Abstract: A prosthesis for replacing a joint between a first bone and a second bone in a human hand or foot includes first and second rigid blocks (110, 120) interconnected by a flexible bridging structure (130). In certain embodiments, the flexible bridging structure employs a helical spring oriented with its central axis aligned with a central axis of a bone anchor portion of the first rigid block. One or more shear-limiting element (101, 140) is deployed within an internal volume of the helical spring (130) to limit an extent of shear deformation applied to the helical spring. Other aspects of the invention relate to adjustable bone-abutment flanges, an alternative bridging structure employing a helically-twisted leaf spring, and a structure and method for bridging between the first metacarpal and the scaphoid in case of removal of the trapezium from the hand.

Abstract: A prosthesis for replacing a joint between a first bone and a second bone in a human hand or foot includes first and second rigid blocks (110, 120) interconnected by a flexible bridging structure (130). In certain embodiments, the flexible bridging structure employs a helical spring oriented with its central axis aligned with a central axis of a bone anchor portion of the first rigid block. One or more shear-limiting element (101, 140) is deployed within an internal volume of the helical spring (130) to limit an extent of shear deformation applied to the helical spring. Other aspects of the invention relate to adjustable bone-abutment flanges, an alternative bridging structure employing a helically-twisted leaf spring, and a structure and method for bridging between the first metacarpal and the scaphoid in case of removal of the trapezium from the hand.

Abstract: A device for generating passive motion of a joint while applying traction includes a proximal bracket for engaging at least one pin inserted into a bone proximal to the joint and a distal bracket for engaging at least one pin inserted into a bone distal to the joint. The device also includes a tension-hinge mechanism connecting between the proximal and distal brackets. The tension-hinge mechanism includes a hinge for permitting rotational movement of the distal bracket relative to the proximal bracket about a hinge axis. At least one of the proximal bracket and the distal bracket is implemented as a movable bracket slidingly mounted so as to be displaceable in a direction generally perpendicular to the hinge axis. The tension-hinge mechanism also includes a traction mechanism for applying roughly constant force over a predefined range of positions of the movable bracket so as to apply tension across the joint. Also provided are jigs for use during insertion of pins around joints for orthopedic devices.

Abstract: A device for generating passive motion of a joint while applying traction has a proximal bracket for engaging a pin drilled into a proximal bone adjacent to the joint, and a distal bracket for engaging a pin drilled into a distal bone adjacent to the joint. The two brackets are connected by a tension-hinge mechanism which includes a hinge for permitting relative rotational movement of the brackets, and an adjustment mechanism. The adjustment mechanism is configured to allow substantially continuous adjustment of the distance between the hinge and at least one of the brackets so as to apply tension across the joint. The adjustment mechanism also includes a number of elastic elements deployed so as to allow elastic variation of the distance between the two brackets.