Abstract
Objectives:
Antimicrobial wound lavages containing chlorhexidine gluconate (CHG) or povidone-iodine (PI) are commonly used to prevent periprosthetic infection during shoulder arthroplasty. However, the potential toxicity of these solutions to the native surrounding rotator cuff tendon is not well understood. In total shoulder arthroplasty, the rotator cuff tendon is often concomitantly repaired, and any toxic effects from antimicrobial wound lavage during surgery may be detrimental to postoperative rotator cuff tendon healing. The purpose of this study was to determine the in vitro effects of a 1-minute CHG exposure and a 3-minute 0.35% PI exposure on the viability and biochemical content of rotator cuff tendon.
Methods:
Infraspinatus tendons (n=6 per group) were isolated from shoulders of Nubian goats (n=3; 2 female and 1 male). Tendons were submerged in Irrisept (0.05% CHG in sterile water) for 1 minute or 0.35% Betadine (PI) for 3 minutes per manufacturer guidelines, followed by phosphate-buffered saline wash and culture in tissue culture medium. Control tendon specimens were similarly exposed to tissue culture medium, followed by phosphate-buffered saline wash and culture in tissue culture medium. After seven days of culture, isolates from both the tendinous and enthesis portions of the rotator cuff were analyzed for viability, collagen content (hydroxyproline assay), and glycosaminoglycan (GAG) content (dimethylmethylene blue assay). Statistical analyses were performed via one-way ANOVA with post hoc Tukey’s test.
Results:
Within the tendinous portion of the rotator cuff, CHG-treated specimens demonstrated a decrease in mean tenocyte viability compared to controls (p=0.045) (Fig.1). While PI-treated specimens exhibited lower mean viability compared to controls, this difference was not statistically significant. Within the enthesis portion of the rotator cuff, tenocyte viability decreased in both CHG- and PI-treated groups; however, these decreases were not statistically significant (Fig. 2). There were no significant differences in mean collagen content/wet weight or GAG/wet weight among groups within the tendinous and enthesis portion of the rotator cuff (Fig. 3).
Conclusions:
Due to the potential catastrophic consequences associated with periprosthetic infection, CHG and PI antimicrobial lavages are commonly used to reduce the risk of periprosthetic infection during shoulder arthroplasty. However, in this study, brief 0.05% CHG and 0.35% PI exposures to rotator cuff tendon resulted in lower tenocyte viability 7 days after treatment. These results are consistent with the toxicity reported with exposure of CHG and PI to other musculoskeletal tissues, including articular cartilage. The toxicity of antimicrobial irrigation to the surrounding native rotator cuff tendon may be detrimental to the postoperative healing of concomitant rotator cuff repair in the setting of shoulder arthroplasty.
