Approach for Muscle Sparing/Precision Implant Placement Technique
is it? It is a technique that is a step further and safer than
minimal invasive hip surgery.
It uses an entirely different surgical approach (anterior) to
get to the hip joint so that no muscles are cut - unlike the
minimal invasive technique.
The cut, of course, is shorter than the 8 to 10 inches standard
The surgeon sees every step of the surgery in getting to the
hip joint. Replacing the joint is fully seen on a TV screen which
is used in conjunction with a standard operating table.
(4) The implant used is designed to find its own way into the
femur. This further prevents any potential in placing the implant
in the incorrect position.
This muscle sparing/precision implant placement technique is preferred
by Dr. Menendez in total hip replacement.
is it done? This technique uses a standard operating room
No special table is needed for the surgery.
patient lies on the operating table facing up, like sleeping in a bed
at home. The table is turned so that the foot of the table is under the head of the patient. So, the patient is not
placed on the side like the posterior and lateral approaches.
When the patient is on their side, the body of the patient
has to be completely supported and held in place so that
the patient does not fall to one side.
is this important? When a shorter incision is used and the surgeon
needs to see
inside the cut open hip, an alternate to the eyes is to see
The reversed operating room tables allow the
low–power x-ray to pass through.
The area around the hip area is clear of metal. So,
x-ray beams are not blocked by the metal parts of the operating
advantage is that at every critical step in preparing
the bone, a low-power x-ray beam machine
be used to check out the hip area and let the surgeon see
on a TV screen what exactly he is doing. This machine is used
before, during and after every critical step of the surgery.
It directs the surgeon as to where the cut is to be made. It
the surgeon if the instruments are placed in the ideal way
to make the cut. The x-ray is shown on a TV screen and the
surgery is like
playing a video game. Since this x-ray vision is done during
surgery (real time), there is no need to wait until the surgery
in the recovery room to find out if everything fits properly.
The moment the artificial parts are put in, the surgeon knows
are in the proper positions. If any changes need to be made,
it can be done right away. So, this is the first part of the
implant placement technique.
hip joint is reached from the front of the body (Anterior Approach).
The hip joint is a lot closer to the skin in the front
than the back of the body. There are less soft tissue and muscles
covering it. So, the cut in the skin needs to be only 2-1/2 inch
long. The length of the cut this is almost the same as the minimal
this is a relatively short cut, it has to be made in the exact
If it is made in the wrong place, then the hip joint
will be missed. So, the exact location of the cut to be made is
fixed by a special instrument and checked on the TV screen.
the skin is cut open, there are two muscles on top of the
hip joint (Tensor Fascia Lata on the outside and Sartorius on
They are not cut but pushed aside (retracted) with standard
instruments. The second layer of muscle (Rectus Femoris) is
to one side. In several short steps, the hip joint capsule
The capsule is then cut open and the ball and socket hip
joint is exposed. So, this is the ‘muscle sparing’ part
of this technique. No muscles are cut in order to get to
the hip joint.
The head of
the leg bone (femur) is cut with a power saw and the ‘ball’ is
removed. This gives room now for preparing the hip socket (acetabulum).
This is done by a special instrument that looks like a chess grader
but round. When the power of this
is turned on, it spins and shapes the hip socket into a hemisphere.
Every step mentioned
is seen by the surgeon using low dose x-ray and shown on the
TV screen. The artificial socket (acetabular) implant is then
by ‘press fit’ into the socket.
or more screws are then used to further secure the acetabular
implant in bone. Now,
the surgeon turns to work on the femur side. The reversed table
allows the heel of the leg to be dropped to the floor and the
leg is turned outwards. Then the inside the femur (femoral
canal) is opened up with instruments.
called broaches or rasps.
A special instrument is used to lift up the femur. Starting with
the smallest broach, bigger and bigger braches are used one after
another. Again they are done under the guidance from the TV screen.
This process takes away the weak ‘honeycomb like’ bone
inside the femur. It is stopped when the broach sits tight in the
femur. It is important to seat the implant in hard bone (cortical)
because of the support needed. The corresponding femoral implant
is then inserted (press fitted) into the femur.
the incision is smaller than usual, not only is the femoral implant
into the femur under direct x-ray vision, but
a particular implant is also made of titanium alloy. Also,
the shape (design) is
based on the research of the shapes and sizes of numerous femurs.
the implant was designed to match the majority of the patients.
This is important because the human body does not have a straight
line but have all sorts of curves. The implant is to fit the
femur like a hand in glove. This implant has been used since
femoral hip implant ‘finds its own way’ into the
canal and give a best fit. This is the second part of the precision
many instances, the other hip joint is good. So, it can be used
as a comparison to the side that is replaced on the TV screen.
This allows the surgeon to adjust the length of both legs. The
suitable length ball component is then placed on the femoral implant.
But the most important part in a total hip is the stability of
the reconstructed hip joint. So, the surgeon checks the stability
by moving the hip joint in various directions to see if the artificial
hip joint can dislocate. Then the final decision is made as to
how long the leg should be. A final picture of the replaced hip
joint is then seen on the TV screen.
When the TV screen shows a satisfactory picture, the hip joint
is ready to be close back up. The soft tissue over the artificial
hip joint is stitched back together with sutures. The skin is closed
metal staples. This closure part takes only a few minutes and the
operation is complete.
The patient is transferred from the operating table to a bed and
wheeled away to the recovery room.
So, by using
a short anterior approach, the hip joint can be exposed under
direct vision. The hip joint is reached without cutting any
muscles. With the reversed table and a low-power x-ray beam, all
the bone cuts can be seen before, during and after on the TV screen.
This makes sure that all the steps are done properly. Then with
a ‘home-seeking’ hip implant, a precision hip placement