When millimeters matter, it helps to have a guide.

Orthopedic surgeon Hans Bengtson, MD uses 3D printing to get an exact model of his patient’s joint to guide accurate placement of implants during joint replacement surgery.  

The metal 3D replica lets Dr. Bengtson see the precise location and angle of the initial pin that guides the rest of the surgery.  The result: More accurate implant fit, shorter surgical time, less anesthesia, more predictable recovery and function, and longer implant life for the new joint. 

The process starts with a CT scan of the patient’s actual joint; those digital images are used to create a digital model of the actual joint surface. Then a 3D printer uses that model to produce a custom metal guide – a jig – that specifically matches the bumps and angles of that patient's unique joint surface. Extensions on the jig help show the precise position and angle needed for the critical first pin placement to attach the implant to the bone. The jig and joint surface fit as snugly as, well, a jigsaw puzzle.

During surgery, Dr. Bengtson lines up the jig with the patient's bone itself, practically snapping the jig’s extensions into place.

“Getting perfect placement of the implant improves its longevity and helps maximize proper function.  It works more smoothly, and is less likely to wear out over time,” Dr. Bengtson says.

“When people have arthritis, especially in the shoulder, the joint can develop significant wear and deformity, and the normal anatomy is lost,” Dr. Bengtson explains. “That makes it challenging during surgery to get the best positioning of the instruments and implant. The jig helps with the planning process – it’s much more precise than squinting to ‘eyeball’ the alignment.”

Using the jig during surgery can shorten the time needed for surgery, minimizing anesthesia time and associated risks, Dr. Bengtson adds: “It’s a great example of interweaving technology with surgical intervention for improved patient outcome.”

3D printing adds a small cost that “in the long run, is extremely valuable: It improves accuracy during surgery, so the new joint has every possible chance to last longer,” Dr. Bengtson says.

After surgery? Each patient gets their one-of-a-kind model to keep. “Patients love having a souvenir from surgery,” Dr. Bengtson smiles. “They love being able to dabble with the implant and say, ‘So that's how it fits . . . this is how it works.’”