We were recently given the opportunity to have a closer look at a Thomas Fetterman Inc. underarm crutch. Our customer’s Fetterman crutch had failed and he was in desperate need of a new one.
Here shown side by side are a Safewalk™ underarm crutch (left ) and our customer’s Thomas Fetterman Inc. underarm crutch (right).
Thomas Fetterman versus Safewalk™ Underarm Crutches – Underarm Pad Comparison
Starting from the top, the underarm pads on the crutches are quite different. The Safewalk™ crutch (left) has a underarm pad made of solid, hand-shaped, high density, marine grade plastic that is carefully designed to significantly reduce chafe while holding the crutch securely in position while walking. The Thomas Fetterman crutch uses a bent tube of titanium welded to the top. While this is very strong, it is much too thick at the crucial middle of the armpit location and the addition of an underarm pad will likely exacerbate chafing. One of the key problems with long term use of underarm crutches is chafing.
Thomas Fetterman versus Safewalk™ Underarm Crutches – Handhold comparison
The handhold of the Thomas Fetterman crutch is made from titanium welded to the vertical tubes. While this is strong it is much more difficult to attach cushioning to the hand grip. As you can see with the Fetterman crutch (right), the owner was forced to wrap padding around the hand grip and tape it. Quite an ugly solution. The Safewalk™ crutch’s handhold can be removed, the padding can be added, and then re-installed. The Safewalk™ hand hold is made from high density, solid, marine grade plastic and is secured by two stainless steel, heavy duty,course thread screws. We have never seen these fail, but if they ever do, they can be easily replaced. As you can see, the screws are countersunk into the titanium tubing so they won’t scratch or catch on fabrics etc.
Thomas Fetterman versus Safewalk™ Underarm Crutches – Tubing and Construction Comparison
We take a close look at the tubing and where the Thomas Fetterman crutch failed. The Thomas Fetterman crutches(right) are made from three lengths of titanium tubing welded together. The Safewalk™ crutches are made from two lengths of titanium tubing with no need for welding. While titanium welds are quite strong, there is no chance of weld failure with the Safewalk™ crutch because a) there is no weld, and b) the titanium is continuous from the arm pad to the tips. A close look at the titanium tubing opposite the “failure” (marked in red) also shows a clue as to why the crutch failed in the first place. The tubes seem to be bent in some kind of hydraulic tool that maintains the shape of the tubes during the bending process. This results in the thinning of the tube wall on the outside of the bend. Safewalk™ tubing is bent in such a way that there is a balance between wall thinning and a slight compression of the tubing, which in our experience, results in much less bend induced strength loss. We have never seen a tube failure of this type. Please note that the owner of this Fetterman crutch is not a large and we live trial test all our crutch designs with a very active 360 pound ex football player.
Thomas Fetterman versus Safewalk™ Underarm Crutches – Tips Comparison
And finally we are down to the tips. Of course the Safewalk™ underarm crutches are double tipped which results in better stability when you need it most, when the crutch is at an angle. They also give the crutch tips a larger effective surface area which helps the crutch to sink less into soft surfaces such as mud, sand and snow. Here, our Safewalk™ crutch is shown with Fetterman’s Tornado tips but while they are excellent tips, they are not nearly as necessary because less expensive tips are quite effective when used on a the double tipped Safewalk™ crutches.