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Advanced Knee Replacement
General information
Affiliation	Aperture Science
Type	Prosthetic heel springs
Usage
Used by	Chell
Game information
Entity / spawn codes	N/A

 

The Advanced Knee Replacement is a technique used by Aperture Science to prevent Test Subjects from injury from huge drops by lessening the impact.

OverviewEdit

• The device consists of two prostheses completely or partially replacing the knee, partially tied to the Test Subject's calves, and prolonged with two flexible curved pieces of metal going under the Test Subject's heels, acting as springs.

• Before being first awoken, Chell had been fitted with Advanced Knee Replacement, which was destroyed when she got dragged by the Party Escort Bot after she defeated GLaDOS.^[1] After being awoken again by Wheatley, she donned Long Fall Boots instead.

• In "Orientation Video no. 1", the diagram about jumping from high ledges suggests Advanced Knee Replacement is not commonly used by Test Subjects, and might have been used exclusively for Chell.

Behind the scenesEdit

• The heel springs were originally created for the Combine Assassin, cut from Half-Life 2.^[2]

• The Advanced Knee Replacement was added into Portal due to disbelief by playtesters that Chell could survive the drops she was subject to, particularly those that involved falling recursively through portals.^[3]

• According to Matt Charlesworth, the team was not sure whether to keep the Advanced Knee Replacement in Portal 2. He stated that some team members were attached to it, and that some were not, so they experimented what to do with them, or how to replace them,^[4] until they decided to replace it with a variant, the Long Fall Boot.

TriviaEdit

• The real-life corollary activity to this is called "powerbocking". A very similarly shaped device is also used as prosthetic legs for amputees (such as Eli Vance's).

• The sound files for the Advanced Knee Replacement footsteps use the name "future shoes".

GalleryEdit

PortalEdit

Diagram showing what happens when a Test Subject jumps without the Advanced Knee Replacement.

Chell and her Advanced Knee Replacements from the back.

Front view.

Clipboard sheet featuring the Advanced Knee Replacement specs.

Two clipboards in an Aperture Laboratories office, including one about the Advanced Knee Replacement.

Portal 2Edit

Concept art for different Advanced Knee Replacement iterations, revealed during the PotatoFoolsDay ARG. Several of these designs would be the basis for the Long Fall Boot that would later be used in Portal 2.

Two early Advanced Knee Replacement models, also revealed during the PotatoFoolsDay ARG.

Views of an early render of the Portal 2 Chell model, with Advanced Knee Replacement.

Views of Chell's Portal 2 model, with Advanced Knee Replacement.

Chell's Advanced Knee Replacement is destroyed as the Party Escort Bot drags her back into the facility.

Outfit study for Chell on a picture of Alésia Glidewell, revealed during the PotatoFoolsDay ARG, featuring several Advanced Knee Replacement iterations.

Pink Advanced Knee Replacement on Mel's placeholder model.

List of appearancesEdit

• Portal (First appearance)
• Portal: First Slice
• Portal: Still Alive (Non-canonical appearance)
• PotatoFoolsDay ARG
• Portal 2: Lab Rat
• The Final Hours of Portal 2

ReferencesEdit