By: Bob Michaels
Published in MPMN, June/July 2011, Volume 27, No. 5From the ligament-replacement procedure known as Tommy John surgery to reconstructive knee surgery, sports medicine is a way of life for many professional athletes. But it’s not just athletes that suffer from sports-related injuries. As a result of such everyday forms of exercise as jogging and recreational activities ranging from snowboarding to basketball, growing numbers of people are turning up at hospitals with sports-related sprains, breaks, or torn tendons.

Addressing the escalating need to repair sports-induced soft-tissue injuries and reattach soft tissue to bone, Biomet Sports Medicine (Warsaw, IN) has introduced the JuggerKnot. This anchor technology, according to the company, may eliminate many soft-tissue repair concerns associated with bone loss and hardware issues. “It’s an all-suture anchor,” comments Kevin Stone, Biomet Sports Medicine’s vice president of research and development. “It does not have the typical plastic or metal anchoring element seen in other anchors, and its small size allows for flexibility in the placement of the anchors to achieve the desired surgical repair.” Additionally, the anchors’ small size preserves more of the patient’s bone.

Made of high-strength polyethylene MaxBraid suture material with a polyester-sleeve anchoring element, the 1.4-mm anchor is placed in a prepared hole. Then, when tension is applied to the sutures, the anchor sets by bunching up to a size larger than the prepared hole. “This anchor technology is the first of its kind made entirely of suture material,” according to Stone. “And it has the added benefits of being very small while maintaining high fixation strength.”

To introduce the JuggerKnot system, special insertion tools and guides are required so that the surgeon can properly locate the insertion point for the implant. Addressing the need to manufacture these components, Biomet turned to supplier PMC Smart Solutions (Cincinnati). PMC was well positioned to collaborate with Biomet because it had prior experience with a challenging application that relied on similar techniques and production methods as those used in the JuggerKnot project. “This earlier orthopedic application was also related to sports medicine, and it provided us with the knowledge, skill, and experience to contribute to the JuggerKnot,” says Phil Cashen, PMC’s director of new business development.

Providing injection- and insert-molded components made from biocompatible materials, PMC uses special manufacturing equipment to optimize the insert molding of complex parts, such as those used in the JuggerKnot. “We manufactured the insertion tools and the guides for the system using biocompatible ABS materials,” Cashen remarks. “The insertion tools are insert molded using proprietary mold designs.”

Insert molding flexible nitinol inserts into the insertion tools proved to be a technical challenge, according to Cashen. “To do this, the mold tooling was designed in such a way as to prevent the insert from moving during the molding process.” Because the nitinol inserts are flexible, they tend to push to one side of the tool if they aren’t secured properly in the mold, Cashen adds. “Thus, we developed a mold design that would allow us to achieve the specifications for the insert-molded flexible insert.”

The scope of the project was developed with the understanding that PMC would have to transition through the prototyping phase quickly to get to the production tooling, Cashen states. “We were able to accomplish this because we designed our production tooling to be able to utilize it in the development phase of the project. Our designs used tooling configurations that allowed us to bypass the prototype tooling phase and go directly into production tooling.” And with an eye toward the future expansion of the product line, PMC also developed tooling configurations that will allow Biomet to add new sizes of the product at minimal cost.

Noting that there are a lot of molders out there, Stone states that one of the things that attracted Biomet to PMC was the supplier’s process control systems and its experience with a range of materials. “Although PMC was historically heavily involved in the automotive space, it had excellent systems in place that are absolutely necessary in the medical device arena, and it invested heavily in its medical business unit.” Those qualities, combined with Biomet’s design and development efforts, resulted in a compact, high-strength orthopedic device that represents a giant step forward in suture anchor technology, Stone concludes.