# Comparative effects of hip capsule repair and cam lesion excision on capsulotomy healing: An in vivo biomechanical and histological analysis

## TL;DR

This study shows that combining hip capsule repair with cam lesion removal improves healing and strength in rabbit hip joints.

## Contribution

The study introduces a novel in vivo comparison of hip capsule repair and cam lesion excision on healing outcomes.

## Key findings

- Combining capsule repair and cam resection significantly improved biomechanical strength compared to repair alone.
- Histological analysis showed better healing in the capsule repair and cam resection group.
- At 8 weeks, the combined treatment group had the highest biomechanical strength.

## Abstract

This study evaluates the effects of hip capsule repair and cam lesion excision on capsular healing by assessing biomechanical strength and histological integrity in an in vivo rabbit model.

An in vivo rabbit model with 80 rabbits was used, where capsulotomy was performed on the right hip of each subject. The rabbits were assigned into four groups: Group 1 (capsulotomy without repair), Group 2 (capsulotomy with capsule repair), Group 3 (capsulotomy + cam resection without repair), Group 4 (capsulotomy + cam resection + capsule repair). Each group was stratified into 4‐week and 8‐week follow‐up subgroups. Biomechanical testing assessed maximum tensile strength, while histological evaluation included semiquantitative grading of collagen arrangement, inflammatory response, osteogenesis, and angiogenesis.

Histological analysis revealed superior healing in the capsule repair + cam resection group (Group 4) compared to the unrepaired capsulotomy group (Group 1) (p = 0.01). Biomechanical testing demonstrated that capsule repair (Group 2) improved strength over unrepaired capsulotomy (135.2 N vs. 111.9 N, p = 0.03). Cam resection alone (Group 3) resulted in significantly higher strength than unrepaired capsulotomy (163.2 N vs. 111.9 N, p = 0.01). The combination of cam resection and capsule repair (Group 4) demonstrated superior strength, outperforming capsule repair alone (176 N vs. 135.2 N, p = 0.01). At 8 weeks, the capsule repair + cam resection group (Group 4a) showed significantly enhanced biomechanical strength compared to the unrepaired capsulotomy group (Group 1a) (181.6 N vs. 120.9 N, p = 0.001) and capsule repair alone (Group 2a) (181.6 N vs. 125.8 N, p = 0.01).

Our findings indicate that cam resection, particularly when combined with capsule repair, significantly improves biomechanical strength and enhances the healing process of the capsule. These findings offer practical guidance for optimising surgical strategies to enhance patient outcomes and long‐term joint function.

Level III, experimental therapeutic study (prospective and controlled).