Knee distractor

A knee distracter comprising a lower element (1) and two upper elements (2,3) located above the lower element, operating means (4) for moving each upper element independently to adjust its distance from the lower element and in which said operating means for each upper element comprises first and second crossed arms (6,7) which are pivoted together at intermediate points (8) in their lengths to provide a scissors action between them, a first end (9) of a first arm (6) being connected by a fixed pivot (10) to an upper element (2) and a second end (5) of said first arm being connected by a sliding pivot (25,33) to the lower element, a first end (11) of the second arm (7) being connected by a fixed pivot to the lower element and a second end (12) of said second arm being connected by a sliding pivot (25,33a) to the upper element, and means (15) for drawing the sliding pivot on one arm towards or away from the fixed pivot on the other arm to cause the distance between the upper and lower element to be adjusted.