Orthopedic variable screw fixation mechanism

A sliding plate variable angle locking mechanism for orthopedic bone fixation, the locking mechanism comprising:

• a bone plate including a bone plate surface, a plate hole adjacent the bone plate surface and a shelf, the plate hole defining a plate hole diameter;
• a first sliding plate having an upper surface, a lower surface and a central hole, the central hole defining a sliding plate hole diameter, the sliding plate hole diameter being smaller than the plate hole diameter, the first sliding plate configured for slidable movement relative to the bone plate;
• a second sliding plate having an upper surface, a lower surface and a central hole, the second sliding plate configured for slidable movement relative to the bone plate and the first sliding plate in an assembled and unlocked configuration with the second sliding plate positioned between the shelf and the first sliding plate;
• a rotating plate having a central hole, a lower surface and an upper surface, the lower surface of the rotating plate positioned on the upper surface of the first sliding plate in the assembled configuration;
• a locking ring movably mountable to the bone plate, the locking ring having a locking ring hole, the locking ring hole defining a locking ring hole diameter, the locking ring hole diameter being greater than the sliding plate hole diameter;
• and
• a bone screw having a head with head threads and a shaft, the head threads defining a bone screw head diameter, the bone screw head diameter being greater than the sliding plate hole diameter, the head threads configured to form internal threads in the central hole of the first sliding plate and the second sliding plate when the bone screw is driven into the first sliding plate and the second sliding plate in the assembled and locked configuration.