Visibility of Site Marking for Surgical Time Out With Two Different Skin Preparation Solutions

Skin preparation solutions are used to clean the skin of the patient before surgery to decrease the rate of infection. This is particularly important for hip replacement to reduce the risk of prosthetic joint infection. The use of a mark on the skin for site identification has become the standard of care to decrease wrong site surgery. The Joint Commission has mandated site identification as part of the surgical "time-out". This procedure is also mandated by hospital policy. Preliminary work on cadaveric skin shows that the type of skin preparation can erase the mark used for surgical site identification. Erasure of the mark presents the surgeon with difficulty in performing the site identification. Any error or lack of visualization of the site marking could lead to catastrophic wrong site surgery. The investigators hypothesis is that chlorhexidine based skin preparation solutions erase site marking in comparison to iodine based skin preparation solutions. The investigators intend to prospectively study twenty patients undergoing total hip arthroplasty. Patients will be randomized to either a chlorhexidine based or an iodine based skin preparation solution. These solutions are both the current gold standard of clinical care. No differences have been shown in infection rates for total hip arthroplasty between these solutions. The site marking will be performed by the same surgeon in a standardized manner. The site marking will include the surgeon's three initials as per usual routine. Underneath the initials three random initials will be placed with a horizontal line drawn underneath. The preparation of the skin will be performed according to the manufacturer's specifications. Digital photographs will be taken of the skin marking after skin preparation. Photographs of the three random initials will be de-identified and placed in a "Powerpoint" presentation form. Ten orthopaedic surgeons will then read the site markings to identify the random initials and to tell whether the mark looks appropriate to perform a surgical timeout. The horizontal line will be digitally analyzed using Adobe Photoshop to quantitatively measure blackness of the mark.