Although rotator-cuff repairs are common procedures, not all orthopedic surgeons can tie the required suture knots. San Diego-based KFx Medical (kfxmed.com) had an idea to solve this problem with a technique it calls Suture-Cross Knotless Anatomic Fixation that involves attaching simpler and stronger fasteners to tissues.

While the fixation device was in development, the company wanted to avoid the high costs and long delays of outsourcing dozens of parts for CNC machining. So the firm bought a PCNC 1100 from Tormach LLC., Waunakee, Wisc. (tormach.com) to cut prototype parts in house for the application fixtures and instruments. Dubbed the “Personal CNC” by Tormach CEO Greg Johnson, the machine targets R&D prototyping and short-run productions.

“We've cut 420 stainless-steel injection molds, and in days rather than the weeks typically quoted by outside shops,” says Senior Product Development Engineer Mike Ko. “The 4th-axis came in handy for making prototype 316 stainless-steel bone screws with a variety of tapering spiral threads. And the machine is so simple to use, we didn't have to hire a skilled programmer or operator.”

The PCNC 1100 also cut plastic prototypes for the handle of the rotator-repair tool the doctor holds during surgery. “Design variations for the handle included complex compound curves and surfaces that made it more functional and comfortable. Current high-tech rapid prototyping methods such as selective laser sintering have could accurately generated the required shapes, but not in materials that withstand the rigors required of orthopedic devices,” says Ko. “And although contract machine shops could make the handles out of suitable materials, the shops usually required a four to five-week lead-time for delivery.”

In contrast, the PCNC 1100, along with current solid modeling and CAM software, let the firm go from a 3D CAD model to a machined handle in one day, and to a completed, fully functional handle-assembly in a week, he says. “Time and costs were even less for the second and third iterations of the same handle because our previous work is stored in the CAM program.”