Patent ID: 8828064
Filing Date: 2014-09-09
Classification: A61B

Abstract:
1. A bone fixation apparatus comprising: a bone fixation plate having a fixation hole; a fastener shaft received in the fixation hole and including a first portion having an outer surface defining a first cam and a second bone-engaging portion; and an annular member received in the fixation hole and including an inner surface defining a second cam for cooperating with the first cam to selectively move the annular member in a radial direction between an unexpanded position permitting movement of the fastener shaft and annular member relative to the fixation hole and an expanded position restricting movement of the fastener shaft and annular member relative to the fixation hole, the annular member including separated ends defining a gap therebetween and being moved between the expanded position and the unexpanded position by rotation of the annular member following insertion of the fastener shaft into a bone; wherein each of the first and second cams include three continuously curved lobes.