Infection Associated with periprosthetic hip in Vietnamese adults

A retrospective case-series study was carried out on 21 patients undergoing postoperative infection following a hip replacement at Vietnam – Germany University Hospital from January 2013 to September 2016. This study were also selected the case for inclusion of the main clinical and paraclinical characteristics of periprosthetic hip joint infection (PJI). The results showed that 47.6% of the cases occurred in the early stage following the Fritzgerald’s classifi cation. Restriction of hip joint movements occurred in 86% of the cases. The incidence of infl ammation around the incision was 100% and fi stula of hip joint was 95%. The sedimentation rate increased in 100% of the cases, with an average value of 53 ± 26.8 mm. More than a quarter of the patients had positive bacterial culture results, of which almost half were Staphylococcus aureus. The clinical and subclinical characteristics of PJI in this study were quite typical and similar to previous studies. The mainly indexes supporting the diagnosis such as the elevated CRP level, the elevated synovial-fl uid leukocyte count, the percentage of neutrophils were consistent with infection and the culture of fl uid results. It is very necessary based on the results of bacterial culture tests to be conducted regularly for postoperative follow-up and antibiotics. Research Article Infection Associated with periprosthetic hip in Vietnamese adults Tran Trung Dung*, Pham Trung Hieu, Nguyen Trung Tuyen, Vu Tu Nam and Nguyen Huy Phuong Department of Orthopedic Trauma, Saint Paul Hospital, Hanoi Medical University, Vietnam Dates: Received: 07 July, 2017; Accepted: 08 September, 2017; Published: 09 September, 2017 *Corresponding author: Tran Trung Dung, vice head Director of Saint Paul Hospital, Hanoi, Department of Orthopedic Trauma Sports Medicine, Hanoi Medical University, Vietnam, Tel: 084 983762005; E-mail:


Background
Periprosthetic hip joint infection (PJI) appears as one of the most serious complications that curbs the success of this measure. Currently, in the United States, PJI rate is 0.88% [1]. The revision surgery treating this complication is predicted to increase signifi cantly in the next 25 years, which leads to an increase in burden for patients, medical staffs and society.
Globally, a range of studies have been conducted to demonstrate the characteristic of PJI, as well as PJI treatment protocols. As hip replacement was applied later in Vietnam than other developed countries, the research about PJI has gradually shown its importance in recent 10 years, when the explosion of the number of hip replacements was witnessed. Nguyen Tien Binh (2004) reported the PJI rate was 0.6% [2], and Do Huu Thang (2004) found at 3% [3]. Tran Dinh Chien and Le Ngoc Hai (2012) assessed the outcome of total hip replacement by the minimally invasive technique with the conclusion that the PJI rate was 1.6% [4]. Among 138 patients undergoing total hip replacement in 108 Military Central Hospital, it's reported that 5% of them suffered from post-op infection [5]. This fi gure in Vietnam -Germany University Hospital was 8.6% [6].
Signs and symptoms of infection are generally poor and late-detected. In addition, the diffi culty in choosing appropriate treatment and management of PJI is signifi cantly considerable, especially in developing countries as Viet Nam where sterile conditions in the surgical fi eld are not fully guaranteed, caring for patients after surgery is inadequate, and the habit of using antibiotics treatment without prescription and the high rate of antibiotic resistance are favorable factors for postoperative and recurrent infection.

Materials and Methods
Subjects: A total of 21 patients diagnosed with periprosthetic hip joint infection and indicated surgical treatment at Vietnam -Germany University Hospital, Hanoi, Vietnam were enrolled into the study from January 2013 to September 2016.
Selection criteria: Selected patients were those who aged over 18, had one or two hip replacements in Vietnamese -Germany University Hospital and were diagnosed with periprosthetic hip joint infection following the criteria of Musculoskeletal Infections Society and were indicated surgical treatment [7].
Exclusion criteria: The patients who were indicated inpatient treatment but did not consent to continue the treatment and could not be contacted after treatment were excluded.
Following the criteria, most of the patients were males (81%) -about four times more than females (19%). The mean age of the patients was 57.4 (range 22-79). Over a half of participants were 55 years and older (66.7%). 71.43% of the patients had not received surgical treatment before admission and 23.81% had surgery for debridement with retention and 4.76% had been treated by implant removal at many different hospitals.
Study design: This is a retrospective case-series. Medical records were retrieved from the hospital's database. In particular, the patients after being diagnosed would undergo surgery to treat the infection. The culture was taken directly in the operation immediately after reopening the incision site, where the Intraoperative periprosthetic tissue was taken, including bone, joint capsule, and soft tissues around the prosthetic. The number of samples taken was at least 3 samples. All of samples were sent to the Laboratory of the Department of Microbiology of Viet Duc University Hospital on the same day for culture, isolation and identifi cation of each bacterium according to standard procedures. These procedures used for culture of periprosthetic tissue is aerobic and anaerobic blood aga, and the duration of incubation is 7 days.

Study indices:
General characteristics of the participants include age and sex. Classifi cation of the clinical stage according to Fritzgerald (1977) is based on onset time and clinical presentation [8]. There were three stage such as early stage occurs within the fi rst month after surgery and is clearly visible at the extremity with signs such as severe pain, fever, and fi stula. It is caused by highly pathogenic bacteria; Delayed stage occurs from about 1 to 24 months after surgery. Symptoms sometimes manifest solely with pain. Symptoms of joint loosening may or may not be present; and late stageusually develops after 2 or 3 years of hip replacement and is derived from blood and lymph vessels. Postoperative clinical symptoms were evaluated such as pain, restriction of hip joint movements, infl ammatory response syndrome (SIRS), and localized localization.
In addition, cases are also evaluated for laboratory tests such as blood culture, culture and identifi cation of bacteria in joint fl uid.

General characteristics of the study subjects
Based on the Fritzgerald's progressive classifi cation, 10 patients (47.6%) were identifi ed as at the early stage. The number of patients at delayed stage of infection was 7 (33.3%). There were four patients (19%) on the last stage of infection. In the early stage, the onset time might be three days postoperatively, but in the late stage, this might last up to fi ve years.

Clinical presentation
Clinical presentation of PJI comprised pain, limitation of hip joint movement, Systemic Infl ammatory Response Syndrome and focal infl ammation as shown in tables 1-3. 13 patients experienced pain after surgery, accounting for 61.9%. Comparing the level of pain between different stages of PJI, the most severe pain was encountered at the early stage and the least severe pain was witnessed in patients at the delayed stage.
Total 18 of 21 patients (86%) developed movement limitation of prosthetic hip joint after surgery. Of these, 18 of these patients (61.9%) included limitation of movement and pain. Table 3 illustrates the SIRS occurring in our participants. SIRS, manifested in 66% of the cases, occurs 100% at the early stage, rarely occurs at delayed-and late stage. Research on the traumatic features of hip replacement indicates that fi stulas, with different numbers, at different levels and positions, accounted for 95%. These fi gures are signifi cant at p<0.01.

Paraclinical characteristics
To assess the severity of PJI, we included below criteria: ESR and CRP, the culture of joint fl uid. The CRP test has only started routinely since 2015. As in our study, we included the small sample size of 21 patients, we did not use this index for the calculation. For blood sedimentation tests (Table 4), the value for the fi rst hour increased in 100% of the cases, ranging from 19 to 140 mm, with an average value of 53 ± 26.8 mm. The highest fi gure was 61±34.2mm, spotted in early stage (p<0.05) ( Figure 1).
The joint fl uid culture showed positive results in 16/21 patients (76.2%), in which 33.3% of the samples were infected with two types of bacteria. The bacteria mostly isolated were Staphylococcus aureus accounting for 42.9% of all cases, and 100% of early stage cases, followed by Gram-negative bacteria (14.3%) with Klebsiella pneumoniae, (7.14%), Escherichia coli

General characteristics
Male patients registered the number of 81%. It is signifi cantly higher than the number of female patients (19%).

This proportion is similar to the study of Tran Dinh Chien and Le
Ngoc Hai (2012) in which the proportion of males and females was 88.7% and 11.3% respectively [4]. This indicates that in Vietnam, male is more likely to have a hip replacement and postoperative complication rather than female. In Vietnam, the male generally does the labor-intensive tasks in order to make a living, therefore, after surgery, they tend to work early than the expected time leading to the poor outcome of treatment and increased infection risk.

Clinical presentation
Of the functional symptoms, pain is considered as one of the most annoying symptoms after surgery that causes patients to have a re-examination. It is reported that pain is also the most common symptom patients experienced after surgery with the proportion of 79% to 100% [11]. In PJI, pain occurs mostly in early stage due to post-op related mechanism, lasting in a certain period. Whereas, pain in patients undergoing antibiotic-loaded cement spacers is more likely from muscle strain, anatomical and physiological incompatibility of temporary joint, presenting by severe pain, continuously and gradually increases [11]. In our study, patients experienced preoperative pain in different levels. Comparing pain levels between stages, the most severe pain was recorded at the early stage and the least severe pain was recorded at delayed stage. As stated by Fritzgerald, pain in the early stage is the most severe. This can be explained by the fact that, in early stage, among the fi rst month postoperatively, local injuries are healing, infl ammation reaction is triggered and vigorous in structures surrounding the joint. Naturally, even if patients did not have an infection, they might have pain in different levels when rehabilitation [8].
Another common symptom is restricted range of movement of the hip joint registering 86%. There are two key situations for this. Firstly, it happens immediately after surgery because of bacterial infections, patients cannot or do not dare to continue rehabilitation training. Therefore, ROM as well as the load-bearing capacity after surgery is not ameliorated or even deteriorated comparing with that before surgery. Secondly, after a successful hip replacement, patients do a good rehabilitation, but after a period, due to bacterial infections, the function of the prosthetic joint movement is decreased. Both the situations require patients to have re-examination and additional treatment. According to Rihard Trebce (2012), the infection causes the artifi cial joint to be gradually loose and painful, even if the loose joint does not appear in all patients [8]. In the delayed stage, the most common manifestation is persistent postoperative pain, and more obvious when the joint works excessively. In some cases, the infection develops later than others, manifested by pain, gradually increasing, with limited range of motion. And at the same time, aside from  pain, focal infl ammation and loose joint appear. In conclusion, manifestation of the delayed stage of bacterial infections may occasionally be painful symptoms only and the loose joint may present or not [8]. Other report by DT. Tsukajama (1996), in 106 patients with prosthetic infections, the number of loose joint was 59% [12].
Of system, systemic manifestations may manifest as the early stage in some cases [8,11].
In the study on features in the hip replacement area, the most commonly encountered symptom in most of the patients is focal infl ammation, in different numbers, levels and locations, accounting for 95%. Trisha N. Peel et al. (2012) found that the proportion was 76% [13]. Such high incidence of focal infl ammation can be explained by the diagnostic criteria of the disease that there must be an infection. The local infection lasts long time, along with infl ammation reaction, leading to a fi ssure, which is passed outside to skin.
In contrast to fi gure for fi stula, the infl ammation around the hip replacement is not the same between the subjects studied.

Conclusion and Recommendation
Clinical and paraclinical characteristics of prosthetic hip joint infection in Viet Nam in our study are generally similar to previous studies. For instance, fi stulas and joint mobility limitation are the two most common symptoms of this type of infection, which accounted for 95% and 86% respectively.
In terms of paraclinical characteristics, ESR increased in 100% of the cases and the highest fi gure was recorded in the early stage of the PJI. Bacterial cultures were positive in 76.2% of the cases.
It is further evidence of the need for surgeons to ensure strict sterilization procedures during surgery. In particular, training should be strengthened in the area of joint surgery in strict compliance with these procedures. In addition, antibiotic prophylaxis should be used prior to hip and postoperative surgery, and close monitoring of bacterial infection, especially bacterial culture.