a mature biofilm.
Fig. 6.2 Biofilm pathogenesis. 1. Planktonic bacteria attachment: reversible and bacteria susceptible to antibiotics and rinsing. 2. Micro-colonies develop: reversible and bacteria susceptible to antibiotics and rinsing. 3. Continued cell division: more adhesion sites, matrix formation, and biofilm maturation. 4. Detachment: liberate planktonic bacteria or small segments and plankontic bacterial may relocate and colonize other surfaces.
c. Persister cells: dormant, multidrug tolerant cells that live within mature biofilm and have the ability to repopulate the biofilm.
d. Quorum-sensing molecules: chemomodulators within a mature biofilm permitting intercellular communication to permit bacterial resistance.
III. Serologic Analysis
A. Subacute postoperative period
1. Markers of inflammation, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are routinely elevated in response to traumatic and surgical events (low specificity for infection diagnosis).
2. The magnitude of inflammatory marker elevation may be valuable.
3. The change of CRP over time is helpful rather than the overall value.
B. Chronic infection
1. ESR and CRP are sensitive markers of infection and relatively nonspecific.
2. Twenty percent of patients undergoing nonunion repair with normal preoperative inflammatory markers may be culture-positive at the time of surgery.
IV. Imaging
A. Diagnostic imaging in the weeks immediately following operative care often fails to show changes that are commonly seen over the course of time.
B. Computed tomography or ultrasound may provide findings of an abscess or presence of air. Such findings may either guide percutaneous drainage with a needle or direct surgical debridement.
V. Classification
Infections are typically referred to as superficial or deep according to whether the infection has penetrated deep to the fascia.
VI. Treatment
A. Surgical debridement (▶Fig. 6.3)
1. Excision of all infected and nonviable tissue may require several operations.
2. Retention versus removal of implants with staged internal fixation after temporary fixation (typically external fixation).
3. Mechanical debridement of implant surfaces.
4. Local antibiotic delivery.
5. Soft tissue coverage as necessary.
B. Antibiotic therapy
1. Six weeks of intravenous (IV) antibiotics is a commonly employed regimen.
2. No conclusive evidence on the effectiveness of IV compared to PO regimens. Basic science and clinical series have not shown a clear benefit of IV antibiotics to date; although, both are routinely used in clinical practice.
C. Modifiable risk factors should be addressed to optimize treatment(s) as local host factors related to reduced host vascularity, neuropathy, trauma, and immunodeficiency increase the likelihood of infection.
D. Predictors of eradication of infection and limb salvage
1. Short-term implant.
2. Absence of a sinus tract.
Fig. 6.3 Treatment algorithm for acute infection following internal fixation for trauma. ORIF, open reduction and internal fixation.
3. Known pathogen susceptible to antibiotics.
4. Stable implant.
E. Predictors of treatment failure include:
1. Intramedullary rod placement.
2. Smoking.
3. Pseudomonas infection.
F. Biopsy
1. Several deep tissue samples should be taken.
a. These should be taken as far apart as possible to represent the entire wound.
b. Superficial swabs may only identify local flora and are discouraged.
G. Factors that prompt implant removal
1. Persistent infection.
2. Loose hardware.
3. Fracture displacement.
H. If implants are removed prior to fracture healing, ensure that fracture stabilization is achieved.
1. Splinting.
2. Revision internal fixation.
3. External fixation.
I. If implants are removed and bone resection is necessary
1. External fixation
a. Place antibiotic spacer and proceed with Masquelet technique.
b. Bone transport.
VII. Outcomes
A. Implant retention—success rates of curing early postoperative infection with maintenance of hardware range from 68 to 90% with surgical debridement and treatment with culture-specific antibiotics.
1. Consider elective removal of hardware after bony union.
B. Implant removal—successful eradication of infection reaches 92% before bony union.
1. Must outweigh the benefits of fracture stabilization.
2. Consider an alternative method of fracture stabilization.
C. Factors increasing risk of treatment failure.
1. Smoking.
2. Pseudomonas infection.
3. Intramedullary nail (IMN).
4. Tibia.
5.
