Early oral celecoxib prevents contracture and modulates capsular fibrosis in a validated model of post-traumatic arthrofibrosis

Figure 1 Flowchart showing the distribution of the initial sample, losses during follow-up and final sample by groups.

Figure 2 Grouped bar chart of biomechanical outcomes by groups. ^aP < 0.05. PEA: Passive extension angle.

Figure 3 Histological evaluation of celecoxib efficacy in central sections of operated knees. A-C: Control; D-F: Celecoxib-treated specimens. Panels are arranged by staining and magnification to facilitate direct comparison between control (A-C) and celecoxib-treated specimens (D-F). Masson’s trichrome-stained sections at 2× magnification (A and D) were used for quantitative assessment of posterior capsule area and thickness. Higher magnification images at 20× (B and E: Masson’s trichrome; C and F: Hematoxylin-eosin) illustrate representative fibrotic tissue. Asterisks indicate collagen-rich fibrotic areas. Orange arrows indicate fibroblast nuclei (elongated cells) and black arrows indicate blood vessels or capillaries. Celecoxib-treated posterior capsules exhibited a greater overall extent of fibrotic tissue (i.e., larger area of connective tissue involvement), along with increased cellular density and vascularity. In contrast, control specimens demonstrated a more limited fibrotic area, but with relatively denser collagen organization and lower cellular and vascular components. These findings were consistent with semiquantitative analyses (P < 0.05).