Tibial section with extramedullary aiming

Preparation of the tibial section requires maximal flexion and anterior subluxation of the patient's knee. If the anterior cruciate ligament is present, it should be resected. Sub-periosteal dissection of the deep part of the medial lateral ligament up to the level of the insertion of the semimembranous muscle, makes anterior subluxation of the tibia easier. The tibial alignent viewer has 3 adjustment settings : -a vertical setting for different tibial lengths -an antero-poterior setting to check flexion/extension or the posterior slope of the tibial resection -a frontal setting to check the varus-valgus alignment of the proximal resection of the tibia The bearing spring puts the distal part of the unit into position : the centre of the peg should line up with the V-shaped part of the instrument. Alignment can be performed by lining up the V-shaped part with a line passing through the second toe.

Right-angled tibial viewer

The right-angled tibial viewer (0 or 5 degrees posterior resection) is slid into place on the tibial alignement viewer. The locking screw is tightened to allow the 2 devices to be installed. The probe for femoral preparation is put into the hole at the top of the tibial aimer. Its spike is placed into the deepest cup of the most damaged tibial plate or at the desired level of resection. The level of resection only gives an initial impression and can be alered according each case and the surgeon's opinion. The aimer has 3 sets of holes. In the middle ones, two 3.2 mm diameter drills or fixing pins. The two proximal holes allow the surgeon should he so wish, to increase the level of bone resection by 2 mm. Alternatively, the two distal holes give the possibility of decreasing by the same amount. The tibial alignement aimer can then be removed by undoing the screw which keeps the guide in place. The tibial plate is resected. To avoid cutting the posterior cruciate ligament by accident it can be protected with an osteotome.