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Conserve Total Hip System
with BFH Technology
BFH
= Big Femoral Head
What is the CONSERVE®
Total Hip with BFH® Technology?
The femoral head of a normal, healthy adult is quite large
in size. Traditionally, total hip replacement has replaced
the large femoral head with a head much smaller than the original.
The new CONSERVE® Total Hip system has been designed to
mimic the natural kinematics of the hip by replacing the body’s
natural head with a large diameter femoral head implant. The
CONSERVE® Total Hip system incorporates a liner-less,
high carbon, cast cobalt chrome cup, with a large diameter
high carbon, cast cobalt chrome femoral head anchored by either
press-fit or cemented stems. This provides a low-wear metal
on metal articulation coupled with large diameter heads.
Why Big Heads?
Dislocation following primary and revision total hip arthroplasty
continues to be one of the primary factors of early implant
failure. Early dislocation still remains a significant problem
despite improvements in surgical technique, joint alignment,
and implant design. Reported occurrence ranges from 2% to
10% for primary replacement and 10% to 20% for revision arthroplasty.1-4,
8 The introduction of the large diameter CONSERVE® Total
Hip femoral heads increases range of motion. This reduces
the chance for impingement and subsequent dislocation. Additionally,
the CONSERVE® Total Hip system has no skirts thus creating
better range of motion. All of these factors coupled with
the low wear metal on metal articulation make CONSERVE®
Total Hip a great choice for today’s orthopaedic surgeon.
DESIGN RATIONALE
The CONSERVE® Total Hip System with BFH® Technology
is designed to eliminate dislocation. Because the human femoral
head is large in nature, it therefore makes sense to implant
a large, anatomic replacement. This was not possible in the
past due to the necessity for polyethylene liners, which decreased
the viability of large, anatomic femoral heads. However, with
the introduction of metal-on-metal articulation we can now
eliminate liners. This not only eliminates the metal liner/metal
cup interface, but it allows surgeons to utilize large femoral
heads. In fact, the BFH® system has heads ranging from
36-54mm in diameter.
The largest head (54mm) coupled with a -3.5mm head length
actually produces 167° range of motion. Along with this
incredible range of motion, the CONSERVE® Total Hip System
has a theoretical jumping distance of up to 24mm. This means
that the femoral head must travel 24mm before it will dislocate,
once it impinges.
The BFH® femoral head design gives surgeons the benefits
of both large head sizes and low wear implants.
ANATOMIC SIZE FEMORAL
HEADS
Forget worrying about reaching the largest acetabular size
possible just to reach a 36mm femoral head. With the CONSERVE®
Total Hip, anatomically sized femoral heads are available
for every acetabular size. Femoral heads range from 36-54mm
in the CONSERVE® Total Hip system.
Head
Outside Diameter |
Cup
Outside Diameter |
%
Increase In Head Size vs. 28mm |
36mm |
46mm |
28% |
38mm |
48mm |
36% |
40mm |
50mm |
43% |
42mm |
52mm |
50% |
44mm |
54mm |
57% |
46mm |
56mm |
64% |
48mm |
58mm |
72% |
50mm |
60mm |
79% |
52mm |
62mm |
86% |
54mm |
64mm |
92% |
* There is always a 10mm difference between
the head and cup.
What About WEAR?
Despite improvements in the manufacturing, processing, and
sterilization of polyethylene, wear related problems still
exist in modern Total Hip Arthroplasty.9 To address this problem,
the CONSERVE® Total Hip System has eliminated polyethylene
from the design altogether. The result is a one-piece, highly
superfinished metal-metal hip design, which provides significantly
less wear particles than a conventional total hip replacement.
MAXIMUM RANGE OF
MOTION
Contemporary systems promote increased range of motion (ROM)
through availability of 32mm and 36mm heads along with narrowed
stem neck geometries. Despite these improvements, impingement
due to limited ROM still exists. With the large femoral head
sizes of the CONSERVE® Total Hip, ROM has been maximized
up to 167°, significantly reducing the opportunity for
impingement.6
Beyond providing a solution for impingement,
the increased ROM and noticeable stability also provide patients
with a more anatomically functioning total hip that can return
them to a more active lifestyle.
For more information on the Conserve Total
Hip System with BFH Technology such as brochures, articles,
video etc., please contact
Ortotech directly or visit the official homepage
http://www.wmt.com/bigfemoralhead
  
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