Mylène Jansen

One-year follow-up after KJD treatment with the KneeReviver 173 9 Statistical analysis Independent t -tests, or chi-square tests in case of categorical parameters, were used to compare baseline characteristics between groups. Primary outcomes were the total WOMAC and minimum JSW; secondary outcomes were the SF-36 and VAS pain; tertiary outcomes were the MAC radiographic JSW, the LAC JSW and the mean joint JSW. Paired t -tests were used to calculate changes at 1 year compared to pre-treatment for all parameters. Differences between groups in 1-year changes were calculated with linear regression, correcting for baseline values. Non-inferiority was calculated using linear regression, using the unstandardized B coefficient as mean difference and 90% confidence interval (90%CI). For the clinical outcome parameters, 2/3 of the minimal clinically important difference (MCID) was chosen as non-inferiority limit, viz. 10 points for the WOMAC, 7 points for the SF-36, and 2 points for the VAS pain. 19–21 For the minimum JSW, the 1-year change observed in the previously treated RCT patients was used as the non-inferiority limit; viz. not accepting a decrease in JSW. A p- value <0.05 was considered statistically significant. IBM SPSS 25 was used for all analyses. Results Patients The baseline characteristics of the 39 included patients per group are shown in Table 1. In both groups, 1 patient underwent a total or unilateral knee arthroplasty within 1 year after treatment, and as such was not included in these analyses. Also, in both groups, 1 patient showed a significant technical difference in radiographic acquisition (positioning) between baseline and 1-year follow-up that was judged to provide unreliable KIDA data. Therefore, these JSW measurement results were excluded from analysis, and JSW results are based on a total of 38 patients per group. Patients treated with the KneeReviver had a clinically (pain and function) worse condition than the Dynamic Monotube treated patients as they had statistically significantly worse baseline clinical scores as reflected by lower scores of WOMAC total and all WOMAC subscales, higher VAS pain, and lower SF-36 PCS (all p< 0.025). Contrarily, the KneeReviver patients had less severe radiographic joint damage with a higher, though not statistically significant, minimum and MAC radiographic JSW ( p= 0.091 and p= 0.169, respectively). Lastly, KneeReviver patients had a significantly lower LAC JSW ( p< 0.038). The baseline parameters of the 39 KneeReviver patients included in this interim analysis did not differ statistically significantly from the whole group of 65 KneeReviver patients (all p> 0.15); JSW parameters were not compared since radiographs were analyzed in pairs (baseline and 1 year) and as such were not available for the patients not included in this interim analysis.