Dr. Kurtz received
special training in Boston that allows him to
replace the hip joint without ever dislocating
the hip joint. This same
technique allows him to return the leg to the
same leg length and offset as before surgery
using his patented leg length technique.
A hip dislocation
occurs when the femoral head is forcible removed
from the hip socket, which can happen with major
trauma like a car wreck or during most hip
replacements. A vast majority of
hip replacement surgeries begin with twisting
and pulling the leg in order to dislocation the
femoral head out of the socket. This
dislocation may occur out of the front of the
socket as in the anterior hip approaches or out
of the back of the socket as in the posterior
hip approaches. However,
new techniques make dislocating
the hip joint unnecessary. Preventing a
post-operative hip replacement dislocation
starts with eliminating the intra-operative hip
dislocation.
Avoiding the hip
dislocation during a hip replacement surgery is
accomplished by preparing the femoral bone
first. In situ femoral preparation refers
to reaming, broaching and implanting the femoral
component without cutting the femoral neck and
without dislocating the hip joint. Since
the femoral head remains in the socket, the hip
joint helps stabilize the leg during the femoral
preparation. Because the femoral neck
remains intact during the femoral preparation,
the femur is stronger and less likely
to fracture.
Interestingly, every
orthopedic surgeon has at one time or another
implanted a femoral IM nail into the femoral
shaft without cutting the femoral neck or
dislocating the hip joint. This in-situ
femoral preparation just utilizes the same skill
set every orthopedic surgeon already has for trauma
cases (broken bones) and applies it to joint
replacement cases.
I personally learned
this in situ femoral preparation during my
fellowship in Boston while training under Dr.
Stephen Murphy. Dr. Murphy has published
this technique multiple times.
Stephen B. Murphy, MD;
THA Performed using Conventional and
Navigated Tissue-preserving Techniques, CORR
(453), pp. 160–167.
There are three unique
aspects about the in situ hip replacement that a
patient or surgeon should understand.
1) The hip
joint is never dislocated. Every other
surgical approach will dislocate the hip joint
at one point or another. Most surgical
approaches dislocate the hip joint immediately
after reaching the joint. Other approaches
will cut the femoral neck in situ and remove the
head, but later dislocate the hip in order to implant the femoral stem in the femoral canal or
attach the femoral head onto the femoral
component. The entire superior approach is
preformed with the femur and the acetabulum in an
anatomic position. The leg is never
twisted, rotated or pulled into an abnormal
position. The components are inserted and
put together inside the hip joint. The main purpose of
this approach is to preserve the anterior and posterior
hip capsule. When the hip is
dislocated during other surgical approaches, either the anterior or posterior
capsule has been cut, torn or disrupted. A
good analogy to understanding this approach is
building a ship inside a bottle.
 The entire total hip components in the superior
approach could not be constructed outside of the
hip capsule and then reduced into the joint
because there is simple not enough space to get
the femoral head over the acetabular rim and
into the joint without cutting the hip capsule.
Therefore, each component is inserted into the
hip joint separately and the hip components are
constructed inside the joint. A hip
dislocation would be equivalent to removing the
ship from the bottle, which is extremely
difficult if the bottle has not been broken
(i.e. the hip capsule has not been cut). A
traditional approach would be equivalent of
breaking open the bottle, placing the ship in
the bottle, and then gluing the bottle back
together.
Second, the femoral
canal is prepared before the femoral neck is
cut. This technique has many benefits.
-
The femur is held in
place by the intact femoral neck and the head
located in the acetabular socket.
-
Femur offset is maintained
during the preparation of the femoral canal which makes entering the
femoral canal with the reamers and broaches
considerably easier.
-
The femoral shaft and
calcar are stronger because the femoral bone
is intact and has not
been cut with a saw, eliminating or at least
decreasing
intra-operative femoral calcar fractures.
-
The femoral anteversion
can be accurately recreated because the
surgeon is looking at the native femoral
head during the insertion of the femoral
component
-
Because the femur is held
in place, leverage retractors greatly
facilitate the exposure. The size of
the patient is not a factor in the exposure
needed to perform the surgery.
Therefore, almost every size patient can
benefit from this approach.
-
By inserting the femoral
component before the femoral neck is cut,
the surgeon can measure the distance from
the femoral component and a fixed point on
the ilium and accurately restore the leg
length and offset. To see more about
this leg length measurement technique and
Dr. Kurtz's research study, click
here.
Third,
the surgeon works in between the interval of the
posterior border of the gluteus medius muscle and the
superior border of the short
external rotators.
The posterior capsule and short external
rotators are preserved, which enhances hip
stability. The hip abductors are protected,
which helps prevent limping after surgery. The gluteus maximus muscle is spread and
leverage retractors are used to protect the
surrounding muscles, so they are not damaged
during the insertion of tools and implants.
Surgical Technique
The
surgery starts by positioning the patient and
the patient's leg in a position similar to one
that the patient might sleep in bed. (leg
adducted, flexed, and internally rotated). The patient's leg
stays in this position for almost the entire
case. The incision is
usually 8 cm and does not typically need to be
increased for larger patients. The
incision starts at the tip of the greater trochanter and extends proximally in line with
the femoral shaft.
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Fig. 1 - Patient
Positioning |
The gluteus maximus
muscle fibers are spread in line with the
incision. The posterior border of the
gluteus medius is identified and leverage
retractors help protect it and pushed the muscle forward during
the case.
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Fig. 2 -
Piriformis released to expose
superior capsule |
The internal rotation of the
leg facilitates moving the abductors out of the
way for the femoral preparation. The
piriformis muscle is identified and released.
This muscle is released or injured during the
insertion of any femoral prosthesis. The superior capsule is then
incised and the superior femoral neck is
exposed.
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Fig. 3 - Superior Capsulotomy |
Fig. 4 - Superior Femoral Neck |
The femoral canal is
opened with a straight reamer just as if the
surgeon was going to insert a femoral nail.
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Fig. 5 - Opening the femoral canal
with a straight reamer. |
The
medial femoral neck bone is removed with an
osteotome and femoral broaches are inserted.
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Fig 6 - Osteotome removes medial
femoral neck bone. |
The femoral broaches are inserted down the
femoral canal. Because the femoral neck is
intact, the femur is stabilized and the
broaching is easier.
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Fig. 7 - Insertion of femoral broach |
The
final femoral broach is left in the femoral
canal and used a template to show the surgeon
where the appropriate femoral neck cut will be
located. The real femoral prosthesis can
also be inserted at this time instead of the
femoral broach. The femoral neck is then
cut with a saw and the femoral head is removed
by inserting a threaded pin into the femoral
head and pulling the head out of the socket.
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|
Fig. 8 - Femoral
Neck Cut |
Fig. 9 - Femoral head removed |
The
acetabulum is reamed with a special angled
reamer. This angled reamer allows the
surgeon to control the anteversion of the reamer
without the femoral bone getting in the way
simply by turning the handle towards the
direction he/she intends to ream. During
traditional approaches, a surgeon may find that
the femoral bone inadvertently pushes his/her reamer
in an wrong direction. Because this reamer
is angled, the femoral bone does not limit or
inadvertently push the reamer in the wrong
direction.
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Fig. 10 - Angled Reamer |
The acetabular
component is implanted with an angled impactor.
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Fig. 11 -
Cup Insertion with angled impactor |
The real femoral
component is exchanged for the trial broach if
it was not inserted before the neck cut. The
prosthetic femoral
head is placed in the acetabular component, and
the leg is distracted so that the femoral neck
can be inserted into the femoral head.
Once the leg is distracted, the neck of the
femoral component is positioned so that it lines
up with the femoral head. The neck then
cold welds into the femoral head. The leg
is never dislocated during this procedure.
The leg can typically be taken through any range
of motion on the operating table and it will not
dislocate even with the patient fully paralyzed.
The
superior capsule is repaired, the piriformis is
repaired, the fascia of the gluteus maximus is
repaired and the incision is
closed with Dermabond.
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Fig. 12 - post operative x ray |
The
above pictures are taken from Dr. Murphy's
original technique guide. The pictures are
meant for educational purposes only.
Click
here
for additional information regarding traditional
hip replacement and risk of a hip replacement.
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