Printed Plié

An ASME IAM3D Creation

for dancers everywhere

Fadel Almashame

Lindsey Grissom

Mark Terry

Description of Problem

Dance studios can be found in every city, from rural towns to large urban centers. Dancers may enroll at a studio at age three and begin competitive dance at age seven, practicing every day of the week. As a dancer ages, the intensity of the movements performed increases, from the simple arm movements and toe points learned as a young child to turns-in-second and calypsos, movements that involve increasing rotational movement and strain on the joints, as well as a higher degree of technical ability.  

One of the characteristics of a talented dancer is flexibility. Medically, a dancer can achieve a higher level of flexibility through a condition called hyperlaxity or hypermobility. Studies show that 11% of professional dancers may have hypermobility (McCormack, et al). This condition means that the connective tissue is loose, allowing joints to hyperextend and allow for greater range of motion. However, this means that tendons and ligaments that hold joints together are also looser, allowing joints to dislocate with more frequency than in dancers without hyperlaxity. After a joint has dislocated once, it is increasingly easier to dislocate the same joint, so it is imperative that dancers prevent dislocations from occurring. Due to the rotational movements involved in dance, lateral and medial knee dislocations are the most common dislocations seen in dancers with hyperlaxity.

Traditionally, these dislocations are prevented by knee braces constructed out of neoprene, sometimes with metal hinges to support the joint, and Velcro closures. Other knee braces can be made without Velcro, relying on the elasticity of the material to keep the brace in place. The most important part of the brace for preventing dislocations is referred to as a J-brace; this is a small, flexible insert that rests alongside the knee cap to prevent it from slipping out of joint, or dislocating.

These traditional knee braces can be effective at preventing dislocations, but they offer many problems for dancers. Knee braces that have metal hinges prevent knees that naturally

Fig. 1: Dislocated Knee (orthopaedics.com)           hyperextend from locking in place, which is important for dancers. Traditional knee braces are also bulky, and the thick materials can interfere with rotational motion. In some dance movements, this can cause the dancer to “fall out,” or be unable to complete a rotation. Many dancers choose not to wear any knee brace during competition, and frequently choose not to wear a knee brace during practices as well (“Dancer Survey”). This lack of adequate bracing can result in thousands ofinjuries per year, surgical procedures, and ultimately limit people’s ability to participate in dance.

Fig. 2: Traditional Knee Brace (physioroom.com)

Solution Enabled by Additive Manufacturing

“Printed Plié” is a customized knee brace fabricated from novel elastic material uniquely designed for an individual dancer’s needs and enabled and created through additive manufacturing. The name “printed plié” combines these seemingly diverse areas of additive manufacturing and dance. Dance is an important social and cultural activity, but one that can be significantly impacted by additive manufacturing.

Fig. 3: One Custom Design

This design eliminates the extraneous supports that might hinder movement. 3D printing also allows for another improvement in the knee brace—by using NinjaFlex, the knee brace can be highly elastic, depending on the infill used, but unlike fabric, will never lose elasticity. The choice of material also allows the dancer to choose from a variety of colors; the brace can match skin tone or costume, depending on the circumstance. The ability to vary infill with 3D printing allows a wide range of elasticity to be designed into the brace and joint.

Time to Produce

Currently, a dancer can obtain a knee brace several ways. Simple, mass-produced knee braces can be purchased at pharmacies and some big-box retailers. More specialized or technical knee braces can be ordered through an orthopedist. We envision our 3D printed knee brace as a dual-step process. First, the orthopedist will scan the dancer’s leg, a process that takes approximately three minutes. The file will be emailed to a central printing location, along with the selected design and any changes to the design that need to be made. When the doctor is satisfied with the design, the printing facility can change the measurements on the modified design and begin printing. The dancer has the option to choose the color of the brace from a variety of choices. Our current design, on low-cost 3D printers, takes approximately twenty hours to print. On multiple printers, the longest single print time is approximately nine hours.

Once printed, the customized, 3D printed knee brace can be mailed to the dancer. By centralizing the location of the printing, we reduce printing time by making it more economical to have a bank of printers and color choices. Once the dancer’s measurements and knee brace design are saved, the dancer can continue to order cheap, customized braces in whatever colors are needed for different competitions. The brace can be manufactured quickly and mailed overnight.

Cost Impact

Currently, dancers might go through several different knee braces in an effort to find one that fits satisfactorily and prevents dislocations. Though insurance might cover these costs, at a certain point, the dancer will pay for the braces out of pocket. Some dancers will pay thousands of dollars for knee braces before the dancer turns 18 (“Dancer Survey”).  A quick, customized, 3D printed brace that meets all of the dancer’s needs and does not interfere with dancing could save the dancer significant costs.

Our surveys show that most dancers will sometimes wear a knee brace when practicing, but will almost never wear a knee brace during competition, a time when dancers are most likely to have practiced intensely in the time leading up to the competition and are likely to be dancing with great force, in order to complete turns and leaps cleanly. This means that dancers are most vulnerable to injury before and during a competition, when they are least likely to be wearing a knee brace. By creating a knee brace that is more comfortable and less likely to interfere with the dancer’s movements, we not only increase the likelihood of the dancer wearing the knee brace during competition, but we have also decreased the likelihood of injury. Multiple dislocations can lead to a need for surgery, which has a significant cost impact on the dancer and their family, requiring time off from work and school.

Sustainability

Traditional knee braces that are mass produced, although they may be specialized, fail to meet the exacting specifications needed to be functional for a dancer. This can lead to a dancer owning multiple knee braces that are never worn. By designing a custom knee brace that meets the criteria a dancer has for a knee brace, a 3D printed brace means that a dancer will not have to keep purchasing multiple braces in order to find one that fits, does not interfere with dance, protects his or her knee, and is comfortable. Further, the material used to in a 3D printed knee brace will not degrade or break down as quickly as elastic or other fabrics will. The 3D printed brace will not only be more functional, it will also last longer.

Our proposal for scanning the dancer’s knee at the orthopedist’s office, then printing at a centralized location, will allow us to have a physical location. This is one of the main requirements for becoming regulated Durable Medical Equipment and being covered by insurance. By meeting these requirements, our brace will be more affordable to a wider population of dancers.

Reduced Materials

A traditional knee brace is cut from fabric and usually designed to be worn on either knee, regardless of the type of dislocation it is preventing. Mass-produced knee braces are also designed to cover a wide range of potential injuries and fit a subset of sizes.

A customized knee brace would use only the materials needed to prevent one specific injury, reducing the material needed. Because the brace is custom fitted to the dancer’s knee,  no excess material is needed to accommodate a range of sizes. Scanners can be used to take precise measurements of the dancer’s leg and knee, further reducing material waste. This reduces the amount of material needed and, therefore, the amount of waste produced in the manufacturing process.

Traditional, mass-produced knee braces made out of fabric also have wasted material, usually around the cut-outs that must be made to accommodate the knee cap. Our design uses only the material needed.  

Energy Consumption or Renewable Energy Generation

Our design’s main reduction in energy consumption will come from a reduction in materials and manufacturing time. By solving the problem of a well-fitting knee brace, we also save energy used to manufacture knee braces that will never be worn.

Fig. 4: 3d Scan of Dancer’s Leg

Promoting Green Design

The technology exists to not only create a custom-fitted, but also custom-designed knee brace that can be effective at preventing lateral and medial dislocations of the knee in dancers. The ability to choose colors without increasing manufacturing time, further increasing the likelihood that the dancer will actually wear the brace and prevent the injury from occurring, only strengthens the argument for 3D printing as opposed to traditional manufacturing methods for this particular product. Even early in a dance career, 60% of dancers surveyed had already purchased 3 or more different knee braces, and found each to be uncomfortable or to interfere with dancing (“Dancer Survey”). Each knee is shaped differently and sized slightly differently. Ensuring the best fit and designing and printing each brace individually prevents a trial-and-error approach to finding a brace that satisfies a dancer’s needs; 3D printing allows us to design a knee brace that will actually be worn when a dancer is most vulnerable to injury.

Social and Economic Impact

A young dancer may first dislocate her knee at age 14. With traditional braces, by age 18, she would have spent over $1000 on knee braces, undergone surgery on both knees, and dislocated both knees several more times. This dancer may make difficult decisions that have lasting effects on her body --- choosing to compete without a brace even though she knows her knee is about to dislocate, because the brace will distract the judges or interfere with her turns, and it is an important competition. Her knee may dislocate during the competition, but she continues to dance. This proposed brace can potentially drastically reduce these injuries and allow dancers a longer lifetime experience of dance.

Concluding Remarks

Technology has always served the world best when it is integrated culturally, and with this knee brace, 3D printing begins to do that. Dance has been an important cultural touchstone for centuries. Competitive dancers are athletes who are always looking to technology to solve physiological problems. With additive manufacturing, we can design a more comfortable, more effective knee brace that allows the dancer to continue dancing longer, without injury.

References

Bird, H. A., and E. C. Foley. "Hypermobility in Dancers." Rheumatology 52.4 (2012): 585-86. Web.

Briggs, J., M. Mccormack, A. J. Hakim, and R. Grahame. "Injury and Joint Hypermobility Syndrome in Ballet Dancers--a 5-year Follow-up." Rheumatology 48.12 (2009): 1613-614.

Grissom, Lindsey. “Dancer Survey.”  Online Survey. 09 March 2016.

"PhysioRoom.com Advanced Hinged Knee Brace - Patella Stabilisers - Knee Supports & Braces - Supports & Braces - from PhysioRoom.com." PhysioRoom.com Advanced Hinged Knee Brace.

"Kneecap Dislocation (Patellar Subluxation) Treatment, Symptom & Causes." Singapore Sports and Orthopaedic Clinic.