Pre-surgical radiologic identification of peri-prosthetic osteolytic lesions around TKRs: a pre-clinical investigation of diagnostic accuracy

Background: Emerging longitudinal data appear to demonstrate an alarming trend towards an increasing prevalence of osteolysis-induced mechanical failure, following total knee replacement (TKR). Even with high-quality multi-plane X-rays, accurate pre-surgical evaluation of osteolytic lesions is often difficult. This is likely to have an impact on surgical management and provides reasonable indication for the development of a model allowing more reliable lesion assessment. The aim of this study, using a simulated cadaver model, was to explore the accuracy of rapid spiral computed tomography (CT) examination in the non-invasive evaluation of peri-prosthetic osteolytic lesions, secondary to TKR, and to compare this to conventional X-ray standards. Methods: A series of nine volume-occupying defects, simulating osteolytic lesions, were introduced into three human cadaveric knees, adjacent to the TKR implant components. With implants in situ, each knee was imaged using a two-stage conventional plain X-ray series and rapid-acquisition spiral CT. A beam-hardening artefact removal algorithm was employed to improve CT image quality. After random image sorting, 12 radiologists were independently shown the series of plain X-ray images and asked to note the presence, anatomic location and 'size' of osteolytic lesions observed. The same process was repeated separately for review of the CT images. The corresponding X-ray and CT responses were directly compared to elicit any difference in the ability to demonstrate the presence and size of osteolytic lesions. Results: Access to CT images significantly improved the accuracy of recognition of peri-prosthetic osteolytic lesions when compared to AP and lateral projections alone (P = 0.008) and with the addition of bi-planar oblique X-rays (P = 0.03). No advantage was obtained in accuracy of identification of such lesions through the introduction of the oblique images when compared with the AP and lateral projections alone (P = 0.13) Conclusion: The findings of this study suggest that peri-prosthetic osteolytic lesions can be reliably described non-invasively using a simple, rapid-acquisition CT-based imaging approach. The low sensitivity of conventional X-ray, even with provision of supplementary bi-planar 45° oblique views, suggests a limited role for use in situ for TKR implant screening where peri-prosthetic osteolytic lesions are clinically suspected. In contrast, the accuracy of CT evaluation, linked to its procedural ease and widespread availability, may provide a more accurate way of evaluating osteolysis around TKRs, at routine orthopaedic follow up. These findings have direct clinical relevance, as accurate early recognition and classification of such lesions influences the timing and aggressiveness of surgical and non-operative management strategies, and also the nature and appropriateness of planned implant revision or joint-salvaging osteotomy procedures.Timothy P. Kurmis, Andrew P. Kurmis, David G. Campbell and John P. Slavotine

Impact Factor: outdated artefact or stepping-stone to journal certification?

A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table