Gross v. Abdel: Avoiding Instability: The Transtrochanteric Approach
OTW Staff • Mon, February 26th, 2018
This week’s Orthopaedic Crossfire® debate was part of the 33rd Annual Current Concepts in Joint Replacement® (CCJR®), Winter meeting, which took place in Orlando. This week’s topic is “Avoiding Instability: The Transtrochanteric Approach.” For is Allan E. Gross, M.D., F.R.C.S.(C), University of Toronto, Toronto, Ontario, Canada. Opposing is Matthew P. Abdel, M.D., Mayo Clinic, Rochester, Minnesota. Moderating is Robert T. Trousdale, M.D., Mayo Clinic, Rochester, Minnesota.
Dr. Gross: I have to tell you right at the beginning that the speaker that was originally given this topic routinely takes off the greater trochanter for primary hip replacements and he does them in the classical Charnley fashion cementing both sides of the joint. I’m sure he does an excellent job.
I do not do this approach for primary hip replacements, but I do it for difficult primaries and complex revisions. So, my mandate is just to convince you when you have to take it off, take it off. Don’t be afraid and I will show you a technique which really decreases instability.
The posterior approach is probably the most commonly used approach in North America and is used in about 60-65% of the cases. So I’m going to compare that to the modified trochanteric slide and the modified extended trochanteric osteotomy which is a type of trochanteric osteotomy which is done exactly the same as we do the modified trochanteric slide.
The advantages of the modified trochanteric slide, which is what we call it—modified trochanteric slide—that’s very important—is that you get extensive exposure of the acetabulum and the femur. There is a decreased dislocation risk, as you’ll see from our data. And it can be converted to a transverse osteotomy by releasing the vastus lateralis if you have to. But that should be very, very rare that you have to do that because that increases the incidence of trochanteric migration.
The disadvantage of taking off the trochanter is that you can get a non-union particularly with the trochanteric slide, but much less so with the extended trochanteric osteotomy because you have a bigger bone apposition surface.
If plating of the ischium is required, if you use our technique, you have to take off the external rotators and the posterior capsule to expose the posterior column. While using our technique decreases the dislocation risk, it doesn’t give that exposure that you would need to plate the posterior column.
The longer the trochanteric fragment, the less the incidence of trochanteric non-union. If you don’t have a greater trochanter because it’s like a third-time revision, then we do something like a fake trochanteric slide where we pretend there is a trochanteric fragment and we have one continuous sheath of conductive muscle where the greater trochanter was in the vastus lateralis.
The posterior approach has the advantage in that it offers extensile exposure including the ischium. If more exposure is needed—and this is very important—you can easily convert it to a trochanteric osteotomy. The disadvantages are the risk of dislocation; exposure of the femoral canal is more limited than with the trochanteric slide; and traction of the superior gluteal nerve when extensive exposure of the ilium is required.