Publié sur : Communication présentée à l'EFORT - Nice - 2008
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Long term results of expanding prostheses for limb salvage surgery in children with bone tumors
Gérard Delépine, Nicole Delépine

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Long term results of expanding prostheses for limb salvage surgery in children with bone tumors

Histology and Locations of tumors

27 early prosthesis implantation

In 18 patients, the expanding prosthesis was inserted immediately after the resection, in 9 during the following year.

23 secondary implantations to treat leg length discrepancy

Active expanding prosthesis

Consists of a tibial and femoral component joined by a metal on polyethylene hinge.
The lengthening mechanism is contained in the part of the prosthesis which replaces the tumor.

The tibial passive part for femoral tumor

6 years after implantation the tibial growth is similar to the controlateral side.

The femoral passive part for tibial tumors

8 years after implantation the femoral growth is similar to the controlateral side.

Morse taper unlimited lengthening

with 1 then 2 extra rods.

The open sky prosthetic mechanism Zimmer Delepine (ZD1)

It was insufficiently stable to maintain position and had to be reinforced by using a wedge of acrylic cement.

The arthroscopic prosthesis

A better anticollapse device elongation is produced arthroscopically using small puncture incisions.

Magnetic prosthesis Soubiran - Delepine (SD3)

The generation 3 prosthesis depends on a compressed spring which can be adjusted by using magnetic stimulation applied externally.
As there is no need for any incision lengthening, it can be achieved in stages, each of a few millimeters.

Elongation of a magnetic prosthesis for distal femur (SD3)

Aspect of elongation of a magnetic prosthesis for proximal tibia (SD3)

Orthopaedic complications

Deep infection

Trophic sequellaes

If we obtain a usually a good lenght, the lenghtening can lead to trophic sequellaes.

Late functional result (according to EMSOS criteria)

- Excellent : 10
- Good : 15
- Fair : 10 (total femoral reconstruction and stiff knees)
- Poor : 5 (among them 4 secondary amputations)

Bifocal Resection

Upper Tibial Ewing's Sarcoma with 3 skip metastases on NMR. Bifocal Resection.

1989 Osteosarcoma in a 4 years old boy

4 years old girl

Osteosarcoma in a 7 years old girl

Osteosarcoma of the proximal tibia in a 10 years old girl (13 Years follow up)

Bipolar Resection

Distal femur expandable prosthesis.

After large lengthening bone stock may become insufficiant

Patient treated for osteosarcoma of proximal tibia when she was 9 years old.
10 years later and after 6 operations the proximal part of femur became too small.

In these cases we advocate to reconstruct the bone defect with an allograft

CONCLUSION :

The expandable prosthesis provides an effective alternative to amputation for about 80% young children.
But the number of operations is high for large lengthening with a high rate of infection,
frequent stiffness of the knee, and at the adult age, poor trophicity of the limb and bone stock frequently insuffisant.


When a prosthesis of the kne is planned in a young child.
Avoiding sterilization of the growing plate of the unaffected side of the articulation is mandatory.

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