Q1. How do I determine the start and end point of the TTA osteotomy?
A. Endpoint=distal limit of tibial crest where it joins the tibial diaphysis.
Start= cranial to cranial intermeniscal ligament and muscular groove of proximal tibial but caudal to insertion of straight ligament of patella. Osteotomy runs roughly parallel to cranial edge of the tibial crest, critically crest fragment must have enough width to accommodate plate and fork holes without risk of fracture.
Q2.How do I select the correct implants?
A. Plate size- Using template against length of tibial crest. Ideally leaving 3mm between distal plate hole and distal crest. Leave room between tip of plate and tip of tibial tuberosity to accommodate ear tab of Ti cage. Advancement cage size determined by use of template against plateau slope and patella ligament angle. Width of cage by use of depth gauge.
Q3.Exactly where do the fork holes go?
A. Plan to have bottom hole 3mm from distal limit of tibial crest fragment. Line of fork holes should run parallel to front edge of tibial crest and be 3mm back from the front edge of the crest.