| BUECHEL-PAPPAS™
HIP REPLACEMENT SYSTEM – RESURFACING |
Resurfacing
Hip Surgical Procedure
Introduction
Effective resurfacing total hip arthroplasty depends on several
significant surgical concepts, namely: the acetabulum should
not be over-reamed; the femoral head should be downsized to
the femoral neck and oriented in valgus; the greater trochanter
should not be osteotomized; and the procedure should be technically
reproducible and easy to perform for a skilled hip surgeon.
Aside from the technical aspects of the procedure, the mechanical
bearings used should minimize wear and torque to provide lasting
results that improve upon prior failures.
With
these concepts in mind, the Buechel-Pappas Resurfacing Hip
Replacement offers both simplicity and reproducibility in
the surgical procedure as well as advanced bearing design
and materials to minimize problems of loosening or osteolysis.
The hemispherical
socket allows for precise positioning of the cup at the acetabular
floor with the ability to adjust minor valgus or version angles
by simple impaction of the acetabular cup rim. Elimination
of fixation fins, pins, or cylindrical fixation geometries
adds to the ease of insertion of this hemispherical cup.
A complete
capsular release is necessary to dislocate the femoral head
superiority and anteriorly to expose the acetabulum. The gluteus
maximus tendon is generally released along with the short,
external rotators to allow mobilization of the femoral head
into this position.
Acetabular
Preparation
Acetabular preparation requires the use of sequential spherical
cheese-grater type reamers to deepen the acetabulum to the
floor (outer table of the tear drop), while retaining the
subchondral plate in the superior, weight bearing dome. Care
is taken to retain the anterior and posterior walls of the
acetabulum and use their anatomical position for proper anteversion,
while orienting the cup at 30° from the horizontal plane.
An interference fit of 1mm in hard bone, such as in osteoarthritis,
and 2mm in soft bone, such as in rheumatoid arthritis, allows
the use of these spherical components without screws.
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Femoral
Head Preparation
Femoral head preparation involves the use of the conical plane
of the calcar to orient the femoral head shaper into a valgus
position, parallel to the medial border of the calcar, and
centered on the femoral neck. Drilling of an osteonecrotic,
or hypoplastic, femoral head, parallel to the central pilot
hole of the shaper, stimulates revascularization. Supplemental,
cancellous bone augmentation can be used to fill in apical
head defects prior to femoral implant impaction. A short,
tapered, central femoral stem is used to align the onlay femoral
component and protect the femoral neck from fracture during
the postoperative period.
The precise,
mechanical fit of these components permits immediate protected
weight bearing.
Resurfacing
Hip Instruments
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