Polycentric Hyperstable Prosthetic Knee Joint

Polycentric Hyperstable Knee Joint

The Polycentric Hyperstable Knee Joint is for users approaching walking who need additional safety. That safety is achieved through a polycentric mechanism whose CIR trajectory sits well posterior to the load line.

• CIR trajectory well posterior to the load line for maximum stability
• At initial contact the knee is locked in a completely extended position
• Studied geometry allows prosthetic shortening during push off to avoid stumbling
• Assisted extension, suitable for different walking speeds through spring stiffness adjustment
• Flexion angle 165 degrees — the widest in the polycentric range
• Aluminum alloy 7075, component weight 550 g
• Maximum user weight 100 kg
• Tested to ISO 10328
• Warranty 36 months
• Pair with a Single Axis foot or Walking MP to build a key level 2 above knee prosthesis

Very high CIR and close to the hip, low fatigue to start flexion.

Posterior CIR to the load line.

Very closed CIR  to the load line, good for voluntary control.

POLYCENTRIC KNEE JOINT SYSTEM

Thanks to the pyramidal adapter suitable for each knee, it’s possible to change the CIR position compared to the LOAD LINE in order to offer users more safety or more voluntary control.

Limited community ambulation.

Able to traverse low-level environmental barriers (curbs, ramps, stairs, uneven surfaces).

If you need another knee joint

Check Single axis foot or Walking MP to obtain Key level 2 AK prosthesis

See our products videos on Roadrunnerfoot YouTube channel

Key specifications

Ordering and technical support

Designed and manufactured in Italy by Roadrunnerfoot Engineering S.r.l. The full range is listed in the Roadrunnerfoot 2025 catalogue. Orthopedic technicians, clinics and international distributors can request technical data sheets, product codes, pricing and fitting support from our team.