Adjustable tibial trial insert

An adjustable tibial trial insert, comprising:

• an upper plate including an upper articular surface configured for articulation with a femoral surface;
• a lower plate positioned below the upper plate along an adjustment axis and including a lower surface configured for tibial fixation;
• and
• an adjustment arrangement arranged between the upper plate and the lower plate and actuatable for adjustment of a gap between the upper plate and the lower plate along the adjustment axis,
• the adjustment arrangement comprising at least a first scissor lift mechanism with a first lever arm arrangement and a second scissor lift mechanism with a second lever arm arrangement, the second scissor lift mechanism being separate from the first scissor lift mechanism,
• each of the first and second lever arm arrangements being indirectly connected to the upper plate and the lower plate,
• each of the first and second lever arm arrangements comprising a length and being pivotally movable between different positions for variation of said length along the adjustment axis to adjust the gap between the upper plate and the lower plate,
• the first scissor lift mechanism comprising an actuator element coupled to the first lever arm arrangement and configured such that actuation of the actuator element varies the length of the first lever arm arrangement, and
• the adjustment arrangement comprising at least one coupling element coupling the second scissor lift mechanism to the first scissor lift mechanism and configured such that the length of the second lever arm arrangement is varied synchronously to the first lever arm arrangement.