Cannulated locking screw system especially for transiliac implant

A screw system useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in a fixation application to another skeletal area, comprising:

• a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;
• a tip on the first end of the body;
• a head about the second end of the body, which can be engaged with a surgical tool;
• and threads on at least part of the body between the first and second ends;
• a locknut with threads generally corresponding to those of the screw for threading on the screw beginning by being placed over the first end of the body of the screw;
• and
• a washer.

A screw system useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in a fixation application to another skeletal area, comprising:

• a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;
• a tip on the first end of the body;
• a head about the second end of the body, which can be engaged with a surgical tool;
• and threads on at least part of the body between the first and second ends;
• a locknut with threads generally corresponding to those of the screw for threading on the screw;
• and
• a washer
• wherein the head has an external convex shape, and the washer has a throughbore with a shoulder and an adjacent surface in the throughbore having a concave shape corresponding with the external shape of the head.

A kit useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in an application to another skeletal area, comprising at least one screw system including a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;

• a tip on the first end of the body;
• a head about the second end of the body, which can be engaged with a surgical tool;
• and threads on at least part of the body between the first and second ends;
• and a locknut with threads generally corresponding to those of the screw for threading on the screw;
• and a guidewire, which is rigid and has a drill bit tip and is essentially as long as or longer than the elongate hollow body of the screw of the at least one screw system, and over which the screw can pass by the openings in the hollow body of the screw.

A kit useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in an application to another skeletal area, comprising:

• at least one screw system including
• a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;
• a tip on the first end of the body;
• a head about the second end of the body, which can be engaged with a surgical tool;
• and threads on at least part of the body between the first and second ends;
• and
• a locknut with threads generally corresponding to those of the screw for threading on the screw, wherein the locknut can lock itself on the screw through an interference fitting with the screw;
• and a guidewire, which is essentially as long as or longer than the elongate hollow body of the screw of the at least one screw system, and over which the screw can pass by the openings in the hollow body of the screw.

A screw system useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in a fixation application to another skeletal area, comprising:

• a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;
• a tip on the first end of the body;
• a head about the second end of the body, which can be engaged with a surgical tool;
• and threads having crest and trough features on at least part of the body between the first and second ends;
• and
• a locknut including a body having a threaded bore with threads of a bone screw type, wherein an interference locking taper is provided to at least one of trough and crest features of the threads of the locknut, with the threads of the locknut generally corresponding to those of the screw for threading on the screw
• wherein locking of at least one of the trough and crest features of the locknut can be carried out with respect to at least one of the crest and trough features of the threads of a threaded screw on which the locknut can be threaded.

A screw system useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in a fixation application to another skeletal area, comprising:

• a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;
• a tip on the first end of the body;
• a head about the second end of the body, which can be engaged with a surgical tool;
• and threads on at least part of the body between the first and second ends;
• and
• a single nut, which functions as a one-piece locknut subsystem, and which nut has threads generally corresponding to those of the screw for threading on the screw.

A screw system useful for transiliac fixation of at least one of a sacrum and a sacroiliac joint, or in an application to another skeletal area, comprising:

• a cannulated bone screw having an elongate, hollow body with openings on a first end of the body and on an opposing, second end of the body;
• a tip on the first end of the body;
• a head essentially at the second end of the body, which can be engaged with a surgical tool for installing the screw;
• and threads on at least part of the body between the first and second ends;
• and
• a locknut with threads generally corresponding to those of the screw for threading on the screw beginning by being placed over the first end of the body of the screw.