Is debridement really the best we can do for periprosthetic joint infections following total ankle replacements? A systematic review and meta-analysis.

BACKGROUND: Ankle periprosthetic joint infections are rising in number, but an evidence-based gold standard treatment has not been defined yet. METHODS: We made a systematic review about the operative treatment of infections following total ankle arthroplasty. Proportional meta-analysis was used to summarize effects of the surgical techniques included. Primary outcome of this study was infection eradication, followed by complications, re-interventions, amputation rates and functions. RESULTS: We included six studies(113 patients) reporting 6 types of surgical interventions, mostly irrigation and debridement (35.4%) and two-stage revisions (24.8%). No differences among all analyzed techniques were found in the infection eradication outcome as well as in the secondary outcomes. Patients receiving a permanent spacer are most likely to end up with amputation. CONCLUSIONS: Literature dealing with infections after total ankle replacement is currently composed by few low-quality articles. The overlapping of confidence intervals related to all analyzed interventions showed no superiority of either technique. LEVEL OF EVIDENCE: III.

Two-stage cementless hip revision for peri-prosthetic infection with an antibacterial hydrogel coating: results of a comparative series.

PURPOSE: The aim of this study was to investigate the hypothesis that a two-stage exchange procedure, performed with an antibiotic-loaded, fast-resorbable hydrogel coating, may provide better infection cure rate than a two-stage procedure without the coating, in patients affected by peri-prosthetic hip infection. METHODS: In this case-control study, 27 patients, treated with a two-stage procedure, using cementless implants coated with an antibiotic-loaded hydrogel (DAC®, "Defensive Antibacterial Coating"), were compared with 27 matched controls, treated with a two-stage cementless revision procedure, without the coating. RESULTS: At a mean follow-up of 2.7 (minimum 2.1-maximum 3.5) years, no evidence of infection, implant loosening, or adverse events were observed in the DAC-treated group, compared to four cases of infection recurrence in the control group. CONCLUSIONS: Although in a relatively limited series of patients our data show that cementless two-stage hip revision, performed with an antibacterial hydrogel coating, may provide better infection control than two-stage without the coating, with reduced hospitalization time, these findings warrant further studies in the possible applications of antibacterial coating technologies to treat implant-related infections.

Does knee revision after an articulated spacer implant provide normal gait restoration?

PURPOSE: The aim of this study was to quantitatively evaluate gait parameters in patients who underwent a revision procedure after an interval articulated spacer for septic knee prosthesis. METHODS: Ten adult subjects underwent three-dimensional computerized gait analysis 12 months after second-stage knee revision procedure. Kinematic and kinetic parameters were acquired and compared with a normal reference population. Data were also compared with those collected in a previous study, in which the same cohort of patients underwent gait analysis 8-14 weeks after spacer implantation. RESULTS: Kinematic and kinetic parameters did not show any significant difference between the affected and unaffected limb. Compared to normal reference population, patients treated with revision knee prosthesis showed a reduced mean gait velocity, step frequency, stride and step length, average knee range of motion, knee power and ground reaction forces. When comparing average data with those observed after spacer implant, no difference was observed in kinematic variables, while kinetic analysis demonstrated a significant improvement in knee power. CONCLUSIONS: This study shows that 1 year after second-stage knee revision surgery, kinematic and kinetic values remain lower than those observed in a normal reference population. Only slight improvements in walking ability are shown, when analysing data in comparison with those collected after a preformed articulated knee spacer. This finding points out the long time to full functional recovery after knee revision surgery and the limited improvement of gait when compared to the one achieved at the time of spacer implant.

Cementless modular intramedullary nail without bone-on-bone fusion as a salvage procedure in chronically infected total knee prosthesis: long-term results.

PURPOSE: Our purpose was to evaluate long-term results of two-stage cementless intramedullary nailing without achieving bone-to-bone fusion for treating chronically infected total knee arthroplasty (TKA). METHODS: Thirty-eight patients treated according to the same protocol were retrospectively evaluated for clinical, functional, laboratory and radiological outcomes. RESULTS: Spacer exchange was necessary for infection persistence in one case. At a minimum two year follow-up, 34 patients (89.5%) showed no infection recurrence; among these 34 patients, 29 (85.3%) reported no or moderate pain [visual analogue scale (VAS) ≤3]; mild to moderate handicap (Lequesne Algofunctional Index < 7.5) was observed in 18 patients (52.9%). No patient underwent revision for aseptic loosening, and no nail breakage was observed. CONCLUSIONS: Two-stage cementless intramedullary nailing without achieving bone-to-bone fusion is a viable option for treating chronically infected TKA in selected, complex cases.

"Combined Diagnostic Tool" APPlication to a Retrospective Series of Patients Undergoing Total Joint Revision Surgery.

Background: Differentiating between septic and aseptic joint prosthesis may be challenging, since no single test is able to confirm or rule out infection. The choice and interpretation of the panel of tests performed in any case often relies on empirical evaluation and poorly validated scores. The "Combined Diagnostic Tool (CDT)" App, a smartphone application for iOS, was developed to allow to automatically calculate the probability of having a of periprosthetic joint infection, on the basis of the relative sensitivity and specificity of the positive and negative diagnostic tests performed in any given patient. Objective: The aim of the present study was to apply the CDT software to investigate the ability of the tests routinely performed in three high-volume European centers to diagnose a periprosthetic infection. Methods: This three-center retrospective study included 120 consecutive patients undergoing total hip or knee revision, and included 65 infected patients (Group A) and 55 patients without infection (Group B). The following parameters were evaluated: number and type of positive and negative diagnostic tests performed pre-, intra- and post-operatively and resultant probability calculated by the CDT App of having a peri-prosthetic joint infection, based on pre-, intra- and post-operative combined tests. Results: Serological tests were the most common performed, with an average 2.7 tests per patient for Group A and 2.2 for Group B, followed by joint aspiration (0.9 and 0.8 tests per patient, respectively) and imaging techniques (0.5 and 0.2 test per patient). Mean CDT App calculated probability of having an infection based on pre-operative tests was 79.4% for patients in Group A and 35.7 in Group B. Twenty-nine patients in Group A had > 10% chance of not having an infection, and 29 of Group B had > 10% chance of having an infection. Conclusion: This is the first retrospective study focused on investigating the number and type of tests commonly performed prior to joint revision surgery and aimed at evaluating their combined ability to diagnose a peri-prosthetic infection. CDT App allowed us to demonstrate that, on average, the routine combination of commonly used tests is unable to diagnose pre-operatively a peri-prosthetic infection with a probability higher than 90%.

Predicting lower limb periprosthetic joint infections: A review of risk factors and their classification.

AIM: To undertook a systematic review to determine factors that increase a patient's risk of developing lower limb periprosthetic joint infections (PJI). METHODS: This systematic review included full-text studies that reviewed risk factors of developing either a hip or knee PJI following a primary arthroplasty published from January 1998 to November 2016. A variety of keywords were used to identify studies through international databases referencing hip arthroplasty, knee arthroplasty, infection, and risk factors. Studies were only included if they included greater than 20 patients in their study cohort, and there was clear documentation of the statistical parameter used; specifically P-value, hazard ratio, relative risk, or/and odds ratio (OR). Furthermore a quality assessment criteria for the individual studies was undertaken to evaluate the presence of record and reporting bias. RESULTS: Twenty-seven original studies reviewing risk factors relating to primary total hip and knee arthroplasty infections were included. Four studies (14.8%) reviewed PJI of the hip, 3 (11.21%) of the knee, and 20 (74.1%) reviewed both joints. Nineteen studies (70.4%) were retrospective and 8 (29.6%) prospective. Record bias was identified in the majority of studies (66.7%). The definition of PJI varied amongst the studies but there was a general consensus to define infection by previously validated methods. The most significant risks were the use of preoperative high dose steroids (OR = 21.0, 95%CI: 3.5-127.2, P < 0.001), a BMI above 50 (OR = 18.3, P < 0.001), tobacco use (OR = 12.76, 95%CI: 2.47-66.16, P = 0.017), body mass index below 20 (OR = 6.00, 95%CI: 1.2-30.9, P = 0.033), diabetes (OR = 5.47, 95%CI: 1.77-16.97, P = 0.003), and coronary artery disease (OR = 5.10, 95%CI: 1.3-19.8, P = 0.017). CONCLUSION: We have highlighted the need for the provider to optimise modifiable risk factors, and develop strategies to limit the impact of non-modifiable factors.

Masquelet technique: myth or reality? A systematic review and meta-analysis.

INTRODUCTION: The induced membrane technique (IMT) or Masquelet technique, is a two-step surgical procedure used to treat pseudoarthroses and bony defects. Many authors have introduced variants to the technique. This study aims to compare the surgical variants of IMT and to evaluate its efficacy in achieving infection eradication and bone union. METHODS: A systematic review was carried out following the PRISMA guidelines. PubMed and other medical databases were explored using keywords "Masquelet technique" and "induced membrane technique". Articles were included if written in English, French or Italian, dealing with IMT employed to long bones in adults, reporting at least 5 cases with a 12 months-mean follow-up. Patients' clinical features, bone defect features, aetiologies, surgical data, complications, reinterventions, union rates and infection eradication rates were searched. Fischer's exact test, chi-square test and unpaired t-test were used for the statistical analysis on the individual patient's data. RESULTS: Seventeen papers met the inclusion criteria (427 patients). Among these, only 10 studies reported individual patient's data (137 cases). The union rate was 89.7% and the infections rectified in 91.1% of cases. The bone defect length ranged from 0.6 to 26 cm. The main complications were superficial (21; 4.9%) and deep surgical site infections (19; 4.4%), failure of one of the IMT steps (persistence of infections or non unions, 77, 18%), with subsequent requirement for further surgery. The surgical variants included the use of antibiotic-coated spacers, internal fixation during the first step, use of Reamer-Irrigator-Aspirator technique, iliac crest grafting, bone substitutes and growth factors. However, univariate analysis only showed a positive correlation of the need for reinterventions with poorer bone union rates (p = 0.005) and complications (p <0.001), while patients undergoing IMT because of bone infections had a higher risk of surgical complications (p <0.001). DISCUSSION: IMT aims to achieve bone union and infection eradication, but persistence of infection or non-union was noted in 18% of cases necessitating re-interventions. This may be related to the different anatomical sites that the technique has been applied and different local and patient related conditions. We believe the choice of a surgical technique to achieve union should be tailored to the individual patient's needs. This systematic review was limited by the few studies meeting our inclusion criteria, and their high variability in data reporting, making it impossible to undertake a meta-analysis. CONCLUSION: Further studies are needed to demonstrate the role the patients' clinical features and IMT variants have upon achieving bone union and infection eradication.

Does an Antibiotic-Loaded Hydrogel Coating Reduce Early Post-Surgical Infection After Joint Arthroplasty?

Background: Infection remains among the main reasons for joint prosthesis failure. Preclinical reports have suggested that antibacterial coatings of implants may prevent bacterial adhesion and biofilm formation. This study presents the results of the first clinical trial on an antibiotic-loaded fast-resorbable hydrogel coating (Defensive Antibacterial Coating, DAC®) in patients undergoing hip or knee prosthesis. Methods: In this multicenter, randomized prospective study, a total of 380 patients, scheduled to undergo primary (n=270) or revision (n=110) total hip (N=298) or knee (N=82) joint replacement with a cementless or a hybrid implant, were randomly assigned, in six European orthopedic centers, to receive an implant either with the antibiotic-loaded DAC coating (treatment group) or without coating (control group). Pre- and postoperative assessment of clinical scores, wound healing, laboratory tests, and x-ray exams were performed at fixed time intervals. Results: Overall, 373 patients were available at a mean follow-up of 14.5 ± 5.5 months (range 6 to 24). On average, wound healing, laboratory and radiographic findings showed no significant difference between the two groups. Eleven early surgical site infections were observed in the control group and only one in the treatment group (6% vs. 0.6%; p=0.003). No local or systemic side effects related to the DAC hydrogel coating were observed, and no detectable interference with implant osteointegration was noted. Conclusions: The use of a fast-resorbable, antibiotic-loaded hydrogel implant coating can reduce the rate of early surgical site infections, without any detectable adverse events or side effects after hip or knee joint replacement with a cementless or hybrid implant.

Antibacterial coating of implants in orthopaedics and trauma: a classification proposal in an evolving panorama.

Implanted biomaterials play a key role in current success of orthopedic and trauma surgery. However, implant-related infections remain among the leading reasons for failure with high economical and social associated costs. According to the current knowledge, probably the most critical pathogenic event in the development of implant-related infection is biofilm formation, which starts immediately after bacterial adhesion on an implant and effectively protects the microorganisms from the immune system and systemic antibiotics. A rationale, modern prevention of biomaterial-associated infections should then specifically focus on inhibition of both bacterial adhesion and biofilm formation. Nonetheless, currently available prophylactic measures, although partially effective in reducing surgical site infections, are not based on the pathogenesis of biofilm-related infections and unacceptable high rates of septic complications, especially in high-risk patients and procedures, are still reported.In the last decade, several studies have investigated the ability of implant surface modifications to minimize bacterial adhesion, inhibit biofilm formation, and provide effective bacterial killing to protect implanted biomaterials, even if there still is a great discrepancy between proposed and clinically implemented strategies and a lack of a common language to evaluate them.To move a step forward towards a more systematic approach in this promising but complicated field, here we provide a detailed overview and an original classification of the various technologies under study or already in the market. We may distinguish the following: 1. Passive surface finishing/modification (PSM): passive coatings that do not release bactericidal agents to the surrounding tissues, but are aimed at preventing or reducing bacterial adhesion through surface chemistry and/or structure modifications; 2. Active surface finishing/modification (ASM): active coatings that feature pharmacologically active pre-incorporated bactericidal agents; and 3. Local carriers or coatings (LCC): local antibacterial carriers or coatings, biodegradable or not, applied at the time of the surgical procedure, immediately prior or at the same time of the implant and around it. Classifying different technologies may be useful in order to better compare different solutions, to improve the design of validation tests and, hopefully, to improve and speed up the regulatory process in this rapidly evolving field.