An analysis of the use of the Kellgren and Lawrence grading system to evaluate peritalar arthritis following total ankle arthroplasty.

ABSTRACT

BACKGROUND: The Kellgren and Lawrence grading system (KLGS) has been used throughout the literature for the radiographic staging of osteoarthritis (OA) of the peritalar joints. Despite its widespread use, the KLGS has never been validated for use in this clinical circumstance. The purpose of this study was to determine the inter- and intrarater reliability of the KLGS in the assessment of radiographic progression of OA in the peritalar joints following total ankle replacement (TAR). METHODS: One hundred twenty pre- and minimum 5-year postoperative weight-bearing lateral radiographs following 60 consecutive cases of TAR were utilized. Each individual film was considered separately for the purposes of this study. Of those films, 93 and 98 were found to have adequate visualization of the subtalar (STJ) and talonavicular (TNJ) joints, respectively. Three qualified reviewers graded the films according to the KLGS on 2 separate occasions, with 1 month separating the 2 readings. The results were analyzed for intra- and interobserver reliability. The degree of agreement was analyzed using the weighted kappa (κ(w)) statistic, Fleiss's kappa (Fleiss's κ), and percentage agreement RESULTS: Interrater agreements were moderate (κ(w) = 0.37 ± 0.06; Fleiss's κ = 0.21 ± 0.03) for the STJ to fair (κ(w) = 0.43 ± 0.06; Fleiss's κ = 0.25 ± 0.03) for the TNJ. Intrarater agreements for the STJ were moderate (mean κ(w) = 0.43 ± 0.07) and moderate for the TNJ as well (mean κ(w) = 0.46 ± 0.07). The reliability of the KLGS, although not originally designed for use in the setting of inflammatory arthropathy, was not notably affected when being used to grade inflammatory versus noninflammatory arthropathy. CONCLUSIONS: The KLGS is likely not a reliable tool for grading the degree of OA present in the peritalar joints prior to treatment and following TAR for research purposes. Using the KLGS in the setting of inflammatory arthritis versus OA did not produce any notable differences in the observed reliability. It is important to remember this has not been assessed in the clinical environment. Further work is required to determine the optimal method for assessment of peritalar OA. LEVEL OF EVIDENCE Level II, prospective comparative study.