Mylène Jansen

50 Chapter 3 and an overall survival of 48% (Figure 1). Baseline characteristics and 1-year improvement for both groups are summarized and compared in Table 1. A statistically significant difference in sex was found between survivors and failures (survivors 88% male; failures 33% male; p= 0.024). Survivors showed a significantly larger initial increase in minimum JSW (survivors 1.5 (SD 0.7) mm; failures 0.4 (0.6) mm; p= 0.002) and a significantly greater decrease in bone density (survivors -6.5 (3.5) mm Al eq; failures -2.7 (3.7) mm Al eq; p= 0.046) than patients whose treatment failed. No statistically significant differences in other initial clinical or structural improvements were found between the 2 groups. Table 1 : Baseline characteristics and clinical and structural improvement in first year after treatment of survivors and patients whose treatment failed 9 years after treatment Survivors (n=8) Failures (n=9) P- value Baseline Age (years), median (IQR) 51.0 (3.3) 50.0 (9.0) 0.961# Male sex, n (%) 7 (87.5) 3 (33.3) 0.024 * BMI (kg/m 2 ) 27.7 (2.0) 30.1 (4.3) 0.161 Kellgren-Lawrence grade, median (IQR) - Grade 0, n (%) - Grade 1, n (%) - Grade 2, n (%) - Grade 3, n (%) - Grade 4, n (%) 3.0 (0.0) 0 (0) 0 (0) 1 (13) 7 (88) 0 (0) 3.0 (0.5) 0 (0) 1 (11) 1 (11) 6 (67) 1 (11) 0.567* WOMAC total (0–100) 46.4 (12.5) 45.4 (16.3) 0.884 VAS pain (100–0) 71.8 (6.9) 74.3 (9.3) 0.532 Mean MAC JSW (mm) 2.6 (1.6) 2.3 (1.0) 0.622 Minimum JSW (mm), median (IQR) 0.4 (1.9) 0.2 (1.5) 0.664# Bone density (mm Al eq) 43.6 (6.5) 40.4 (2.9) 0.231 Mean cartilage thickness (mm) 2.2 (0.7) 2.2 (0.4) 0.891 Denuded bone area (%) 30.0 (20.1) 21.5 (17.4) 0.367 Initial (First-year) changes Δ WOMAC total (0–100) 32.3 (19.5) 39.9 (24.1) 0.489 Δ VAS pain (100–0) -48.0 (30.9) -45.4 (29.1) 0.863 Δ Mean MAC JSW (mm) 1.4 (1.0) 0.6 (1.1) 0.157 Δ Minimum JSW (mm) 1.5 (0.7) 0.4 (0.6) 0.002 Δ Bone density (mm Al eq) -6.5 (3.5) -2.7 (3.7) 0.046 Δ MRI mean cartilage thickness (mm) 0.9 (0.6) 0.4 (0.7) 0.068# Δ MRI Denuded bone area (%) -25.9 (20.2) -15.5 (15.8) 0.254 Mean and standard deviation are given unless otherwise indicated. Significant p- values (<0.05) are in bold and calculated using independent t -tests, except values indicated with *, for which chi-square tests were used, or values indicated with # , for which Mann-Whitney U Tests were used. Al eq: aluminum equivalent; BMI: body mass index; IQR: interquartile range; JSW: joint space width; MAC: most affected compartment; VAS: Visual Analogue Scale; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index.