PFFD What?
stands for proximal Femoral Focal Deficiency. It is a congenital malformation, which is not well developed in the upper part of the femur.
What are the causes?
There is a genetic disease. The causes are not detected. Some suppose that could be caused by anoxia (lack of oxygen), ischemia (temporary shortage of blood supply), from chemical products, hypothermia, radiation, bacterial toxins, viral infections, by enzymes and hormonal changes. In fact the only known cause is the drug thalidomide.
How often appears in the population?
is a rare disease. There are several studies about it. The frequency varies from 1 to 4 cases per 200,000 births, and is thus well above the request 1:10.000 cases, you need to be classified as a rare disease.
comparison with Down syndrome, which has a frequency of 1:800, or with cleft lip, appearing approx. 1 in 1000 times, you wonder why most people are not familiar with this disease.
The clinical picture (ie: What can be seen from the outside?)
The leg is more short in the femoral segment, turned slightly outwards, and with a contracture at the hip and knee. Furthermore, in most cases, the knee appears to be unstable because of the lack of cruciate ligaments.
classifications (ie: What forms are there?)
There are various classifications. The most used is that of Aitken, which includes cases being taken as the criterion the formation of the joint good or bad hip joint (ie, hip):
Type A: the acetabulum is well-formed, the femoral head is present at the femoral neck may have a nonunion (ie, a part of the femoral neck and cartilage), but tende a solidificarsi nell'arco degli anni, causando peró una deformazione a livello del trocantere. Questi sono i migliori candidati per un allungamento femorale.
Tipo B: l'acetabolo risulta essere piú piatto, la testa del femore é molto piccola e non completamente ossificata, la congiunzione tra femore e testa del femore non é presente o comunque resta cartilaginea. In questi casi gli allungamenti sono molto piú difficili da eseguire e devono comunque essere preceduti da un intervento di stabilizzazione dell'anca.
Tipo C: manca la testa del femore e l'acetabolo risulta essere molto piatto, il femore é molto piú corto che nel caso B, visto che tutta la parte prossimale dell'osso, compreso il trocantere are absent.
D: is the most serious. The bone is very short, and often occurs only as small irregular segment of the distal femur (ie, this is only the lower part of the femur near the knee). The acetabulum is non-existent and the lateral pelvic area is completely flat.
What are the possible treatments?
Which allows choosing treatment depends on the severity of the case. It is basically divided into: *
upward manual, which can be made with a base in or under the shoe, or a orthoprotesi (ie with a brace, which is applied under a fake foot)
*
bone lengthening, which is implemented through a speech, in which a fixator is applied to the femur. For cases of type A and B this intervention must often be preceded by an exposé of the coxo femoral reconstruction.
epiphysiodesis *, that is blocking the growth of the contralateral femur
proteizzazione *, associated with various interventions, such as epiphysiodesis, amputation, rotation of Van Ness, the fusion of the knee in order to ensure greater efficiency the prosthesis and to improve their appearance.
* a mix of the above treatments
What is the best treatment? ... Disputes doctors
The hardest thing for a parent is to understand which path to choose and there are many controversies, especially with regard to extensions, amputation, and the rotation of Van Ness.
Stretches: in some centers tend to discourage the stretch, especially if the projected path is too long and risky due to a too high or asymmetry of hips not very stable. Currently borderline cases are provided with a dysmetria of 20-25 cm, and PFFD type B. Dr. Paley in Baltimore extended the limit cases to those with a final limb-length of 30 cm.
Amputation: In some European and American centers is recommended amputation of the the front foot, so as to make the prosthesis more aesthetically beautiful. This technique is now considered obsolete in other places (see, for example commitment Sinai Hospital of Baltimore).
rotation of Van Ness: involving a 180 ° rotation of the femur, so as to ensure greater effectiveness of the prosthesis. However, being a very invasive surgery and psychologically heavy to bear, is disputed by doctors.
internal fixation and external ... you can use both?
techniques for stretching the bones are all based on the technique of distraction of bone segments: the bone is cut into two parts, and these are gradually being removed with each other, allowing the bone to regenerate and to form callus in the fracture caused. There are various types of external fixators. The most famous are: *
Fixer Illizarov circular or monolateral fixator
* *
the Taylor-frame
* * The Fixer Paley
unilateral external fixator associated with intramedullary nails
Also here is not easy to determine which technique is the best, depends on the case, and is the subject of controversy among physicians. Each of these has advantages and disadvantages, which must be thoroughly evaluated by a doctor. The major centers of European and American working with the Ilizarov method, or the Taylor-frame, more rarely with the unilateral fixator. Dr. Paley is developing a new fixative, which would reduce the risks associated with elongation. The internal fixation or
intramodullari: not currently used for PFFD and especially not the children are never on. In fact, the section of a femur affected by PFFD is never circular, but flattened, and therefore leaves no room for an intramedullary nail. Also never used on children, because the insertion causes the damage to areas of growth, blocking it completely.
What are the risks of stretching?
The extensions are always related to many risks. TOP the stiffening of the knee are frequent, infections, poor production of callus and the fracture after treatment.
In general, the elongation of the bones is more difficult on congenital malformations of the bones that were born "healthy" just because a child sleeps by the cells to reproduce. Also it is much harder than on the tibia on the femur because of increased resistance of the muscles of the thigh, which oppose the stretch. If the tibia growth for each intervention may vary from 8 to 10 cm, on the femur hardly exceeds 5 to 6 cm.
