Q :

 What kind of prosthesis is a good one?

A :

It should have the following qualities.
-  Comfortable, snug fitting socket with no pressure points which can cause pain
   and ulcer.
- Produces a natural gait causing no tightness or pulling or discomfort in the body 
   above the stump.
- Light-weight, conserving energy. This is especially important for cardiac patients.
- Durable, long-lasting and strong enough to ensure it won’t break during walking.
- No long-term side-effects for a disabled person. It need not be expensive.