Improved bone fixation system

Claim 2

An external bone fixation system including at least one elongate member (38) for coupling to a bone fragment characterised in that it includes, at least two pin carriers (37) mountable on the elongate member and adjustable thereon between a first condition in which the pin carrier may rotate about and slide along the elongate member and a second condition in which the pin carrier is rigidly fixed to the elongate member, each pin carrier having means (15, 30, 31) at one end thereof rigidly to hold a bone fixation pin and being adapted so as to allow at least two adjacent pins to be inserted into the single bone fragment with a minimum axial separation of not greater than lcm and with a maximum included angle (B) between the longitudinal axes of said adjacent pins of at least 30 0 .

Claim 3

An external bone fixation system according to Claim 1 characterised in that it includes an articulation block (1) for mounting between a first elongate member (38) coupled to a first bone fragment and a second elongate member (39) coupled to a second bone fragment, the articulation block having at least one bore (4) for accommodating an end of the first elongate member (38) and at least one other bore (5, 6) for accommodating an end of the second elongate member (39), at least one of said elongate members having attached at said end means (10) to allow the elongate members to be angularly and rotationally moved with respect to each other.

Claim 4

An external bone fixation system according to Claim 1 or Claim 2 characterised in that each pin carrier comprises a first block (13) including at one end a semi-cylindrical cut-out (15), a second block (12) including a matching semi-cylindrical cut-out (14), the cylindrical bore so produced being capable of slidably and rotatably accommodating said first or second elongate member, the first and second blocks each including at least two aligned bores for accommodating tightening screws (19), the pin carrier also including end members (18) having aligned bores for placing at each end of the pin carrier, the end of the pin carrier being adapted so as to accommodate a bone fixation pin such that an end member may be tightened against the end of the pin carrier to hold the pin in position in the pin carrier.

Claim 5

An external bone fixation system according to any of the preceding claims characterised in that the bone fixation pin (17) has a tapered end (32) of which the point is planar with a self-drilling cutting edge and clearance angle.

Claim 6

An external bone fixation system according to any of Claims 2 to 4 characterised in that it includes a first easily detachable device (11) for allowing, when fitted to the fixation system, the two elongate members to rotate and slide axially with respect to each other, so that both torsional forces and axial loading may be transmitted through the bone.

Claim 7

An external bone fixation system according to Claim 5, characterised in that it includes a second easily detachable device (41) for allowing, when fitted to the fixation system in addition to the first device (11), the two elongate members to slide axially with respect to each other whilst preventing relative rotation therebetween, so that axial loading only is transmitted through the bone.

Claim 8

An external bone fixation system according to any of the preceding claims characterised in that it includes a wrench having means (56, 57) for loosening and tightening all the screws within the bone fixation system.

Claim 9

An external bone fixation system according to any of the preceding claims characterised in that it includes a first modified pin carrier (20b) for allowing two adjacent pins to be inserted into the bone fragment with an included angle between the respective longitudinal axes of the pins of up to 90°.

Claim 10

An external bone fixation system according to any of the preceding claims characterised in that it includes a second modified pin carrier (20a) for allowing two adjacent pins to be inserted into the bone fragment with an axial separation of Ocm or more.