ASSESSMENT OF POLYETHYLENE WEAR IN TOTAL HIP ARTHROPLASTY: A COMPARITIVE STUDY OF COMPUTER SOFTWARE VERSUS THE LIVERMORE METHOD.

Abstract

Aim: Assessing Polyethylene wear is very important in following up patients after Total hip replacement (THR) and Livermore method (using callipers) is routinely used by clinicians in calculating this wear. Our aim was to assess if ‘Imagika’, a new computer software programme can accurately assess polyethylene wear(PE-wear). We also compared the computer software with the Livermore method in calculating wear.

Method: We used 15 different THR X rays of patients who had an ABG total hip replacement done. X rays that were included for the calculations were taken at different time intervals following the operation. Wear was calculated on each X ray by 3 clinicians using both the methods, on 3 separate occasions. We compared the Livermore method and the computer software for consistency of measurements and also calculated the inter and intra observer variability for both.

Results: There was a statistically significant difference (at the 5% level) between the measurements taken by the Imagika software and the Livermore method. F(1,88) = 5.38, p< 0.05. There was a statistically significant difference in the inter-observer measurements using the Livermore method. F(2,42) = 4.18, p< 0.05, but there was no significant inter-observer variation using the Imagika computer software. There was no statistically significant difference (at the 5%level) in the intra-observer variability of both groups.

Conclusion: The Imagika computer software proved to be better than the Livermore method in calculating wear with regards to inter-observer bias. There was also a significant difference between measurements taken using both methods. We conclude that the computer software may be a more accurate tool in the assessment of PE-wear in the future.