Session 14: Trauma

18. November
9:00 - 10:00
Lokale: Vingsal 1
Chair: Rikke Bielefeldt and Rasmus Stokholm

107. Risk of Reoperation due to Deep Surgical Site Infection in 74,771 Hip Fracture Patients aged 65 years or older. A Nationwide, Population based, Cohort Study.
Nicolai K. Kristensen¹³4, Jeppe Lange¹³, Trine Frøslev², Alma B. Pedersen²
¹Department of Orthopedics, Regional Hospital of Horsens, Denmark; ²Department of Clinical Epidemiology, Aarhus University Hospital, Denmark; ³Departmen of Clinical Medicine, Aarhus University, Denmark; 4Department of Orthopedics, Aarhus university hospital, Denmark

Background: Surgical Site Infection (SSI) after hip fracture surgery is a feared condition. Moreover, mortality rates in patients with a registered reoperation due to SSI have been reported to be 2.9 times higher than in patients with no SSI event.
Aim: To investigate the incidence and time-trend in reoperation due to deep SSI following hip fracture surgery.
Materials and Methods: This was a population-based, nationwide, cohort study. We included 74,771 patients from the Danish Multidisciplinary Hip Fractures Register consisting of patients 65 years of age or older, who underwent surgery between January 1st 2005 and December 31st 2016 for all types of hip fracture. Cross-linkage with the Danish National Patient Register and The Danish Civil Registration system was made. Demographic data extracted included vital status, civil status, gender, age, Body Mass Index (BMI), fracture classification and surgical procedures binary registered as joint replacement or internal fixation as well as Charlson comorbidity index (CCI). Outcome was reoperations due to deep SSI in accordance with the definition from Centre for Disease Control. We computed cumulative incidence rates and risk ratios (RR) by calendar year periods and by different risk factors, considering death as competing risk and adjusting for age, gender, CCI, fracture type and surgery type.
Results: One year from primary surgery 2.1% of all hip fractures had undergone reoperation due to deep SSI. During the period 2005-2016, the incidence of reoperation due to SSI decreased from 2.7% to 1.7%, Patients aged above 85 had 50% lower risk of being reoperated compared with the youngest age group; 65-74 years (RR: 0.5; 95% CI: 0.4:0.6). The RR for reoperation due to deep SSI was lower for patients with pertrochanteric or subtrochanteric fractures versus femoral neck fractures, RR was 0.7 (95%CI: 0.7:0.8). However, RR for surgery type (joint replacement vs internal fixation) at 365 days was significantly lower for joint replacement, RR: 0.6 (95% CI: 0.6:0.7).
Interpretation / Conclusion: We believe we contribute to evaluate “the true” deep SSI reoperation rate, regarding the exceptional validity of the danish registers. More research is necessary to confirm and elaborate the results

108. Risk factors for infection following surgically managed tibial fractures; A systematic review and meta-analysis
Thomas Mattson, Diana Niebuhr, Niels Martin Jensen, Bjarke Viberg, Signe Steenstrup Jensen
Department of Orthopedic Surgery and Traumatology, Kolding Hospital; Department of Orthopedic Surgery and Traumatology, Odense University Hospital; Emergency Department, Randers Regional Hospital,

Background: Infection is a severe complication in the treatment of fractures and evidence on risk factors for infection following surgically managed tibial fractures is limited.
Aim: To systematically review and assess risk factors for postoperative infection following surgically managed tibial fractures.
Materials and Methods: A search string was developed with aid from a scientific librarian and used in Medline, Embase, Scopus, and Cochrane. No date restrictions were made and title+abstract were screened independently by two authors using Covidence, then full text was read for final inclusion. Eligible study data was extracted and random-effects-meta-analyses were performed if potential risk factors were found in five or more studies. Infection and risk factors were assessed as a binary outcome, and a 2x2 contingency table was made for each risk factor. The evidence synthesis was performed using odds ratio (OR) as effect measure.
Results: Of 3.901 records screened, 33 were included in the meta-analyses, totaling 22.103 patients. Three studies were prospective, the remaining were retrospective. High energy trauma and diabetes were not significant risk factors for infection, however, patients with open fractures or compartment syndrome had a four times higher risk of infection. Male sex, higher Gustilo or ASA grade, smoking, and polytrauma were also significant risk factors for infection (p<0.05).
Interpretation / Conclusion: Establishing compelling evidence on risk factors for postoperative infection is challenging due to the heterogeneity and complexity of infections, and because the current studies are predominantly retrospective. However, with this study, we can conclude that male sex, high Gustilo or ASA grading, smoking, open fracture, polytrauma and compartment syndrome are significant risk factors for infection following surgically managed tibial fractures.

109. Adding glue to the surgical site after surgery for lower extremity fractures – temporary results
Sukriye Corap Gellert, Abdullahi Hirsi, Michael Brix, Bjarke Viberg
Department of Orthopaedic Surgery and Traumatology, Odense University Hospital

Background: Surgical site infection continues to be an issue after surgery for lower extremity fractures and can lead to serious complications. Oozing from the surgical wound has been proposed as a risk factor for surgical site infections, and a method to reduce oozing is adding glue to the wound.
Aim: To compare the rate of adhesive patch (AP) change in surgical treated lower extremity fractures with and without glue added to the surgical wound.
Materials and Methods: On the 1st of February 2022, a new treatment protocol was introduced regarding requirements for change of AP. All AP used for surgery after lower extremity fractures were labelled with the number 1, and should be changed during admission if more than 50% of the AP were filled or if it leaked. If the AP were changed, the forthcoming number should be written on the AP. On the 1st of March 2022, an addition was made and all surgical wounds should have glue added. At discharge, the number on each AP were recording. A sample size based on a 10 percentpoint reduction in AP use was 398 (alpha 0.05, power 0.80). Group comparison was performed using Wilcoxon rank-sum or chi-square test.
Results: There were 157 lower extremity fractures, 64 treated without glue and 93 had glue added. The median age was 77 (range 22-100), there were 53% females, and the predominant fracture was in the hip. There were no difference between the groups regarding age, sex, comorbidity or length of admission. There were 29% in the non-glue group with change of the AP compared to 18% in the glue group (p=0.156). The median AP use in the non-glue group was 2.5 (range 1-14) compared to 2 (range 1-12) in the glue group (p=0.640). When subanalysing hip fracture surgery, there were 53% with AP change in the non-glue group compared to 22% in the glue group (p<0.045), while there were no statistical differences for arthroplasty, plate, or screw surgery.
Interpretation / Conclusion: We found no effect in AP change when adding glue to the surgical wound. However, these are temporary results, as the calculated sample size has not been reached yet. Data from the full sample size is expected to be collected in June 2022.

110. Tibial bone and soft-tissue concentrations following combination therapy with vancomycin and meropenem – evaluated by microdialysis in a porcine model: Should patients with open fractures have higher doses of antibiotics?
Sofus Vittrup, Pelle Hanberg, Martin Bruun Knudsen, Sara Kousgaard Tøstesen, Josephine Olsen Kipp, Jakob Hansen, Nis Pedersen Jørgensen, Maiken Stilling, Mats Bue
Aarhus Denmark Microdialysis Research (ADMIRE), Orthopaedic Research Laboratory, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Infectious Diseases, Aarhus University Hospital; Department of Forensic Medicine, Aarhus University Hospital

Background: The nature of open fractures introduces an obligate bacterial contamination of the wound. The reported infection rates following open fractures vary from 0% to 50% reflecting the broad contamination profile necessitating empirical antibiotic Gram-positive and Gram- negative coverage.When administering antibiotics to prevent infection of a contaminated open fracture, antibiotic target site concentrations should, as a minimum, reach and remain above relevant bacteria’s minimal inhibitory concentrations (MICs) for a sufficient amount of time.
Aim: To evaluate vancomycin and meropenem T>MIC in tibial compartments for the bacteria most frequently encountered in open fractures. Low and high MIC targets were applied: 1 and 4 µg/ml for vancomycin, and 0.125 and 2 µg/ml for meropenem.
Materials and Methods: Eight pigs received a single dose of 1,000 mg vancomycin and 1,000 mg meropenem simultaneously over 100 minutes and 10 minutes, respectively. Microdialysis catheters were placed for sampling over eight hours in tibial cancellous bone, cortical bone, and adjacent subcutaneous adipose tissue. Venous blood samples were collected as references.
Results: Across the targeted epidemiological cut-off values, vancomycin displayed longer T>MIC in all the investigated compartments in comparison to meropenem. For both drugs, cortical bone exhibited the shortest T>MIC. For the low MIC targets and across compartments, mean T>MIC ranged between 208 and 449 minutes (46% to 100%) for vancomycin and between 189 and 406 minutes (42% to 90%) for meropenem. For the high MIC targets, mean T>MIC ranged between 30 and 446 minutes (7% to 99%) for vancomycin and between 45 and 181 minutes (10% to 40%) for meropenem.
Interpretation / Conclusion: The differences in the T>MIC between the low and high targets illustrate how the interpretation of these results is highly susceptible to the defined MIC target. To encompass any trauma, contamination, or individual tissue differences, a more aggressive dosing approach may be considered to achieve longer T>MIC in all the exposed tissues, and thereby lower the risk of acquiring an infection after open tibial fractures.

111. Prepping In The Ex-Fix To Facilitate ORIF Of Complex AO/OTA 41-C Bicondylar Tibial Plateau Fractures: Is Infection Risk Increased?
Derek Stenquist, Yeung Caleb , Guild Theodor , Weaver Michael , Harris Michtel, Arvind von Keudell
bHarvard Orthopaedic Trauma Initiative, Harvard Medical School, Boston, Massachusetts, USA cDepartment of Orthopaedic Surgery, Brigham and Women's Hospital, Boston, Massachusetts, USA dDepartment of Orthopaedic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark

Background: The effect of prepping in external fixator devices into the surgical field is unknown.
Aim: To compare the risk of deep infection and unplanned reoperation after staged ORIF of bicondylar tibial plateau (BTP) fractures whether elements of the temporizing external fixator were prepped into the surgical field or completely removed prior to definitive fixation.
Materials and Methods: Two Academic Level One Trauma Centers.Patients/Participants: 147 OTA/AO 41-C (Schatzker 6) BTP fractures treated with a two-stage protocol of acute spanning ex-fix followed by definitive ORIF between 2001-2018.78 fractures had retained elements of the original ex-fix prepped in situ during surgery for definitive internal fixation and 69 had the ex-fix construct completely removed prior to prepping and draping.
Results: Among 147 patients treated with staged ORIF, the overall deep infection rate was 26.5% and reoperation 33.3%. There were high rates of deep infection (26.9% vs 26.1%, p=0.909) and unplanned reoperation (30.8% vs 36.2%, p=0.483) in both groups but no difference whether the ex-fix was prepped in or completely removed. Within the retained ex-fix group, there was no difference in infection with retention of the entire ex-fix compared to only the ex-fix pins (28.1% vs 26.1%, p=0.842).
Interpretation / Conclusion: We observed high complication rates in this cohort of OTA/AO 41C bicondylar tibial plateau fractures treated with staged ORIF, but prepping in the ex-fix did not lead to a significant increase in rates of infection or reoperation. This study provides the treating surgeon with clinical data about a common practice used to facilitate definitive fixation of unstable BTP fractures.

112. Host Factors And Risk Of Pin Site Infection In External Fixation: A Review Examining Age, Body Mass Index, Smoking, Comorbidities Including Diabetes
Marie Fridberg ¹, Mats Bue ², Jan Duedal Rölfing ², Søren Kold ¹
1. Interdisciplinary Orthopedics, Aalborg University Hospital, Aalborg, Denmark 2. Department of Orthopedics, Aarhus University Hospital, Aarhus, Denmark

Background: External fixation is widely used for initial and final treatment of complex fractures as well as for limb lengthening and reconstruction of bone deformities including infection with good and reliable results. The incidence of pin site infection varies widely in the literature from 0-100 %. Most pin site infections are superficial, but it can cause loosing of fixation or development of osteomyelitis.
Aim: The aim was to report the frequency of studies reporting the specific host factor as a significant association with pin site infection.The host factors to be assessed were: age, smoking, BMI and any comorbidity, diabetes, in particular. Data was extracted if feasible, however no meta- analysis was performed.
Materials and Methods: This systematic literature search was performed according to the PRISMA guidelines. The protocol was registered before data extraction in PROSPERO (ID: CRD42021273305). The search string was based on the PICO (Population, Intervention or Exposure of interest, Comparison, Outcomes) criteria. The host factors to be assessed were: age, smoking, BMI and any comorbidity, diabetes in particular. The literature search was executed Embase MEDLINE (1111 hits), CINAHL (2066 hits) and Cochrane Library CENTRAL (387 hits). Inclusion and exclusion criteria was defined and followed during the screening and selection process using Covidence.
Results: A total of 3564 titles was found. 3162 records were excluded by title and abstract screening. 140 studies were assessed for full text eligibility. 11 studies were included for data extraction. All included studies was designed retrospective and generally assessed to have a high risk of bias. Individual retrospective studies reported significant associations between pin site infection for following host factors: a) increased HbA1C level in diabetic patients; b) congestive heart failure in diabetic patients; c) less co- morbidity; d) preoperative osteomyelitis.
Interpretation / Conclusion: This systematic literature search identified a surprisingly low number of studies examining for risk of pin site infection and host factors. This review demonstrate a gap of evidence about correlation between host factors and risk of pin site infection.

113. KKR: Kamme Lindberg biopsies in fracture-related infections and periprosthetic infections.
Martha Ignatiussen, Peter T. Tengberg, Mathias Bæk Rasmussen

Background: Accurate diagnostics is important when dealing with infections related to fracture-related infections (FRI) and periprosthetic infections (PJI). Accurate diagnostics plays a big part when choosing a patient’s treatment when it comes to choosing the right surgery or getting the right antibiotics. Evidence shows that tissue sample culturing is the gold standard when diagnosing FRI and PJI. But how many, where and how is debated.
Aim: The aim of this guideline is to update the current guideline from 2017. The guideline from 2017 investigates three main subjects: How many culture samples are needed, where should the samples be taken from and how should the tissue samples be handled.
Materials and Methods: A new search on pubmed was conducted on the 08.03.2022 with the help from a research librarian. New literature from 2017 and forward was evaluated.
Results: 934 new titles were available. We found 73 relevant abstracts and after reading though these 16 relevant studies were found. In the end 12 studies were included. One systematic review, four primary studies and seven expert opinions of high quality.
Interpretation / Conclusion: In between 4-6 tissue samples should be taken when suspecting an infection during an operation preferably from inflammatory tissue. The sample should be taken from the tissue-implant interface and not from a sinus or fistula. Do not use swaps. The tissue samples should be taken before debridement. Use separate sterile instruments for each tissue sample and transfer direct to sample container.