Background: Total knee arthroplasty (TKA) is 1 of the top 2 most common and expensive surgical procedures among Medicare beneficiaries. Due to the procedure's high annual cost, overdiagnosis and subsequent overutilization of TKA has substantial health-policy implications. Concerns regarding the overexaggeration of radiographic findings and overutilization of TKA have been expressed by medical insurers. Currently, the standard of care for assessing potential knee arthroplasty candidates includes assigning a Kellgren-Lawrence (KL) radiographic score. Our study investigated the accuracy of reported preoperative KL scores in patients undergoing TKA.
Material and methods: Records of 277 patients who had underwent TKA at our institution for knee osteoarthritis were randomly selected from a large patient data registry and retrospectively reviewed. Two blinded raters assigned KL scores to the radiographs obtained during the preoperative assessment, which were compared to the scores reported by the operative surgeon. An intraclass correlation coefficient (ICC) was calculated to determine inter-rater reliability.
Results: Between blinded raters, ICC3k = 0.88 (95% confidence interval: 0.86-0.90, P < .001), demonstrating good reliability. Between all raters, ICC2k = 0.89 (95% confidence interval: 0.86-0.90, P < .001), also demonstrating good agreement. Raters fully agreed on the KL classification for 196 patients (70.76%). Compared with blinded raters, the operative surgeon assigned lower KL scores.
Conclusion: Reporting of KL score is consistent between operative surgeons and independent reviewers. In cases of disagreement between reviewers, the operative surgeon was generally more conservative in their estimation of the extent of osteoarthritis present radiographically. Concerns regarding inflation of radiographic findings to support surgical preauthorization are unwarranted.
Keywords: Inter-rater reliability; Kellgren-Lawrence; Osteoarthritis; Radiographs; Total joint arthroplasty; Total knee arthroplasty.
© 2022 The Authors.