Compact external fixation device

A compact external fixation device, suitable for the treatment of fractures of bones of reduced dimensions and of children, comprising a pair of clamps (2, 3) for bone screws (V) connected by respective lockable ball joints (5, 6) to a central body (4) of adjustable length formed of at least one male element (7) and one female element (8), which elements can be coupled telescopically, wherein said telescopic elements (7, 8) are at least partially radiotransparent so as to permit radioscopy of the fracture even through the central body (4);

• each clamp (2, 3) comprising a substantially prismatic portion (9, 10) having a continuous axial cavity (20, 21) in which there is housed a ball (24, 25) connected to a respective telescopic element (7, 8);
• a stop sleeve (28, 29) inserted in a respective continuous axial cavity (20, 21), said sleeve (28, 29) having at one longitudinal end a first substantially semispherical seat 30, 31 adapted to interact with a respective ball (24, 25) and at the opposite longitudinal end a diametral cylindrical seat (32, 33);
• and a transverse eccentric pin (34, 35) rotatably supported at the free end of each clamp (2, 3) so as to interact with a respective bushing (28, 29) in correspondence with the diametral seat (32, 33) of the latter and to lock said ball (24, 25).

An external fixator comprising an adjustably extendable elongate body with first and second bone-screw clamps ball-joint-connected to the respective longitudinal ends of said body, each of said longitudinal ends having an affixed ball element extending outward for socket reception at the bone-screw clamp to which it is thus connected, and each bone-screw clamp comprising:

• a rectangular-prismatic body with a first flat clamping surface, a clamping plate with a second flat surface overlapping said first flat surface, at least two bone-screw locating grooves on one of said surfaces, and a bolt through said plate and engaged to said prismatic body for securing bone screws to said prismatic body, said prismatic body having an elongate clamp bore sized for running clearance with a ball element and having a ball-retaining inward lip formation at a ball-retaining end of said clamp bore, and means including a rotary cam journalled in a transverse bore of said prismatic body for releasably driving the ball element into locked engagement with said lip formation.

An external fixator, comprising an elongate central body with first and second bone-screw clamps connected to the respective longitudinal ends of said body,

• said body comprising an elongate outer-body member having a cylindrical bore with a distally open end and a closed proximal end adapted for connection to one of said bone-screw clamps, and an elongate inner-body member having a cylindrical body portion telescopically guided by said cylindrical bore, said outer body member being of radiopaque material,
• said inner-body member having (i) a distal end received in said bore via the distally open end of said outer-body member and (ii) a proximal end adapted for connection to the other of said bone-screw clamps, said inner-body member being of radio-transparent material.