MANAGEMENT OF EXPOSED TOTAL KNEE PROSTHESES WITH MICROVASCULAR TISSUE TRANSFER CURTIS L. CETRULO, Jr., M.D., 1 * TRAVIS SHIBA, B.S., 1 MICHAEL T. FRIEL, M.D., 2 BRIAN DAVIS, B.S., 1 RUDOLPH F. BUNTIC, M.D., 2 GREGORY M. BUNCKE, M.D., 2 and DARRELL BROOKS, M.D. 2 Introduction: Exposure of a knee endoprosthesis represents a limb-threatening condition, requiring long-term antibiosis, irrigation, and se- rial debridement to avoid knee arthrodesis or amputation. Although traditional orthopedic surgical doctrine mandates removal of exposed hardware under a dehisced wound, salvage of exposed prostheses using local muscle flap coverage has been reported. However, the complex three-dimensional geometry of the soft tissue surrounding the knee as well as the requirement for sustained local tissue levels of antibiotics to re-sterilize the hardware suggest that microvascular tissue transfer may constitute an advantageous means of wound cover- age, increasing both limb and prosthesis salvage rates. We report our experience with free tissue transfer reconstruction of these complex wounds. Methods: We treated 11 complex wounds with exposed total knee arthroplasty prostheses with free tissue transfer. Three of 11 patients had failed previous local muscular rotation flap coverage. Five latissimus dorsi muscle flaps and 6 rectus abdominis muscle flaps were used in our series. Wounds were closed after aggressive surgical debridement, antibiotic irrigation, and intravenous antibiosis. Results: Eleven of 11 free flaps were successful (100%), and we achieved limb salvage in 11/11 limbs (100%) and prosthesis salvage in 10/11 knees (91%), with one prosthesis removed at an outside facility followed by knee arthrodesis. Conclusion: The advantages of micro- vascular tissue transfer are well suited to the treatment of exposed knee endoprostheses. The reliable rectus and latissimus flaps provide robust local perfusion to the wound, fill complex three-dimensional contour defects around knee implants, and lead to a high rate of salvage of both limbs and prostheses. V V C 2008 Wiley-Liss, Inc. Microsurgery 28:617–622, 2008. A total knee prosthesis that becomes exposed constitutes a complex reconstructive problem, requiring long-term antibiosis, irrigation, and serial debridement to avoid knee arthrodesis 1 or above-knee amputation. Contrary to tradi- tional orthopedic surgical doctrine, which dictates removal of exposed hardware under a dehisced wound, a number of authors have reported salvage of exposed prostheses using aggressive irrigation and debridement, early local muscle flap coverage, and extended antibiotic regimens. 2–5 The medial gastrocnemius muscle flap represents the current ‘‘gold standard’’ for genicular soft tissue reconstruction. 6,7 Although most wounds around the knee can be man- aged by pedicled local flaps, 8,9 more complex defects may require the use of free flaps. 10,11 Both local and free flaps provide a robust local blood supply, 12 allowing for adequate distribution of antibiotics, exposure to humoral defenses, and vascular drainage to reduce the probability of failure due to infection. 13,14 However, when pedicled local muscular flaps have failed, are unavailable, or can- not provide adequate coverage of the exposure, a free rectus abdominis or latissimus dorsii flap can provide an excellent alternative. 15–17 Surprisingly little has been reported regarding the use of free tissue transfer in complex wounds involving the knee in general and for total knee arthroplasty wounds with exposed hardware in particular. Rao’s series described a staged endoprosthetic revision using the latissimus dorsi, which required removal of the endopros- thesis, implantation of a spacer, and soft tissue recon- struction, followed by replacement of the spacer by an endoprosthesis. Rao et al. found the broad, flat latissimus dorsi flap ideal for prosthesis coverage. 18 Nahabedian’s series described complex post-total knee replacement wounds, and included 13 knees with exposed prostheses that were managed successfully with local gastrocnemius or local fasciocutaneous flap coverage. 19,20 We report our experience using free tissue transfer to reconstruct these difficult three-dimensional wounds. METHODS Between September 2002 and February 2008, we treated 11 complex wounds with exposed total knee arthroplasty prostheses with free tissue transfer. Three of 11 patients (27%) had failed previous local muscular rotation flap coverage. Six women and five men, aged 43–76, underwent treatment at our center. Six latissimus dorsi muscle flaps and 5 rectus abdominis muscle flaps were used in our series. Wounds were closed after aggressive surgical debridement, antibiotic irrigation, and intravenous antibiotic therapy. One patient required a medial gastrocnemius flap after free tissue transfer of a lattissimus dorsi to achieve closure. We utilized an implantable venous Dopper probe attached on the recipient vein proximal to the venous micro- surgical anastomosis in all flaps (see Fig. 1). All patients were maintained on an anticoagulation regimen that included 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 2 The Buncke Clinic, California Pacific Medical Center (Davies Campus), San Francisco, CA *Correspondence to: Curtis L. Cetrulo, Jr., M.D., Division of Plastic and Reconstructive Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA. E-mail: curtis.cetrulo@surgery.usc.edu Received 12 August 2008; Accepted 25 August 2008 Published online 9 October 2008 in Wiley InterScience (www.interscience.wiley. com). DOI 10.1002/micr.20578 V V C 2008 Wiley-Liss, Inc.