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Comfort-Brake Knee (mech Ext. Assist)

Item #: 3R90
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Suggested HCPCS Coding: L5812 + L5845 + L5850

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The innovative load-dependent adjustable brake mechanism offers targeted safety for the patient. Heel strike activates the brake which in turn provides high stability in the stance phase.  The amount of stance flexion provided by the 3R90 is affected by adjusting the brake.

The swing phase can be controlled by means of a mechanical extension assist which, integrated in the lower section of the joint, has a progressively acting spring combination. Two combined spring elements form the integrated mechanical extension assist of the 3R90. The interaction of the springs results in an extension assist effect dependent on the knee angle. Extension assist can be preset to one of five different levels by means of a ratchet unit.
When fitting users with mobility grade 1, the following applies: these knee joints with friction brake are contraindicated for unsure patients who are unable to systematically use the braking mechanism during the gait cycle i.e. to lock the knee joint at heel contact and unlock it when the forefoot is loaded.

Scope of Delivery: 3R90 Knee + 2R77 Pylon



Activity Level K1, K2
Maximum Body Weight 275 lbs (125 kg)
Material Aluminum
Proximal Connection Pyramid Adapter
Distal Connection Tube Clamp
Maximum Knee Flexion Angle 135 degrees
Knee Center to Proximal Connection 40 mm
Product Weight 745 g
Build Height 216 mm
Distal Build Height 190 mm
Proximal Build Height 26 mm


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LLP Prosthetist Documentation

Reimbursement: Documentation Guide


PDF Document | Published: Apr 17, 2023

LLP Physician Documentation Guide


PDF Document | Published: Apr 17, 2023

3R90 / 3R92 Brochure

Product Information

PDF Document | Published: Jul 1, 2016

3R90 / 3R92 Instructions for Use

Instructions for Use

PDF Document | Published: Jul 13, 2020