Abstract
Purpose: To assess the clinical utility of a computer-based program (discrete dynamic contour method of boundary refinement; Matlab®) to quantify the location and extent of periprosthetic osteolysis around cemented total knee arthroplasties.
Methods: The radiographs of 171 primary Anatomical Modular Knee arthroplasties were reviewed by three independent, blinded raters using Matlab® software program. The location, size (mm2), polyethylene sterilization technique, alignment, presence or absence of femoral osteolysis and patient characteristics was recorded.
Results: The mean duration of follow-up was 8.47 ± 1.10 years with minimum in vivo wear interval= 2.0 years. The overall incidence of radiographically apparent osteolysis was estimated at 30.41%. Furthermore, the average intra-class correlation coefficient for this measurement technique for three independent observers was found to be significant for medially and laterally located zones of osteolysis (I.C.C. value = .7801; 95% C.I. = .7161–.8316; (p< .05). There was a statistically significant trend towards higher rates of osteolysis occurring within the series of polyethylene inserts gamma irradiated in air. Lowest rates of osteolysis were measured in the series sterilized in gas plasma (27.09 mm2 per year vs. 16.24 mm2 per year respectively; p< .001).
Conclusions: The Discrete Dynamic Contour method of boundary refinement represents an acceptably reliable means by which one can quantify the location and extent of osteolysis based upon digitalized radiographs of total knee replacements.
Correspondence should be addressed to Cynthia Vezina, Communications Manager, COA, 4150-360 Ste. Catherine St. West, Westmount, QC H3Z 2Y5, Canada
