Dr. Bose:

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. Therefore 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!