Femke Mathot

Chapter 7 116 Functional outcome measurements Cross-sectional tibial muscle area (figure 2) No significant differences between the groups were found. Within group comparisons only showed significant differences between the consecutive time points zero and two weeks after surgery for autografts, allografts and allografts seeded with differentiated MSCs. The lowest tibial muscle area in all groups was reached at two weeks (40-60% of the unoperated side) and improved up to 16 weeks, with a cross-sectional tibial muscle area ratio of approximately 75%. Figure 2. Cross-sectional tibial muscle area ratios (R/L) over time. No significant differences were found between groups. Autografts (+15.77 ±6.56%) and unseeded allografts (+11.33 ±9.22%) had the strongest increase in muscle area between 8 and 12 weeks, while allografts seeded with undifferentiated MSCs (+16.13 ±3.83%) and differentiated MSCs (+10.87 ±9.29%) experienced their strongest increase between 4 and 8 weeks after surgery. uMSCs = undifferentiated Mesenchymal Stem Cells; dMSCs = differentiated Mesenchymal Stem Cells. Error bars = Standard error of the mean Compound Muscle Action Potential (CMAP) (figure 3) At 12 weeks, CMAP ratio of unseeded allografts (13.48 ± 5.00%) was significantly inferior to autografts (53.78 ± 5.82%) (p<0.001), allografts seeded with undifferentiated MSCs (44.32 ± 7.20%) (p=0.004) and differentiated MSCs (48.89 ± 5.37%) (p<0.001). At 16 weeks, CMAP ratio was normalized between all groups, with 57.51 ± 7.54% for autografts, 52.26 ± 5.80% for allografts, 66.04 ± 7.28% for allografts with undifferentiated MSCs and 61.49 ± 8.16% for allografts with differentiated MSCs.