Abstract: A joint endoprosthesis system has first and second prosthetic components. The second prosthetic component has a bearing surface. The interface of the bearing surface and the first prosthetic component defines the joint articulation. A signal source and sensor are affixed on opposite sides of the joint articulation. The signal source generates a first signal that is received by the sensor. The sensor generates a second signal that has a characteristic that varies depending on the distance between the sensor and the signal source. A transmitter transmits a signal. The signal has a characteristic that varies depending on the characteristic of the second signal. This system can be used to measure a dimension of the joint space and to determine whether a dimension of the joint space has changed over time. The system may alternatively use magnets and magnetic sensors.

Abstract: A tibial milling guide which incorporates a combination of instruments for producing a planar surface on a portion of the tibia using a milling device. The system includes: an extramedullary alignment guide with a detachable reference guide, an adjustable milling base assembly, a detachable milling template, a sizing gauge, and a milling depth gauge. The reference guide is used to position the alignment guide to the tibia. The reference guide has a T-shaped member which provides a planar reference and a centering reference to the tibial head. The reference guide also allows the surgeon to set the rotational alignment before the alignment guide is secured in place. The adjustable milling base assembly is also detachably connected to the alignment guide. The milling base assembly includes a slide and a shiftable base that allows for lateral adjustments of the template with respect to the articular surface after the alignment guide has been properly secured to the tibia.

Abstract: The milling instrumentation of this invention provides a milling guide connected to the femur for accommodating a milling device. The milling instrumentation includes an alignment guide which is used by the surgeon to set a femoral bracket or base on the medial and lateral sides of the exposed femur adjacent its distal end. Once the brackets are set, the alignment guide is removed and a milling guide is connected to the bases. The milling guide establishes a series of reference planes each including a slot. A powered milling device having a burr connected thereto is guided by the slots along the reference planes to accurately mill away a portion of the bone. The milling device includes a bobbin-shaped tip which positively engages the slots to ensure that the milling device is held substantially perpendicular to the reference planes of the milling guide.

Abstract: The milling instrumentation of this invention provides a milling guide connected to the femur for accommodating a milling device. The milling instrumentation includes an alignment guide which is used by the surgeon to set a femoral bracket or base on the medial and lateral sides of the exposed femur adjacent its distal end. Once the brackets are set, the alignment guide is removed and a milling guide is connected to the bases. The milling guide establishes a series of reference planes each including a slot. A powered milling device having a burr connected thereto is guided by the slots along the reference planes to accurately mill away a portion of the bone. The milling device includes a bobbin-shaped tip which positively engages the slots to ensure that the milling device is held substantially perpendicular to the reference planes of the milling guide.

Abstract: The guide of this invention provides an alternative to a system requiring a plurality of guides or for a guide with a plurality of slots by providing a single guide which slides along the distal femur and which articulates to accommodate a variety of angles. The guide includes a base portion defining a pair of parallel rails having a dove-tail shaped groove formed therein. The base is fixed to the distal end of the femur after an initial cut has been made to flatten the distal end. The device further includes an upper frame which is carried by the base and slides along the rails. The upper frame pivotally supports a carriage assembly in a plurality of discrete angles as determined by detents. The carriage includes a pair of parallel rods which extend in a direction transverse to the parallel rails of the base portion. In the preferred embodiment, the parallel rods support a milling guide which is slidable along the rods.

Abstract: The invention is directed to milling instrumentation used for preparing a bone for receiving a prosthetic implant. The milling instrumentation includes a milling template for connection to an exposed end of a bone for guiding a milling device along the bone. A detachable cutting guide is removably connected to the milling template to permit a surgeon to either utilize either milling or cutting techniques in resecting the bone.

Abstract: An apparatus is provided for milling bone. The apparatus includes a template having a reference surface for controlling depth of cut and a track for guiding the cutter in two dimensions to cut a planar surface.

Abstract: The milling instrumentation of this invention provides a milling guide connected to the femur for accommodating a milling device. The milling instrumentation includes an alignment guide which is used by the surgeon to set a femoral bracket or base on the medial and lateral sides of the exposed femur adjacent its distal end. Once the brackets are set, the alignment guide is removed and a milling guide is connected to the bases. The milling guide establishes a series of reference planes each including a slot. A powered milling device having a burr connected thereto is guided by the slots along the reference planes to accurately mill away a portion of the bone. The milling device includes a bobbin-shaped tip which positively engages the slots to ensure that the milling device is held substantially perpendicular to the reference planes of the milling guide.

Abstract: An alignment guide comprises a guide block locator having surfaces for engaging a prepared femur and establishing a specific position relative to an intercondylar slot in the femur. The guide block locator contains an aperture for directing a guide block to the specific position. The guide block includes a leg that can be driven into the femur to hold the guide block in place. The guide block is adapted to precisely engage the cam box of a femoral implant. Upon removal of the guide block locator, the femoral implant can be positioned over the guide block where the cam box will engage the guide block before the anterior and posterior flanges of the implant grip the anterior and posterior surfaces of the femur thereby providing proper alignment of the femur and implant.

Abstract: An apparatus and associated method are provided for milling bone. The apparatus includes a template having a reference surface for controlling depth of cut and a track for guiding the cutter in two dimensions to cut a planar surface.

Abstract: The milling guide of this invention provides a guide having a base with a track formed therein to slidably accommodate a milling device and guide the milling device along the bone. The milling device provides a smooth bone surface and the guide is provided to maintain the milling device generally transverse to the longitudinal axis of the tibia. A slider is carried by the track and accommodates the milling device to maintain the milling device generally perpendicular relative to the guide. The slider is shiftable within the guide in an medial-lateral plane. The milling device is shiftable relative to the slider and guide in the anterior-poster plane as well.