Table 1.
Allocation of rats into groups.
Fig 1.
(a) Rat knee joint fixed with deep bending using Kirschner wire and resin; (b) fixed after incision of the inner joint capsule; (c) fixed after dislocation of the patella from the femoral pulley groove for 5 min. A line drawing of the surgical fixation method. (d) Insertion of K-wire into the femur (e) Insertion of K-wire into the tibia (f) Fixation using resin. (g). Assessment regions of the adhesion length of the anterior knee joint in the histological image of a standard sagittal section with hematoxylin and eosin staining. (A) The suprapatellar bursa. (B) The patellofemoral joint. (C) The distal part of the patella. P, patella; F, femur. Scale bar: 1000 μm. (h). Microphotograph of the sagittal section of the medial region of the rat knee joint. (D) Posterosuperior capsule length. (E) Posteroinferior capsule length. Hematoxylin and eosin staining. Scale bar: 1,000 μm.
Fig 2.
Knee joint angle at the point in each evaluation period.
(a) Restriction of extension range of motion (ROM) involving the skin and muscles. A two-way ANOVA revealed significant effects by group (F[4, 31]: 56.18; p <0.001). (b) Restriction of extension ROM excluding the skin and muscles. Two-way ANOVA revealed significant effects by group (F[4, 31]: 26.67; p <0.0001). Data are expressed as mean ± standard error. n = 4 in each group. †p <0.05 (vs. 1 week), ‡p < 0.05 (vs. 2 weeks), *p <0.05 (vs. group I), §p <0.05 (vs. group II).
Fig 3.
a. Adhesion sites of the anterior knee joint. Hematoxylin and eosin (H&E), picrosirius red staining, and scanning electron microscopy (SEM) images of adhesion sites. Upper panels: In the control group (13-week-old), the images show a well-organized structure with an articular cavity. Lower panels: In the experimental groups (picrosirius red staining: 4 weeks group III, SEM: 1 week group III), the images show disorganized dense collagen fiber structure (arrowheads) between the patella and femur. Scale bar: H&E staining, 100 μm; picrosirius red staining, 100 μm; SEM, 10 μm. b. Changes in the histologic appearance of the adhesion of the knee joint with H&E staining. The arrowheads show adhesion sites. P, patella; F, femur. Scale bar: 1,000 μm.
Fig 4.
Length of knee adhesions and posterior capsule.
(a) Adhesion length. Two-way ANOVA revealed significant intergroup effects (F[4, 31]: 7.71; p = 0.0002). (b) Suprapatellar bursa adhesion length. Two-way ANOVA revealed no significant intergroup effects (F[4, 31]: 1.99; p = 0.12). (c) Patellofemoral joint adhesion length. Two-way ANOVA revealed no significant intergroup effect (F[4, 31]: 2.24; p = 0.09). (d) Distal length of patellar adhesion. Two-way ANOVA revealed significant intergroup effects (F[4, 31]: 4.31; p = 0.0069). Data are expressed as mean ± standard error (n = 4 in each group). †p <0.05 (vs. 1 week), ‡p < 0.05 (vs. 2 weeks), *p <0.05 (vs. group I), §p <0.05 (vs. group II). (e). Posterior capsule length after immobilization. Two-way ANOVA revealed significant intergroup effects (F[4, 31]: 61.66; p < 0.0001). Data are expressed as mean ± standard error (n = 4 in each group). †p <0.05 (vs. 1 week), ‡p < 0.05 (vs. 2 weeks), *p <0.05 (vs. group I), §p <0.05 (vs. group II).