During my several years of
learning and reading about hip resurfacing, I have heard of two
people having dislocations. There may be more, but I only know
if people post their dislocation on the various discussion
boards I belong to.
One young man was doing an
exercise bringing his knee to his chest. His leg was tight and
he jerk his knee toward his chest and caused a dislocation of
his hip resurfacing.
One lady was 11 months post op
from bi-lateral surgery of BHR's in both hips and was bending
over to move her boots and dislocated her hip.
One of the reasons many people
want a hip resurfacing is that they normally don't dislocate and
allow you to be as active as possible. I guess having a
few dislocations out of the over 90,000 hip resurfacings world
wide is not a large number. But when it happens, people
are always interested in WHY?
The following is an email in
which Dr. Bose describes Dislocations:
It is a
commonly used statement that a BHR is as 'stable' as a normal
hip. However this is a highly qualified statement.
This
statement is true only if the following criteria are met.
1. Native
angles, inclination , offsets and all anatomical parameters have
to be replicated.. If this is not done fully and only accuracy
of say 80% is obtained - then the stability is likely to be
approx in the region of 80% only. Having said this ,even in this
situation, the stability is likely to be many times that of a
conventional THR. Therfore i would not call it a surgical
error.As surgeons, we get better and better at this replication
as we gain experience.
2. The
capsule should be repaired to capsule preferably as it restores
the joint 'proprioception'( or position sense). This would kick
in the event of a potential dislocation as it would in a normal
hip. If the capsule is repaired to bone , it is many times
better than doing nothing but does not achieve the proximity to
the stability of a normal hip. Again it is not a surgical error
if capsule to capsule repair is not done but one cannot expect
natural stability.
3. Other
factors that can potentially cause dislocation like impingement
must be carefully addressed . The most common offender is the
non -restoration of the head neck offset
One must
keep in mind that the BHR is the Ferrari of hips and the
conventional THR is an old fiat.
Even if the
Gear knob of a ferrari is not the right size for the driver it
shows up because it is pushed to the limit and built for
performance. However even if the chassis is broken in an old
fiat , it would probably go unnoticed by the owner as it is
never 'pushed' for performance. There are many patients after
THR s with trochanteric non-unions going on for many years
without even being aware of it!
coming to
the specifics of this patient.- The Relocated BHR is likely to
be stable with time and is unlikely to affect longevity. THe
only issue is that this patient must avoid extremes of movement
to prevent another episode.
I hope this
helps
with best
regards
vijay bose
chennai
Asian Regional Center for Hip Resurfacing
