Abstract
Introduction: Computerised navigation has been a recent addition to the armamentarium of both total hip and knee arthroplasty, following earlier experiences in neurosurgery and trauma. The first navigation devices available for total hip arthroplasty (THA) provided the surgeon with information on acetabular component placement. The current generation of hip navigation packages provide guidance with both acetabular and femoral component placement, as well as information on restoration of leg length and offset.
Method: We used the Stryker hip navigation system.
Results: We have performed in excess of 60 total hip replacements using imageless computerised hip navigation through a number of approaches including: standard posterior, mini-posterior and double-incision approaches. Our results show an increase in accuracy of component placement using computerised navigation as compared with conventional alignment guides, which is in keeping with previous cadaver and clinical studies. The accuracy of the navigation unit appears independent of incision type or size. The limiting factor with all current forms of navigation is the requirement for rigid tracker fixation to both the pelvis and the femur. Until recently, this required insertion of threaded pins and soft-tissue dissection. Loosening of pins or inadvertent pressure on a tracker may lead to false readings and the potential for inaccurate readings. The introduction of percutaneous tracker fixation has decreased problems associated with this. The streamlining of the software program, as well as the introduction of smart tools has decreased the extra time taken to 10 minutes per case.
Conclusion: The first generation of hip navigation units have been able to provide the surgeon with additional information with regard to the normal patient anatomy and allow the surgeon to more accurately place both the femoral and acetabular components. In this introductory period we have seen massive advancements with hardware (trackers and cameras have doubled in accuracy and halved in size) and the software has become more intuitive and less intrusive in the surgical process. We now await clinical studies that confirm that the use of navigation devices in total hip arthroplasty provide clinical advantages to the patient in the form of decreased dislocation rates, more accurate leg length and offset correction and better functional outcome. Navigation is being increasingly used as an adjunct to minimally invasive surgery, ensuring more accurate component position in the face of limited visibility.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
