Comparison of Biological Augmentation in Rotator Cuff Repair Using Inflamed Versus Noninflamed Bursal Tissue in Rats

Abstract

PurposeTo examine how augmentation of a rotator cuff repair with inflamed versus non-inflamed bursal tissue affects tendon-to-bone healing in a rat model of rotator cuff repair. Methods136 Sprague-Dawley rats were randomly assigned to an inflamed or non-inflamed bursal tissue application group. After detachment the supraspinatus tendon was re-attached with bursal tissue sewn onto the tendon-to-bone interface. The specimens were analysed biomechanically 6 and at 7 weeks and immunohistologically at 1 and at 7 weeks after surgery. ResultsImmunohistological results showed no significant difference in the percentage of collagen type II in the tendon-to-bone interface at 1 (p = 0.97) and 7 weeks (p = 0.42) when utilising autologous non-inflamed bursal tissue in comparison to inflamed bursal tissue specimens. The inflamed bursa group also showed no significant difference in collagen I to III quotient (p= 0.14) after surgery in comparison to post-surgery non-inflamed bursa groups. Biomechanical assessment showed that tendon stiffness (p = 0.87 resp. p = 0.1) and the tendon viscoelasticity (p = 0.12 resp. p = 0.07) was the same after 6 and 7 weeks comparing inflamed bursa to the non-inflamed bursa group. There was no significant difference (p = 0.8 resp. p = 0.97) in load to failure between in both inflamed and non-inflamed bursa groups after 6 and 7 weeks. ConclusionAutologous inflamed bursal tissue derived from the Achilles bursa and implanted to the tendon-to-bone interface after rotator cuff repair facilitates the same histological and biomechanical healing response as using a non-inflamed bursa interposition in rats. Clinical relevanceDuring augmentation of a rotator cuff repair, it is irrelevant whether the bursa tissue is inflamed or not.