Table 1 Major histological characteristics at each time-point in ST graft
1 week | 4 weeks | 6 weeks | 8 weeks | 12 weeks | 24 weeks | 48 weeks | |
|---|---|---|---|---|---|---|---|
Necrosis | Focal cell-free areas with small necrosis | Cell-free areas with poor necrosis | Gradually disappeares | No necrosis sign | |||
Neovascularization | No vessel | Poor and located on the grafts periphery | Vessel located in the periphery of the graft and runned parallel to the collagen fiber bundles in the septa | Vessel located from periphery to central area | Normal vascularity | ||
Organization of the collagen fibers | ST tendon characteristics | Disorganized collagenous fibers | Initial longitudinal arrangement | Collagen fibers aligned in parallel with the new capillaries and with the fibroblastic cells | Loss of regular collagen orientation and crimp pattern | Slight separation with increased waviness of fibers | |
Shift of the diameter of the collagen fibrils, from large to small | Unimodal appearance of collagen fibrils | ||||||
Reduction of collagen type I fibrils | Failure restauration of collagen orientation to normality | ||||||
Increase of collagen type III synthesis | |||||||
Cellularity | Inflammatory cell population | Aligned longitudinally, more rounded fibroblastic cells with large nuclei and abundant cytoplasm | Highly differentiated fibroblastic cells | Normal cellularity | |||
Disorganized and randomly arranged fusiform-like fibroblastic cells with plump nuclei | Gradual disappearance of the typical inflammatory cell population | Fibrocyte have different characteristics from fibroblastic cells | |||||