A mobile bearing prosthetic implant may include a fossa implant seated in the fossa cavity of the skull and secured to the zygomatic arch. The fossa implant may define a primary recess constructed and arranged to mimic the articular eminence of the temporal bone such that a floating bearing connected to a ramus implant may translate along the original path that the condylar head would take during movement of the jaw. The floating bearing may be constructed and arranged to move from the first jaw angle recess to the second jaw angle recess and is positionable therebetween such that a longitudinal axis of the floating bearing is perpendicular to the direction of movement of the floating bearing within the fossa implant.

A system including a prosthesis assembly for a constrained knee including a tibial baseplate, a mobile bearing, and a fixed bearing. The tibial baseplate can include a distal surface and a proximal surface that can be configured to receive a hinge post. The mobile bearing can be configured to couple with the tibial baseplate and to rotate about at least a first axis approximated by a centerline of the hinge post. The rotation about at least the first axis can be limited by at least the first engagement feature. The fixed bearing can be configured to be coupled to the tibial baseplate. The fixed bearing can be restrained from rotating about the first axis by at least the first engagement feature of the tibial baseplate. The tibial baseplate can be configured to be assembled with either the mobile bearing or the fixed bearing.

Medical devices in accordance with various embodiments of the present invention employ one or more coaxial screw gear sleeve mechanisms. In various embodiments, coaxial screw gear sleeve mechanisms include a post with a threaded exterior surface and a corresponding sleeve configured to surround the post, the corresponding sleeve having a threaded interior surface configured to interface with the threaded exterior surface of the post and a geared exterior surface. A drive mechanism can be configured to interface with the geared exterior surface of the sleeve, causing the device to expand.

Medical devices in accordance with various embodiments of the present invention employ one or more coaxial screw gear sleeve mechanisms. In various embodiments, coaxial screw gear sleeve mechanisms include a post with a threaded exterior surface and a corresponding sleeve configured to surround the post, the corresponding sleeve having a threaded interior surface configured to interface with the threaded exterior surface of the post and a geared exterior surface. A drive mechanism can be configured to interface with the geared exterior surface of the sleeve, causing the device to expand.

A method of tailoring a spinal implant to correspond to a specific patient's needs includes: pre-operatively evaluating a patient to determine a desired spinal segment response; and modifying one or more features of flexures of an implant to provide the desired spinal segment response. Modifying one or more features of flexures of the implant can include modifying one or more of a thickness, width, length and/or shape of the features of the flexures. Various systems for executing the methodologies taught herein are also provided.