Orthopedics

Feature Article 

Positive “Surprise” Broth Cultures in Nonunion Surgery Do Not Require Antibiotic Treatment

William A. Cantrell, BS; Joshua M. Lawrenz, MD; Heather A. Vallier, MD

Abstract

The objective of this study was to review the efficacy of a treatment approach for patients with positive intraoperative cultures during fracture nonunion surgery. The authors performed a retrospective case series at a level I trauma center. In this series, 60 patients without preoperative concern for infection were surgically treated for fracture nonunion. The treatment course of patients after fracture nonunion surgery, including culture results, antibiotic administration, and the presence of clinical infection and radiographic union, was studied. Sixty patients underwent fracture nonunion surgery. Twenty-four patients had a positive intraoperative culture. Fourteen patients had only a positive broth culture, 6 had only a positive routine culture, and 4 had positive mixed (routine and broth) cultures. The most common bacteria was coagulase-negative staphylococci, isolated in 19 of 24 patients, and the only isolated organism in 13 of 24 patients. Patients with a positive broth culture were not treated with antibiotics. Four of 10 patients with either a positive routine or mixed culture grown within 3 days of surgery were treated with antibiotics. All patients achieved clinical healing without signs of infection, and all but 2 patients achieved radiographic union at a mean follow-up of approximately 5 years. In the setting of fracture nonunion surgery, patients with only a positive broth culture and those with only a positive routine or mixed cultures that grew in a delayed fashion (>3 days postoperatively) did not require antibiotic treatment to achieve healing. [Orthopedics. 2019; 42(6):e532–e538.]

Abstract

The objective of this study was to review the efficacy of a treatment approach for patients with positive intraoperative cultures during fracture nonunion surgery. The authors performed a retrospective case series at a level I trauma center. In this series, 60 patients without preoperative concern for infection were surgically treated for fracture nonunion. The treatment course of patients after fracture nonunion surgery, including culture results, antibiotic administration, and the presence of clinical infection and radiographic union, was studied. Sixty patients underwent fracture nonunion surgery. Twenty-four patients had a positive intraoperative culture. Fourteen patients had only a positive broth culture, 6 had only a positive routine culture, and 4 had positive mixed (routine and broth) cultures. The most common bacteria was coagulase-negative staphylococci, isolated in 19 of 24 patients, and the only isolated organism in 13 of 24 patients. Patients with a positive broth culture were not treated with antibiotics. Four of 10 patients with either a positive routine or mixed culture grown within 3 days of surgery were treated with antibiotics. All patients achieved clinical healing without signs of infection, and all but 2 patients achieved radiographic union at a mean follow-up of approximately 5 years. In the setting of fracture nonunion surgery, patients with only a positive broth culture and those with only a positive routine or mixed cultures that grew in a delayed fashion (>3 days postoperatively) did not require antibiotic treatment to achieve healing. [Orthopedics. 2019; 42(6):e532–e538.]

Fracture healing is a complex mechanical and biologic process and can lead to nonunion without an adequate mechanical and biological environment.1–3 Management of aseptic non-unions has been discussed well in the literature.4 However, a significant challenge is presented when the nonunion surgery is complicated by unexpected positive intraoperative culture results, particularly when preoperative clinical and laboratory suspicion is low.5–8 The significance of these “surprise” positive cultures has been questioned,6,9 and treatment approaches vary from aggressive antibiotic treatment to no antibiotic treatment at all.6,9–11

Appropriate use of antibiotics is important to minimize resistance12 and decrease unnecessary spending13; in addition, potential negative effects have been reported on fracture healing via effects on bone cell metabolism.14 Many techniques have been developed to localize the effect of antibiotics while minimizing the potentially negative systemic effects, including using antibiotic powder, antibiotic-impregnated cement,15 and antimicrobial scaffolds.16 Nevertheless, indications for systemic antibiotics are important because they remain central to treatment of deep infection.

Furthermore, clinical interpretation becomes increasingly difficult when cultures only result positive on broth media. When examining the correlation of positive broth cultures with true prosthetic joint infection based on Musculoskeletal Infection Society criteria, Smith et al17 showed that broth cultures have an 88% specificity but a 19% sensitivity. Another report demonstrated that adding broth cultures to routine cultures increases sensitivity from 83% to 95% and increases negative predictive value from 77% to 91%.18

To the current authors' knowledge, there has been no evidence in support of or against the efficacy of broth-positive cultures in the setting of fracture non-union surgery. Therefore, the purpose of the study was to describe the management and clinical outcome of patients undergoing surgical treatment of fracture nonunion who were found to have an unexpected intraoperative positive culture result.

Materials and Methods

The authors conducted a retrospective review of patients who underwent surgery for fracture nonunion or for scheduled bone grafting of a known bone defect secondary to open fracture, and were treated between 2007 and 2015 by 1 fellowship-trained trauma surgeon (senior author, H.A.V.) at a level I trauma center. The authors identified all patients who underwent nonunion surgery and for whom there was not any clinical or laboratory suspicion of underlying infection.

Patients with known septic nonunion, those with chronic diffuse osteomyelitis, and those who exhibited any signs that would indicate clinical suspicion of infection were excluded. For the 60 eligible patients remaining, electronic medical records and imaging were reviewed. The authors also recorded demographic data, injury features, medical comorbidities, treatments, and laboratory data, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count (WBC). Radiographs were reviewed to determine fracture healing.

Patients were treated with a variety of re-interventions, including removal of implants and revision internal fixation techniques, with or without associated autograft or allograft. During surgical debridement, any nonviable soft tissue was removed and gravity flow irrigation was conducted with normal saline. Representative intraoperative tissue samples were then taken for culture from bone and/or deep soft tissue in 49 patients in a traditional manner with sharp blade and rongeur. Aerobic and anaerobic culture media were used to incubate the samples for 7 days. Removed implants were not routinely sent for culture. Wounds were closed in all patients except 2. One patient required a soleus flap, split-thickness skin graft, and latissimus flap; the other required a free rectus muscle flap.

During the perioperative period, all patients received either 1 dose (outpatient surgeries) or 3 doses (overnight admission) of routine intravenous antibiotics. Intraoperative culture results and associated treatment are described in Figure 1. Patients did not receive antibiotics if they did not have a culture taken, had a negative routine culture, or had a positive broth culture.

Intraoperative culture results and treatment. Abbreviations: Abx, antibiotics; PICC, peripherally inserted central catheter; PO, oral.

Figure 1:

Intraoperative culture results and treatment. Abbreviations: Abx, antibiotics; PICC, peripherally inserted central catheter; PO, oral.

Of the 6 patients who tested positive for a routine culture, 1 patient received oral antibiotics and 1 patient received systemic intravenous antibiotics, whereas the remaining 4 patients did not receive antibiotics. Of the 4 patients who had a positive mixed (both routine and broth) culture, 2 received systemic intravenous antibiotics and 2 did not receive antibiotics. The primary outcome measures were the development of postoperative clinical infection and radiographic union.

Results

Summarized demographic data can be seen in Table 1 for the 37 men and 23 women included in the study. Mean age was 44.1 years (range, 20–80 years), and mean patient body mass index was 28.9 kg/m2. Five (8%) patients had diabetes mellitus, and 27 (45%) were either current or former smokers. A majority of the initial injuries were open fractures (72%), with the tibia as the most commonly injured site (40%). Mean time from the index procedure to the revision procedure was 7 months (range, 1–38 months). Mean pre-revision surgery values were 7.5 cells/mm3 (normal reference, 4.5–11.5 cells/mm3) for WBC, 20.7 mm/h (normal reference, 0–15 mm/h) for ESR, and 1.0 mg/L (normal reference, 0–0.8 mg/L) for CRP. Although some patients had mildly elevated CRP and ESR values (as noted by the reported means), suspicion for underlying infection was low in all patients when laboratory data were assessed together with clinical presentation because 15 of these patients were returning to the operating room shortly after their initial injury to have a scheduled bone graft.

Demographic Data

Table 1:

Demographic Data

Intraoperative cultures were obtained for 49 of the 60 patients. Twenty-four (49%) of the 49 cultured patients were found to have at least 1 positive routine and/or broth culture (Figure 1). Fourteen patients had only a positive broth culture, 6 had only a positive routine culture, and 4 had positive mixed (both routine and broth) cultures. The intraoperative culture bacteria results can be found in Table 2 and Table 3. The most common bacteria was coagulase-negative staphylococci (CNS), isolated in 79% (19 of 24) of patients with a positive culture and found to be the only organism in 54% (13 of 24) of patients with a positive culture. The second most common bacteria was polymicrobial and was found in 29% (7 of 24) of patients with a positive culture.

Broth Positive Cultures

Table 2:

Broth Positive Cultures

Routine and Mixed Positive Cultures

Table 3:

Routine and Mixed Positive Cultures

In patients with only a positive broth culture (Table 2), the most common bacteria was CNS, found in 71% (10 of 14). All 14 patients did not receive antibiotic treatment because these positive results were thought to be either contaminants or clinically insignificant. All patients went on to clinical healing without subsequent infection, and 13 of 14 patients achieved radiographic union. The 1 patient who did not achieve radiographic union had a distal femur nonunion, was non-ambulatory at baseline, and elected for nonoperative management; she had no evidence of infection.

In patients with positive routine cultures, all 6 patients grew different bacteria (or combination of bacteria), including 4 patients with polymicrobial growth. Treatments consisted of oral antibiotics for 5 weeks in 1 patient, intravenous antibiotics for 6 weeks in 1 patient, and no antibiotics given in the remaining 4 patients. The decision not to treat with antibiotics was based on low clinical suspicion in those 4 patients because cultures did not grow until postoperative days 5, 6, 6, and 10 in the absence of any prior antibiotics. All patients went on to clinical healing without subsequent infection and achieved radiographic union.

In patients with positive mixed cultures, the most common bacteria was CNS, present alone in 2 patients and combined with another organism in the other 2 patients. Treatments consisted of intravenous antibiotics in 2 patients and no antibiotics in 2 patients because their cultures grew on postoperative days 4 and 5. All of these patients proceeded to heal their fractures without subsequent infection, although 1 was deceased 5 months later, unrelated to his nonunion, and while progressing to radiographic union.

Finally, all of the patients with negative culture growth (25 of 60) or patients who did not have a culture sent (11 of 60) healed in an unremarkable fashion. In all 60 patients, no further surgeries were required during the mean follow-up time of 59 months.

Discussion

Positive intraoperative cultures in patients undergoing elective nonunion surgery with no preoperative concern for infection pose a challenge regarding their diagnostic importance and necessity of the treatment. This case series reports the antibiotic treatment of patients undergoing elective nonunion surgery, who resulted in surprise positive routine and/or broth cultures. In this study, all patients with only a positive broth culture were not treated with antibiotics. Four of 10 patients with either a positive routine or mixed culture grown within 3 days postoperatively were treated with antibiotics, whereas the remaining 6 patients were not treated with antibiotics. In total, all patients achieved clinical healing without signs of infection after mean follow-up of nearly 5 years.

Current evidence does not provide a clear treatment recommendation for patients undergoing elective orthopedic surgery that result surprise positive cultures. In an analysis of specimens taken during clean orthopedic procedures in 40 patients, Dietz et al11 reported only 1 clinical infection to have developed in 23 patients with positive cultures. They concluded that routine cultures were not likely to provide information that would improve either diagnosis or management of postoperative infections.11

A similar conclusion was echoed when Moussa et al9 reported no subsequent infection development in 9 patients with positive tissue cultures (all of which were not treated with antibiotics) during elective implant removal, demonstrating the clinical insignificance of positive cultures in this setting.

Newer molecular techniques (using polymerase chain reaction or fluorescent in situ hybridization) have demonstrated improved sensitivity compared with routine cultures, casting further doubt on the accuracy and utility of positive cultures in clean procedures.8 Nevertheless, a recent large multicenter study recommended treatment of all positive cultures in elective fracture nonunion surgery (in patients with no preoperative suspicion for infection) with antibiotics, with the rationale that treatment to potentially prevent recurrent/chronic infection outweighed the costs and risks of antibiotic treatment.6 They made no distinction in their treatment recommendations between routine and broth cultures.6

It is important to distinguish the difference between the routine culture growth and broth culture growth. Routine cultures involve the tissue specimen being plated directly onto a solid agar and being allowed to grow for 3 to 7 days, whereas broth cultures involve placing the tissue specimen in an enrichment broth (often thioglycolate) to theoretically provide more favorable growth conditions.19,20

In an effort to quantify the impact broth cultures can lend to clinical decision making, Morris et al20 demonstrated in a cohort of 356 broth-positive cultures that of the 27% (91 cultures) regarded at the time as “non contaminants,” only 11% (11 cultures) of those were actually clinically relevant, concluding that adjunctive broth cultures rarely provide information that favorably changes patient management.

The current authors attest that this clinical discernment is not always easy and often requires the support of infectious disease colleagues. However, in clean orthopedic procedures with no intraoperative suspicion of infection, the authors' clinical experience would parallel prior studies that positive broth cultures can be treated with benign neglect.11,21 In the current study, all 14 patients with only a positive broth culture did not receive antibiotic treatment and none developed a subsequent infection.

The most common type of bacteria was CNS, found in 79% (19 of 24) of patients with a positive culture, and was the only isolated bacteria in 54% (13 of 24) of patients with a positive culture. The second most common positive result was polymicrobial in 29% of patients. These findings are consistent with other studies in prior literature. In 1995, Morris et al22 reported the 2 most common species found in positive broth cultures to be CNS species and Propionibacterium species. Moreover, only 16% (22 of 140) of CNS species and 7% (6 of 92) of Propionibacterium species were treated as true positives.22 In a cohort of arthroplasty patients, Smith et al17 also reported that CNS was the most isolated organism in positive broth culture results (67%, 16 of 24) and was often considered a contaminant, whereas only 3 of the 16 were found to be true-positives.

The authors' treatment strategy for patients with surprise positive routine cultures was more heterogeneous. Although 4 of 6 patients with a positive routine culture were not treated with antibiotics, 2 were. The authors' basis for antibiotic treatment of positive routine cultures was based on the timing of when the positive culture resulted. The authors did not treat positive routine cultures that turned positive in a delayed fashion (>3 days postoperatively) because they were thought to be contaminants. Positive culture results within 3 days postoperatively were more suspicious for a true infection and were treated with antibiotics.

Two patients had positive routine cultures that were treated with antibiotics. The first patient (patient 4 in Table 3) was positive for both CNS and Pseudomonas aeruginosa on postoperative day 3. This patient was treated with oral ciprofloxacin 500 mg twice daily for 7 days, and then with oral trimethoprim and sulfamethoxazole, 800 to 160 mg for 4 weeks. The second patient (patient 7 in Table 3) was positive for methicillin-resistant Staphylococcus aureus on postoperative day 3. This patient was treated with intravenous vancomycin 1 g for 6 weeks and then with oral rifampin 300 mg twice daily for 6 months.

Four patients had positive mixed cultures. Two received no antibiotic treatment (patients 5 and 8 in Table 3) because cultures grew after postoperative day 3, whereas the other 2 patients were treated with intravenous antibiotics. One of these 2 (patient 6 in Table 3) was positive for CNS from 2 different sites on postoperative day 5 (routine culture of the distal femur; broth culture of the distal humerus). Despite these cultures developing in a delayed fashion (>3 days postoperatively), this patient was treated with antibiotics over several weeks, secondary to infection with cultures growing from 2 different locations. The second patient (patient 9 in Table 3) was positive for S aureus on routine cultures and for CNS on broth cultures on postoperative day 3. Given the early timing of his culture result on postoperative day 3, this patient was treated with intravenous vancomycin 1 g for 8 weeks and then with oral rifampin 300 mg twice daily for 6 months.

Although the authors propose that treatment for surprise positive cultures is often not necessary, they acknowledge that deciding on a treatment plan in response to positive intraoperative cultures can be difficult. Given the limited literature and guidelines regarding appropriate use of antibiotics in the setting of clean orthopedic procedures, it is possible that many of these patients would have received likely unnecessary courses of intravenous or oral antibiotics. Given the current medicolegal environment that promotes the practice of defensive medicine and the associated risks with unnecessary antibiotic use including the facilitation of antibiotic resistance23 and the risks associated with long-term intravenous catheter use (including drug abuse, phlebitis, thrombosis, mechanical failure, and line sepsis), the decision to treat with antibiotics should not be made lightly.24,25

In addition, unnecessary antibiotic treatment can lead to a significant economic burden on the health care system.26 Estimates of the daily cost can be up to $811 at a skilled nursing facility or even $1196 in the hospital.27–30 In light of these factors, the authors support this limited approach to treating surprise cultures in clean orthopedic procedures, particularly in the setting of elective nonunion surgery. In all cases, the culture results were reviewed with the patient and the recommendations were agreed upon.

This study had several limitations. It is a retrospective case series of limited size with no control group. In addition, the authors would ideally have intraoperative culture results for all 60 patients, which were not sent in 11 patients. Furthermore, the authors were not able to provide information from their hospital microbiology laboratory regarding positive control cultures during the period of study. However, this series supports literature suggesting limited treatment of surprise positive cultures. Nevertheless, this series serves as a treatment strategy for what the authors believe to be a common clinical scenario in orthopedic surgery.

Conclusion

In the setting of elective nonunion surgery with little preoperative suspicion for underlying infection, the authors recommend antibiotic treatment of surprise positive cultures should only occur for patients whose routine cultures become positive within a 2 to 3 day period. Patients with only a positive broth culture or those in which routine cultures become positive after a longer period may not warrant antibiotic treatment to prevent infection and for complete healing to occur.

References

  1. Brinker MR, O'Connor DP. The biological basis for nonunions. JBJS Rev. 2016;4(6). doi:10.2106/JBJS.RVW.15.00078 [CrossRef]27486720
  2. Einhorn TA. Enhancement of fracture healing. Instr Course Lect. 1996;45:401–416.8727759
  3. Praemer A, Furner S, Rice D. Musculoskeletal Conditions in the United States. Rosemont, IL: American Academy of Orthopaedic Surgeons; 1999.
  4. Brinker MR, O'Connor DP. Management of aseptic tibial and femoral diaphyseal non-unions without bony defects. Orthop Clin North Am. 2016;47(1):67–75. doi:10.1016/j.ocl.2015.08.009 [CrossRef]
  5. Struijs PA, Poolman RW, Bhandari M. Infected nonunion of the long bones. J Orthop Trauma. 2007;21(7):507–511. doi:10.1097/BOT.0b013e31812e5578 [CrossRef]17762489
  6. Olszewski D, Streubel PN, Stucken C, et al. Fate of patients with a “surprise” positive culture after nonunion surgery. J Orthop Trauma. 2016;30(1):e19–e23. doi:10.1097/BOT.0000000000000417 [CrossRef]
  7. Miclau T, Schmidt AH, Wenke JC, et al. Infection. J Orthop Trauma. 2010;24(9):583–586. doi:10.1097/BOT.0b013e3181eebf12 [CrossRef]20736799
  8. Palmer MP, Altman DT, Altman GT, et al. Can we trust intraoperative culture results in nonunions?J Orthop Trauma.2014;28(7):384–390. doi:10.1097/BOT.0000000000000043 [CrossRef]
  9. Moussa FW, Anglen JO, Gehrke JC, Christensen G, Simpson WA. The significance of positive cultures from orthopedic fixation devices in the absence of clinical infection. Am J Orthop (Belle Mead NJ). 1997;26(9):617–620.
  10. Marsh J, Nepola J, Seabold J. Subclinical infection in delayed nonunion of fractures. J Orthop Trauma. 1989;3(2):169. doi:10.1097/00005131-198906000-00038 [CrossRef]
  11. Dietz FR, Koontz FP, Found EM, Marsh JL. The importance of positive bacterial cultures of specimens obtained during clean orthopaedic operations. J Bone Joint Surg Am. 1991;73(8):1200–1207. doi:10.2106/00004623-199173080-00009 [CrossRef]1890121
  12. Campbell KA, Stein S, Looze C, Bosco JA. Antibiotic stewardship in orthopaedic surgery: principles and practice. J Am Acad Orthop Surg. 2014;22(12):772–781. doi:10.5435/JAAOS-22-12-772 [CrossRef]25425612
  13. Hackett DJ, Rothenberg AC, Chen AF, et al. The economic significance of orthopaedic infections. J Am Acad Orthop Surg. 2015;23(suppl):S1–S7. doi:10.5435/JAAOS-D-14-00394 [CrossRef]25808964
  14. Kallala R, Graham SM, Nikkhah D, et al. In vitro and in vivo effects of antibiotics on bone cell metabolism and fracture healing. Expert Opin Drug Saf. 2012;11(1):15–32. doi:10.1517/14740338.2012.643867 [CrossRef]
  15. Selhi HS, Mahindra P, Yamin M, Jain D, De Long WG, Singh J. Outcome in patients with an infected nonunion of the long bones treated with a reinforced antibiotic bone cement rod. J Orthop Trauma. 2012;26(3):184–188. doi:10.1097/BOT.0b013e318225f77c [CrossRef]
  16. Johnson CT, García AJ. Scaffold-based anti-infection strategies in bone repair. Ann Biomed Eng. 2015;43(3):515–528. doi:10.1007/s10439-014-1205-3 [CrossRef]
  17. Smith EB, Cai J, Wynne R, Maltenfort M, Good RP. Performance characteristics of broth-only cultures after revision total joint arthroplasty. Clin Orthop Relat Res. 2014;472(11):3285–3290. doi:10.1007/s11999-014-3507-z [CrossRef]24566888
  18. Blackmur JP, Tang EY, Dave J, Simpson AH. Use of broth cultures peri-operatively to optimise the microbiological diagnosis of musculoskeletal implant infections. Bone Joint J. 2014;96-B(11):1566–1570. doi:10.1302/0301-620X.96B11.33852 [CrossRef]25371476
  19. Varettas K. Broth versus solid agar culture of swab samples of cadaveric allograft musculoskeletal tissue. Cell Tissue Bank. 2013;14(4):627–631. doi:10.1007/s10561-013-9365-1 [CrossRef]23378168
  20. Morris AJ, Wilson SJ, Marx CE, Wilson ML, Mirrett S, Reller LB. Clinical impact of bacteria and fungi recovered only from broth cultures. J Clin Microbiol. 1995;33(1):161–165.7699035
  21. Moussa FW, Anglen JO, Gehrke JC, Christensen G, Simpson WA. The significance of positive cultures from orthopedic fixation devices in the absence of clinical infection. Am J Orthop (Belle Mead NJ). 1997;26(9):617–620.
  22. Morris AJ, Wilson SJ, Marx CE, Wilson ML, Mirrett S, Reller LB. Clinical impact of bacteria and fungi recovered only from broth cultures. J Clin Microbiol. 1995;33(1):161–165.7699035
  23. Campbell KA, Stein S, Looze C, Bosco JA. Antibiotic stewardship in orthopaedic surgery: principles and practice. J Am Acad Orthop Surg. 2014;22(12):772–781. doi:10.5435/JAAOS-22-12-772 [CrossRef]25425612
  24. Galloway S, Bodenham A. Long-term central venous access. Br J Anaesth. 2004;92(5):722–734. doi:10.1093/bja/aeh109 [CrossRef]15003979
  25. Merrell SW, Peatross BG, Grossman MD, Sullivan JJ, Harker WG. Peripherally inserted central venous catheters. low-risk alternatives for ongoing venous access. West J Med. 1994;160(1):25–30.8128698
  26. Hackett DJ, Rothenberg AC, Chen AF, et al. The economic significance of orthopaedic infections. J Am Acad Orthop Surg. 2015;23(suppl):S1–S7. doi:10.5435/JAAOS-D-14-00394 [CrossRef]25808964
  27. Cyriac JM, James E. Switch over from intravenous to oral therapy: a concise overview. J Pharmacol Pharmacother. 2014;5(2):83–87. doi:10.4103/0976-500X.130042 [CrossRef]24799810
  28. Dalovisio JR, Juneau J, Baumgarten K, Kateiva J. Financial impact of a home intravenous antibiotic program on a Medicare managed care program. Clin Infect Dis. 2000;30(4):639–642. doi:10.1086/313755 [CrossRef]10770722
  29. van Zanten AR, Engelfriet PM, van Dillen K, van Veen M, Nuijten MJ, Polderman KH. Importance of nondrug costs of intravenous antibiotic therapy. Crit Care. 2003;7(6):R184–R190. doi:10.1186/cc2388 [CrossRef]14624694
  30. Ross Nolet B. Update and overview of out-patient parenteral antimicrobial therapy regulations and reimbursement. Clin Infect Dis. 2010;51(suppl 2):S216–S219. doi:10.1086/653522 [CrossRef]

Demographic Data

CharacteristicValue
Patients, No.60
  Male37
  Female23
Age, mean (SD), y44.1 (14.2)
Body mass index, mean (SD), kg/m228.9 (7.2)
Diabetes mellitus, No.5
Smoking status, No.
  Current18
  Former9
  Never33
Fracture site, No.
  Tibia29
  Femur16
  Talus4
  Humerus3
  Ulna3
  Radius/ulna2
  Fibula1
  Forefoot1
  Calcaneus1
Closed fracture, No.17
Open fracture (by Gustilo and Anderson), No.43
  11
  21
  341
    3A31
    3B8
    3C2
Surgical indication, No.
  Nonunion44
  Bone defect15
  Malunion1
Pre-revision value, mean (SD) [normal reference]
  White blood cell count, cells/mm37.5 (2.9) [4.5–11.5]
  Erythrocyte sedimentation rate, mm/h20.7 (23.3) [0–15]
  C-reactive protein, mg/L1.0 (1.4) [0–0.8]

Broth Positive Cultures

Type of BacteriaNo. of Patientsa
Coagulase-negative staphylococci10
Coagulase-negative staphylococci, alpha streptococci, Propionibacterium granulosum1
Micrococcus1
Alpha streptococci2
Total14

Routine and Mixed Positive Cultures

Patient No./Sex/Age, yBMI, kg/m2DMSmokingOpen vs Closed FractureInjury FractureSymptomsTime, moaWBC, cells/mm3ESR, mm/hCRP, mg/LIntraoperative CultureCulture Positive TimebAntibiotic TreatmentFollow-upc
1/M/57NANoNeverOpenTibial shaft and fibulaBroken implants2.66.2150.9MSSA and CNS (routine)6None81.1
2/M/54NANoFormerClosedCalcaneusPain, swelling29.6NANANAKlebsiella pneumoniae and Proteus mirabilis (routine)5None27.8
3/F/5228.7NoNeverClosedDistal tibia and fibulaNone4.15.910.5CNS (routine)10None109.1
4/M/3026.7NoNeverOpenTalar neck, tibial shaftHardware prominence, pain, trace edema2.65.8NANACNS and Pseudomonas aeruginosa (routine)3PO ciprofloxacin 500 mg BID × 7 days + PO trimethoprim and sulfamethoxazole DS 800–160 mg × 4 wk18.0
5/M/2221.3NoCurrentOpenDistal humerusPain3.06.690.5MSSA (broth), CNS and diphtheroids (routine)4None36.6
6/M/4126.1NoCurrentOpenDistal femur and distal humerusMinimal effusion, minimal pedal edema1.47.7491.6CNS routine (femur) and broth (humerus))5

IV vancomycin + PO rifampin × 6 wk

PO trimethoprim and sulfamethoxazole + PO rifampin × 2 wk

IV vancomycin + PO rifampin × 6 wk

109.5
7d/M/3021.9NoNeverOpenTibial shaftNone2.95.360.5MRSA (routine)3IV vancomycin × 6 wk + PO rifampin × 6 mo2.7
8d/M/3225.8NoNeverOpenDistal femurNone1.95170.8CNS (routine and broth)5None179.2
9/M/3046NoNeverOpenFirst metatarsalNone3.012.3160.8MSSA (routine), CNS (broth)3IV vancomycin × 8 wk + PO rifampin × 6 mo178.8
10/M/3728NoNeverOpenDistal femurNone1.86.5351.2Propionibacterium acnes and CNS (routine)6None14.0
Authors

The authors are from the Department of Orthopaedic Surgery, MetroHealth Medical Center, Cleveland, Ohio.

The authors have no relevant financial relationships to disclose.

Correspondence should be addressed to: Heather A. Vallier, MD, Department of Orthopaedic Surgery, MetroHealth Medical Center, 2500 MetroHealth Dr, Cleveland, OH 44109 ( hvallier@metrohealth.org).

Received: July 21, 2018
Accepted: November 15, 2018
Posted Online: October 07, 2019

10.3928/01477447-20191001-04

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