Approaches in hip resurfacing by Dr. Gross

The path that surgeons choose to arrive at the hip joint is called the
“approach”. There are many different basic approaches used for hip resurfacing.
None has been proven to be superior to others based on valid scientific
research. Basically, I recommend that a surgeon use the method that he/she is
already most comfortable with when performing standard total hip replacement and
modify it as needed for the more complex hip resurfacing operation. My preferred
approach is the posterior. This is used in at least 70% of hip resurfacings done
worldwide. The next most common approach is the lateral (two versions:
anterior-lateral and direct-lateral). Finally the direct anterior and the Ganz
(or trochanteric, or internal dislocation) approach are far less commonly used.
All of these approaches are adapted slightly by different surgeons.

I am aware of one nonrandomized comparison study comparing the anterior lateral
and posterior approaches by different surgeons published by Ronan Treacy that
found no difference. Most clinical series on hip resurfacing are based on the
posterior approach. In a comparative report that I published, we found that the
results were slightly better with a minimally invasive posterior as opposed to a
standard posterior approach. There is another variant of the posterior approach
where a small cuff of hip capsule is left as a remnant on the neck of the femur.
This is called the “vascular-sparing” posterior approach. Many surgeons have
recommended this, but evidence is scant. I started using this routinely several
years ago, but found no difference compared to the standard posterior approach.
We are currently working on a paper on this topic.

The theoretical advantages of various approaches are:

1. Posterior: Less harm to abductor muscles
2. Lateral: Lower dislocation rate with smaller bearing THR
Less disruption to the femoral head blood supply
3. Direct Anterior: Lower dislocation rate with smaller bearing THR
Less disruption to the femoral head blood supply
4. Ganz*: Less disruption to the femoral head blood supply

* described by Dr. Reinhold Ganz of Switzerland for open hip impingement
surgery. It has been used for hip resurfacing by some surgeons. The abductor
muscles are detached from the remaining femur by cutting through the greater
trochanteric bone. The bone is reattached by screws. Dr. Paul Beaule was one of
the early proponents, but has abandoned this because of the high rate of
trochanteric complications.

The theoretical disadvantages of the various approaches are:

1. Posterior: More disruption to the femoral head blood supply
Higher dislocation rate with smaller bearing THR
2. Lateral: More Harm to the abductor muscles
3. Direct Anterior: None
4. Ganz: Problems with bone healing of the greater trochanter

My personal opinion (not scientific evidence) is that recovery is slower with
the lateral and Ganz because patients need more restrictions to avoid damaging
the detached/repaired abductor muscles. While failure of the muscles is
relatively common and easily diagnosed with the Ganz approach because the bone (trochanter)
repair is easily monitored on XR, this same problem exists with the lateral
approaches but is more difficult to diagnose because muscles are not seen on XR.

Direct anterior approaches are rarely used. Reports are scant. Two meeting
presentations that I am aware of show a very high rate of femoral neck fractures
(>5%), probably because a lot of force is required on the bone when this
approach is used. I am aware of no published results.

Actually complications are much more related to a surgeon’s experience, as
opposed to the approach he uses. There is a lot of evidence to support this
theory.

Therefore, the best advice that I can give you is to ask your surgeon how many
hip resurfacing operations he has done through a certain approach and what his
individual complication rate is (not what some paper says the rate is). Every
experienced surgeon should keep track of his complications and publish them.
Most surgeons believe they have fewer complications than they actually discover
if they rigorously analyze and publish their own data. My data are published
online for 2500 cases with a 92% rate of follow-up done using the posterior
approach.

Regards,

Thomas P. Gross, MD
11/1/2011