Orthopedics

Antibiotic-Coated Spacers for Total Hip Arthroplasty Infection

Michael R. Bloomfield, MD; Alison K. Klika, MS; Wael K. Barsoum, MD

  • Orthopedics. 2010;33(9)
  • Posted September 1, 2010

Abstract

Total hip arthroplasty infection imposes a significant burden on the patient and the health care system. Two-stage revision with interval placement of an antibiotic-cement spacer is the standard of care for chronic periprosthetic infections. This treatment allows for the direct delivery of antibiotics to the infected tissues, and maintains soft tissue tension to facilitate the re-implantation procedure. Evidence suggests that articulating spacers, compared to nonarticulating designs, enhance postoperative ambulation and make the second-stage procedure less difficult. Prefabricated spacers are easy to use; however, they cannot be used to alter the antibiotic composition and dosage. Custom-molded spacers prepared in the operating room from commercially available kits are a popular option; however, like prefabricated spacers, limited sizes are available and thus, they may be contraindicated in situations with significant bone loss. Custom-made total hip spacers are significantly less expensive than commercially-available options, are useful in cases of bone loss, and optimize patient function prior to re-implantation. An inexpensive cemented femoral stem is covered with antibiotic-loaded bone cement. This is done once the cement has the consistency of dough to prevent interdigitation with the host femur. The authors use at least 3.6 g of tobramycin and 1 g of vancomycin per packet of cement. A thin polyethylene is cemented into the acetabulum, followed by placement of the femoral prosthesis. Combined component position must be optimized to prevent instability.

Considerable attention has been focused on the treatment of infection following total hip arthroplasty (THA). Not only is this complication life-altering for the patient, but also imposes a significant burden on the health care system as infected arthroplasties consume significant resources at tertiary care centers. Current infection rates following primary THA in the United States are approximately 0.9%, and the odds of being diagnosed with an infection are increasing at approximately 5% per year.1

The modern era of periprosthetic infection management began with the introduction of the two-stage revision,2 which became the treatment of choice for chronic infections. Two-stage procedures have significantly lower re-infection rates than one-stage procedures.3 Interval treatment with an antibiotic-eluting spacer, as opposed to a simple resection arthroplasty, offers the dual advantages of delivering antibiotics locally to the effective joint space while maintaining soft tissue tension to facilitate re-revision. Rates of infection eradication have correspondingly increased with placement of antibiotic-loaded spacers.3

General antibiotic spacer categories include non-articulating (ie, static cement beads and blocks) and articulating (ie, mobile prostheses loaded with antibiotic cement) types. Hsieh et al4 found that when compared to an articulating spacer design, patients with cement-bead spacers had a longer hospital stay as well as worse ambulation after the initial stage. The nonarticulating spacer patients also had higher operative times, blood loss, and transfusion requirements at the re-implantation procedure. Recent clinical experience at our institution corroborates these findings, which has led us to abandon the use of non-articulating designs.5

Published results of articulating spacer designs are summarized in the Table. These reports generally indicate a >90% rate of infection eradication. As antibiotic resistance patterns of commonly encountered pathogens change, resistant organisms have become prevalent. The success rate of 2-stage revision in this patient population is likely lower, between 66% and 75% in 2 series.12,13

Many permutations of spacer designs exist based on the antibiotic composition and dosages used, the need for assembly in the operating room, the presence of a central metallic reinforcement, and the presence or absence of exposed metal at the spacer surface.14 Three main categories of articulating spacers are currently used in clinical practice. Prefabricated prostheses (Figure 1) have the advantage of being available off-the-shelf with relative ease of implantation. However, the surgeon is then unable to…

Abstract

Total hip arthroplasty infection imposes a significant burden on the patient and the health care system. Two-stage revision with interval placement of an antibiotic-cement spacer is the standard of care for chronic periprosthetic infections. This treatment allows for the direct delivery of antibiotics to the infected tissues, and maintains soft tissue tension to facilitate the re-implantation procedure. Evidence suggests that articulating spacers, compared to nonarticulating designs, enhance postoperative ambulation and make the second-stage procedure less difficult. Prefabricated spacers are easy to use; however, they cannot be used to alter the antibiotic composition and dosage. Custom-molded spacers prepared in the operating room from commercially available kits are a popular option; however, like prefabricated spacers, limited sizes are available and thus, they may be contraindicated in situations with significant bone loss. Custom-made total hip spacers are significantly less expensive than commercially-available options, are useful in cases of bone loss, and optimize patient function prior to re-implantation. An inexpensive cemented femoral stem is covered with antibiotic-loaded bone cement. This is done once the cement has the consistency of dough to prevent interdigitation with the host femur. The authors use at least 3.6 g of tobramycin and 1 g of vancomycin per packet of cement. A thin polyethylene is cemented into the acetabulum, followed by placement of the femoral prosthesis. Combined component position must be optimized to prevent instability.

Considerable attention has been focused on the treatment of infection following total hip arthroplasty (THA). Not only is this complication life-altering for the patient, but also imposes a significant burden on the health care system as infected arthroplasties consume significant resources at tertiary care centers. Current infection rates following primary THA in the United States are approximately 0.9%, and the odds of being diagnosed with an infection are increasing at approximately 5% per year.1

The modern era of periprosthetic infection management began with the introduction of the two-stage revision,2 which became the treatment of choice for chronic infections. Two-stage procedures have significantly lower re-infection rates than one-stage procedures.3 Interval treatment with an antibiotic-eluting spacer, as opposed to a simple resection arthroplasty, offers the dual advantages of delivering antibiotics locally to the effective joint space while maintaining soft tissue tension to facilitate re-revision. Rates of infection eradication have correspondingly increased with placement of antibiotic-loaded spacers.3

General antibiotic spacer categories include non-articulating (ie, static cement beads and blocks) and articulating (ie, mobile prostheses loaded with antibiotic cement) types. Hsieh et al4 found that when compared to an articulating spacer design, patients with cement-bead spacers had a longer hospital stay as well as worse ambulation after the initial stage. The nonarticulating spacer patients also had higher operative times, blood loss, and transfusion requirements at the re-implantation procedure. Recent clinical experience at our institution corroborates these findings, which has led us to abandon the use of non-articulating designs.5

Published results of articulating spacer designs are summarized in the Table. These reports generally indicate a >90% rate of infection eradication. As antibiotic resistance patterns of commonly encountered pathogens change, resistant organisms have become prevalent. The success rate of 2-stage revision in this patient population is likely lower, between 66% and 75% in 2 series.12,13

Table: Published Series of Antibiotic Spacers for THA Infection


Many permutations of spacer designs exist based on the antibiotic composition and dosages used, the need for assembly in the operating room, the presence of a central metallic reinforcement, and the presence or absence of exposed metal at the spacer surface.14 Three main categories of articulating spacers are currently used in clinical practice. Prefabricated prostheses (Figure 1) have the advantage of being available off-the-shelf with relative ease of implantation. However, the surgeon is then unable to alter the antibiotic composition and dosage, and limited sizes and lengths of the implant are available. Commercially available kits, which include a central metallic reinforcement and molds which are filled with cement at the time of surgery, are a popular option. These prostheses allow the antibiotic agents and dosages to be selected by the surgeon; however, limited sizes of the component are available. Finally, a custom spacer may be created by the surgeon using either the autoclaved existing stem or a new, low-cost stem covered with antibiotic-laden cement (Figure 2). This option also gives the surgeon the advantage of tailoring the antibiotic choice to the given situation and the optimization of implant size and length, which is particularly useful in cases of significant bone loss.

Figure 1A: Infected primary THA Figure 1B: Placement of a prefabricated antibiotic-cement hemiarthroplasty spacer Figure 1C: A distally-fixed modular stem
Figure 1: Infected primary THA (A). Placement of a prefabricated antibiotic-cement hemiarthroplasty spacer (Interspace Hip; Exactech, Gainesville, Florida) (B). Extended trochanteric osteotomy was used for component removal. Final reconstruction with a primary acetabular shell (Trident; Stryker Orthopaedics, Mahwah, New Jersey) (C) and a distally-fixed modular stem (Restoration Modular; Stryker Orthopaedics).

Figure 2A: A custom-made articulating antibiotic-cement spacer Figure 2B: A custom-made articulating antibiotic-cement spacer
Figure 2: Radiograph (A) and clinical photograph (B) of a custom-made articulating antibiotic-cement spacer.

The authors’ preference is to use the latter custom-made spacer in most cases of THA infection. We routinely use a custom-total spacer made with a thin polyethylene acetabular component and a low-cost cemented stem. We believe that this option best preserves the remaining femoral and acetabular bone stock for the re-implantation procedure, and improves the postoperative functional capacity between stages. At our institution, this option is less than half the cost of the commercially-available spacers.

We typically use at least 3.6 g of tobramycin and 1 g of vancomycin per package of bone cement,15 and consider using additional vancomycin in cases of infection with resistant organisms. The powdered antibiotics are added after the cement is mixed to ensure optimal elution from the cement once hardened.16 Once the cement has a doughy consistency, it is formed around the femoral stem. Implanting the stem with the cement in a more liquid phase will cause interdigitation with the bone and thus a more difficult explant at the time of the second-stage procedure. The acetabular component is cemented in place first, followed by the antibiotic-laden stem (Figure 3). Component position must be scrutinized to minimize the risk of postoperative instability.17 Only touchdown weight bearing is allowed to protect the construct.

Figure 3A: A custom-made total hip-style antibiotic spacer implantation showing polyethylene Figure 3B: Femoral components
Figure 3: Intraoperative photographs of a custom-made total hip-style antibiotic spacer implantation showing polyethylene (A) and femoral components (B).

Complications following antibiotic spacer placement (Figure 4) appear to be more common than after primary THA. Jung et al18 found that mechanical failures were surprisingly prevalent in a series of 88 custom-molded cement spacers performed over 9 years. Dislocations (15 cases, 17%), periprosthetic femur fractures (12 cases, 13.6%), and spacer fractures (9 cases, 10.2%) were the most frequent spacer-related complications. Other complications such as systemic toxicity from aminoglycoside antibiotics contained in spacers are also a theoretical concern. To our knowledge, no studies have been published that compare the incidence of complications among spacer types.

Figure 4A: Complications after antibiotic spacer placement Figure 4B: Revision with a long-stem prefabricated spacer
Figure 4: Complications after antibiotic spacer placement in an elderly patient who sustained a displaced femoral neck fracture treated with a bipolar hemiarthroplasty which became infected (A). Periprosthetic fracture after debridement and placement of custom-made hemiarthroplasty spacer. Revision with a long-stem prefabricated spacer (Interspace Hip, Exactech, Gainesville, FL) (B) with placement of cerclage cables to secure the fracture. The procedure was subsequently complicated by dislocation.

References

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  2. Insall JN, Thompson FM, Brause BD. Two-stage reimplantation for the salvage of infected total knee arthroplasty. J Bone Joint Surg Am. 1983; 65(8):1087-1098.
  3. Garvin KL, Hanssen AD. Infection after total hip arthroplasty. Past, present, and future. J Bone Joint Surg Am. 1995; 77(10):1576-1588.
  4. Hsieh PH, Shih CH, Chang YH, Lee MS, Shih HN, Yang WE. Two-stage revision hip arthroplasty for infection: comparison between the interim use of antibiotic-loaded cement beads and a spacer prosthesis. J Bone Joint Surg Am. 2004; 86(9):1989-1997.
  5. Stefancin J, Apostopoulos V, Kilka A, Barsoum W. Complications associated with antibiotic hip spacer options used in two stage total hip arthroplasty. Paper presented at: Annual Meeting of the Mid-America Orthopaedic Association; April 21-25, 2010; Lost Pines, Texas.
  6. Younger AS, Duncan CP, Masri BA, McGraw RW. The outcome of two-stage arthroplasty using a custom-made interval spacer to treat the infected hip. J Arthroplasty. 1997; 12(6):615-623.
  7. Leunig M, Chosa E, Speck M, Ganz R. A cement spacer for two-stage revision of infected implants of the hip joint. Int Orthop. 1998; 22(4):209-214.
  8. Wentworth SJ, Masri BA, Duncan CP, Southworth CB. Hip prosthesis of antibiotic-loaded acrylic cement for the treatment of infections following total hip arthroplasty. J Bone Joint Surg Am. 2002; 84(Suppl 2):123-128.
  9. Etienne G, Waldman B, Rajadhyaksha AD, Ragland PS, Mont MA. Use of a functional temporary prosthesis in a two-stage approach to infection at the site of a total hip arthroplasty. J Bone Joint Surg Am. 2003; 85(Suppl 4):94-96.
  10. Takahira N, Itoman M, Higashi K, Uchiyama K, Miyabe M, Naruse K. Treatment outcome of two-stage revision total hip arthroplasty for infected hip arthroplasty using antibiotic-impregnated cement spacer. J Orthop Sci. 2003; 8(1):26-31.
  11. Durbhakula SM, Czajka J, Fuchs MD, Uhl RL. Spacer endoprosthesis for the treatment of infected total hip arthroplasty. J Arthroplasty. 2004; 19(6):760-767.
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  13. Murray T, Cochran J, Klika A, et al. Outcome of prosthetic hip infections with resistant organisms at a tertiary care center. Paper presented at: 77th Annual Meeting of the American Academy of Orthopaedic Surgeons; March 9-13, 2010; New Orleans, Louisiana.
  14. Burnett R, Clohisy J, Barrack R. Antibiotic Cement Spacers in Total Hip and Total Knee Arthroplasty: Problems, Pitfalls, and Avoiding Complication. In: Meani E, Romano C, Crosby L, Hofmann G, eds. Infection and Local Treatment in Orthopaedic Surgery. New York, NY: Springer-Verlag Berlin Heidelberg; 2007:92-111.
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Authors

Drs Bloomfield and Barsoum and Ms Klika are from the Department of Orthopedic Surgery, Cleveland Clinic, Cleveland, Ohio.

Dr Bloomfield and Ms Klika have no relevant financial relationships to disclose. Dr Barsoum receives research support from Stryker Orthopaedics, Zimmer, Smith & Nephew, Salient Surgical Technologies, Brand X, and Cool Systems, Inc; receives royalties from Exactech, Inc, Wright Medical Technology, Inc, and Shukla Medical; has company equity in OtisMed; and is a consultant with Stryker Orthopaedics, Wright Medical Technology, Inc, and Shukla Medical.

Presented at Current Concepts in Joint Replacement 2009 Winter Meeting; December 9-12, 2009; Orlando, Florida.

Correspondence should be addressed to: Wael K. Barsoum, MD, Department of Orthopedic Surgery, Cleveland Clinic, 9500 Euclid Ave, Desk A41, Cleveland, OH 44195 (barsouw@ccf.org).

doi: 10.3928/01477447-20100722-21

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