Abstract
It is believed by some that knee radiographs may underestimate the extent of osteoarthritis. Often severe changes are noted at arthroscopic assessment despite the observation of preserved joint spaces on plain radiographs. This has important implications regarding the indications for different types of partial joint replacement if damage is underestimated.
Aims:
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To determine the correlation if any between radiographic findings and arthroscopic findings.
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To determine which radiographs are consistently useful for assessment of osteoarthritis and to determine the limitations.
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To identify the proportions of patients with certain patterns of damage who might be suitable in the future for different types of partial replacement.
Methods and patient selection: The pre-operative radiographs and intra-operative articular surface mappings were collected for 100 consecutive patients undergoing prospectively audited outcome of arthroscopic debridement. All the patients examined were aged 40 and above with knee pain. The intra-operative findings and any work done (debridement of meniscal tears or cartilage flap tears) were also recorded on zoned articular maps and meniscal diagrams. The pre-operative radiographs (AP standing, lateral, Rosenberg and skyline views) were examined and graded using the Kellgren and Lawrence grading system.
Results: Correlations made between arthroscopic findings and AP standing views yielded a sensitivity of 72% and specificity of 64%. The positive predictive value was 91% and negative predictive value was 32%. Rosenberg views were better at predicting the presence of osteoarthritis (sensitivity 76%, specificity 88%, positive predictive value 97%, negative predictive value 44%). Skyline views were found to particularly unreliable in assessment of patello-femoral damage. Analysis of the actual patterns of articular damage found at arthroscopy did show that it is possible to identify cohorts of patients who may in future be suitable for different types of partial replacement.
Conclusions: Radiographs and in particular skyline views are limited in terms of sensitivity and specificity in the prediction of osteoarthritis. Rosenberg views offer better prediction of osteoarthritis compared with weight bearing AP radiographs. Arthroscopy carried out in any event for clinical indications appears to offer useful additional information regarding indications for future surgery.
Correspondence should be addressed to BOSA at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE, England.
