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A Parent's Guide to PFFD: Archived Version

NOTE: This is an archived verison.
The current version is here

PFFD: A Parent's Guide

PFFD: A Parent's Guide


Mike Malloy (PoC-PFFD)

Parent of Child with PFFD

Disclaimer: The author of this document is not a doctor. I am just a
parent of a child with PFFD who is very frustrated by all the hard to understand
medical papers about PFFD. This document is my attempt at trying to describe
PFFD in easy to understand terms. By no means is it to be considered medical
advice. All the PFFD experts will tell you that each case is different and
needs to be judged on it's own merits. Please consult a doctor for the best

Revised 11/24/98

Table of Contents


First, it's important to at least understand the name PFFD. It's really not
as bad as it seems. Let's look at each word:

  • Proximal   -    nearest the point of attachment or center
  • of the body

  • Femoral    -    pertaining to the thigh bone or femur
  • Focal        -    pertaining to a focus or
  • starting point

  • Deficiency -   a lack; less than the normal amount

In other words, the end of the thigh bone closest to the hip is too short
or not completely developed.

PFFD is a congenital anomaly (birth defect) characterized by a failure of
normal development of the proximal (upper) end of the femur (thigh bone).
In most cases, the iliofemoral joint (hip) is also poorly developed. PFFD
varies in severity from the mild case with a short femur but normal hip joint
- to the more severe case where no hip joint is present.1 The
condition may be unilateral (one leg) or bilateral (both legs) and is often
associated with other birth defects.2

The appearance of a child born with PFFD is very typical. The thigh is abnormally
short, held in flexion (bent), abduction (moved to the side), and external
rotation.1 Some have described the leg as an upside down L-shape
or resembling a ship's funnel. The foot of the affected leg is frequently
at the level of the opposite knee.

Etiology (What causes it?)

As a fetus develops the location of each cell and its surroundings determine how
the cells and tissues develop. The process is called morphogenesis. If something goes wrong in morphogenesis, the time at which it occurs influences the occurance and type of effect. If something occurs at a primary stage it is called a "malformation." (As opposed to a "deformation" which is usually at a later stage and arises from mechanical factors. )

Limb buds on the fetus develop at about 28-32 days into pregnancy and at 33-36 days the foot plate is visible. If something affects the growth of the fetus around this critical limb-formation time (2 - 5 weeks) it can lead to PFFD. A "teratogen" is the term given to the agent that causes a malformation in an embryo or fetus.

The teratogen for PFFD is unknown. PFFD is not genetic. Some have proposed that it is caused by anoxia (oxygen deficiency), ischemia (temporary blood supply deficiency), chemicals, hypothermia, radiation, bacterial toxins, viral infections, enzyme
and hormone changes. The only definite cause
is the drug Thalidomide which was used as a sedative and sleeping pill in
Europe before being discontinued in the early 1960's.2

Embryology (How does it happen?)

PFFD occurs during the first 2-7 weeks of fetal life. The limb buds start
to develop at about 32 days. The most proximal (toward center) parts of the
limbs develop first, followed by the hands and feet, which are fully formed
by the seventh week.3 The acetabulum (hip socket) and the femoral
head and neck develop from a common block of cartilage, with subsequent cleft
(opening) to create a hip joint cavity.2 The cleft gradually separates
until a definite joint cavity is formed. This point is critical for proper
diagnosis. Dr. King pointed out that the development of the acetabulum and
femoral head are mutually dependent (can't have one without the other). The
presence of an adequate acetabulum on early (1st year)  X-rays always
means that the femoral head is also present - even though it's development
may be delayed and it may not be visible on the X-ray. Similarly, if no
acetabulum can be seen, no femoral head will develop.1

Whatever affects the developing limb bud during the first 2-7 weeks, it also
affects muscle development in the thigh, knee joint, and sometimes in the
lower leg.1

Clinical Findings (What does it look like?)

The appearance of a child born with PFFD is very typical. The thigh is abnormally
short, held in flexion (bent), abduction (moved to the side), and external
rotation.1 Some have described the leg as an upside down L-shape
or resembling a ship's funnel. The foot of the affected leg is frequently
at the level of the opposite knee. There is always significant anteroposterior
(front to back) instability of the knee joint due to deficient or missing
cruciate ligaments.1 70-80 percent of the cases also experience
fibula (smaller bone of lower leg) defects - ranging from mild tissue
defects to complete absence of the fibula and a deformed foot.1

Presence or absence of a foot deformity affects treatment options (see Van
Nes rotation). 50 percent of patients also experience defects in other
limbs.1,4 Approximately 15 percent of PFFD cases are bilateral
(both legs), with those cases frequently having the more severe fibula and
foot defects.1

Diagnosis is almost always possible on the first physical examination due
to the typical PFFD characteristics. However, the physical exam is
of little value for determining the severity of the defect. X-rays
(or maybe even MRI) will be required to determine severity and classification.

Classifications (How bad (or good) is it?)

Several classifications have been proposed for PFFD, but the most commonly
used one was developed by Dr. George T. Aitken in the early 1960's. Dr. Aitken
developed a four class (Class A,B,C,D) classification system based on X-ray
results. Class A is the least severe and Class D is the worst case.
It is hard to classify into only four classes a condition that has varying
degrees of severity with no clear agreement on end points. Despite it's flaws,
the Aitken Classes appear to be the most widely used and recognized.

Sketch of Aitken subclasses

FIGURE 2 Schematic representation of the four radiographic subclasses
of proximal femoral focal deficiency.

Aitken Classifications

Class A

In Class A the head of the femur is present, together with an adequate acetabulum
(hip socket) and a very short femoral shaft. Initially, there is no bony
connection between the femoral shaft and the head of the femur. At skeletal
maturity a bony connection will be present between the femur head and shaft.

Class B

In Class B the acetabulum and head of the femur are present, but the femur
head may not be visible due to delayed ossification (formation of bone).
Based on the presence of the acetabulum, Dr King's theory can be used to
deduce that the femur head will develop. No bony connection exists between
the femoral shaft and head, and the upper end of the femoral shaft usually
has a small bony tuft. Unlike Class A, at skeletal maturity a bony connection
will not exist between the femur head and shaft. Studies show that the head
and shaft do not move together, and , therefore it is believed that there
is no cartilaginous connection between the shaft and head.4

Class C

In Class C the acetabulum is severely dysplastic (abnormally developed) and
the head of the femur never develops. The shaft of the femur is short with
a small bony tuft on the upper end.

Class D

Class D is characterized by the absence of both the acetabulum and femoral
head.4 The femoral shaft is extremely short and the upper end
is pointed.1 In the most severe cases only a small part of the
lower femur is present, with marked knee abnormality.1


A number of treatment options have been described over the years. Even now
a uniformity of opinion does not exist. It has been frequently said that
each case of PFFD needs to be treated on it's own merit. To a degree
this is true, yet some basic principles do apply and help with the decision

The goal of treatment is to provide optimal function and acceptable appearance.
The treatment plan is based on three basic factors: 1)bilateral (both legs)
or unilateral (one leg), 2) severity (length discrepancy, Aitken Class, etc.),
and 3) presence or absence of a functional foot and ankle.1

Treatment for Bilateral PFFD

Bilateral PFFD usually only requires prosthetic treatment. Children with
bilateral PFFD can usually walk well on their own feet, and prostheses are
only needed to bring them to the height of their peers.Surgery is not usually
recommended because it would destroy the child's ability to walk without
the prosthesis. Surgery would only be needed in cases with severe foot
deformities that inhibit normal weight bearing.

Almost all bilateral PFFD cases are Aitken Class D (no acetabulum and no
femoral head).

Treatment for Unilateral PFFD

Treatment options for unilateral PFFD are based on 1) severity (length
discrepancy, Aitken Class), and 2) presence or absence of a functional foot
and ankle. A knowledge of the anticipated final leg-length discrepancy is
probably the best guide to treatment options.5 By the time
a child is approximately 3 yrs of age, one should be in a position to predict
leg-length difference.5 (Probably much sooner if the difference
is great.)

If the predicted difference at maturity is 3 inches or less, then
it can be treated with shoe lifts, limb lengthening, or leg shortening on
the long leg.5 Keep in mind that the 3 inch difference
is at maturity.
3 inches on a newborn baby may become 10 inches at maturity.
For example, assume the femur is 50% short. 50% of a newborn femur may be
only 3 inches, but 50% of an adult femur is much greater. Plus, Drs. Amstutz
and Wilson observed that there is always retarded growth in the affected
leg, so the difference may increase from 50% to 70% or greater.

If the predicted difference is greater than 5 inches, then a prosthesis will
be required. Prosthetic options available are 1)fit over foot, 2)amputate
foot and fit with above knee prosthesis (knee joint in prosthesis), and 3)
Van Nes rotation with below knee prosthesis (rotated ankle functions as knee

When the discrepancy is likely to be between 3 and 5 inches, then one is
dealing with a borderline situation, and decisions must be made based on
surgical and prosthetic judgment and discussion of the problem with the parents
and with the child, if he is old enough to participate.5

In summary, the treatment options available are 1)limb lengthening or shoe
lift, 2)prosthesis (with or without surgery), and 3) Van Nes rotation.

Limb Lengthening

Limb lengthening is only possible in cases with lower grade PFFD (Aitken
class A) and a small length difference (less than 3 inches predicted at
maturity). The presence of a stable hip and foot are also very important.

All of the information that I have strongly advises against leg lengthening.
Drs. Westin and Guderson wrote "leg lengthening has been attempted with little
real success". Dr Krajbich wrote "With newer methods it may be possible that
in the future some of these patients may benefit from leg-length equaling
procedures. At this stage, however, it would be very much an experimental
undertaking."  Drs. Westin and Gunderson wrote "Leg lengthening has
been attempted in nine cases with little success and frequent complications.
One of the criteria for for consideration of femoral lengthening is the presence
of of a stable hip and knee rarely found in PFFD." Keep in mind that all
these articles were written in the 60's or 70's. Perhaps those 'newer methods'
that Dr. Krajbich mentioned are available today in 1997.  

On the brighter side, information at
Alfred I. DuPont Institute
indicates that lengthening is possible if
the following criteria are met:

  • patient has greater than 60% of predicted femoral length
  • predicted length difference at maturity is less than 17 cm (6 1/2 inches)
  • stable hip
  • stable foot

The patient will require one or more femoral lengthening and/or contralateral
epiphysiodesis (slowing growth in other leg).2 However, they warn
that "parents should understand the magnitude of the operative procedures
for length equalization, the potential risk, including amputation at less
desirable level, and the lengthened extremity will still not be

I'll keep looking for more information. Currently, the only source I have
is the Maryland Center for Limb Lengthening
and Reconstruction

Note 11/14/98 - I just received an e-mail from the mother of an 11 year old
girl that has had good success with Dr. Paley with a very long lengthening.
She writes "Her foot on her right leg came to her knee of the left leg when
she was born. She is now only 6 inches off the ground. At birth, she was
estimated to be 22 inches at maturity difference." Perhaps those newer methods
that Dr Krajbich referred to are finally here and lengthening is now an option
for more and more patients. For the complete story about Rebeccah's progress,
please see [[Rebeccah's Story]] on the vsg page.

Prosthesis Without Surgery

The simplest and most straight forward treatment option is to fit a prosthesis
over the foot. No surgical treatment is required. A prosthesis with knee
joint is fitted around the foot.

Two problems arise with this option. If the foot is left in it's natural
pointing forward position, the prosthesis will have a large bulky socket
which may be cosmetically unacceptable. If the foot is pointed downward to
make the socket smaller, the stump is now longer and may cause the knee joint
to be too low.

The major benefit of this treatment is that the child does not have to endure
any surgeries. Also, if the parent is hoping for some newer limb lengthening
methods in the future the foot would still be in place.

Prosthesis With Surgery (Foot Amputation , Knee Fusion and possibly Hip Surgery)

The most common treatment for unilateral PFFD is surgical treatment and a
prosthesis. The goal of the surgical treatment is to provide a more stable
hip whenever possible and to optimize the leg as a stump for prosthetic

Foot Amputation

The first goal is to create a long, above-knee, end-bearing stump that can
be easily fitted in a standard prosthesis.3 The previous
section described the problems associated with trying to fit a prosthesis
over a foot. A good end-bearing stump can be made by performing a Syme's
or Boyd amputation, and fusing the ankle. (I'm still looking for a good
description of the Syme's and Boyd procedure). My personal experience
is that the amputation involves removing only the front part of the
foot. The heel bone and heel pad are left in place to be a good
end-bearing stump.

The ankle fusion is performed during the amputation surgery. The procedure
involves pushing a thin metal rod up thru the heel and into the tibia. This
rod holds the ankle immobile until the fusion is complete. The patient
will have to wear a mini cast or 'sleeve' to protect the incision and the
metal rod that will be sticking out of the heel. The sleeve and rod will
usually be removed in about 6 to 8 weeks.

The foot amputation is typically performed at about age 10-12 months. This
is about the time the child will begin to walk, and many feel that it's important
to get them fitted with a prosthesis as soon as possible. Of course, some
prefer to fit the prosthesis over the foot and make the amputation decision
at a later time - just keep in mind the fitting problems. Also, some feel
the psychological problems will  be less severe if the amputation is
done at an earlier age.

Knee Fusion

The second goal of surgery is to try to correct the hip contracture, and
create a thigh bone of approximately normal length, allowing a good lever
arm to be fitted inside a prosthesis.1 Both of these goals can
be accomplished by a knee arthrodesis (surgical immobilization of a joint).
In other words, the fibia and tibia are fused to the femur to form one long
bone that acts like a normal femur. Extension at the hip joint generated
by the momentum of the long lever arm with the standard above knee prosthesis
allows for gradual stretching of the flexion contracture of the hip
joint.1  It was found that after knee arthrodesis in full
extension, the hip-flexion contracture was spontaneously

When knee joint arthrodesis is to be performed, the time to do this surgery
must be carefully selected so that the growth potentials of of the proximal
tibial and distal femoral epiphyses (growth plates) are not destroyed at
too early a date.4 Miscalculation may produce an above-knee type
of stump which is too short for satisfactory prosthetic fitting.4
Knee surgery is usually performed at the age of 2 or 2 1/2 years, and one
of the epiphysis around the knee is preserved to allow for some additional
growth of the thigh segment.1 One or both of the epiphyses at
the knee can be excised (surgically removed), the goal being a long above-knee
stump at maturity.

Hip Surgery

In properly selected cases, reconstructive surgical procedures about the
hip joint to improve hip stability and thus facilitate maximum usage of hip
musculature are desirable. As previously emphasized, only Class A and
Class B PFFD cases have adequate acetabula and femoral heads. Hence, it is
only in these two groups that reconstructive surgery about the hip would
seem to be indicated.
It is, therefore, essential that the four classes
be clearly differentiated and that hip surgery be carried out only in those
cases where there is a femoral head and an acetabulum.4

The hip surgery is performed between the ages of 5 and 7 years, when significant
portions of the proximal femur show evidence of ossifications  in Aitken
Class A or B cases.At the present time there is no universally accepted
surgical treatment for the unstable hip of class C and D
1 (Our doctor says that current thinking is to leave
the hip alone in almost all cases.)

Van Nes Rotation

The most controversial PFFD treatment is the Van Nes Rotationplasty (also
called Van Nes Rotational Osteotomy or just Van Nes Procedure). The operation
was originally performed by Borggreve in Germany in the 1930's, and it was
Van Nes who applied it to PFFD patients in 1950. The procedure rotates the
foot 180 degrees so that the ankle joint now functions as a knee joint.The
rotated foot becomes the below-knee stump for the below-knee prosthesis.
The surgical procedures are not complicated, but the prosthetic fitting is
difficult, and it requires the the services of a skilled
prosthetist.5 In 1983, Torode and Gillespie outlined their technique
of combined knee fusion and tibia rotation.

The main prerequisites for the Van Nes procedure include a normal foot, presence
of the fibula, a stable hip, unilateral involvement, and an active range
of motion of the ankle of at least 45 degrees.6 A stable hip improves
the gait but is not an absolute prerequisite to the Van Nes
procedure.6 The operation is extremely useful to convert what
would be a functional above-knee amputee to functional near below knee
amputee.1  The Van Nes rotation-plasty is functionally beneficial
to the patient as it gives the child a knee that has active extension and
flexion and significantly improves the biomechanics of gait.1
We still recommend it for children who have an adequate foot and

There appears to be no concensus on the value and success rate for Van Nes
Rotation. The two main concerns appear to be the poor cosmesis and derotation.
Different studies give different results. The best I can do is list the different
results here and let the reader decide for themselves.

Dr. Van Nes, 1950: Patients are very satisfied and grateful for the
aesthetic, functional and social improvements they have gained.6

Dr. Krajbich: The primary drawback to this operation has been said
to be its poor cosmesis and hence poor psychological acceptance by the patient.
This has not been our experience. The operation is well accepted by patients
and their families if one explains the benefits. The second objection to
rotation-plasty is that it has a tendency to derotate and thus the operation
has to be repeated one or two times during the child's growth. This is a
valid observation, and many of our patients did, indeed, require a second
procedure to correct gradual derotation. In the last few years we have
concentrated on accomplishing the rotation completely through the knee joint
at the time of knee fusion and with reattachment of all muscles crossing
the knee joint. Results of patients treated with this approach have so far
been satisfactory with not a single patient requiring further derotation.
Follow up, however, is still short term and final evaluation of these patients
is not available.1

Drs. Westin and Gunderson: In our group of cases, only two of the
eight patients so treated can be classified as successful. Two cases were
complet failures, necessitating return to the original position. The other
four patients failed to gain full rotation. The cosmetic deformity of a foot
pointing the wrong way could be distressing to some patients, especially
girls. This, together with the prolonged treatment time, may outweigh the
functional advantage.3

Drs. Friscia, Moseley, and Oppenheim, 1989: Thirteen patients who
had PFFD and were treated with a Van Nes procedure were evaluated at
an average of five years after operation. Five patients needed a repeat rotation
of the tibia: four because the limb had spontaneously derotated toward the
original position and one because the limb had had insufficient rotation
at the time of operation. The overall results were excellent in six patients,
good in four, fair in one, and poor in one. One patient was excluded because
they converted to a Syme amputation, due to the mother's inability to accept
the cosmetic deformity. The number of operations related to the rotationplasty,
including the initial procedure, ranged from one to five (average, three
operations for each patient). Some authors have advocated amputation of the
toes of the rotated foot to make the deformity more acceptable to the patient
and the family; however, none none of our patients wanted to have the toes
amputated to improve the appearence of the extremity.

Psychological preparation is is essential for both the patient and the parents.
The case of the patient who had had conversion to a Syme amputation for
psychological reasons emphasizes that selection of the patients and preparation
of the family is important. Early operation seems to provide for better emotional

The girls and boys were equally satisfied with the result. The five girls
who had an excellent result had no objection to the cosmetic
appearance. Our study is in agreement with others in that, perhaps
surprisingly, none of the patients who completed the surgical program were
dissatisfied with the cosmetic result, including the girls. Therefore, male
gender need not be a criterion for the procedure.6

Finally, my personal opinions: My wife and I were split on this issue.
I felt that since our daughter had a perfectly good foot and ankle, we should
try to use them to improve her walking ability. I saw the benefits of the
Van Nes procedure, and felt a 'real knee joint' (even if it is a backward
ankle joint) would be better than any artificial knee joint. Plus, I just
hated the thought of amputating a perfectly good foot. (My wife says I just
can't throw anything away.) On the other hand, my wife felt very strongly
that the backward foot would be a severe cosmetic problem. For a boy she
said she could possibly accept it, but for a girl she said no way. I was
not yet prepared for a stump, but I had to agree with her that a backward
foot would be much harder to accept. In the end my wife prevailed and I have
no regrets, but I still think everyone should explore the Van Nes procedure.
If the psychological hurdles can be overcome, the functional improvement
may be very beneficial.

Most Important Treatment Option - A Positive Attitude

No matter which course of treatment you decide to pursue, it's extremely
important to maintain a positive attitude. Remember, if you as a parent can't
deal with the deformity, it will make it much harder for your child to accept
it. Here are some comments from people who can say it much better than I

Dr. Amstutz: We have been impressed by the fact that the development of the
child and his adjustment to life with a deformity are strongly dependent
on the parents' understanding and attitudes.7

Dr. Clark in Things To Remember: The most important
factor influencing the eventual outcome for your child as she or he grows
up is not the kind of prosthesis, not the kind of surgery, if any, not even
how early he or she was seen by an experienced team, or even the extent of
your child's physical differences - It's your attitude toward the situation.
If you can see all your child's abilities, see her as capable, emphasize
all the things he can do - if you can look at them with or without a prosthesis,
in or out of the bathtub - if you can consider then normal children who happen
to have their differences, that is the picture of themselves they will grow
up with. Love them, challenge them, applaud them and they will develop the
self-esteem and self-confidence they need.8 

Emily Perl Kingsley in Welcome To Holland:
But ... if you spend your life mourning the fact that you didn't get to Italy,
you many never be free to enjoy the very special, the very lovely things
... about Holland.


PFFD is a rare birth defect characterized by lack of development of the upper
end of the femur (thigh bone).  The typical appearance is an abnormally
short thigh that is pulled upwards and rotated toward the outside. The foot
of the affected leg is frequently at the level of the opposite knee. The
causes of PFFD are unknown, but it is known that it is not genetic.
PFFD varies in severity from the mild case with a short femur but normal
hip joint - to the more severe case where no hip joint is
present.1 Severity is usually classified using the Aitken system
in which Class A (femur head and hip socket present) is the least severe
and Class D (femur head and hip socket  absent) is the worst. Treatment
options vary based on severity and patient and family psychological factors.
The simplest treatment for the mildest case is to use a shoe lift. Another
option for the mildest cases is limb lengthening. The more severe cases will
probably require a prosthesis (artificial leg). The prosthesis can simply
be fitted over the foot, or the more common treatment is to amputate the
foot and fuse the knee. This forms one long bone that acts like a normal
femur and fits nicely into a prosthesis. The most controversial treatment
is the Van Nes Rotation in which the lower leg and foot are rotated 180 degrees
so that the ankle joint functions as a knee joint. Some doctors have reported
good functional results with the Van Nes procedure, while others report
 poor results and cosmetic problems. No matter which course of treatment
you decide to pursue, it's extremely important to maintain a positive attitude
- especially for your child's sake. The most important factor influencing
the eventual outcome for your child as she or he grows up is your attitude
toward the situation. Love them, challenge them, applaud them and they will
develop the self-esteem and self-confidence they need.8


1.  Krajbich, Ivan: Proximal Femoral Focal Deficiency. In ???, pp.108-125,
year unknown.

2. Abdel-Mota'al, Magdy and Jayakumar, Shanmuga: Proximal Femoral Focal
Deficiency - Clinical Case Presentation. On WWW at

3. Westin, G.W. and Gunderson, F.O.: Proximal Femoral Focal Deficiency -
A Review of Treatment Experience. In Proximal Femoral Focal Deficiency.
A Congenital Anomaly, pp. 100-110. Edited by G. T. Aitken. Washington, D.C.,
National Academy of Sciences, 1969.

4.  Aitken, G.T.: Proximal Femoral Focal Deficiency - Definition,
Classification, and Management. In Proximal Femoral Focal Deficiency.
A Congenital Anomaly, pp. 1-22. Edited by G. T. Aitken. Washington, D.C.,
National Academy of Sciences, 1969.

5. Hall, John E.; and Bochmann, Deitrich: The Surgical and Prosthetic Management
of Proximal Femoral Focal Deficiency. In Proximal Femoral Focal
Deficiency. A Congenital Anomaly, pp. 77-99 . Edited by G. T. Aitken. Washington,
D.C., National Academy of Sciences, 1969.

6.  Friscia, David A.; Moseley, Colin F.; and Oppenheim, William L.:
Rotational Osteotomy for Proximal Femoral Focal Deficiency. Journal of Bone
and Joint Surgery, pp. 1386-1392, 1989

7.  Amstutz, Harlan C.: The Morphology, Natural History, and Treatment
of Proximal Femoral Focal Deficiencies. In Proximal Femoral Focal
Deficiency. A Congenital Anomaly, pp. 50-76. Edited by G. T. Aitken. Washington,
D.C., National Academy of Sciences, 1969.

8.  Clark, Mary Williams: Things To Remember
For Families of Children with Congenital or Early-Acquired Amputations

In IN MOTION the official magazine of the Amputee Coalition of America,
year unknown.

Edit History

03/17/97 Original writing.
03/18/97 Added table of contents.
11/24/98 Revised Lengthening section to add link to Rebeccah's Story.
09/20/02 Changed to XML
05/11/04 Added to Etiology section