Comparative evaluation of the tendon-bone interface contact pressure in different single- versus double-row suture anchor repair techniques

Abstract

The aim of the study was to evaluate the time zero contact pressure over a defined rotator cuff footprint using different repair and stitch techniques in an established sheep model. Forty fresh-frozen sheep shoulders were randomly assigned to five repair groups: single-row repair using simple stitches (SRA-s), single-row repair using horizontal mattress stitches (SRA-m), and single-row repair using arthroscopic Mason-Allen stitches (SRA-ama). Double-row repair was either performed with a combination of simple and horizontal mattress stitches (DRA-sm) or with arthroscopic Mason-Allen/horizontal mattress stitches (DRA-amam). Investigations were performed using a pressure-sensitive film system. The average contact pressure and pressure pattern were measured for each group. Contact pressure was lowest in SRA-m followed by SRA-s. SRA-ama showed highest contact pressure of all single-row treatment groups (P < 0.05). DRA-amam presented the highest overall contact pressure (P < 0.05), whereas DRA-sm exerted contact pressure equal to that of SRA-ama. Both double-row techniques showed the most expanded pressure pattern. Average contact pressures for the more complex single- and double-row techniques utilizing arthroscopic Mason-Allen stitches were greater than were those of the repair techniques utilizing simple and horizontal mattress stitches. However, the contact pattern between the anchors could be increased by using the double-row technique, resulting in more footprint coverage compared to patterns utilizing the single-row techniques. These results support the use of the more complex arthroscopic Mason-Allen stitches and may improve the environment for healing of the repaired rotator cuff tendon.

Fig. 1

Schematic line drawing of the used repair techniques. a One line of two double-loaded suture anchors using simple stitches (SRA-s). b One line of two double-loaded suture anchors using horizontal mattress stitches (SRA-m). c One line of two double-loaded suture anchors using arthroscopic Mason-Allen stitches (SRA-ama). d Two lines with a total of four suture anchors using a combination of simple (lateral/double-loaded) and horizontal mattress stitches (medial/single-loaded) (DRA-sm). e Two lines with a total of four suture anchors using a combination of arthroscopic Mason-Allen (lateral/double-loaded) and horizontal mattress stitches (medial/single-loaded) (DRA-amam)

Fig. 2

Typical pressure pattern of a (a) single- (SRA-ama) and (b) double-row (DRA-amam) repair. Contact pattern between the anchors could be increased by the double-row technique, resulting in more footprint coverage. The pressure around the insertion of each anchor system was higher than in the area between the anchor systems as represented by the colour density

Fig. 3

Mean pressure distributions of the evaluated repair techniques. Contact pressure was lowest in SRA-m and SRA-s. SRA-ama showed highest contact pressure of all single-row treatment groups (P < 0.05). DRA-amam presented the highest overall contact pressure (P < 0.05), whereas DRA-sm exerted contact pressure equal to that of SRA-ama (P > 0.05)