Abstract
This study investigated the intra-observer errors in obtaining visually selected anatomic landmarks that were used in registration process in a non-image based computer assisted TKR system.
The landmarks studied were centre of distal femur, medial and lateral femoral epicondyle, centre of proximal tibia, medial malleolus and lateral malleolus. Repeated registration in the above sequence was done for one hundred times by one single surgeon.
The maximum combined errors in the mechanical axis of the lower limb were only 1.32 degrees (varus/valgus) in the coronal plane and 4.17 degrees (flexion/extension) in the sagittal plane. The maximum error in transepicondylar axis was 8.2 degrees.
The errors using the visual selection of anatomic landmarks for the registration technique of bony landmarks in non-image based navigated TKR did not introduce significant error in the mechanical axis of the lower limb in the coronal plane. However, the error in the transepicondylar axis was significant in the “worst case scenario”.
The abstracts were prepared by Editorial Secretary Jean-Claude Theis. Correspondence should be addressed to NZOA at Department of Orthopaedic Surgery, Dunedin Hospital, Private Bag 1921, Dunedin, New Zealand.
