Comparison of two different superior capsule reconstruction methods in the treatment of chronic irreparable rotator cuff tears: a biomechanical and histologic study in rabbit models

Background: In the treatment of irreparable rotary cuff (RC) tears, the superior capsule of the shoulder is reconstructed using tensor fascia lata (TFL) or several allografts to prevent progressive joint degeneration. This study compared the healing qualities of acellular human dermal graft (HDG) and the TFL autograft in superior capsule reconstruction (SCR) from biomechanical and histologic perspectives. Methods: Chronic retracted RC tear models were created bilaterally in 9 rabbits, and 7 rabbits with intact RC were used as a control group. SCR was performed 8 weeks after the tear using HDG in right shoulders and TFL in left shoulders. At 12 weeks after SCR, 2 shoulders from each experimental group were investigated for histologic healing, and 7 samples from the experimental and control groups were biomechanically tested. Results: Complete healing was observed macroscopically in the glenoid and humeral sides of both groups. No difference was observed in the enthesis maturation scores between the experimental groups. Collagen fiber density was higher and the orientation was better in TFL group. Inflammatory cell infiltration was not seen in the TFL group, but inflammatory cell infiltration was pronounced in the HDG group. The mean pullout strengths of the TFL group, HDG group, and intact RC group were 139.7 ± 40.5 N, 123.9 ± 47.9 N, and 105.1 ± 11.8 N (P =.187), respectively. The mean stiffness values (P =.711), yield forces (P =.404), and displacements (P =.135) were also statistically not different between the groups. Conclusion: In SCR, the healing qualities of HDG and TFL were similar in rabbit models.