Impact of graft width and chondrolabral junction preservation on labral suction seal integrity in bovine hip models.

Objective: This study investigates the biomechanical effects of graft width and chondrolabral junction (CLJ) preservation on the labral suction seal in a bovine hip model and aims to validate this model as a practical alternative for hip biomechanical research by comparing it with human cadaver studies.

Materials and methods: Twenty hips from two-year-old male bovines were divided into two main groups: CLJ preserved (CLJ+) and CLJ excised (CLJ-). These groups were further divided into eight subgroups: Group 1 with an intact labrum; Group 2 with labrum excision preserving CLJ; Groups 3 and 4 with labral reconstruction on preserved CLJ using 4.5 mm and 9 mm grafts, respectively; Group 5 with a labral tear at 12 to 3 o'clock position without CLJ preservation; Group 6 with complete labrum excision without CLJ preservation; and Groups 7 and 8 with labral reconstruction on excised CLJ using 4.5 mm and 9 mm grafts. Mechanical tests measuring compression and distraction forces were conducted, recording force-displacement values.

Results: Both CLJ+ and CLJ- groups showed that labrum excision resulted in the lowest distraction forces, emphasizing labral integrity. Notably, reconstruction with 9 mm grafts improved distraction forces more than 4.5 mm grafts (p<0.001). The change in distraction forces from intact to excised stages was nearly significant between CLJ+ and CLJ- groups (Δ Intact-excised: CLJ+ vs. CLJ-: 92 N vs. 105 N, p=0.08). Distraction forces were measured at 206±27 Newtons in the CLJ preserved group and 186±24 Newtons in the resected group.

Conclusions: This study demonstrates that increasing the width of the graft, despite being approximately half and a quarter of the native labrum's size, significantly enhances the distraction force in labral reconstruction within a bovine hip model. This improvement is more pronounced than the effects of preserving the CLJ, highlighting the critical role of graft size in maintaining the biomechanical integrity of the labral suction seal.