An implantable prosthetic joint has a first component for attaching to a
first bone and a second component for attaching to a second bone wherein
the first and second components are connected in an articulating manner
to provide the motion of a prosthetic joint. The joint includes at least
one spring to provide compliance to the prosthetic joint. The at least
one spring is preloaded in the artificial joint such that the spring is
not allowed to move to a completely relaxed position. This preloading of
the spring allows the maximum deflection of the spring to be used for
shock absorption because the spring does not deform substantially when
the implanted prosthetic joint is moved from an at rest position to a
loaded or standing position. The prosthetic joints according to the
present invention can include artificial hips, knees, shoulders, ankles,
and intervertebral discs.