An instrument for establishing orientation of a pelvic prosthesis comprises a hub, a first arm attached to and extending from the hub, and a second arm attached to and extending from the hub. The first and second arms define a nominal plane of the apparatus, and may extend from the hub at an angle relative to each other. Distances between the first and second legs and between the first and third legs are adjustable. The first, second, and third legs have tips, and the tips of the first, second, and third legs define a plane having a predefined geometric relationship to the nominal plane of the apparatus.

An instrument for establishing orientation of a pelvic prosthesis comprises a hub, a first arm attached to and extending from the hub, and a second arm attached to and extending from the hub. The first and second arms define a nominal plane of the apparatus, and may extend from the hub at an angle relative to each other. Distances between the first and second legs and between the first and third legs are adjustable. The first, second, and third legs have tips, and the tips of the first, second, and third legs define a plane having a predefined geometric relationship to the nominal plane of the apparatus.

An instrument for establishing orientation of a pelvic prosthesis comprises a tripod having an angularly adjustable guide rod on it. The tips of the legs define a plane, and the guide rod is set by the surgeon to a defined orientation with respect to this plane on the basis of preoperative studies. In use, two of the legs of the instrument are positioned by the surgeon at defined anatomical locations on the pelvis (e.g., a point in the region of the posterior/inferior acetabulum and a point on the anterior superior iliac spine). The third leg then lands on the pelvis at a point determined by the position of the first two points, as well as by the separations between the third leg and the other two legs. The position of the guide rod then defines with respect to the actual pelvis the direction for insertion of a prosthesis.

An instrument for establishing orientation of a pelvic prosthesis comprises a tripod having an angularly adjustable guide rod on it. The tips of the legs define a plane, and the guide rod is set by the surgeon to a defined orientation with respect to this plane on the basis of preoperative studies. In use, two of the legs of the instrument are positioned by the surgeon at defined anatomical locations on the pelvis (e.g., a point in the region of the posterior/inferior acetabulum and a point on the anterior superior iliac spine). The third leg then lands on the pelvis at a point determined by the position of the first two points, as well as by the separations between the third leg and the other two legs. The position of the guide rod then defines with respect to the actual pelvis the direction for insertion of a prosthesis.

An adapter for a tripodal stereotactic reference frame for use in arthroplastic surgery mounts a third leg of the frame at an angle with respect to the other two legs to facilitate use of said frame with varying surgical exposures.

A bicycle seatpost assembly comprises a first cylinder, a second cylinder, a positioning structure, and an adjusting structure. The second cylinder is configured to be telescopically received in the first cylinder. The positioning structure is configured to relatively position the first cylinder and the second cylinder and configured to switch a state of the bicycle seatpost assembly among a first adjustable state and a second adjustable state. In the first adjustable state, a positional relationship between the first cylinder and the second cylinder is adjustable within a first adjustable position range. In the second adjustable state in which the positional relationship between the first cylinder and the second cylinder is adjustable within a second adjustable position range different from the first adjustable position range. The adjusting structure is configured to adjust at least one of the first adjustable position range and the second adjustable position range.

An articulated joint pivotably connects first leg and second legs. A first joint member attaches to the first leg. A second joint member attaches to the second leg. The joint members have facing abutment surfaces. Each joint member has a shaft opening receives a shaft for connecting the joint members, such that the legs may pivot between an open and a closed position. A clamping means releasably presses abutment surfaces of the joint members toward each other. A locking means releasably positively secures the joint members in at least the open position. Each joint member has a first aperture. The first aperture is radially offset from the shaft opening. The first apertures of each joint member are coaxially arranged in at least the open position. A device for supporting a person is included.

A pipe holding device includes a fixed clamp member, a movable clamp member, an upper ring and a lower ring. The fixed clamp member and the movable clamp member each have inner peripheral surfaces as metal surfaces coming into contact with the outer peripheral surface of the small diameter pipe. Furthermore, inner peripheral surfaces of cylindrical bodies correspond to a first resin surface and a second resin surface coming into contact with the outer peripheral surface of the small diameter pipe, respectively. The inner peripheral surface of the cylindrical body, the inner peripheral surfaces of the fixed clamp member and the movable clamp member, and the inner peripheral surface of the cylindrical body are adjacent to one another in an axial direction of a large diameter pipe.

An instrument for establishing orientation of a pelvic prosthesis comprises a tripod having an angularly adjustable guide rod on it. The tips of the legs define a plane, and the guide rod is set by the surgeon to a defined orientation with respect to this plane on the basis of preoperative studies. In use, two of the legs of the instrument are positioned by the surgeon at defined anatomical locations on the pelvis (e.g., a point in the region of the posterior/inferior acetabulum and a point on the anterior superior iliac spine). The third leg then lands on the pelvis at a point determined by the position of the first two points, as well as by the separations between the third leg and the other two legs. The position of the guide rod then defines with respect to the actual pelvis the direction for insertion of a prosthesis.