[Knee endoprosthesis: aspects of surgical techniques].

The implantation of a condylar knee has remained a challenge for surgeons and the equipment of the hospital. In contrast to total hip arthroplasty, not only is the correct insertion of the implant crucial, but also the treatment of the surrounding soft tissues. Mediolateral soft tissue balance and balance between flexion and extension gaps, as well as centering the patella, have to be done carefully. The soft tissue envelope of the knee joint is thin and prone to necrosis after multiple incisions. Damage to the extension mechanism can make a total joint useless. Tearing the patellar ligament from the tibial tuberosity must therefore be avoided by all means during operation. Precise cutting of the distal femur is only possible if excellent equipment is used by a skillful surgeon. The same is true for orientating saw cuts related to the long leg axes. These tasks can probably be taken over by navigation systems and robots in the future. Because the definite choice of implants has to be made intraoperatively, a complete modular system has to be present in the hospital. Only hospitals that can properly equip their surgeons to manage upcoming soft tissue problems and bony deficiencies should offer treatment to patients requiring condylar knee arthroplasty.