The Furlong® Hydroxy-apatite Ceramic (Supravit®) Coated Femoral Stem

The Furlong H-A.C. Supravit® Coated Femoral Stem is based on the biomechanical teaching of Pauwels and has three distinct sections providing separate functions to satisfy the stressing requirements at different locations in the femur. The distal portion prevents toggle and because it is cylindrical will not allow axial distal loading.

The distal femur is reamed 2mm larger than the size of the stem so that trabeculae bridge the gap and provide an elastic cradle. The central section is in the form of a cone to provide good transfer of body weight under hoop stressing. A cone is the most effective method of conveying compressive stress from one component to another. The proximal section is rectangular and tapered to resist torsion and to allow proximal body weight transfer, thus avoiding stress bypass. The femoral stem is fully coated with a vacuum plasma sprayed hydroxy-apatite coating of high density, purity and crystallinity, named Supravit®. This ensures no metal to bone contact and allows the transfer of all forces over the maximum surface area possible.

Furlong® Revision Plus System

JRI has introduced the Furlong® Revision Plus range of implants to add greater versatility to the current revision range. They specifically address the problems of the 'arum lily' type of femoral canal, which has a disproportionately larger metaphysis compared to the diaphysis.

The Furlong® Revision Plus range has an increased body section for the corresponding stem size in order to occupy the space of this larger metaphysis.

Supravit® Zoned Coating

Push out tests have shown an increased shear strength at the hydroxy-apatite to bone interface as a function of surface roughness. The greater surface area and interdigitation of the increased surface roughness provides an improved proximal bonding - a great advantage in revision surgery. With the Furlong® Revision Plus System the cone area of the implant needs to be in close contact with the mouth of the diaphysis, and the distal stem should not take axial bodyweight forces, the smoother Supravit® coating is required. The overall surface finish is therefore a Supravit® Zoned coating.

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