Abstract: A distraction apparatus for an external fixation device used to rigidly immobilize bone fragments during bone lengthening and angular deformity correction includes distractor mechanisms and pivotable spacers for connecting frame members of an external fixator, and wire and half pin fasteners. The interconnected distractor mechanisms, pivotable spacers and frame members form a rigid structure with rigidity which is maintained during adjustment of the distraction. For linear distraction, the distraction mechanism is a single screw assembly with a single-threaded rod and dual plastic nuts, or one of three various types of telescoping screw assemblies having a single-threaded rod, a coaxial sleeve for receiving the rod and one of three types of plastic connector assemblies. For angular distraction, the distraction mechanism includes an angular distractor with a rotatable knob and pivotable spacers which are connected to the frame members.

Abstract: A fastener for wires or pins used with an external fixation device to rigidly immobilize bone fragments during linear or angular distraction thereof includes a fixation bolt with either a transverse asymmetrical shank bore, or a transversely slotted bolthead for providing multiple contact surfaces to secure the wires or pins, regardless of their diameters. Alternatively, the fastener can include a washer or a threaded washer-like member having nonparallel opposing planar surfaces with a transverse slot in one. The transverse slots in the bolthead, washer and/or threaded washer-like member preferably include multiple cavities so as to increase the number of surfaces for contacting the wires or pins.

Abstract: A fastener for wires or pins used with an external fixation device to rigidly immobilize bone fragments during linear or angular distraction thereof includes a fixation bolt with either a transverse asymmetrical shank bore, or a transversely slotted bolthead for providing multiple contact surfaces to secure the wires or pins, regardless of their diameters. Alternatively, the fastener can include a washer or a threaded washer-like member having nonparallel opposing planar surfaces with a transverse slot in one. The transverse slots in the bolthead, washer and/or threaded washer-like member preferably include multiple cavities so as to increase the number of surfaces for contacting the wires or pins.

Abstract: Computer control apparatus uses sensing apparatus converts a mechanical movement into a direct current electrical signal. An electrical interface circuit is connected to the sensing apparatus for converting the direct current electrical signal into a pulse output used in controlling a computer. The preferred sensor is an inclinometer, which comprises an opaque body having a chamber. A light source is connected to the body to provide light in the chamber. Photocell apparatus is connected to the body to receive light emitted from the light source for providing an electrical resistance in relation to the amount of light received. Supported in the chamber is a liquid filter medium to absorb light emitted from the light source. A sufficient quantity of liquid filter medium is provided in the chamber to prevent light emitted from the light source from impinging upon the photocell apparatus in response to the angular placement of the body with respect to gravity.