Alan Y. Yan, MD; Frances D. Faro, MD; Lew C. Schon, MD
Operative foot and ankle osteomyelitis is challenging for orthopedic surgeons because of the area’s unique anatomy, high trauma incidence, local and systemic disease effects, and often limited space. Standard treatment includes aggressive operative debridement with local and systemic antibiotic administration to control infection. Dead space management is critical yet technically demanding. The authors report a modified antibiotic cement bead therapy technique in which antibiotic sticks, minnows, and mushroom-shaped plugs are used to strike a balance between the stability of the load-bearing unit and radical removal of infection to preserve a functional foot. Three cases are presented. [Orthopedics. 2014; 37(1):32–36.]
The authors are from the Department of Orthopaedic Surgery (AYY), The Johns Hopkins University; and the Department of Orthopaedic Surgery (FDF, LCS), MedStar Union Memorial Hospital, Baltimore, Maryland.
The authors have no relevant financial relationships to disclose.
The authors thank W. Chad Hembree, MD, for providing the procedure details on the third patient for this article.
Correspondence should be addressed to: Lew C. Schon, MD, c/o Elaine P. Henze, BJ, ELS, Medical Editor and Director, Editorial Services, Department of Orthopaedic Surgery, The Johns Hopkins University/Johns Hopkins Bayview Medical Center, 4940 Eastern Ave, Baltimore, MD 21224-2780 (email@example.com).
Received: May 06, 2013
Accepted: July 25, 2013
Posted Online: January 15, 2014
Operative foot and ankle osteomyelitis is likely in part a product of this area’s unique anatomy, high trauma incidence, and local and systemic disease effects.The lower extremity’s thin soft tissue envelope is occasionally further compromised by poor vascularity from high-energy trauma, diabetes mellitus, smoking, and peripheral vascular disease.1–3 Standard treatment includes aggressive operative debridement with local and systemic antibiotic administration to control infection.2,4–7 Such debridement can be technically demanding,7 but the removal of all nonviable tissue is essential to creating a healthy tissue bed and decreasing the infectious load. However, this process creates a dead space that needs to be managed.5–7
One way to manage such space is with cement spacers that can be molded into various shapes and loaded with antibiotics. This local delivery of high concentrations directly to the tissues offers a distinct advantage over the vascular-supply–dependent delivery of high and potentially toxic levels via systemic delivery.8–13 Antibiotic cement can be molded into large blocks and spheres to fit a patient’s anatomy, providing structural integrity and preventing soft tissue contracture, or into beads strung on suture for smaller areas (eg, those in the lower extremity). This bead technique has been modified for use within the crowded anatomy of foot and ankle operative osteomyelitis. The authors have successfully used this technique for many patients, resulting in infection resolution and more preservation of normal tissue and structural stability.
Contouring the shape of the antibiotic forms creates maximum surface contact and facilitates insertion into tight spaces (Figures 1–2). Long “sticks” are used for penetrating sinuses, tunnels, and abandoned hardware paths; they have a large surface area for eluting the antibiotic and can be easily shortened to a custom length even after the cement hardens. After hardware removal, plugs or “mushrooms” are used in the screw holes to provide structural integrity and direct delivery of antibiotics to the bone. “Minnows” are used to help contour voids created by surgical debridement.
Mushroom-shaped antibiotic cement plugs applied to screw holes after plate removal.
Antibiotic cement sticks, minnows, and mushroom plugs made intraoperatively.
Institutional review board approval was waived for this study. Informed consent was obtained from the patients.
Patient 1: Antibiotic Mushrooms
A 20-year-old man had swelling and serous wound drainage 4 months after a left ankle fibula fracture was treated with a plate and syndesmotic tightrope device. He underwent debridement.
After dissection, the screws securing the plate were removed. A tunnel from the superficial tissue extending deep was found with 3 to 4 mL of purulent material.The hardware was removed. The bone plate interface and screw holes were debrided with a curette. All wounds were copiously irrigated and closed primarily. A packet of cement was mixed with tobramycin (2.4 g) and vancomycin (2.0 g) until tacky and fashioned into small mushrooms (Figure 2), which were inserted into the screw holes. Because the cement was still slightly pliable, it formed to the bone hole, leaving a flat disk shape on the outside of the bone. Biplanar fluoroscopy confirmed removal of all hardware (Figure 3) and indicated syndesmosis widening, but no additional fixation was undertaken, given the infected tissue bed. The patient was allowed to bear weight as tolerated postoperatively. The patient had excellent infection resolution and no recurrence 3 years postoperatively.
Intraoperative biplanar fluoroscopic image confirming plate removal and mushroom plug placement.
Patient 2: Antibiotic Sticks
A 54-year-old man had a history of morbid obesity, ankylosing spondylitis, and peripheral neuropathy. He had had severe right forefoot deformity, hallux valgus, and laterally deviated and clawed second through fifth toes and had undergone reconstructive surgery elsewhere, with subsequent recurrent deformity and ulcerations on the plantar aspect of the second metatarsal. One month after revision surgery, he jammed his right second toe, pushing the pin in farther. He presented 1 day later with edema, blistering, erythema of the foot, and purulent pin site drainage.
He underwent a second-toe amputation at the metatarsophalangeal joint, where purulence and necrotic tissue were debrided. After copious irrigation, cement sticks and plugs fashioned with vancomycin and tobramycin were placed in and around the second metatarsal (Figures 4–6). Two stitches were lightly applied to secure the sticks and plugs in place, allowing fluid egress.
Placement of antibiotic cement sticks in a surrounded fashion.
Toe site packed with antibiotics with the plugs placed over the tip after debridement.
Mushroom antibiotic plugs applied. (©2012 Alan Yan. Used with permission.)
One week later, the patient had clean soft tissue and markedly decreased swelling. He returned to the operating room for suture and spacer removal.Minimal devitalized tissue was noted and debrided with curette and scalpel.New antibiotic cement sticks and plugs were placed, and the wound was closed with 3-0 nylon horizontal mattress and simple sutures. The wound was covered and placed into a bulky dressing. The patient was restricted to heel weight bearing only for 2 weeks. The patient had infection resolution at 1 week and no recurrence at 4 years.
Patient 3: Antibiotic Minnows
A 47-year-old man had a chronic draining sinus after open debridement elsewhere for plantar fasciitis of the right foot (Figure 7). Aggressive debridement was performed, and a large medial portion of the plantar fascia was excised and sent for culture (Figure 8). The bone was not involved. The wound was copiously irrigated. A packet of cement containing tobramycin (2.4 g) was mixed with vancomycin (2.0 g). Several minnow spacers (Figure 9) were placed, the “heads” deep to fill the void from the debridement and the “tails” wrapped around the medial aspect of the calcaneus. The wound was closed with 2-0 nylon simple, deep stitches. The patient was kept nonweight bearing for 6 weeks. The wound healed uneventfully, and the drainage stopped.Intraoperative cultures showed no growth. The patient was treated with a 7-day course of oral cephalosporin for the first week postoperatively. The spacers were removed 8 weeks postoperatively. The patient healed with some delay. There was no recurrence at 1 year.
A 47-year-old man with a chronic draining sinus after open debridement of plantar fasciitis.
Intraoperative image showing a large medial portion of the plantar fascia was excised and sent for culture. The bone was not involved in the infection.
A pack of antibiotic cement containing 2.4 g of tobramycin was mixed with 2 g of vancomycin. Several minnow-shaped cement spacers were fashioned for insertion into the wound.
Operative infection control is facilitated by a thorough debridement and microbial-specific antibiotic administration,12 but the surgical management of osteomyelitis is challenging. A suboptimal technique can result in recalcitrant chronic infection.7,14
Antibiotics can be delivered systemically or locally. Effective systemic application requires a high serum level, which can cause systemic side effects.11,15 However, an effective local delivery system incorporated surgically can provide the needed concentration of antibiotics while minimizing systemic toxicity.16
Antibiotic-loaded bone cement represents the gold standard for local antibiotic delivery16 and provides for dead space management.8 This concept is based on the pioneering work of Buchholz and Engelbrecht in the 1970s.4,12,17 In 1979, Klemm18 extended the indications for antibiotic bone cement by developing gentamicin-polymethylmethacrylate bead chains for chronic osteomyelitis surgery. He reported that 91.4% of 128 patients with chronic osteomyelitis treated with this technique had complete infection subsidence.18
The local delivery system works primarily via elution and some passive diffusion,12,19 affording high local concentrations, low serum levels, and no system toxicity.11–13,20 It also reduces systemic complications, compliance issues, and intravenous access problems12 and may address systemic antibiotics’ poor bone penetration, especially in devascularized bone.8 Local delivery also provides antibiotics independent of vascular support,8 an advantage in foot and ankle infection, where peripheral vascular condition is often compromised by systemic diseases.
Some studies have shown that the local deposit of antibiotics is a safe and useful method and provides favorable results for osteomyelitis and open fractures.11,21 However, Level I evidence is still limited.12
The original principles of osteomyelitis surgery included an atraumatic approach and removal of all necrotic or nonviable material with reconstruction in mind.6,7 However, management of the ensuing dead space is a key factor for a successful outcome.7,14 When serial debridement is indicated or inadequate local tissues require additional surgeries for closure, antibiotic-impregnated beads or spacers are implanted to inhibit and kill remaining pathogens13 and to preserve useful dead space for maintaining working length, facilitating closure, and preparing for later clean reconstruction.7,22
Because antibiotic spacers are intended for subsequent removal, generally after soft tissues have completely recovered (3 to 4 weeks, or 10 to 14 days if they are within the medullary canal), the second stage of surgery includes bead or spacer removal, repeat irrigation and debridement, and exchange for bone graft or a bone graft substitute.7 The longest recommended removal time is 4 to 6 weeks after implantation; removal thereafter can be incomplete or difficult because of fibrous tissue or callus enclosure.23
Although the current literature still has limited clinical data on foot and ankle infection treated with local antibiotic-loaded cement, complications related to the use of antibiotic beads for bone infection are uncommon.8,11,21
This technique modifies existing antibiotic bead therapy for the often-limited space in foot and ankle surgery and deep sinuses that are difficult to reach. It is designed to strike a balance between the stability of the load-bearing unit and radical removal of infection to preserve a functional foot. The sticks, minnows, and mushroom-shaped plugs are easy to place and retrieve. The mushroom-shaped plugs are most useful in the screw holes and local defects created by surgery or disease process. The sticks can be placed around the crowded locus in foot and ankle anatomy. The minnows are a hybrid shape that fills a long narrow tunnel and a larger zone of dead space. In the authors’ experience, the technique is a useful adjunct for infections in the foot and ankle.
Ansari MA, Shukla VK. Foot infections. Int J Low Extrem Wounds. 2005; 4(2):74–87. doi:10.1177/1534734605277312 [CrossRef]
Malizos KN, Gougoulias NE, Dailiana ZH, Varitimidis S, Bargiotas KA, Paridis D. Ankle and foot osteomyelitis: treatment protocol and clinical results. Injury. 2010; 41(3):285–293. doi:10.1016/j.injury.2009.09.010[CrossRef]
Verhelle N, Van Zele D, Liboutton L, Heymans O. How to deal with bone exposure and osteomyelitis: an overview. Acta Orthop Belg. 2003; 69(6):481–494.
Buchholz HW, Engelbrecht H. [Depot effects of various antibiotics mixed with Palacos resins]. Chirurg. 1970; 41(11):511–515.
Cierny G III, DiPasquale D. Treatment of chronic infection. J Am Acad Orthop Surg. 2006; 14(10):S105–S110.
Cierny G III, Mader JT, Penninck JJ. A clinical staging system for adult osteomyelitis. Clin Orthop Relat Res. 2003; 414:7–24. doi:10.1097/01.blo.0000088564.81746.62 [CrossRef]
Tetsworth K, Cierny G III, . Osteomyelitis debridement techniques. Clin Orthop Relat Res. 1999; 360:87–96. doi:10.1097/00003086-199903000-00011 [CrossRef]
Decoster TA, Bozorgnia S. Antibiotic beads. J Am Acad Orthop Surg. 2008; 16(11):674–678.
Elson RA, Jephcott AE, McGechie DB, Verettas D. Antibiotic-loaded acrylic cement. J Bone Joint Surg Br. 1977; 59(2):200–205.
Hanssen AD. Local antibiotic delivery vehicles in the treatment of musculoskeletal infection. Clin Orthop Relat Res. 2005; 437:91–96.doi:10.1097/01.blo.0000175713.30506.77 [CrossRef]
Wahlig H, Dingeldein E, Bergmann R, Reuss K. The release of gentamicin from polymethylmethacrylate beads: an experimental and pharmacokinetic study. J Bone Joint Surg Br. 1978; 60(2):270–275.
Zalavras CG, Patzakis MJ, Holtom P. Local antibiotic therapy in the treatment of open fractures and osteomyelitis. Clin Orthop Relat Res. 2004; 427:86–93. doi:10.1097/01.blo.0000143571.18892.8d [CrossRef]
Adams K, Couch L, Cierny G, Calhoun J, Mader JT. In vitro and in vivo evaluation of antibiotic diffusion from antibiotic-impregnated polymethylmethacrylate beads. Clin Orthop Relat Res. 1992; 278:244–252.
Lazzarini L, Mader JT, Calhoun JH. Osteomyelitis in long bones. J Bone Joint Surg Am. 2004; 86(10):2305–2318.
Schentag JJ, Lasezkay G, Plaut ME, Jusko WJ, Cumbo TJ. Comparative tissue accumulation of gentamicin and tobramycin in patients. J Antimicrob Chemother. 1978; 4(Suppl A):23–30. doi:10.1093/jac/4.suppl_A.23 [CrossRef]
Nelson CL. The current status of material used for depot delivery of drugs.Clin Orthop Relat Res. 2004; 427:72–78.doi:10.1097/01.blo.0000143741.92384.18 [CrossRef]
Buchholz HW, Elson RA, Engelbrecht E, Lodenkamper H, Rottger J, Siegel A. Management of deep infection of total hip replacement. J Bone Joint Surg Br.1981; 63(3):342–353.
Klemm VK. [Gentamicin-PMMA-beads in treating bone and soft tissue infections (author’s transl)]. Zentralbl Chir. 1979; 104(14):934–942.
Baker AS, Greenham LW. Release of gentamicin from acrylic bone cement: elution and diffusion studies. J Bone Joint Surg Am. 1988; 70(10):1551–1557.
Holtom PD, Warren CA, Greene NW, et al. Relation of surface area to in vitro elution characteristics of vancomycin-impregnated polymethylmethacrylate spacers. Am J Orthop (Belle Mead NJ). 1998; 27(3):207–210.
Walenkamp GHIM, Vree TB, van Rens TJG. Gentamicin-PMMA beads: pharmacokinetic and nephrotoxicological study. Clin Orthop Relat Res. 1986; 205:171–183.
Cierny G III, . Chronic osteomyelitis: results of treatment. Instr Course Lect.1990; 39:495–508.
Salvati EA, Callaghan JJ, Brause BD, Klein RF, Small RD. Reimplantation in infection: elution of gentamicin from cement and beads. Clin Orthop Relat Res. 1986; 207:83–93.