Orthopaedic done screw apparatus

A bone screw apparatus comprising;

• a) an elongated shaft having proximal and distal end portions, the distal end portion having a cutting head and the proximal end portion being sized and shaped to fit a driver tool such as a drill chuck;
• b) the shaft being externally threaded along a majority of its length and having a plurality of longitudinally extending, circumferentially spaced apart shaped surfaces thereon;
• c) a removable head with a central opening that enables the head to slide along the shaft;
• d) the head having ratchets thereon that prevent sliding movement of the head along the shaft in a distal to a proximal direction;
• e) the head central opening being shaped to conform to the shaped surfaces of the shaft so that the head and shaft can be rotated as a unit by engaging and rotating the head;
• and
• f) a tool receptive surface portion of the head that accepts a driver tool for rotating the head and the connected shaft.

A method of implanting a bone screw through a patient's bone tissue, comprising the steps of:

• a) inserting a bone screw shaft into a patient's bone tissue, the shaft having an external surface with shaped longitudinally extending portions;
• b) placing a removable head on the shaft after the shaft is embedded in step "a" by sliding the head proximally to distally along the shaft until the head engages the patient;
• c) severing the shaft proximally of the head;
• and
• d) interlocking the head and shaft so that they rotate together.

A method of implanting a bone screw through a patient's bone tissue, comprising the steps of:

• a) inserting a bone screw shaft into a patient's bone tissue, the shaft having an external surface with shaped longitudinally extending portions;
• b) placing a removable head on the shaft after the shaft is embedded in step "a" by sliding the head in a proximal to distal direction along the shaft until the head engages the patient;
• c) severing the shaft proximally of the head;
• d) interlocking the head and shaft so that they rotate together;
• and
• e) further comprising the step between step "b" and "c" of disallowing movement of the head in a distal to proximal direction with a ratchet mechanism.