Long Transfemoral Amputation + Flexion Contracture + Shuttle Lock = Fabrication Nightmare

RapidFit Adapter lets you bolt on a shuttle lock anteriorly while placing the knee posteriorly, even in the presence of hip flexion contractures up to 10 degrees
RapidFit Adapter lets you bolt on a shuttle lock anteriorly while placing the knee posteriorly, even in the presence of hip flexion contractures up to 10 degrees

I made some presentations recently at POINT Health Centers of America "Links to Learning" meeting in Cincinnati, Ohio and spotted a new piece of hardware that was developed by an Ohio practitioner to facilitate the use of shuttle lock suspension for long transfemoral sockets, even in the presence of significant hip flexion contractures. The RapidFit Adapter is available in three configurations that are preset to accommodate 5, 10, and 15 degrees of socket preflexion.

One of the more difficult considerations when using a shuttle lock system for transfemoral suspension is that the long axis of the residual limb and the biomechanically optimal position of the prosthetic knee center are never congruent. For this reason, the shuttle lock/pyramid adapters that work so well for transfemoral cases are often unsuitable for this level.

The more socket flexion the patient requires, or the more stable the knee position must be, the greater the magnitude of this discrepancy. The feeble, elderly gentleman with a moderate pre-existing hip flexion contracture who now has a long transfemoral amputation is the worst-case scenario.

RapidFit kit includes a stiff foam spacer and a machined alloy part that can be thermoformed into the test socket
RapidFit kit includes a stiff foam spacer and a machined alloy part that can be thermoformed into the test socket

Shorter residual limbs often allow enough room to place the knee adapter separately from the shuttle lock, but this can be a real struggle for the long transfemoral case. The RapidFit Adapter offers a novel solution to this fabrication nightmare.

The sample prosthesis on display at the PEL booth included a clear thermoplastic test socket that was drape molded to incorporate the RapidFit Adapter. A small piece of pre-shaped semi-rigid foam fills the void between the socket and the Adapter, simplifying fabrication and keeping the weight to a minimum.

The final result is about as compact as it possible with a shuttle lock and a long residual limb. According to the instructions in the kit, you can also laminate it into a definitive prosthesis and cover it with a one or two-piece protective foam cosmesis.

RapidFit Adapter aligns the shuttle lock with the long axis of the socket yet places the knee center well posterior to TKA. Knee stability can be decreased by adding socket flexion to move the trochanter posteriorly.
RapidFit Adapter aligns the shuttle lock with the long axis of the socket yet places the knee center well posterior to TKA. Knee stability can be decreased by adding socket flexion to move the trochanter posteriorly.

For more information, go to www.swansonopcenter.com/rapidfit.htm or to the PEL web site at www.pelsupply.com



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