Do wound protectors reduce contamination in total shoulder arthroplasty? A randomized controlled trial.
HYPOTHESIS: Cutibacterium acnes is the most frequent cause of shoulder prosthetic joint infection with skin edges as a source of wound contamination. The primary purpose of this study was to determine if the use of a wound protector device decreases the deep wound bacterial colonization in primary shoulder arthroplasty. The secondary purpose was to assess the effect of device usage on deltopectoral muscle and cephalic vein injury. METHODS: This was a prospective, randomized controlled trial. A total of 100 patients undergoing primary total shoulder arthroplasty were enrolled and randomized into 2 groups: a wound protector group and a control group. Five patients withdrew from the study, leaving 48 patients in the wound protector group and 47 controls. Three deep wound culture swabs were taken after final arthroplasty implantation. The surgeon also graded deltoid, pectoralis major, and cephalic vein injury on a 0-3 scale based on modification to the Tscherne classification of soft tissue injury. The primary outcome of this study was positive culture results for C acnes. Secondary outcomes included total bacterial culture positivity as well as soft tissue injury grades. A subanalysis removing likely contaminant positive cultures (growth >7 days and 1 colony only) was also performed. Comparisons between groups were made using Fisher exact test for categorical outcomes and t tests and Mann-Whitney U tests for continuous variables. RESULTS: The use of a wound protector did not result in any significant differences compared with controls in the rate of positive cultures for C acnes (15% vs. 21%, P = .593) or all bacteria (15% vs. 26%, P = .304). Removing likely contaminant positive cultures did not demonstrate any significant difference in culture positivity (9% vs. 17%, P = .355, for C acnes; 9% vs. 19%, P = .231, for all bacterial species). The wound protector group had better soft tissue injury scores for the deltoid muscle (P < .001) and pectoralis muscle (P < .001). No difference in cephalic vein injury was noted between the 2 groups (P > .05). No difference in surgical time was noted. CONCLUSION: The use of a surgical wound protector device in total shoulder arthroplasty did not significantly decrease bacterial colonization of the deep wound. However, soft tissue damage to the deltoid and pectoralis muscle was less severe in the wound protector group. These findings suggest that this device reduces iatrogenic soft tissue injury.