Hands-Free Crutch

Sommer Amundsen

Summary:

The Hands-Free Crutch provides an answer to the mobility dilemma numerous people face in the aftermath of a lower leg injury. Many people are unable to support their body weight on a traditional crutch for any length of time and resting their weight on their underarm areas can cause not only pain and bruising, but also damage to important nerves (uimc.discoveryhospital.com and Scanlon). The goal of this design is to create an innovative technique for supporting and allowing motion for patients with a broad range of leg injuries by providing another means of support, other than arm strength, on a crutch. Other major considerations in the design included the user needed to be able to walk down stairs and ramps as well as across level ground while keeping weight off of at least injuries of the knee and lower leg and hopefully injuries at the thigh and hip as well. The crutch should be detachable from the user to for ease of sitting at tables or in cars, etc. The crutch should not damage any nerves in the body and it should be comfortable to use.

Several concepts to reach this goal were considered. The first concepts depended upon a rock-climbing harness with a pole attached to the harness via carabineers at the side of the hip and in the center of the harness. The pole curved under the knee of the user, and was held tight to the leg of the user with Velcro straps. Other designs considered were variations on this concept by using a straight pole or a different type of harness. Some designs also featured a handle near the hip or an extra rubber platform at the ground to act as a foot for added stability. Another design had symmetrical poles coming down either side of the body with an attaching pole going around the front of the person, which, when lifted up, moved the side poles to facilitate walking. The main problem with these designs, however, was that a climbing harness does not support the wearer in a standing position, but requires a seated position. As it is difficult to walk in a seated posture, the final design took an unexpected route.

The final concept is completely different than all the others because it uses a knee platform as the mode of weight support. The inspiration for the final design came from two sources. The first source was another crutch that simply supports the knee. This crutch comes at a high cost of $600 (www.fetterman-crutches.com). The second inspiration came from the Free Wheelchair Mission (www.freewheelchairmission.org) which supplies wheelchairs to disabled persons in third world countries. Each wheelchair costs only $44.40 to produce and distribute. This senior design project produced a functional crutch that is comfortable, safe, and at $36.45 for the first prototype, it is affordable for even short-term crutch users.

In the final design, the main pole attaches to the front of the thigh with Velcro on nylon straps. At the knee region, it curves under the knee to provide a more accurate center of weight. It meets the ground with a standard crutch tip. All the poles are made of steel conduit because conduit is bendable, but strong. At the knee region, two pieces attach on either side of the main pole and provide a horizontal support for the knee sling. Two other pieces of conduit attached lower on the main pole support the two horizontal pieces. Together, the four attachments to the main pole form two parallel triangles in the transverse plane of the body. Nylon and Velcro straps attached to the horizontal pieces support and anchor the knee and lower leg.

While this design did not meet the goal of the project to provide novel support for knee and hip injuries, it does provide a handy, affordable option to crutch users with short or long term injuries of the lower leg, ankle, and foot. While using the Hands-Free Crutch takes some practice, it provides mobility for patients by allowing them to walk as normally as possible.