Mylène Jansen

360 Chapter 17 Comparison with untreated osteoarthritis patients In the 44 knees that received a TKA in CHECK, 124 KIDA measurements were available in the years before the TKA, which were used to confirm a linear approach to osteophyte change over time could be assumed, as the variable ‘years to TKA squared’ did not contribute significantly to the linear regression model predicting osteophyte size ( p= 0.759). CHECK patients showed a significant decrease in total WOMAC (-6.3; 95%CI -12.1 to -0.5; p =0.04) and MAC JSW (-0.67; 95%CI -0.86 to -0.47; p< 0.001) before undergoing TKA, as shown in Table 2. Before TKA, CHECK knees showed a small non-significant increase in osteophyte size (+2.1mm 2 ; 95%CI -1.2 to 5.5; p= 0.207; Figure 3A). Correcting for baseline osteophyte size, all KJD patients together ( p= 0.027), KJD HTO patients ( p= 0.043) and HTO patients ( p= 0.027) showed a significantly greater osteophyte increase than CHECK patients prior to TKA. Taking the average of both knees in patients with a TKA in both knees, instead of using the knees separately, did not change significance. Figure 3B displays the 2-year changes in total osteophyte size for the different groups. Figure 3 : Two-year changes in total joint osteophyte size in mm 2 . (A) Osteophyte size after treatment for all patients treated with knee joint distraction (KJD), high tibial osteotomy (HTO), HTO-indicated KJD patients (KJD HTO ), and for untreated knee osteoarthritis patients before receiving a total knee arthroplasty (CHECK). Mean and standard error of the mean (SEM) are shown, * indicates significant changes ( p< 0.05) compared to baseline using paired t -tests. (B) Two-year osteophyte size changes for individual KJD, HTO, KJD HTO and CHECK patients. Mean and 95% confidence interval are shown, p- values above groups indicate significance of 2-year changes. Relation with synovial fluid markers None of the 4 osteophyte locations showed statistically significant 1-year changes in Altman score compared to baseline in the SF patients (all p> 0.074; Supplementary Table S3). The total Altman osteophyte score summarized for the entire joint was at 1 year not different from