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