Tosfos 78b DH veha''Kite'a cites the explanation of Rabeinu Porat, who describes the Kav ha'Kite'a as follows: The amputee bends his lower leg back and ties wooden Semuchos, or stilts, to his hip and supports his leg with it ("Bo") and walks with it ("Bah").
Are the "Bo" and "Bah" referring to two different things? Aren't they both referring to the stilts? Can you check this in the Venice printing or Dikdukei Sofrim?
Pesach Feldman, Yerushalayim
Indeed, in the Venice (Soncino) edition of the Talmud both words in Tosfos are in the feminine, "Bah." (Dikdukei Sofrim only records Girsa'os in Gemara and Rashi, not in Tosfos.)
Kollel Iyun Hadaf