الفهرس 
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Abstract
Better understanding of the interaction between microorganisms, the implant and the host may improve approach to the diagnosis and treatment of implant associated infections.
The pathogenesis of infections associated with fracture fixation devices is related to microorganisms growing in biofilms, which render these infections difficult to treat. These infections are classified as early (< 2 weeks), delayed (2−10 weeks) or late infections (> 10 weeks) according to the implant surgery.
Most infections are caused by staphylococci and are acquired during trauma (in penetrating injuries) or subsequent fracture fixation procedures.
A combination of clinical, laboratory, histopathology, microbiology, and imaging studies are usually needed to accurately diagnose infection.
Laboratory tests that are helpful in establishing the diagnosis of an infected implant include a complete blood cell count with differential, determination of the erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Of these tests, the CRP may be the most useful for evaluating and monitoring the patient’s response to therapy.Positron emission tomography (PET) and PET-CT are promising new tools for diagnosing implant associated osteomyelitis.
The treatment goal is achieving bone consolidation and avoiding development of chronic osteomyelitis.
The treatment modality depends on duration of infection, stability of the implant, antimicrobial susceptibility of the pathogen and condition of the surrounding soft tissue.
In conclusion we can maintain implants in infection after internal fixation of a fracture until fracture union occurs in patients have the following criteria:
1-Acute infection with signs and symptoms less than28 days.
2-Stable implant with no signs or symptoms of loosening.
3-Clearly established diagnosis by isolating single microorganism
from multiple specimens by aspiration or preferably intra operative
culture during debridement.
4-Positive histopathologic results, preferably by frozen section.
5-Pathogen susceptible to oral, preferably bactericidal and antimicrobial agent.
6-Antimicrobial agent with proven effectiveness in preferably human or animal studies.
7-Patient able and willing to undergo long-term antimicrobial therapy.
If infection occurs in the immediate postoperative period (i.e., the first 1 to 4 weeks) immediately return the patient to surgery. Open the surgical wound down to the bone and implants. Extensive and meticulous debridement and irrigation the wound.
Initial treatment with antimicrobial agents should always be given iv for 4 weeks. The treatment can be changed to oral therapy for a minimum of 3 months. Until the fracture is healed and implants are eventually removed.
Antimicrobial treatment should be continued for about 4−6 weeks
after hardware removal to avoid development of chronic osteomyelitis.
In fractures with delayed union or nonunion that are infected, surgical treatment is nearly always necessary and begins with debridement of bone and soft-tissue abscesses, removing all infected and nonviable tissues. Remove infected implants .
The sequence of serial wound debridements, leaving the wound open or managing it with close suction irrigation or antibiotic impregnated beads is performed.
Convert fixation to external fixation, and administer culture-directed parenteral antibiotics for 6 week then start oral treatment
The vast majority of these infections resolve after hardware removal.