Benzoyl peroxide + chlorhexidine versus chlorhexidine alone skin preparation to reduce Propionibacterium acnes: a randomized controlled trial.

BACKGROUND: Traditional skin preparation for shoulder surgery is not specific for Propionibacterium acnes. Topical benzoyl peroxide for 48 h preoperatively has been shown to reduce the bacterial load of P. acnes on the skin. Our aim was to investigate whether skin preparation with a single application of benzoyl peroxide combined with 2% chlorhexidine/alcohol immediately prior to surgery was superior to 2% chlorhexidine/alcohol alone at inhibiting P. acnes. METHODS: We conducted a single-blinded interventional study. Each shoulder of the participant was assigned a different preparation through a randomization process. Two sites were assessed per shoulder. The intervention was the application of benzoyl peroxide followed by chlorhexidine/alcohol to the shoulder. The control was two applications of 2% chlorhexidine/alcohol. Superficial skin swabs for semi-quantitative culture were taken pre- and post-skin preparation. RESULTS: A total of 22 male participants were randomized. All participants were colonized with P. acnes on baseline swabs. We found complete inhibition of P. acnes at 14 days at 80% of sites prepared with benzoyl peroxide + chlorhexidine/alcohol compared with 86% inhibition at shoulder sites prepared with chlorhexidine alone. CONCLUSION: There was no reduction in the growth of P. acnes over 14 days with chlorhexidine/alcohol and benzoyl peroxide compared with chlorhexidine alone. On the basis of these results, the addition of benzoyl peroxide at the time of surgery does not appear to increase the efficacy of the surgical preparation for inhibiting P. acnes growth.

Radius morphology and its effects on rotation with contoured and noncontoured plating of the proximal radius.

BACKGROUND: The radius has a sagittal bow and a coronal bow. Fractures are often treated with volar anterior plating. However, the sagittal bow is often overlooked when plating. This study looks at radial morphology and the effect of plating the proximal radius with straight plates and then contoured plates bowed in the sagittal plane. We report our findings and their effect on forearm rotation. MATERIALS AND METHODS: Morphology was investigated in 14 radii. Attention was paid to the proximal shaft of the radius and its sagittal bow; from this, 6-, 7-, and 8-hole plates were contoured to fit this bow. A simple transverse fracture was then made at the apex of this bow in 23 cadaver arms. Supination and pronation were compared when plating with a straight plate and a contoured plate. Ten cadavers underwent ulna plating at the same level. The effect on rotation of fractures plated in the distal-third shaft was also measured. RESULTS: A significant reduction in rotation was found when a proximal radius fracture was plated with a straight plate compared with a contoured plate: 10.8°, 12.8°, and 21.7° for 6-, 7-, and 8-hole plates, respectively (P < .05). Forearm rotation was decreased further when a longer plate was used. Ulna or distal shaft plating did not reduce rotation. CONCLUSION: This study has shown a significant sagittal bow of the proximal shaft of the radius. Plating this with contoured plates in the sagittal plane improves rotation when compared with straight plates. Additional ulna plating is not a source of reduced forearm rotation.