Fused loop of filamentous material and apparatus for making same

An ultrasonic suture welding apparatus comprising a first member extending along a first (Y) axis and having a first surface at an end thereof, said first member being capable of vibrating and delivering mechanical energy at ultrasonic frequencies to said first surface, a second member having a second surface, means for moving said first member relative to said second member to define a gap between said first surface and said second surface, wherein said second member is stationary relative to said first member, and fixture means adapted to receive and maintain adjacent two or more segments of a suture material to be welded together in a predetermined alignment at least in part in the direction of a second (X) axis in said gap between said first and second surfaces of the first and second members during a welding operation, where said Y axis is perpendicular to said X axis:

• wherein a contour of at least said first surface substantially is concave with respect to said X axis, and corresponds to the contour of a segment of said suture material to be welded, so as to promote acoustic coupling therebetween and establish substantially continuous contact between said first surface and said segment over the length of said first surface.