Mylène Jansen

282 Chapter 14 Table 1 : Baseline characteristics of the 3 patient groups KJD HTO (n=18) HTO (n=33) KJD TKA (n=18) P- value Age (years) 50.6 (5.3) 49.6 (5.5) 56.6 (6.5) <0.001 Male sex, n (%) 13 (72) 19 (58) 8 (44) 0.240* BMI (kg/m 2 ) 27.6 (3.4) 27.3 (3.4) 26.9 (3.8) 0.825 Leg axis (degrees) 5.7 (2.6) 6.1 (2.4) 2.1 (7.0) # 0.013 Kellgren-Lawrence grade, n (%) - Grade 0 - Grade 1 - Grade 2 - Grade 3 - Grade 4 0 (0) 5 (28) 4 (22) 9 (50) 0 (0) 1 (3) 4 (12) 10 (30) 14 (42) 4 (12) 0 (0) 0 (0) 1 (6) 7 (39) 10 (56) 0.001* Baseline cartilage MAC ThCtAB (mm) 2.5 (1.0) 2.4 (0.8) 1.8 (0.8) 0.044 LAC ThCtAB (mm) 4.1 (0.8) 4.0 (0.5) 4.0 (1.1) 0.881 MAC dABp (%) 16 (15) 14 (14) 34 (16) <0.001 LAC dABp (%) 5.6 (6.6) 3.3 (3.9) 8.4 (12) 0.075 Mean MAC JSW (mm) 2.4 (1.4) 2.2 (1.3) 2.1 (2.2) 0.786 Mean and standard deviation or n (%) are given. P- values were calculated with 1-way ANOVA, with post-hoc Tukey HSD tests in case of statistical significance (bold p- values), or chi-square (indicated with *). All statistically significant differences were between knee joint distraction patients indicated for total arthroplasty (KJD TKA ) and the other 2 groups; there were no statistically significant differences between KJD patients indicated for high tibial osteotomy (KJD HTO ) and HTO. # Leg axis measurements in the KJD TKA group were available in only 8 of 18 patients. dABp: percentage of denuded subchondral bone area; JSW: joint space width; LAC: less affected compartment; MAC: more affected compartment; ThCtAB: mean cartilage thickness over the total subchondral bone area. For around half of the included patients (46%) 3T MRIs were performed at baseline and 2 years (KJD HTO 33%, HTO 52%, KJD TKA 50%); the other patients received 1.5T MRI scans at baseline and 2 years. This number was not statistically significantly different between groups ( p= 0.432), so comparisons between groups were not corrected for field strength. Longitudinal changes by patient group MRI MAC cartilage thickness and denuded bone area (Figure 2A/B) in the KJD HTO group showed no significant changes over time; neither did the radiographic MAC JSW (Table 2). The HTO group, in contrast, displayed a significant decrease in MAC cartilage thickness and an increase in MAC denuded bone area. Yet, the HTO group showed a significant increase in radiographic mean MAC JSW. The KJD TKA group displayed a substantial increase in the MAC cartilage thickness and in mean MAC JSW, and a decrease in MAC denuded bone area.