The aim of tissue sparing surgery in total knee arthroplasty is to reduce surgical invasivity to the entire knee joint. Surgical invasion should not be limited only toward soft tissues but also toward bone. The classic technique for total knee arthroplasty implies intramedullary canal invasion for proper femoral component positioning. This phase is associated to fat embolism, activation of coagulation, and occult bleeding from the reamed canal. The purpose of our study was to validate a new extramedullary device which relies on templated data. Two-hundred patients in four different orthopaedics centres were randomized to undergo primary total knee arthroplasty either using standard intramedullary femoral instruments (IM group) or using a new extramedullary device (EM group). A new set of instruments was developed to control the sagittal and coranl plane of the distal femoral resection. The extramedullary instrument was calibrated referencing to templated data obtained from the preoperative long-limb radiograph (Fig 1, 2). Varus-valgus orientation of the resection were established by moving the two paddles according to templated data. An L-shaped sliding tool (5 centimetres long) over the anterior cortex controls the flexion-extension parameter of the resection and is intended to allow a cut flush with the anterior cortex at 0° of angulation with the distal aspect of the femoral diaphysis on the sagittal plane Femoral component coronal alignment was within 0±3° of the mechanical axis in 86% of the IM group and 88% of the EM group. Sagittal alignment of the femoral component was 0±3° in 80% of the IM group and 94% of the EM group. There was no difference in the average operative time between the two groups. The EM group showed a trend toward less postoperative blood loss Extramedullary reference with careful preoperative templating can be safely utilized during total knee arthroplasty.
The chioce of the graft and its fixation in LCA reconstruction is basic for the outcome of the surgical procedure. Several solutions have been proposed; each of them had advantages and disavantages. The choice of the graft and the surgical technique is often due to surgeon’s opinion. The goal of the fixation is stability which allowes incorporation of the graft in the bone tunnels. Bone-patellar tendon-bone graf has the advantage of bone to bone fixation which is impossible using tendon grafts. Femoral fixation techniques for hamstrings can be classified in: compression tecniques, expansion tecniques and suspension tecniques (cortical or canellous). TTS (Top Traction System) is a new tecnique for femoral fixation using hamstrings. The fixation is achieved by a retrograde screw that allowes fixation to the antero-lateral cortex of the femur. A ring is fixed to the screw to allow tendons passing. The screw is sefl-threading, its lenght is 28 millimeters and its diameter is 6,5 millimeter; its pull-out strenght is 1350 N. The screw is built in titanium alloy and only one size. Surgical technique is simple an reproducible and the instruments are easy to use. The positioning of the screw is fully guided by instruments that minimize errors. This fixation device allowes further graft traction after tibial fixation without twisting hamstrings. Results after 5 years are good but we need long term follow-up for final opinion.
