Orthopedics is a branch of medicine that focuses on the care of the musculoskeletal system. This system is made up of muscles and bones, as well as joints, ligaments and tendons. The applications of Additive Manufacturing (AM) have increased extensively in the area of orthopedics. The AM applications are for making anatomic models, surgical instruments & tool design, splints, implants and prosthesis. AM provides benefits for orthopedics area, where customized implants can be formed as per the required shape and size and can help substitution with customized products.

Printing surgical instruments – The two methods – Fused Filament Fabrication (FFF) and Selective Laser Sintering (SLS), offer complementary approaches. The first is ideal for low volume, customized parts with complex geometries that can be produced at or close to the point of care. The second lends itself to centralized production of higher-volume components with complex geometries. Together, these technologies offer benefits for orthopedics industry, the proven advantages of polymers over traditional metal (lighter weight, high-performance properties, support for bone ingrowth) plus the unique capabilities of additive manufacturing, including patient/surgeon personalization and production of complex designs.

In SLS, a laser heats a powdered material to just above its melting point, bonding it to create a 3D structure. SLS equipment typically can print multiple components simultaneously, making it a good choice for producing complex instruments when intermediate volumes are required, such as for orthopedic trials. Using specialty polymers, alone or with metal for these applications, allows manufacturers to reduce the overall weight of individual instruments as well as the total set weight of surgical trays. These materials also enable improved ergonomics to reduce surgeon fatigue and build in functionality through part consolidation for enhanced designs and faster production.

Printing orthopedic implants – While metals such as titanium and cobalt chrome continue to be widely used in orthopedic implants, specialty thermoplastics offer several advantages over metal, including radiolucency. PEEK (polyether ether ketone) is particularly suitable for load-bearing applications due to its outstanding fatigue or repeats loading performance. Unlike metal, PEEK is similar to cortical bone in terms of density, stiffness and weight.

PolyLactic Acid (PLA) and related chemistries, in combination with a ceramic, are being used to replace titanium screws in knee ligament surgery. The PLA compound is bio-resource able, avoiding the need to remove the metal screws in a second procedure.

Using additive manufacturing to create thermoplastic implants offers further benefits. Intricate new implant designs can be created to optimize osseointegration – permanent fixation of the implant via bone on growth and ingrowth without fibrous tissue interference at the implant/bone interface.