In total knee arthroplasty, mechanical alignment guides have improved the accuracy of implant alignment, but errors are not uncommon. In the present study, an image free computer assisted navigation system was used to analyse the accuracy of an extramedullary (tibial) alignment system, which is based on predetermined, fixed anatomical landmarks. Comparisons were made between two surgeons, with different levels of competency in order to determine if experience affected the accuracy of extramedullary tibial
Orthopaedic ; ; ;

Current available implants for total knee replacement are based on the mormphometry of the Caucasian knee. We believe there are significant morphometric differences in the Asian knee that will be relevant in future implant designs. Sixty nine consecutive patients (80 knees) underwent computer navigated primary total knee arthroplasty. The anterior posterior (AP) length, and the medial lateral (ML) width of the distal femur, were analyzed, with respect to the final sizing details of four implants (femoral component) commonly used locally. The mean AP length was 59.9 (SD 4.8) mm, and the mean ML width was 65.0 (SD 5.0) mm. The overall mean aspect ratio (ML/AP) was 1.09 (SD 0.07). The mean aspect ratio for females was 1.08 (SD 0.07). Both were smaller than the aspect ratio of the implants which ranged from 1.11 to 1.13. All four implants tend to overhang at the medial lateral width of the distal femur. This is more obvious in females. Future implant designs should provide more ML wdth sizes for a given AP length, in addition to gender differences, for ths population.
Orthopaedic

The PROSTALAC (PROSThesis Antibiotic Loaded Acrylic Cement) functional spacer is made with antibiotic-loaded acrylic cement. We use it as an interim spacer in two-stage exchange arthroplasty in cases of infected total knee or total hip replacement. PROSTALAC allows continuous rehabilitation between stages as it maintains good alignment and stability of the joint with a reasonable range of movement. It also helps to maintain the soft-tissue planes, thereby facilitating the second-stage procedure. We report here early outcomes of the use of PROSTALAC in 5 patients - 3 in total knee replacements, 1 in a total hip replacement and 1 in a bipolar hemiarthroplasty.

This retrospective radiographic analysis of 57 patients (62 knees) examined two possible factors involved in pin tract fractures of the femur due to navigated total knee arthroplasty (TKA): the angle of the tracker pin with respect to the lateral femoral cortex, and the distance between the tracker pin and the lateral joint line. Our findings demonstrate a relationship between postoperative pin tract induced stress fractures (3 patients), with pin tract angles exceeding 15. Pin placement at a site more th
Orthopaedic