Medical-grade polycarbonate assists with knee replacements

Polycarbonate strikes the right balance for knee replacements

Makrolon® polycarbonate helps surgeon optimize implant placement

Previously, surgeons had to subjectively determine the amount of pressure to apply to a knee implant during surgery. Now, a device provides real-time data to the surgeon to make adjustments.

Ortho Sensor
Makrolon® Rx1851 polycarbonate from Covestro provided the necessary biocompatibility and superior strength for the OrthoSensor™ Knee Balancer.


The OrthoSensor™ Knee Balancer is a revolutionary, intelligent orthopedic device that uses sensors and wireless technology to provide evidenced-based data for surgeons to optimize the positioning and balance of implants. Using a high-quality material in the manufacture of the device was paramount.


The device is available in four transparent colors, each indicating a specific surgical size. OrthoSensor had several criteria for choosing a material for the innovative OrthoSensor™ Knee Balancer, including biocompatibility, superior strength and technical support from the supplying company.


Makrolon® Rx1851 polycarbonate from Covestro checked all the boxes. Not only does this medical grade of resin offer improved flow, lubricity, easy release and strength, it’s also compliant with FDA-modified 10993, Part 1. Critical to the project was Covestro’s ability to provide custom color formulations for its biocompatible grades of Makrolon®. During development, Covestro worked with the molder to safeguard the integrity of the material and assure that OrthoSensor’s high standards were met.

Case Profile


Covestro LLC




OrthoSensor™ Knee Balancer orthopedic device


Covestro’s custom color technologies

Makrolon® polycarbonate - the state of the art material for a broad range of design applications that possesses phenomenal properties

The device utilizes the material in four translucent colors – brown, green, blue and yellow – each indicating a specific surgical size to meet the manufacturer’s needs.

Lightweight Makrolon® Rx1851 polycarbonate is exceptionally durable and features high impact strength.

Makrolon® Rx1851 stands up to harsh disinfectants and satisfies major bio-compatibility requirements, including ISO 10993-1.

This grade of Makrolon® features easy release from the mold after processing and low viscosity or thickness.

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