Objective: Irrigation is a conventional treatment for acute and chronic periprosthetic joint infections (PJI). However, there has been no unified standard for irrigation during surgery for PJI in the past, and the efficacy is uncertain. The purpose of this study is to create a new irrigation protocol to enhance the infection control rate and reduce the postoperative recurrence rate of PJI patients. Methods: We conducted a single‐institution retrospective review with a total of 56 patients who underwent revision total hip or knee arthroplasties due to PJI from January 2011 to January 2022. Conventional irrigation (CI) was used in 32 cases, and standard operating procedure of irrigation (SOPI) was used in 24. The CI protocol carries out an empirical irrigation after debridement, which is quite random. Our SOPI protocol clearly stipulates the soaking concentration and time of hydrogen peroxide and povidone‐iodine. The irrigation is carried out three times, and tissue samples are taken from multiple parts before and after irrigation, which are sent for microbial culture. The important statistical indicators were the rate of positive microbiological culture and postoperative recurrence rate with an average follow‐up of 24 average months. Results: The drainage volume was lower in the SOPI group than in the CI group on postoperative day 3 (p < 0.01) and 7 (p = 0.016). In addition, the percentage of positive microbiological cultures after the third irrigation was less than that before (p < 0.01) and after (p < 0.01) the first irrigation. The most common causative organism was Staphylococcus aureus, which was detected in 25.0% and 12.5% of the SOPI and CI groups, respectively. The failure rate at the final follow‐up was 8.3% and 31.3% (p = 0.039) for the SOPI and CI groups, respectively. Conclusion: Compared with the traditional CI method, SOPI standardized the soaking time of hydrogen peroxide and povidone‐iodine, increased the frequency of and irrigation, and proved that microorganisms were almost completely removed through the microbial culture of multiple tissues. SOPI has the potential to become a standardized irrigation process worthy of promotion, effectively reducing the postoperative recurrence rate of PJI patients.
Keywords: Irrigation protocol; Periprosthetic joint infection; Recurrence; Revision; Staphylococcus aureus
The recurrence rate of SOPI group was significantly lower than that of CI group.
Periprosthetic joint infection (PJI) is a rare but catastrophic complication of total joint arthroplasty (TJA) and partial joint arthroplasty (PJA).[[
Initially, irrigation was generally performed with normal saline. With advances in medical treatment, multiple additives have been introduced in irrigation protocols.[
Based upon the conditions described above, we have proposed two scientific points: (i) the recurrence of PJI may be related to the residual pathogenic microorganisms caused by incomplete intraoperative irrigation; and (ii) the removal of pathogenic microorganisms depends on appropriate soaking time and irrigation times. Our research aims to promote a standardized irrigation process: finding the most suitable soaking time and irrigation frequency. We validated the scavenging effect of pathogenic microorganisms through multiple times and sites of microbiological culture, and ultimately demonstrated the effectiveness of the new protocol by calculating the recurrence rate. Therefore, we formulated a standard operating procedure of irrigation (SOPI) protocol to eradicate pathogenic microorganisms more effectively and improve clinical outcomes. We compared patients in the SOPI and conventional irrigation (CI) groups to explore whether the new irrigation protocol reduced the postoperative recurrence rate. We estimate that the SOPI protocol can more effectively eliminate pathogenic microorganisms, thereby reducing the recurrence rate of patients.
We conducted a single‐center retrospective cohort study to compare the differences between the SOPI and CI groups. All patients with PJI who underwent revision total joint arthroplasty between 2011 and 2022 were identified. Patients with PJI were confirmed according to the diagnostic criteria of the Musculoskeletal Infection Society (MSIS).[
Physical examination, history taking, and preoperative assessment were performed for all patients. Preoperative examinations included laboratory examination, radiography, CT, and MRI. The patients underwent surgery with proper management of blood pressure and blood glucose levels. Vancomycin and rifampicin were used to treat PJI postoperatively, and the administration of antibiotics was adjusted according to the outcome of the microbiological culture. Heparin or factor Xa inhibitor was administered 24 h after the operation to prevent deep venous thrombosis. The medial parapatellar approach was applied in revision total knee arthroplasty, and the posterior lateral approach was applied in revision hip arthroplasty. All operations were performed by one of four experienced arthroplasty surgeons in our hospital.
Forty‐five patients included in the study admitted for treatment were diagnosed with chronic PJI, which were treated with two‐stage arthroplasty. Four patients diagnosed with acute PJI were treated with DAIR, and seven patients were treated with one stage revision arthroplasty. Therefore, they were not sub‐grouped for further analysis. The joint fluid and tissues obtained from joint cavity puncture from all patients were used for microbiological culture. Methods combined spinal‐epidural anesthesia (CSEA) and general anesthesia were operated. Median tourniquet time overall was 60 min. Intravenous infusion of tranexamic acid (20mg/kg) was given 5–10 min before skin incision. The prosthesis of antibiotic‐loaded acrylic cement (Smith & Nephew, USA) was implanted in the primary operation of two‐stage arthroplasty. After implantation, it was slightly pressurized and maintained until the bone cement solidified. This method refers to the 2018 PJI Philadelphia International Consensus. The bone cement augmented screw fixation was performed when bone defect encountered during surgery. For serious cases, endoprosthesis with longer shaft should be utilized to improve the stability. When the prosthesis was difficult to remove, we further cleaned the scar tissue, prominent bone tissue and bone cement.
The patients were treated with vancomycin (0.5–1 g, iv, q12 h) and rifampicin (450 mg, po, qd) for 2 weeks. Rifampicin and oral sensitive antibiotics were continued for 3 months after discharge. The patient's weight and muscle function recovered about 1 month after discharge. The postoperative knee flexion angle of the patients recovered to 90–120°. The X‐ray image showed good positioning of the prosthesis with infection significantly cleared.
The SOPI for patients with PJI was initiated at our institution in January 2017. Patients with one‐or two‐stage revision arthroplasty or DAIR were included in our study (Table 1).The detailed procedure was as follows: (i) resect the infected and necrotic tissue and completely remove the prosthesis and prosthetic membrane between the prosthesis and the bone (except DAIR); (ii) infuse the incision, articular cavity, and medullary cavity with H
1 TABLE Operative methods used for patients in the SOPI and CI groups.
Surgical method CI ( SOPI ( One‐stage revision arthroplasty 6 1 Two‐stage revision arthroplasty 23 22 DAIR 3 1
1 Abbreviations: CI, conventional irrigation; DAIR, debridement, antibiotics, and implant retention; SOPI, standard operating procedeure of irrigation.
We calculated the preoperative demographic data and clinical features of patients, including gender, age, body mass index (BMI), postoperative complications, joint function score, and the correlation indicators including drainage volume, temperature, C‐reactive protein (CRP), white blood cell (WBC) count, neutrophil count (NEUT), lymphocyte count (LY), and NEUT/LY on the 1st, 3rd, and 7th postoperative days. The follow‐up results were determined as recurrence: (i) admission due to recurrent infection; (ii) pus exudation from the incision; and (iii) persistent pain that cannot be relieved.
Measurement data (Age, BMI, Joint function score, Correlation indicators) were analyzed using the independent sample t‐test, and enumeration data (sex, position, postoperative complications, positive rate and recurrence rate) were analyzed using the chi‐square test. All normally distributed data are presented as mean ± standard deviation. All statistical analyses were performed using SPSS 22.0 (IBM Corporation, Armonk, NY, USA). Statistical significance was set at p < 0.05.
The demographic and clinical characteristics of the enrolled patients in the SOPI (n = 24) and CI (n = 32) groups are shown in Table 2. There were no statistically significant differences in age, sex, classification, antibiotic use time, incision effusion, periprosthetic loosening, periprosthetic fracture, hospital for special surgery (HSS) score (knee) and Harris score (Hip) between the two groups (p > 0.05). We always monitored the indicators of liver function during the application of antibiotics, and did not find significant changes.
2 TABLE Demographic data and clinical features of the patients in the SOPI and CI groups.
Demographic data and clinical features CI ( SOPI ( Age (years) 67.47 ± 11.76 64.50 ± 12.84 0.379 Sex 0.530 Male 12 11 Female 20 13 Joint 0.352 Hip 16 15 Knee 16 9 BMI (kg/m2) 24.63 ± 4.13 23.26 ± 3.45 0.194 Postoperative complications Incision effusion 5 2 0.686 Periprosthetic loosening 2 0 0.501 Periprosthetic fracture 0 0 >0.99 Joint function score HSS score (knee) 82.25 ± 9.54 88.22 ± 7.98 0.126 Harris score (Hip) 79.44 ± 9.54 78.33 ± 8.23 0.733
- 2 * p‐value was calculated by the sample t‐test.
- 3 † p‐value was calculated by the χ
2 ‐test. p < 0.05 was regarded as statistically significant.
Univariate analysis was used to compare differences in laboratory‐related indicators and drainage volume between the SOPI and CI groups. There was a significant difference in drainage volume on days 3 and 7 between the SOPI and CI groups (p < 0.05). The differences in temperature, CRP, WBC count, NEUT, LY, and NEUT/LY between the SOPI and CI groups were not significant (p > 0.05) (Table 3).
3 TABLE Correlation indicators at different time points of PJI.
Correlation indicators Detection CI ( SOPI ( Drainage volume (mL) a 281.79 ± 196.68 194.32 ± 178.82 0.093 b 111.35 ± 88.98 54.63 ± 43.32 0.003 c 12.50 ± 34.30 6.99 ± 12.32 0.016 Temperature (°C) d 36.56 ± 0.23 36.72 ± 0.46 0.102 a 36.79 ± 0.40 37.05 ± 0.67 0.073 e 36.77 ± 0.31 36.58 ± 0.33 0.036 CRP (mg/L) d 30.43 ± 27.77 53.50 ± 61.46 0.097 a 53.96 ± 29.12 73.76 ± 48.27 0.083 e 20.57 ± 14.91 23.15 ± 23.95 0.646 WBC (×109/L) d 7.10 ± 2.36 8.28 ± 2.56 0.078 a 8.70 ± 2.70 9.81 ± 2.22 0.104 e 6.53 ± 1.95 6.83 ± 2.46 0.613 NEUT (×109/L) d 4.61 ± 2.05 5.43 ± 2.30 0.164 a 6.89 ± 2.59 7.98 ± 1.94 0.089 e 3.81 ± 1.47 4.19 ± 1.79 0.382 LY (×109/L) d 1.73 ± 0.73 1.70 ± 0.81 0.912 a 1.19 ± 0.42 1.07 ± 0.46 0.326 e 1.62 ± 0.85 1.52 ± 0.57 0.602 NEUT/LY d 3.41 ± 2.89 4.22 ± 3.15 0.322 a 7.78 ± 7.70 9.70 ± 6.18 0.319 e 3.06 ± 1.82 2.88 ± 0.97 0.655
- 4 Abbreviations: CI, conventional irrigation; CRP, C‐reactive protein; LY, lymphocyte count; NEUT, neutrophil count; PJI, periprosthetic joint infection; SOPI, standard operating procedure of irrigation; WBC, white blood cell count.
- 5 Notes: a, first postoperative day; b, third postoperative day; c, seventh postoperative day; d, admission day; e, discharge day. p‐value was calculated by the sample t‐test. p < 0.05 was regarded as statistically significant.
The most common causative organism was Staphylococcus aureus, which was detected in 25.0% and 12.5% of the SOPI and CI groups, respectively (Figure 1).
SOPI patients were divided into four groups according to irrigation frequency: before irrigation, after the first irrigation, after the second irrigation, and after the third irrigation. One patient was excluded because of sample contamination due to an operational error. Microbiological cultures were performed on the samples before and after each irrigation. Positive microbiological cultures decreased after the second (p < 0.05) and third irrigations (p < 0.05) compared with before irrigation. More importantly, it decreased after the third irrigation compared with that after the first irrigation (p < 0.05) (Figure 2).
All patients were followed up for 24.1 ± 7.4 months. The shortest follow‐up time was 12 months. There were 2/24 recurrences in the SOPI group (8.33%) and 10/32 in the CI group (31.25%). This difference was statistically significant (p = 0.039) (Figure 3).
In an effort to improve the success of PJI, the authors of this study implemented a protocol with new irrigation method. To our knowledge, no study has reported on the effect of irrigation in the setting of established PJI. In looking at further adjuncts to maximize the success of PJI treatment, the authors of this study decided to increase soaking time and irrigation. The results showed that compared with the CI group, our SOPI group showed a significant decrease in drainage volume at 7 and 14 days after surgery, although there was no statistically significant difference in postoperative temperature, CRP, WBC, NEUT, LY, and NEUT/LY. Moreover, the positive rate of microbial cultivation significantly decreased after completing three rounds of irrigation. SOPI protocol successfully reduced the recurrence rate of PJI.
Several studies have been conducted on the application of irrigation solutions. Researchers have applied various types of irrigation solutions, such as surfactants, antibiotics, and antiseptics to PJI surgery, where they have different efficacies.[[
Povidone‐iodine was also included in multiple protocols for the surgical treatment of PJI.[[
We effectively decreased the prevalence of pathogenic microorganisms by increasing irrigation time and frequency. Usually, the wound is irrigated with diluted povidone‐iodine for 3 min;[[
No research have ever collected specimens separately to detect pathogenic microorganisms after multiple standard irrigation procedures. At present, there is no unified standard for intraoperative irrigation, so it is difficult to know what degree of irrigation can completely remove microorganisms. Although there is much research on irrigation fluid, it seems that no researcher has paid attention to the methodology of the whole irrigation process. We developed an optimal process to remove pathogenic bacteria through intraoperative multi‐site and multi‐step microbial detection, and its effectiveness has been proved. Through multiple irrigation, we effectively reduced the percentage of positive microbiological cultures from 34.8% to 4.3% after the third irrigation. This finding is of great significance for the eradication of pathogenic microorganisms. In addition, the rate of positive microbiological culture results in our study was low, and the most likely reason was the application of antibiotics before the operation. In chronic PJI, most pathogenic microorganisms exist in the biofilm and attach to the prosthesis surface surrounding the tissues. However, the culture of pathogenic microorganisms depends on separate floating particles, which also contributes to the low detection rate. Our results showed that the rate of positive microbiological culture in the SOPI group was significantly higher than that in the CI group, indicating that microbiological culture in multiple parts of the surgical site was more effective for identifying pathogens. Therefore, we recommend taking tissue samples from multiple sites for microbiological culture in PJI surgery to avoid false negatives.
We implemented SOPI to remove pathogenic microorganisms successfully to the maximum extent through standardized debridement and irrigation procedures. However, our ultimate aim is to improve the prognosis and survival quality of patients, and reduce the recurrence rate. It was found that the possibility of permanent eradication of infection in PJI reoperation was less than 50% through long‐term follow‐up.[[
Our study refined and standardized conventional irrigation solutions, and the findings were validated regarding the rate of positive microbiological cultures and follow‐up recurrence rates. There are some limitations beyond those inherent in retrospective studies. The sample sizes were relatively small, with only 24 cases in the SOPI group. The duration of follow‐up was short, with a minimum follow‐up of 3 months. The different pathogenic microorganisms and virulence could also contribute to the different incidences of recurrence, and these variables were not controlled. Thus, a longer follow‐up period with a larger number of cases is needed to validate our protocol.
The SOPI protocol is safe and effective in improving the success of PJI treatment compared to CI. It effectively reduced the percentage of positive microbiological cultures and the postoperative recurrence rate.
The authors thank all the participants and researchers who participated in this study.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All methods were carried out in accordance with relevant guidelines and regulations. This study was approved by the institutional review board and ethics committee of our hospital. All human subjects signed informed consent in the study.
Puyi Sheng and Xiaoyu Wu conceived the research topic; Xiaoyu Wu, Ziji Zhang, and Minghui Gu collected the raw data from clinical record. Xiaoyu Wu constructed the database files and drafted the manuscript together with Weishen Chen and Rong Rong. Ziji Zhang and Minghui Gu provide writing assistance. Xiaoyu Wu, Rong Rong, Baiqi Pan, Xuantao Hu, Linli Zheng, Aerman Alimu, Chenghan Chu, and Yucheng Tu performed proof reading of the article.
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding authors.
This study was supported by the National Natural Science Foundation of China (Grant number 81972050 and 82172405), Guangdong Basic and Applied Basic Research Foundation (Grant number 2023A1515030030), Science and Technology Projects in Guangzhou (Grant number 2023A04J2187). No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
By Xiaoyu Wu; Weishen Chen; Rong Rong; Baiqi Pan; Xuantao Hu; Linli Zheng; Aerman Alimu; Chenghan Chu; Yucheng Tu; Ziji Zhang; Yongyu Ye; Minghui Gu and Puyi Sheng
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