Rotator Cuff Tendon Blood Flow in a Sheep Model – A Comparison of Single- vs. Double-Row Repairs (SS-19)

Abstract

Double-row suture anchor repair of rotator cuff tears has been shown to be superior to single-row techniques with regard to footprint reconstruction, load to failure and tendon-to-bone contact pressures. We hypothesized that anchor repair can impair intratendinous blood flow and that the greater contact pressures of double-row techniques would compromise blood flow to a higher degree than single-row repair. The aim of this experimental study was to evaluate the effect of a double-row and a single-row technique on tendon blood flow in a sheep model. 18 sheep underwent detachment and immediate suture anchor repair of the right infraspinatus tendon using either an arthroscopic Mason-Allen suture or a double-row suture-bridge technique. Tendon blood flow was measured using laser Doppler flowmetry before detachment, immediately after repair and 12 weeks thereafter. Six regions of interest were measured, three over the lateral aspect of the footprint and three over the medial aspect. Immediately after repair, tendon blood flow decreased significantly in both repair groups when compared to the native tendons (P= .004). At 12 weeks, a significant increase in flow was observed in both repair groups when compared to the measurements immediately after repair (P= .016). In the single-row group, blood flow decreased by 87.5% after repair, in the double-row group the decrease was 90.6%. The difference between the groups was not statistically significant (P> .05). Subgroup analysis showed that blood flow over the lateral aspect of the footprint decreased by 90% in both groups, whereas over the medial aspect it decreased by 81% in the single-row and by 89% in the double-row group. However, none of these differences were found to be statistically significant. Intratendinous blood flow was significantly compromised immediately after suture anchor repair regardless of the technique used, but appeared to recover within 12 weeks. Since we did not find a significant difference between the two repair groups, our initial hypothesis was rejected.