare fit and geometry of reconstruction
of femoral components of 4 canine cemented
total hip replacement implants and determine
which implants are most compatible with current principles
of cemented arthroplasty.
Sample Population—Paired femurs from 16 adult
Procedure—Femurs were prepared for femoral stem
implantation of either the Bardet, BioMedtrix,
Mathys, or Richards II implant. Mediolateral and craniocaudal
radiographs were obtained with femoral
components in situ. Cross-sectional analysis of
implant fit was performed on transected cemented
specimens. Computer-aided analyses of digitized
images were performed.
Results—The Bardet and Richards II implants
reconstructed the original femoral head position significantly
better than the other 2 implants. None of
the implants allowed neutralization of the implant
axis in the sagittal plane or were routinely centralized
in the femoral canal. The Bardet implant had the
smallest minimum distal tip offset in the sagittal
plane. Greatest tip to cortex distance was provided
by the Richards II implant in the transverse plane
and the Mathys implant in the sagittal plane. The
thinnest cement mantle regions for all implants
were in the central longitudinal third of the femoral
Conclusions and Clinical Relevance—The Bardet
and BioMedtrix implants had stem design characteristics
that were most compatible with principles of
cemented stem fixation. None of the implants completely
satisfied the theoretically optimal conditions of
centralization and neutralization of the femoral stem.
Innovative design modifications, therefore, may be
needed if these conditions are important to the longterm
success of canine total hip replacement. (Am J
Vet Res 2000;61:1113–1121)
Objective—To calculate normative joint angle, intersegmental
forces, moment of force, and mechanical
power at elbow, antebrachiocarpal, and metacarpophalangeal
joints of dogs at a walk.
Animals—6 clinically normal mixed-breed dogs.
Procedure—Kinetic data were collected via a force
platform, and kinematic data were collected from
forelimbs by use of 3-dimensional videography.
Length, location of the center of mass, total mass,
and mass moment of inertia about the center of mass
were determined for each of 4 segments of the forelimb.
Kinematic data and inertial properties were combined
with vertical and craniocaudal ground reaction
forces to calculate sagittal plane forces and moments
across joints of interest throughout stance phase.
Mechanical power was calculated as the product of
net joint moment and the angular velocity. Joint
angles were calculated directly from kinematic data.
Results—All joint intersegmental forces were similar
to ground reaction forces, with a decrease in magnitude
the more proximal the location of each joint.
Flexor moments were observed at metacarpophalangeal
and antebrachiocarpal joints, and extensor
moments were observed at elbow and shoulder
joints, which provided a net extensor support
moment for the forelimb. Typical profiles of work
existed for each joint.
Conclusions and Clinical Relevance—For clinically
normal dogs of a similar size at a walk, inverse
dynamic calculation of intersegmental forces,
moments of force, and mechanical power for forelimb
joints yielded values of consistent patterns and magnitudes.
These values may be used for comparison in
evaluations of gait in other studies and in treatment of
dogs with forelimb musculoskeletal disease. (Am J Vet Res 2003;64:609–617)