Zimmer Gmbh

Ramesh Annayappa

Adam H Sanford

Brian D Byrd

Jeffery A VanDiepenbos

A tibial prosthesis, and, particularly, a fixed bearing tibial prosthesis is disclosed that has a two-pronged securement mechanism. The securement mechanism may or may not be angled. Advantageously, the securement mechanism, working alone or in cooperation with other securement features, minimizes micromotion between the tibial tray and tibial bearing component.

Tibial prosthesis

A tibial prosthesis has a bearing component configured for an anterior-medial insertion, which advantageously avoids the extensor mechanism of the knee. A tibial tray may include a banana-shaped boss that corresponds to a notch formed in the bearing component. After the bearing component is inserted along the anterior-medial path, the boss is received within the notch by rotating the bearing component with respect to the tibial tray. This rotation seat the bearing component upon the tibial tray in the manner of a fixed-bearing prosthesis. Alternatively, the boss and notch may define angled central axes which allow straight anterior-medial insertion of the bearing component and locking engagement to the tibial tray.

Tibial prosthesis with a fixed bearing component

A tibial prosthesis can include a bearing component and a tibial tray. The bearing component can include at least one concave articulating surface, a distal surface opposite said concave articulating surface, and a notch formed in said distal surface. The notch can define a longitudinal axis, the longitudinal axis defining an offset axis angle relative to the sagittal plane. The offset axis angle can range from greater than zero degrees to about 90 degrees. The tibial tray can include a support surface capable of supporting said bearing component, the support surface having a lateral edge and a medial edge opposite said lateral edge. The tibial tray can further include a boss having a longitudinal axis, the longitudinal axis angled with respect to the sagittal plane. The boss can be lockingly engageable with said notch along said offset axis angle to lock said tibial tray to said bearing component.

A tibial prosthesis has a bearing component configured for an anterior-medial insertion, which advantageously avoids the extensor mechanism of the knee. A tibial tray may include a banana-shaped boss that corresponds to a notch formed in the bearing component. After the bearing component is inserted along the anterior-medial path, the boss is received within the notch by rotating the bearing component with respect to the tibial tray. This rotation seats the bearing component upon the tibial tray in the manner of a fixed-bearing prosthesis. Alternatively, the boss and notch may define angled central axes which allow straight anterior-medial insertion of the bearing component and locking engagement to the tibial tray.

Methods related to seating of bearing component on tibial tray

A tibial prosthesis, and, particularly, a fixed bearing tibial prosthesis has a two-pronged securement mechanism. The securement mechanism may or may not be angled. Advantageously, the securement mechanism, working alone or in cooperation with other securement features, minimizes micromotion between the tibial tray and tibial bearing component.

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Bengaluru, India

Ramesh Annayappa