A medical device for implantation in a hip joint of a human patient, the natural hip joint having a ball shaped caput femur as the proximal part of the femoral bone with a convex hip joint surface towards the center of the hip joint and a bowl shaped acetabulum as part of the pelvic bone with a concave hip joint surface towards the center of the hip joint. The medical device comprising; an artificial caput femur, comprising a convex surface towards the center of the hip joint. The artificial convex caput femur is adapted to, when implanted: be fixated to the pelvic bone of the human patient, and be in movable connection with an artificial acetabulum surface fixated to the femoral bone of the patient, thereby forming a ball and socket joint. The medical device further comprises a fixation element comprising a fixation surface adapted to be in contact with the surface of the acetabulum and adapted to fixate the artificial convex caput femur to at least the acetabulum of the pelvic bone.

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.

An adaptable spinal facet joint prosthesis may include a pedicle fixation element; a laminar fixation element; and a facet joint bearing surface having a location adaptable with respect at least one of the pedicle fixation element and the laminar fixation element. Methods of implanting an adaptable spinal facet joint prosthesis may include determining a desired position for a facet joint bearing surface; and attaching a prosthesis comprising a facet joint bearing surface to a pedicle portion of a vertebra and a lamina portion of a vertebra to place the facet joint bearing surface in the desired position. A facet joint prosthesis implant tool may include a tool guide adapted to guide a vertebra cutting tool; and first and second fixation hole alignment elements extending from the saw guide. Systems for treating spinal pathologies may include intervertebral discs in combination with spinal and facet joint prostheses.

Hip tethering devices comprise a femoral implant including a housing that anchors the femoral implant to the femur, at least one spring, and a slider, such that the slider can move relative to the housing via compression and expansion of the at least one spring. A tether has a first end that anchors to the acetabulum, the tether passes through the femoral head, and a second end couples to the slider of the femoral implant, such that the tether spans across the patient's hip joint and relative motion between the slider and the housing allows a limited degree of separation of the femoral head from the acetabulum, while the at least one spring applies a variable tension load to the tether that resists separation of the femoral head from the acetabulum.

A system and method for sharing and absorbing energy between body parts. In one particular aspect, the system facilitates absorbing energy between members forming a joint such as between articulating bones. Springs may be used to transfer loads across a joint, and can be used in conjunction with pistons and sleeves.

An adaptable spinal facet joint prosthesis may include a pedicle fixation element; a laminar fixation element; and a facet joint bearing surface having a location adaptable with respect at least one of the pedicle fixation element and the laminar fixation element. Methods of implanting an adaptable spinal facet joint prosthesis may include determining a desired position for a facet joint bearing surface; and attaching a prosthesis comprising a facet joint bearing surface to a pedicle portion of a vertebra and a lamina portion of a vertebra to place the facet joint bearing surface in the desired position. A facet joint prosthesis implant tool may include a tool guide adapted to guide a vertebra cutting tool; and first and second fixation hole alignment elements extending from the saw guide. Systems for treating spinal pathologies may include intervertebral discs in combination with spinal and facet joint prostheses.

An arthroplasty trial assembly for a human shoulder can include a first implant securable to a first bone and a second implant securable to a second bone. The second implant can include a body, a stem, an articulation component, and a sensor. The stem can extend from the body, and the stem can be insertable into the second bone. The articulation component can be coupled to the body opposite the stem, and the articulation component can be articulable with the first implant. The sensor can be connected to the articulation component and can be configured to monitor a condition of the second implant and can produce a sensor signal as a function of the condition that is indicative of stability of the shoulder.

This invention relates to an intervertebral motion disc having two motion surfaces and. wherein the radius of the upper articulation surface of the core member is greater than the radius of the lower articulation surface of the core member, and wherein the first articulation surface of the core member is spherical and the second articulation surface of the core member is curved and non-spherical.

A medical device for treating hip joint osteoarthritis in a human patient by providing at least one artificial hip joint surface is provided. The hip joint having a ball shaped caput femur as the proximal part of the femoral bone with a convex hip joint surface towards the centre of the hip joint and a bowl shaped etabulum as part of the pelvic bone with a concave hip joint surface towards the centre of the hip joint. The medical device comprises the artificial hip joint surface comprising at least one of; an artificial caput femur or an artificial caput femur surface comprising, a convex form towards the centre of the hip joint, and an artificial acetabulum or an artificial acetabulum surface comprising, a concave form towards the centre of the hip joint. The artificial convex caput femur or the artificial convex caput femur surface is adapted to be fixated to the pelvic bone of the human patient and the artificial concave acetabulum or artificial concave acetabulum surface is adapted to be fixated to the femoral bone of the human patient.

An expandable intervertebral implant includes a first endplate and a second endplate, a first wedge member and a second wedge member spaced from the first wedge member that couple the first and second endplates together. The first and second wedge members configured to translate along an actuation member housed between the first and second endplates to cause the implant to expand from a first collapsed configuration into a second expanded configuration. The actuation member has a first threaded section spaced apart from a second threaded section where the first and second threaded sections are at an angle with each other. Between the first and second threaded sections on the actuation member there is a section that permits the first and second threaded sections to rotate in the same rotational direction. The actuation member is configured to move the first and second wedge members from the first collapsed configuration into the second expanded configuration so that the first and second endplates separate from each other to contact and engage the endplates of the adjacent vertebral bodies.