Hip Varus Rotational Osteotomy (VRO)
Faith Based Surgery?
The femur is the thigh bone. At the lower end is the knee. At the upper end is the hip. Look at figures 2, 3, & 4, above. You can see that the femur is angled and ends in a ball
shaped top (called the head). The short slanted segment below the "head" is the neck of the femur. You might call the long vertical shaft of the femur, the "body", if you like.
The round head sits in the hip socket (also called the acetabulum). The hip joint is of two
halves, the pelvic socket and the ball of the femur.
Problems of the hip can be many.
The socket can be too shallow, too large, too small, lacking proper round contour etc.
These problems of plasticity of shape are lumped in a name "dysplasia". That's another page.
In figure 2, we see a problem of the femoral neck. It is too vertical. It does not point
toward the socket sufficiently. That is called femoral neck "valgus" (or just plain valgus). The opposite of valgus is varus. In femoral varus the neck would be more horizontal.
The most common femur intervention for cerebral palsied persons, is to deal with a
dislocating hip. In that setting the hip dislocates because the hip socket is too shallow (1) and perhaps the femoral neck too vertical (2 valgus).
Cutting (tome) any bone (osteo) is called osteotomy. Osteotomy of the thigh bone just
below the neck, in order to angle the upper femur (the neck) more sharply into the socket is performed at times. The advantage is that a single operation can handle an array of
issues. Even if the femur neck angle is proper, a steeper varus angle causes muscles to pull less vertically toward the socket top edge but rather more horizontally toward the socket center.
In fact, most surgeries to produce varus are not to undo excess valgus, but rather to
produce more varus than is normal so as to offset less vertically stable sockets.
Often, in order to further stabilize or to redirect the direction of the knee below, the
reattachment of the femoral neck back to the body of the femur (with a metal plate and screws) after it has been divided is in an altered horizontal rotation (called derotation or just rotation).
The name VRO means Varus Rotational Osteotomy.
The name VDO means Varus Derotational Osteotomy
They mean about the same thing.
The disadvantage is that this femur surgery shortens the leg, makes it strangely wide at the
hip, and causes the leg to track oddly between sitting posture to standing. Bone healing (to standing time) is about 8-12 weeks. A hip metal 'nail' (a specialized angled metal plate
and screw affair) is needed to hold the two pieces of divided femur together until bone healing and takes over. The "nail" is removed about one year later. Loss of position is not
rare, requiring potential revision surgery.
Muscle operations are often performed at the same time. Most VROs require a body cast that includes the legs (spica cast).
Anteversion is when the femoral head+neck point too forward relative to the direction of
the knee. This is the strongest argument for VRO type surgery. Another anteversion link.
Let us take on reality. When children with neuromuscular disorders are having this
surgery proposed - something must be very wrong to propose it. The headaches for the surgeon are many. The complications are many. And yet this is one of the MOST
common surgeries of all in this field. As an approximation the western cooperative statistics were terrible, with good outcomes simply rare and close to 60% less than fair
based on anatomy. The more recent and very comprehensive Harvard reported series used different criteria but there too, almost 100% of cases had to be revised or in some unplanned way revisited.
Getting to 'normal' isn't really even a goal. Getting back to past level of mobility can take
over two years. If you think about it, this surgery tends to happen in older kids (over 7 years old) when remodeling of joints is about zero. The fundamental defect is not the femur but the hip socket.
So the VRO is supposed to alter forces so that the socket will grow better. But - not so
much so at the older ages. It's a stacked deck. And yet there are cases, many, wherein the deformity that VRO produces helps keep the hip ball in the less than adequate socket.
Hmmm? Did he just say that VRO produces a deformity?
Yes. Very obvious, too. That's why MOST surgeons doing VRO operate on BOTH hips
so as to get symmetry. So in a series of 100 hips (two per person) operated, with 50% complications that means roughly every case had a big problem (likely with the bad hip
and less likely with the hip operated on just for symmetry).
So preventing NEEDING this operation is what much of the other stuff in this web site is
about. Not a better operation than VRO but preventing VRO. Preventing? In some large and well known clinics about 75% of kids with four limb involvement get VROs (and nearly all the dystonic cases).
(The following is an mp4 movie - a long one. ):
You can skip what follows. It is mere frustrated venting.
Clearly VRO is not a preferred method of this web site. Kind of obvious huh? But why the foot stamping
snit? It is because of the thinking jumble which gets us here. VRO was devised to deliver an outcome for CONGENITAL hips or DDH (baby hips). Femoral anteversion is normal and ever present in babies.
Normal baby hips cannot be dislocated. They will break first. This normal very strong hip structure transmits
torsional forces onto the upper femur during activities. These forces gradually nudge the growing partly
cartilaginous upper femur and produce natural gradual derotation - over time - years (10 or 12). A secure ball in an intact socket is key.
But when the hip is born deficient, too flat, not a cup but more like a saucer, then that strong link is not only
missing, it makes repairing the hip difficult. Normal baby anteversion makes trying to build a socket shape to
last difficult. The femoral head is more likely to unseat than derotate from the forces normally transmitted by
an insecure cup. So, sometimes we need to move the calendar up and derotate the upper femur so as to not
to require torsional stress on a compromised hip socket (after reduction & repair). OK. So derotating the femur in that setting makes sense. Useful.
Some doctors have made excellent use of VRO in Perthes to try to get softened compromised femoral head
surfaces better covered. Fine. Makes sense there, too.
But somehow the late hip changes of paralytic diseases (as is the case in cerebral palsy) gets lumped in with
DDH and VRO and emerges as a treatment for BOTH? Every study performed says it does not work so well and has many complications in THAT application. Then the academics come swooping in inflamed if
anybody does something else that does not have a high 'p' value. (They don't know that p values ain't what
they crack them up to be. They are NOT a substitute for direct observation. But that aside, no matter. The
only high p values out there all say this application stinks. If it stinks with a high p value... SCIENCE...it is
OK, it has lots of 'p' all over it. It seems to be OK to do something stupid if the statistics are good to show that, though stupid, it is stupid to four decimal places.
Somebody has to try another path through these woods.
Faith based? Well, in DDH the kids are babies. The VRO takes the torsion redislocation pressure off the
main target of interest - the hip socket - to allow it to use that great baby regeneration ability to (quickly) deepen the socket and make nice nice.
In paralytic hip dysplasia, socket defects come very late and socket regeneration ability coming from older
structures and tissues (built in genetically in the socket itself) is wishful thinking. Doing a VRO will alter
certain forces and all that baby regeneration potential (?? long gone ) will come swooping from on high and
make those hips just fine - God willing and the creek don't rise. Right now in New Orleans there are people
rebuilding their flood destroyed homes - below sea level. It's kind of like that. God will provide. Historically,
when God provides it is usually wind and very high walls of water... but hey! Is 40% fair outcome the hand of God? Faith? 'Faith requires a proper deity.'*
Ooooo, that was kinda dark. Yeesh, let's go to the movies! Three movies follow.
Click a Mandela to watch.
Petri to VRO