Can you tell me a little about the Ganz approach and the difference between it and the posterior approach?
October 23, 2011
Dr. Vijay Bose
The ganz trochanteric flip is an excellent approach for doing open FAI surgery, for fixing fracture on the femoral head ( pipkin #) and for doing osteotomy of the femoral neck in post SUFE situations. In these non - arthritic situations a surgical dislocation of the hip is warranted without damaging the blood supply and I employ it routinely for these indications.
However its use in hip resurfacing is a bit of an overkill. It has been documented without a shadow of doubt that the post approach does not compromise the vascularity of the femoral head in an arthritic hip after resurfacing. Thousands of patients who have crossed the 10 yr mark with the post approach & BHR bear testimony to this.
Doing the ganz for resurfacing is a much more morbid procedure than a standard post approach. Any osteotomy will take more time to heal and recover function. The extended trochanteric osteotomy ( ETO) which is the bigger version of the Ganz flip will take about 6 months for the patient to regain function.
Intuitively the Ganz looks appealing as regards preserving blood supply but this issue is not relevant in an arthritic hip.
with best regards
Also see the paper published by Paul Beaule here
From Dr. Thomas Gross November 1, 2011
Approaches in hip resurfacing
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:
- Posterior: Less harm to abductor muscles
- Lateral: Lower dislocation rate with smaller bearing THR
Less disruption to the femoral head blood supply
- Direct Anterior: Lower dislocation rate with smaller bearing THR
Less disruption to the femoral head blood supply
- 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:
- Posterior: More disruption to the femoral head blood supply
Higher dislocation rate with smaller bearing THR
- Lateral: More Harm to the abductor muscles
- Direct Anterior: None
- 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.
Thomas P. Gross, MD