Mylène Jansen

Cartilage collagen structure after KJD and HTO using T2-mapping 311 15 Comparison with Osteoarthritis Initiative Regression analysis investigating the influence of baseline measures on cartilage T2 change were calculated from the (combined medial and lateral) femur and tibia using T2 times of 421 OAI participants that had at least 2 time points available. None of the patient characteristics had a significant influence on these changes over time, but baseline T2 times were negatively associated with the change in T2 times in the tibia ( B =-0.070, p= 0.001) and femur ( B =-0.079, p< 0.001), respectively. In all treated (KJD and HTO) patients together, only BMI ( B =-0.209, p= 0.029) and baseline femur T2 times ( B =-0.330, p< 0.001) had a significant influence on the change in femur T2 relaxation times. As such, case control matching between treated and untreated patients was based on baseline T2 values and BMI. For both the tibia and femur, tolerances of 4 ms and 5 kg/m 2 resulted in a match for all but 1 treated patient for tibia and femur. Changes over time as represented by regression coefficients are shown for all treated (KJD and HTO) patients together and the matched OAI patients in Figure 4. Treated patients showed an increase of 2.2 (95%CI 1.5–3.0) ms/year in the tibia and 2.1 (1.4–2.7) ms/year in the femur; Cartilage T2 in untreated OAI patients showed no change with 0.1 (-0.2 to 0.4) ms/ year in the tibia and -0.1 (-0.8 to 0.7) ms/year in the femur. Figure 4 : T2 relaxation time changes for treated and untreated patients, expressed as regression coefficients (ms/ year), for (A) the tibia and (B) the femur. Treated patients consisted of 32 patients treated with knee joint distraction (indicated for total knee arthroplasty (circles) or high tibial osteotomy (squares) or high tibial osteotomy (triangles); untreated patients consisted of 32 patients from the Osteoarthritis Initiative matched separately for the tibia and femur (diamonds), based on baseline T2 values and BMI. For both the tibia and femur matched patients, patient age, baseline T2 relaxation time, sex, and KLG were statistically significantly different between the 2 groups (all p< 0.03). Corrected for these parameters, differences in T2 relaxation time changes were statistically significantly different between treated and untreated patients for the tibia ( p= 0.003) and femur ( p< 0.001).