Labral Graft Volume Augmentation and Femoral Remplissage Have Positive Impact on Hip Distraction Stability After Excessive Cam Resection: An Ovine Model.

PURPOSE: To biomechanically assess the effects of femoral remplissage and labral volume augmentation, individually and in combination, on restoring hip distraction stability after excessive cam resection in an ovine model.

METHODS: Forty-eight fresh-frozen ovine hips were randomized into 6 groups (n = 8): (1) remplissage, (2) baseline labral reconstruction, (3) combined baseline reconstruction, (4) increased thickness (2×), (5) combined augmented (2× + remplissage), and (6) excessive thickness (4×). A 10% over-resection defect was created at the anterosuperior head-neck junction. Autologous tendon grafts were fixed with 2.0 mm titanium anchors. Distraction testing at 90° flexion was performed under a 200 N load at 60 mm/min. Suction seal strength was defined as the peak resistance force (N) during femoral head separation. Two parameters were calculated: Δ1 (Postop-Intact) for residual loss and Δ2 (Postop-Excised) for stability recovery. Statistical analysis used Kruskal-Wallis and Bonferroni-corrected Mann-Whitney U tests (P < .003).

RESULTS: Excessive cam resection significantly reduced suction seal strength (P < .001). The 4× reconstruction and 2× + remplissage groups achieved the best stability restoration (4×: Δ1 = 0.78 N, Δ2 = 24.06 N; 2× + remplissage: Δ1 = 4.53 N, Δ2 = 23.12 N; both P < .003 vs baseline). Remplissage alone provided partial recovery, whereas baseline reconstruction had the weakest performance (Δ1 = 11.48 N, Δ2 = 14.92 N). Increasing graft thickness improved both Δ1 and Δ2, correlating with greater stability recovery.

CONCLUSIONS: Standard labral reconstruction alone did not fully restore suction seal strength after excessive cam resection. Increasing graft volume improved distractive stability compared with the resected state, and combined 2× labral augmentation with femoral remplissage achieved stability restoration comparable to the 4× reconstruction group. Remplissage alone provided partial recovery but did not consistently restore intact-level stability.

CLINICAL RELEVANCE: These findings suggest that increased graft thickness and femoral remplissage may improve distractive stability in an ex vivo over-resection model.