US 5,496,324 AGranted

Proximal body milling apparatus

AssigneeZimmer, Inc.

InventorMilton F. Barnes

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Abstract

A milling apparatus 2 including an articulated cutter 20 and an inverted L-shaped frame 10 for removing a unique geometric volume of bone to receive a prosthetic implant stem. Cutter 20 is housed within frame 10 for rotational movement about its longitudinal axis and lateral movement along a guide 16, which extends laterally from frame 10. Cutter 20 includes a pair of articulated arms 30, 32 each carrying a plurality of cutting blades 40. The proximal end 22 of cutter 20 is seated in an elongated non-radial race 17 formed in guide 16. Articulated arms 30, 32 provide a "scissoring" action which allows cutter 20 to be compressed longitudinally when shifted to one end of race 17 and extended longitudinally when shifted to the opposite end of race 17. The scissoring action of arms 30, 32 also changes the angle of the cutting face of blades 40 carried by arms 30, 32. Consequently, milling apparatus 2 creates a receiving cavity having an egg-shaped cross section.

Claims3

Dependent claims

An apparatus used to cut a cavity in a bone for receiving an implant comprising:

a frame part having a distal end insertable into said bone,
a guide extending laterally from said frame and having a race defined therein, said race having a first end and a second end,
an articulated cutter having a longitudinal axis and being pivotally connected to said frame and carded within said guide for rotation about the cutter's longitudinal axis and for movement within said race,
said articulated cutter including a first arm part, a second arm part and a shaft, the second arm part includes blade means for removing a portion of said bone when said cutter is rotated, the first arm part is hingeably connected to the shaft at one end and to the second arm part at an opposite end, said shaft defining the longitudinal axis of the articulated cutter, said articulated cutter being responsive to contact with said race for positioning said second arm part and the blade substantially parallel to said cutter's longitudinal axis when said cutter is shifted to the first end of said race and for angularly positioning said second arm part and the blade away from said cutter's longitudinal axis when said cutter is shifted toward its second end.

1 more element

Dependencies are inferred from the claim text.