Step 9

If the zero position of the cutting guide produces a resection which removes too much bone, then the 2mm,4mm or 6mm plates may be added to raise the level of the cut so that notching of the anterior femoral cortex does not occur. If in doubt always use a thicker cutting plate to remove the minimum amount of bone, more can be removed later if required.

Step 10

Once a satisfactory resection of the anterior trochlea has been achieved, place the Trial Template onto the cut bone surface. Sizing is correct when a gap of 2mm is present between the template and the anterior part of the intercondylar notch. This will allow a thin bridge of intact articular cartilage between the intercondylar notch and the posterior edge of the prosthesis. The articular cartilage at the edge of the template is marked with a pen. (see step 12b).

Step 11

The articular cartilage underlying the area of the template is removed so that the prosthesis can be inset close to the articular edge. This can be lifted off the sub-chondral bone using a 10mm osteotome held in bold hands and moved vertically across the surface. A 5mm osteotome is used to complete the removal at the tip of the prosthesis.