Consensus Principles In Addressing Fracture-Related Hardware Infections

Postoperative infections involving hardware are challenging to manage and may potentially lead to devastating amputations. 

With this dilemma in mind, recently published consensus findings offer diagnostic criteria for defining fracture-related infections as well as recommendations on diagnostic pathways and treatment concepts for fracture-related infections.¹ Accordingly, let us take a closer look at the work of Govaert and colleagues and their general recommendations for the management of infected hardware.

The first step in the workup of a patient with a fracture-related infection is arriving at a well-established diagnosis.¹ It is important to keep in mind that the general term, ”fracture-related infection,” does not differentiate between acute or chronic, the depth of infection and anatomic location. 

Diagnostic criteria can be confirmatory or suggestive. Confirmatory criteria include:¹

1. fistula, sinus and wound breakdown with bone or implant contact; 

2. purulent drainage from the wound; 

3. microbiology examination identifying pathogens from at least two separate specimens; and 

4. histopathology examination showing presence of microorganisms with presence of greater than five polymorphonucleocytes per high-power field (PMN/HPF).¹

In cases involving pathogens from two separate specimens in a microbiology examination, Govaert and coworkers recommend stopping pre-operative antibiotics for at least two weeks, and getting five or more tissue samples from the area in question (no swabs) from the implant-bone interface.¹

Suggestive criteria include:¹

1. local and systemic clinical signs of infection (such as redness and fever);

2. signs of infection on radiological (bone lysis, implant loosening, sequestration, lack of bone healing and presence of periosteal reaction) and/or nuclear imaging; 

3. elevated serum markers (erythrocyte sedimentation rate (ESR), white blood cells (WBC) or C-reactive protein (CRP)); 

4. pathogenic organism identified by single deep culture; and 

5. persistent wound drainage beyond the first few days postoperatively or new onset joint effusion.¹

In regard to nuclear imaging, white blood cell scintigraphy and fluorodeoxyglucose positron emission tomography show high diagnostic accuracy for fracture-related infection.¹

Implementation of a comprehensive multidisciplinary team approach is critical for maximizing recovery potential.² When it comes to general host status, the American Society of Anesthesiologists (ASA) score has good predictive value regarding perioperative risk, complication rate and postoperative outcomes.² Other key factors in the multidisciplinary team approach include soft tissue assessment (open wounds and edema), local neurovascular status (vascular insufficiency), baseline blood analysis and initiation of patient optimization.  Systemic targets for optimization include malnutrition, smoking, diabetes and cardiopulmonary status.² 

Members of the multidisciplinary team require expertise in bone and soft tissue reconstruction, microbiology, antibiotic treatment and advanced imaging. One should involve a minimum of three disciplines: surgeons, infectious disease specialists and clinical pharmacists. This comprehensive type of approach can maximize a successful outcome to preserve a functional limb in most patients.² The planning and treatment of complex revision cases require dedication from a multidisciplinary team, preferably one with volume performance with many complex procedures.

The two main surgical principles in fracture-related infections are: 

1. debridement, antimicrobial therapy and implant retention; and

2. debridement, implant removal or exchange (one or multiple stages).¹

The primary aims for surgical treatment include fracture consolidation, restoration of function, healing of the soft tissue envelope, prevention of chronic infection/osteomyelitis and eradication of infection as the final outcome. One should note that complete eradication is not always the primary goal. The following factors will influence decision making for removal or exchanging hardware: time interval since surgery; stability of the osteosynthetic construct; sufficient debridement access (i.e. intramedullary nail), infection severity, fracture localization, condition of the soft tissue envelope; and host physiology.¹

The two main antimicrobial principles include: 

1. infection eradication; and

2. infection suppression.²  

One should start empiric intravenous (IV) antimicrobial therapy shortly after obtaining tissue samples.  The antimicrobial agent(s) should be broad spectrum (including a glycopeptide and an agent against gram-negative bacilli). Targeted antimicrobial therapy should commence according to culture results as soon as possible. There is no consensus on the duration of antimicrobial therapy. Short-term IV therapy reportedly has the same outcome in comparison to long-term IV therapy as long as one implements appropriate antibiotic therapy.² Common coverage time is six to 12 weeks but the multidisciplinary team should agree on this. A curative approach is only effective with biofilm-active antibiotics (rifampin against most gram-positive bacteria and fluoroquinolones against most gram-negative bacteria).²

The multidisciplinary team should regularly review surgical and antimicrobial treatments, and adjust appropriately based on culture results and patient optimization. Successful management depends on following a rehabilitation plan and ensuring multidisciplinary patient follow-up during a minimum of 12 months after cessation of (surgical and antibiotic) therapy.²

Following a well-established protocol will help ensure the proper diagnosis of infected hardware, effective surgical and antimicrobial management of the infection, and optimize patient outcomes.

Dr. Husain is the Residency Director of the McLaren Oakland Hospital Podiatric Surgery and Medicine Residency Program in Pontiac, Michigan. He is a Fellow of the American College of Foot and Ankle Surgeons, and a Fellow of the American Society of Podiatric Surgeons. Dr. Husain is also the President-Elect of the Michigan Podiatric Medical Association and Chairman of the Michigan Podiatric Residency Consortium.

References

1. Govaert GAM, Kuehl R, Atkins BL, et al. Diagnosing fracture-related infection: current concepts and recommendations. J Orthop Trauma. 2020;34(1):8-17.

2. Metsemakers WJ, Morgenster M, Senneville E, Borens, O, Govaert GAM, Onsea J, Depypere M, Richards RG, Trampuz A, et al. General treatment principles for fracture-related infection: recommendations from an international expert group. Arch Orthop Trauma Surg. 2020;140(8):1013-1027.