Computer Navigation Joint replacement Surgery

Computer navigation is a technique which aids the surgeon during surgery to achieve perfect alignment.

Conventionally, mechanical jigs were used for this surgery. The use of these jigs involved certain amount of judgment, so called “eye-balling” on the part of the surgeon. Ironically, sometimes even when the case is in best hands, the judgment can be incorrect in 30% of cases. The reason for this is that human anatomy is variable, and it is not always possible to predict the variation in surgical technique required to match a particular patient. In other words, a ‘cook book’ approach does not work all the time.

It is important to realize that conventional techniques in TKR Surgery have resulted in a high prosthesis survival rate lasting up to 15–20 years. As the CAS has survived its infancy, it is therefore important that functional and clinical outcomes be collected on a regular basis in order to elucidate the role of it.

Navigation was first introduced experimentally in the 1980s and clinically in the 1990s, but has only entered mainstream orthopaedics in the last 7 years. CAS is developing rapidly and undergoing drastic evolution. It is being used in orthopedics with a multiple applications, ranging from knee and hip arthroplasties to pedicle screw placement. The current optical systems are likely to be replaced by electromagnetic or other types of registration and tracking systems.

The Computer-assisted systems (CAS) are active (surgical robots) or passive i.e. systems that do not perform any part of the knee replacement surgery, but assist in the positioning of the surgical instruments.


 Dynamic assessment of deformity at any angle of flexion with patella in situ as opposed to conventional TKR where tensioning devices can be used in zero and 90° only.

– Calculation of soft tissue tension to give a perfectly balanced knee.

– Accurate restoration of mechanical limb axis.

– Reduced blood loss.

– Decrease in incidence of fat embolism due to extra-medullary instrumentation.

– Accuracy of data on soft tissue tensions even in 1 mm and 1°. Surgeon is given control, feedback, ability to correct errors and documentation needed by CAS.


  • Prolonged operative time.
  • Certain learning curves.
  • Significant cost implication for purchase and maintenance of the system.
  • Lack of adequate evidence of the long-term benefits of CAS over conventional surgery in terms of implant survivorship and patient benefits for TKA.