CHAPTER 1: INTRODUCTION

1.1 Background

An open fracture is defined as an injury in which the fractured site and/or hematoma communicate with the external environment(1). Fractures are a public health concern worldwide. In 2019, there were 458 million total cases and 178 million new cases of fractures, (2). It has also been estimated that 1 in every 120 persons under the age of 65 years will have fracture and 3% of these fractures are open fractures(3). Three to six million fractures occur yearly in the United States(3). In Cameroon ,57% of surgical emergencies are fractures(1). Studies also reveal that 17.3%  of these fractures are open (4). Open fractures are traditionally classified according to Gustilo-Anderson grading system which takes into consideration the energy of the fracture, soft-tissue damage, and the degree of contamination(5). This grading system has remained in use since 1976 because it provides a quick assessment tool that helps to determine the antibiotic regimen that will be used as prophylaxis. This classification system divides open fractures into 3 grades (grade I to grade III) (6).

Bone infection following open fractures remains a common and serious complication affecting both high and low-income countries and are well known to pose high rates of both morbidity and mortality (7,8). Such Fracture related infection( FRI)   has been defined by Metsemaker et al. as the development of a fistula, sinus, wound breakdown, or pus discharge  from the fracture site that may be evident clinically or through culture or histopathological analysis(9).

 A 10-year retrospective study in Europe revealed that the  proportion of fractures in Germany   resulting in bone infection was determined to be 1.23% (10).However, the study design didn’t permit the   researchers to assess whether these fractures were open or close.  Another study in Asia revealed FRI rate in China was 1.5 % with 65% of these infections occurring in patients with open fractures (11). Studies in South America  have shown  open fracture infection rates to range from  8 % and 13% (12,13). Meanwhile studies on open fractures in Africa  have revealed a relatively higher prevalence of  FRI rates of 42.9 % and 42.5% as reported by Nigerian authors (3,14). Also, studies in Cameroon reveal even higher rates than in Nigeria.  A 5-year retrospective review of 4 major hospitals in the South        West region of  Cameroon had revealed 65.1%  prevalence of  fracture-related infection (1). Another 5-year study in  4 hospitals in the south west region Cameroon had equally revealed 42.6% and 24.7% prevalence of FRI as early and late complication respectively (4). It is  therefore, reasonable to think that the differences in the infection rates across the different settings can be explained by the degree of contamination of the open fracture, the grade of open fracture, presence or absence of comorbidities, the time between open fracture and onset of primary care, availability of expertise and the antibiotic regimens used. To the best of our knowledge the antibiotics used in the management of the above fractures were not published. However, the single most important factor to prevent development of FRI is the  early administration of antibiotics that provide antibacterial activity against both gram-positive and gram-negative microorganisms(15). A Cochrane systematic review has shown that antibiotic administration following open fractures reduces the risk of infection by 59%(16).

Prophylactic antibiotic regimens as determined by the Gustilo-Anderson classification for open fractures have been the scientific approach for  preventing the development of  FRI (17). Also, the choice of PAR for the same fracture grade has evolved due to the development of resistance and the need for good antibiotic stewardship(17,18). In a study by Gustilo-Anderson ,antibiograms done pre-operatively and post-operatively reveal a 70% contamination (50% before surgical intervention and 20 % after)(6). This led to the conclusion that open fractures are by definition contaminated. According to the sensitivity results of their study, cephalothin (cefazolin equivalent in spectrum; both are 1st generation cephalosporins) emerged as the most potent molecule for a comprehensive gram-positive coverage. The most common germ obtained before and after debridement was MRSA which also showed a 100% sensitive cloxacillin. Gentamicin and chloramphenicol revealed the best gram-negative coverage.  Gustillo et al. in conclusion recommended cephalosporins for all grades of open fractures with the addition of Gentamycin for grade III open fractures(5). Similar studies by Benson et al. have shown that clindamycin and cefazolin have similar potency in the management of open fractures(19). In a study by Patzakis et al., they compared cefazolin monotherapy to the penicillin-streptomycin regimen and the infection rates were significantly different i.e., 2.3% and 9.7% respectively. In another study by Patzakis and colleagues comparing ciprofloxacin monotherapy (which has good gram-positive and gram-negative spectrum) and cefamandole-gentamycin regimen, the infection rates were similar for grade I and II open fractures but were respectively 7.7% and 31% for grade III (20). In conclusion, the literature reveals cephalosporins and aminoglycoside as best treatment options. It is also recommended to associate these regimens with a penicillin when there a is high risk of soil contaminations like open fractures sustained in the farm(21).In the setting of Cameroon, there is paucity of data and lack of uniformity in the use of preventive antibiotic regimens or  cases of open fracture.

1.2 Problem statement

In Cameroon, 57.3% of surgical emergencies are due to fractures  affecting mainly the young people and usually these fractures  get infected. The prevalence rate averages  65.1 % (1). This is concerning because other African countries including Nigeria have reported 42%(3,14);  Europe 1.23%(10); and  Asia 1.5% (11). These differences can only be explained fully after considering all the factors associated with fracture-related bone infection. However, given our setting, most open fractures are sustained by motorbike riders and farmers occurring in very dirty conditions. Mindful of the possibility of severe contamination, this makes antibiotic usage the foremost important factor to consider. Moreover, the well-known impact of PAR on development of FRI was proven to reduce the occurrence of FRI by 59% (16). Also, in Cameroon, there is a paucity of data on FRI and also lack of uniformity in the use of antibiotic regimens for open fractures. This lack of uniformity may be due to the different literature recommendations on antibiotics usage for open fractures. Hence our setting is yet to define which regimens are most effective based on local data and antibiogram patterns. This study, therefore, aims to compare the preventive antibiotic regimens used in different hospitals in order to identify regimens with good and bad outcomes.

1.3 Significance of the study.

In Cameroon, there is a paucity of data on FRI and a lack of uniformity in the use of antibiotics for open fractures. To the best of our knowledge, no such work has been carried out previously in the North West Region to evaluate antibiotic regimens and the occurrence of bone infections. Therefore, the findings from this study will provide useful baseline data to understand the burden of FRI within the North West Region that can be compared with data from other regions, and other countries at large. Additionally, the results will provide evidence-based recommendations that will equally shape the use of antibiotics in the management of open fractures that will in turn improve infection prevention control guidelines in the country.

1.4 Research Questions

• What are the common preventive antibiotic regimens used for open fractures in Nkwen Baptist Hospital (NBH) and The Peoples’ Clinic (TPC)?
• What is the prevalence of fracture-related infection in NBH and TPC?
• What are the common preventive antibiotic regimens associated with high rates of fracture-related infection?
• What are the other factors associated with high rates of fracture-related infection?

1.5 Objectives

1.5.1   General Objective

• To compare the prevalence of FRI among patients on different preventive antibiotic regimens.

1.5.2 Specific objectives

• Describe common preventive antibiotic regimens used in the management of open fractures at NBH and TPC.
• Determine the prevalence of fracture-related infection for the different PAR used in NBH and TPC.
• Identify preventive antibiotic regimens with high rates of fracture-related infection.
• Identify other factors associated with a high risk of fracture-related infection

1.6 Research Goals

• To provide baseline data on fracture-related infection in the region.
• To create an awareness of the burden of fracture-related infection in the region.
• To propose the best preventive antibiotic regimens in our resource-limited setting that may reduce the incidence of FRI.