Abstract
Background: Various techniques have been described to reduce or shrink the volume of the hip capsule in the treatment of hip microinstability. Recently, a new arthroscopic capsular suture-lifting technique has been proposed for treating femoroacetabular impingement patients with a high risk of postoperative anterior instability. However, this new suture-lifting technique requires animal experiments and biomechanical experiments to prove its effectiveness. Methods: A total of 16 mature male porcine were selected for study in vivo. The animals were grouped randomly into two groups: a blank group without closure of capsule; and an experimental group with capsule closed by suture-lifting technique. At 6 and 12 weeks after surgery, the pigs were sacrificed by over-anaesthetizing. All samples were evaluated by magnetic resonance imaging (MRI) at 12 and 24 weeks after surgery. Hematoxylin and eosin staining, Masson trichrome staining, sirus red staining and immunohistochemistry staining were performed. Tensile test was conducted to confirm the biomechanical properties of the capsule 6 weeks and 12 weeks after surgery. Results: Postoperative MRI showed capsular defect was observed in 75% sample in blank group and all samples at 6 weeks and 12 weeks were found to have continuous capsule in experimental group. Histological study showed fibrous tissue in experimental group was distributed with denser structure than blank group in 12 weeks after surgery. The collagen volume fraction in experimental group was significantly higher than that in blank group at 6 weeks post operation (P=0.0066) and was higher than that in the blank group at 12 weeks post operation. The expression level of collagen (COL) I in the experimental group was higher than that in the blank group at 6 weeks (P=0.0185) and 12 weeks (P=0.0073) after surgery. The expression of COL II in the experimental group was significantly upregulated than the blank group at 12 weeks after surgery (P=0.0479). Conclusion: The hip capsular suture-lifting technique has shown good results in promoting capsule healing and enhancing capsular tension. This innovative technique may be regarded as a viable and effective treatment approach for individuals experiencing hip instability.