Partha Unnava, Andrew Varghese, Frankie Swindell
In the U.S. alone, approximately 18 million people use crutches each year. The human body was not designed to bear its weight on the forearms and wrists, but all designs of the crutch force patients to do just this. In just a few steps with the underarm crutch, forearm fatigue sets in, resulting in patients resting upon the underarm padding. The upward force from the padding leads to pain, chafing, blood vessel compression, nerve compression, and possible nerve damage. Forearm crutches, while avoiding the underarm area, are difficult to use and direct a large amount of torque to the shoulder, resulting in shoulder injuries, frequent imbalance, and falls. Not including the costs of treatments for the side effects of crutch use, patients spend over $800 million each year on these 5000 year old, inefficient devices.
The Better Walk crutch puts a patient’s mind at ease. The redesigned support system reduces the risk of underarm nerve damage, reduces forearm fatigue, and improves patient comfort resulting in increased compliance and a safer, more comfortable rehabilitation process.
After personal experience on crutches, as well as interviews with over 100 orthopedic surgeons, physical therapists, and crutch users, there was a clear demand for crutches that did not cause underarm pain. Orthopedic surgeons and physical therapists explained that if underarm crutches are used properly, there is no force in the underarm, but in the resting position, everyone is forced to apply force to the sensitive underarm area. Compression of these nerves is known as crutch palsy.
In addition, because of the lack of upper body strength of most temporary crutch users, there is a high incidence of misuse. The forearm crutch, an alternative, is not ideal for short term users because of the lack of an anchoring point against the body. This causes shaking in the arms during the motion.
Design a crutch that makes contact with the side of the user’s body to provide stability, but does not apply any force to the underarm during the resting position or the typical motion.
Design and Development
Tubing – The crutch tubing is made of aluminum 6061, and is telescoping. There is adjustment at the top near the side piece, as well as at the bottom near the foot. These two adjustments use a push button mechanism in order to adjust for different heights and different arm lengths. The heights and arm lengths used account for a 50 percentile female height to 99 percentile male height. This ranges from 5’2″ to 6’6″.
Forearm Support – The forearm support is made of injection molded ABS plastic, and serves to support the forearm and allow more weight to be offloaded from the underarm without being applied directly to the wrist.
Side Contact Piece – The side contact piece is made of injection molded ABS plastic, and alters the resting position of the crutch. Because of this piece, the user are provided stability through their motion, but when they choose to rest, the piece applies horizontal force into the body.
Below is a theory drawing of the crutch through the swing, and the use of the forearm piece to allow the user to propel themselves forward using a greater surface area of contact. This drawing uses an early alpha prototype.
Iterations of the Better Walk crutch were done through repeated testing sessions with orthopedic surgeons, physical therapists, and their patients at 5 different hospitals and orthopedic surgery centers.
This transitioned the product from a PVC model to the final version
All weight bearing testing was done in CAD, and as manufacturing prototypes are completed, we will be conducting tests according to the ISO protocol for forearm crutches.
In order to show user demand, we created a preorder link on our website (www.bwcrutches.com) . The preorder link has resulted in customer requests to purchase the product.
We have also exhibited at AAOS 2014 which resulted in 6 letters of intent, and AAOS 2015, which resulted in a large number of hospitals interested in ordering, and the beginning of our sales process with these hospitals
The Better Walk Crutch can be reimbursed using HCPCS code E0110 as a forearm crutch. We can provide the average American hospital a cost-neutral switch to our product.
Discussion & Conclusion
Through our customer validation, we believe we have shown that there is a need for a crutch that does not apply force to a user’s underarms, and we have also shown that our crutch is a crutch that our customers would purchase.
There are still many steps to building a business around this concept.
Initially, we need a solid manufacturing core and we need to test these units in the field to make sure they perform properly. After the design is validated at a larger scale than prototypes, we then need to begin the process of building a sales team and scaling manufacturing.
We also need to confirm our manufacturing costs and create a set of financial projections that can help us to build a business model around the sales of this product.
The primary missing feature of this product is the lack of friction on the side contact piece. The piece can be slippery if a user is wearing a slick garment. However, by adding friction across this entire pad, we run the risk of inducing chafing for users, and wrinkling their clothes. The difficulty with this portion of the design is to balance friction while minimizing chafing for users to improve experience.
We’ve received a lot of positive feedback and initial orders, and at this point, our challenge will be to build a business around this product.
We’d like to thank Emory University Hospital, the Campbell Clinic, and Resurgens Orthopaedics for their support and feedback during the development of the Better Walk crutch.
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