Partial Foot Amputation and Ankle Dis-articulation
A partial foot amputation can be anything from a single toe to the entire foot forward of the heel. There are a number of distinct surgical techniques for certain levels, such as Lisfranc, Chopart and Pirogov (each named for the surgeon who invented them). Another common amputation is a ray amputation, where one or a number of toes are removed along with the corresponding metatarsal bone.
The majority of partial foot amputees are able to bear weight on their foot and walk without a prosthesis, but they may find walking difficult or painful. The prosthesis required will vary depending on the level of amputation, and may consist of a moulded insole, a silicone prosthesis that encloses the ankle, or a rigid plastic prosthesis that comes up as far as the knee. Generally speaking, the more of the foot that is lost, the larger and stronger the prosthesis needs to be to support the body and allow for a natural gait.
The ankle dis-articulation, commonly known as a Symes amputation (again after the surgeon who invented the technique), is similar to a partial foot amputation but with the heel bone also removed. Because the shin bones are not cut it is often possible to bear some weight through the residual limb, but a person may only be able to take a few steps and only on soft grass or carpet. Their gait will be very unnatural due the shortening of the leg. A Symes prosthesis has a prosthetic foot that provides stability and leverage for walking, and a socket that encloses the entire lower leg; some weight can be taken through the end of the residual limb but some must be taken through the socket below the knee cap.