A wheelchair was a chair mounted on wheels used by disabled or injured people.
Among those who required a wheelchair were Dr Judson, (TV: The Curse of Fenric) Jeremy Winterdawn, (PROSE: Falls the Shadow) John Lumic, (TV: Rise of the Cybermen / The Age of Steel) Fiona Bellows (TV: Last Christmas) and Dortmun. (TV: The Dalek Invasion of Earth)
When Channing abducted the Third Doctor from Ashbridge Cottage Hospital, he transported him in a wheelchair; however, the Doctor used the wheelchair to escape. (TV: Spearhead from Space)
Having been sent back to Event One, the TARDIS appeared to provide the newly regenerated Fifth Doctor with an electric wheelchair to help him get around. (TV: Castrovalva)
Hugh Curbishley pretended to need a wheelchair to keep his wife Clemency Eddison from leaving him. (TV: The Unicorn and the Wasp)
Amfetriti used a wheelchair to disguise her nature. (AUDIO: Cryptobiosis)
Rex Matheson used a wheelchair to make his way to the hospital exit. (TV: The New World)
In an alternate timeline in which the British Empire had conquered Earth with Dalek technology, the Sixth Doctor was confined to a wheelchair after his legs had been cut off for attempting to escape. (AUDIO: Jubilee)