Proposal (Not Edited)

ENGR 103 - Spring 2013 Freshman Engineering Design Lab

“ACL Prevention” Project Design Proposal 

Date Submitted: April 09, 2013

Submitted to: Group Members:

Dr. Sorin Siegler, ssiegler@coe.drexel.edu 
Danielle Fernandez, ddf33@drexel.edu
 Amanda Tilles, alt75@drexel.edu
Padma Shenoy, pas98@drexel.edu
Steve Enriquez, see36@drexel.edu

Abstract:

The Anterior Cruciate Ligament (ACL) is a ligament in the human knee with prevents the sliding of the joint forward or backward. When it tears, due to excessive stress in the wrong directions, stability is lost in the knee and reconstructive surgery is required to restore it. The goal of this project is to construct a knee brace that will assist an athlete who would like to prevent further damage or damage in general to their ACL. In the end, a prototype knee brace will be created that can provide greater support for the ACL and greater flexibility to the joint than the original knee brace. Challenges encountered will include the need to constantly identify improvements required for each prototype, and the redesign process. The deliverables include the final design for the new, improved knee brace, all of the prototypes, physical and virtual, tested throughout the design process, and the test results for each. The final knee brace should allow the athlete maximum support and flexibility.

ENGR-103 Freshman Design Proposal Section 093, Group 04

1 Introduction
The common injury of an ACL tear is one that affects countless athletes in almost every sport. Unfortunately while common, this injury can ruin an athlete's career. Recovering fully from an ACL tear could take 8 months to a year to recover, meaning an athlete could be "benched" or "red-shirted" for this time. And while a year may not seem like much time, to an athlete, especially one injured and watching from the sidelines, one year is an eternity.
This mission of this project is to design and manufacture a prototype for a new ACL brace that would help athletes prevent a career ending or limiting injury to the ACL: a brace that they could wear that would be equally supportive and mobile.
The anterior cruciate ligament, or the ACL is one of the four major knee ligaments. This ligament connects the tibia and femur, and prevents the tibia, or the shin bone from sliding forward and rotating the femur, or thigh bone. It is a very crucial ligament for the stability of the knee joint. A sudden change in direction is the most common cause of a torn ACL. Immediately after the ACL is torn, the knee will swell, and the athlete will feel a sharp pain in their knee. Most likely when the injury occurs, the athlete will hear a sudden "pop" as the ACL tears. To recover functionality of the ligament, reconstructive surgery is required to sew the ligament back together. After recovery, the athlete may be able to return to his or her sport. Our brace will help to prevent such an injury from occurring or becoming worse. It will be flexible, allowing the athlete to move naturally, but it will also provide support and stability, so as not to damage the ligament.


2 Deliverables
At the conclusion of this project, the final deliverable will be a newly designed knee brace that will optimize support and flexibility. This brace will be a finished product that can actually be worn by an athlete who is recovering from ACL reconstruction surgery. In addition previous prototypes of the design will be provided, with the weaknesses and shortcomings identified on each. Some of the prototypes will be built physically, while others, which are in intermediate steps will be shown as computer models. Finally, a comprehensive report will be included, which documents the progress of the project through each week along with results from the tests performed on each prototype.

3 Technical Activities
3.1 Testing of Current Knee Brace
A generic ACL recovery knee brace will be tested in terms of support and flexibility, the two criteria that are the focus of this project. It will be tested for support by placing it on an apparatus and measuring the load it can take before it breaks, and it will be tested for flexibility by measuring the maximum angle of flexion. The brace will be analyzed so that the points that need to be improved can be identified.

3.2 New Knee Brace Design
This portion of the process will take the longest as it involves a lot of trial and error testing. The design errors identified in the general knee brace will be taken into account to produce new designs that address these shortcomings. These will then be printed and incorporated into a newly built brace. Each brace will be tested again, and improvements will be made to modify the any other problems that are identified.

3.3 New Design Testing
The new designs will be tested the same way that the original brace is tested: weighted to the point of breaking, to test the ability to support, and the angle measured, to test the flexibility. All braces will also be tested using a simulated ACL, using ballistics gel. This will show how the ACL is stressed with each brace, so that minimum strain will be placed on the ligament. The goal of using the ballistics gel is to be certain that although the knee brace is strong and flexible, it is still not further damaging the ACL.

Table 1: Project timeline for knee brace design process.

For the next 10 weeks the group will be constructing a model of an ACL recovery knee brace that will help with one’s disability, that is caused by injury. For the beginning of the term the most important focus for the group is to come up with a plan of how to develop a model of the actual recovery brace. With the use of AutoCAD and Creo Parametrics it will be possible to create a 3D model which will allow for further modifications and give the group a foundation for the making of the product. Weeks 4 to 6 will be crucial, this is the time the group will be gathering the necessary materials needed to construct the final model. These materials include ballistic gel, PVC pipes, electronic servos (possibly), and a cheap functioning knee brace. Towards the end of the term, the group should start testing the final product and make sure no further modifications will be made. A final report will be written to describe the purpose of the invention and this will conclude the project.


5 Facilities and Resources
Resources that will be used during the course of this project are computer-aided drafting systems such as AutoCAD and Creo, to design each prototype and print out the required pieces from the 3-D printer. In the freshman engineering lab, the 3-D printer will be used to print required parts of the new knee brace so that it can be tested again, in the engineering labs. The machine shop will need to be used to create and assemble some parts of the brace.
To test the brace, a simulation leg will be used to test the flexibility, and it will be measured with poster board, on which the angle will be drawn out. Also, to test the support, the brace will be placed on an apparatus that mimics a human leg, which is another resource that is needed, and will be weighted with textbooks or weights, to the point of failure.

6 Expertise
Some specialized skills that are needed in order to complete the project include knowledge of knees and the ligaments that compose them, knowledge of current knee braces that are available, the timeline of the recovery, and the use of CREO. Knowledge of knees is imperative because the group needs to make sure that the knee is still being protected by the brace while allowing for the greatest range of motion and comfort. Since the group will be modifying a current ACL recovery knee brace, knowledge about the specific knee brace is important in order to know what parts of the brace should be modified and which parts cannot be changed. The timeline of the recovery is also important to the project because the group needs to understand how strong the repaired ACL is at a given point in time and how long after the surgery it is appropriate to go back to sports with the brace accompaniment. The group will use CREO in order to print out parts in order to construct the mechanical knee and make modifications to the knee brace.

7.1 Knee Brace
A knee brace is needed in order to make modifications in order to improve the current model of the ACL recovery knee brace.
7.2 Ballistics Gel
The ballistic gel simulates the behavior of human tissue and ligaments so it will be used in order to monitor the range of motion of a mechanical leg in order to make sure that no more injuries to the ACL would occur.
7.3 Hinge Hardware
These are the pieces necessary for the construction of the knee in order for it to move like a human knee. These pieces include metal hinges, nuts, bolts, and screws.
7.4 PVC Pipe
The PVC pipe will be used in order to construct the mechanical knee in order to test the effectiveness of the brace in order to make sure that the ACL is efficiently protected while allowing for the most range of motion and comfort.
7.5 Mold
The mold will be used in order to get the correct shape of the ballistic gel for the ACL ligament in the mechanical leg.
7.6 Poster Board
The poster board will be used in order to measure the range of motion that the knee is allowed with and without the knee brace and also between the current knee brace and the modified version.

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