Patient reported outcome measures after revision of the infected TKR: comparison of single versus two-stage revision

Single-stage revision in the management of prosthetic joint infections after total knee arthroplasty - A review of current concepts

Introduction

Prosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA); and the gold standard surgical approach involves a two-staged, revision TKA (TSR). Owing to the newer, emerging evidence on this subject, there has been gradual shift towards a single-stage revision approach (SSR), with the purported benefits of mitigated patient morbidity, decreased complications and reduced costs. However, there is still substantial lacuna in the evidence regarding the safety and outcome of the two approaches in chronic PJI. This study aimed to comprehensively review of the literature on SSR; and evaluate its role within Revision TKA post PJI.

Methods

The narrative review involved a comprehensive search of the databases (Embase, Medline and Pubmed), conducted on 20th of January 2024 using specific key words. All the manuscripts discussing the use of SSR for the management of PJI after TKA were considered for the review. Among the screened manuscripts, opinion articles, letters to the editor and non-English manuscripts were excluded.

Results

The literature search yielded a total 232 studies. Following a detailed scrutiny of these manuscripts, 26 articles were finally selected. The overall success rate following SSR is reported to range from 73 % to 100 % (and is comparable to TSR). SSR is performed in PJI patients with bacteriologically-proven infection, adequate soft tissue cover, immuno-competent host and excellent tolerance to antibiotics. The main difference between SSR and TSR is that the interval between the 2 stages is only a few minutes instead of 6 weeks. Appropriate topical, intraoperative antibiotic therapy, followed by adequate postoperative systemic antibiotic cover are necessary to ascertain good outcome. Some of the major benefits of SSR over TSR include reduced morbidity, decreased complications (such as arthrofibrosis or anesthesia-associated adverse events), meliorated extremity function, earlier return to activities, mitigated mechanical (prosthesis-associated) complications and enhanced patient satisfaction.

Conclusion

SSR is a reliable approach for the management of chronic PJI. Based on our comprehensive review of the literature, it may be concluded that the right selection of patients, extensive debridement, sophisticated reconstruction strategy, identification of the pathogenic organism, initiation of appropriate antibiotic therapy and ensuring adequate follow-up are the key determinants of successful outcome. To achieve this will undoubtedly require an MDT approach to be taken on a case-by-case basis.

Patient-Reported Outcome Measures in High-Risk Medical Device Registries: A Scoping Review

Little is known about the methods and outcomes of patient-reported outcome measure (PROM) use among high-risk medical device registries. The objective of this scoping review was to assess the utility and predictive ability of PROMs in high-risk medical device registries. We searched Ovid Medline, Embase, APA PsychINFO, Cochrane Library, and Scopus databases for published literature. After searching, 4323 titles and abstracts were screened, and 262 full texts were assessed for their eligibility. Seventy-six papers from across orthopedic (n = 64), cardiac (n = 10), penile (n = 1), and hernia mesh (n = 1) device registries were identified. Studies predominantly used PROMs as an outcome measure when comparing cohorts or surgical approaches (n = 45) or to compare time points (n = 13) including pre- and postintervention. Fifteen papers considered the predictive ability of PROMs. Of these, 8 treated PROMs as an outcome, 5 treated PROMs as a risk factor through regression analysis, and 2 papers treated PROMs as both a risk factor and as an outcome. One paper described PROMs to study implant survival. To advance methods of PROM integration into clinical decision-making for medical devices, an understanding of their use in high-risk device registries is needed. This scoping review found that there is a paucity of studies using PROMs to predict long-term patient and clinical outcomes in high-risk medical device registries. Determination as to why PROMs are rarely used for predictive purposes in long-term data collection is needed if PROM data are to be considered suitable as real-world evidence for high-risk device regulatory purposes, as well as to support clinical decision-making.

Level of Evidence 4

The outcomes of acute periprosthetic joint infection following unicompartmental knee replacement managed with early debridement, Antibiotics, and implant retention

BACKGROUND

Periprosthetic joint infection (PJI) following unicompartmental knee replacement (UKR) is an uncommon, yet serious, complication. There is a paucity of evidence regarding the effectiveness of Debridement-Antibiotics-and-Implant-Retention (DAIR) in this setting. The aim of this study is to investigate the effectiveness of DAIR for acute UKR PJI.

METHOD

Between 2006 and 2019, 5195 UKR were performed at our institution. Over this period, sixteen patients underwent DAIR for early, acute PJI. All patients met MSIS PJI diagnostic criteria. The median age at DAIR was 67 years (range 40-73) and 12 patients were male (75.0%). The median time to DAIR was 24 days (range 6-60). Patients were followed up for a median of 6.5 years (range1.4-10.5) following DAIR.

RESULTS

0.3% (16/5195) of UKR in our institution had a DAIR within 3 months. 15 of 16 patients (93.8%) were culture positive, with the most common organism MSSA (n = 8, 50.0%). Patients were treated with an organism-specific intravenous antibiotic regime for a median of 6 weeks, followed by oral antibiotics for a median duration of 6 months. The Kaplan-Meier survivor estimate for revision for PJI was 57% (95%CI: 28-78%) at five years, and survivor estimate for all cause revision 52% (95%CI: 25-74%).The median Oxford Knee Score for patients with a viable implant at final follow-up was 45 points (range 39-46).

CONCLUSION

Early, acute PJI after UKR is rare. DAIR had a moderate success rate, with infection-free survivorship of 57% at 5 years. Those successfully treated with DAIR had excellent functional outcome and implant survival.

Do one-stage indications predict success following two-stage arthroplasty for chronic periprosthetic joint infection?

Introduction: The 2018 International Consensus Meeting (ICM) proposed criteria for one-stage exchange arthroplasty in treating periprosthetic joint infection (PJI). Our study aimed to determine what proportion of PJI patients met the 2018 ICM criteria and how this affected infection-free survivorship for patients. Methods: All chronic PJI patients treated with two-stage exchange within our institution between 2017-2020 were retrospectively reviewed. Included cases met 2011 Musculoskeletal Infection Society (MSIS) criteria for PJI and had a 2-year minimum follow-up. Treatment success was defined as Tier 1A in the 2019 MSIS working group definition. ICM one-stage criteria included non-immunocompromised host, absence of sepsis, adequate soft tissue for closure, known preoperative pathogen, and susceptibility. Immunocompromised host was analyzed as two separate definitions. Kaplan-Meier survivorship, Cox regression, and univariate analyses were performed. Results: A total of 293 chronic PJI patients were included. Overall, treatment failure occurred in 64 / 293 (21.8 %) patients. Only 13 % (n = 37 ) met ICM criteria definition no. 1 for one-stage exchange; 12 % (n = 33 ) met definition no. 2. In both definitions, infection-free survivorship at 2 years did not differ between patients who met and did not meet criteria (p > 0.05 ). Cox proportional hazard regression analyses demonstrated that the only variable predicting treatment failure was knee joint involvement (p = 0.01 ). Conclusions: We found that a very limited number of chronic PJI patients were suitable for a one-stage exchange. Furthermore, the supposition that healthier hosts with known pathogens (the basis of the ICM criteria) yield better PJI treatment outcomes was not observed. These results justify the ongoing multicenter randomized control trial comparing one-stage versus two-stage treatment for chronic PJI.

Systematic review and meta-analysis of single-stage vs two-stage revision for periprosthetic joint infection: a call for a prospective randomized trial

BACKGROUND

Periprosthetic joint infection (PJI) is a severe complication of joint arthroplasty that causes significant pain and economic loss. This study aimed to determine whether the current evidence supports single-stage revision for PJI based on reinfection and reoperation rates.

METHODS

We searched the PubMed, EBSCO, Medline, and Cochrane Library databases from inception to 30 May 2023 to identify studies that compared single-stage revision and two-stage revision for PJI. Data on reinfection and reoperation rates were pooled.

RESULTS

This meta-analysis included a total of 40 studies with 8711 patients. Overall, there was no significant difference between single- and two-stage revision regarding the postoperative reinfection rate and reoperation rate. Subgroup analysis by surgery period and different surgical sites revealed no difference between the two groups in the reinfection and reoperation rates.

CONCLUSIONS

Based on the available evidence, our study did not identify a significant difference in reinfection and reoperation rates between single- and two-stage revision for PJI. Given the limitations in inclusion/exclusion criteria and the observed heterogeneity, we acknowledge the complexity of drawing strong conclusions. Therefore, we suggest that the choice between single- and two-stage revision should be carefully considered on an individual basis, taking into account patient-specific factors and further research developments.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature

BACKGROUND

Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection.

MATERIAL AND METHODS

A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded.

PROSPERO ID

CRD42022362767.

RESULTS

Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%).

CONCLUSION

Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

Periprosthetic knee infection: treatment options

Infection is one of the most catastrophic complication following total knee arthroplasty (TKA) and represents the second most common cause of TKA failure. Treatment of a patient with periprosthetic joint infection (PJI) could require often costly and prolonged hospital stays, weeks or months of antibiotic therapy, and multiple surgical procedures. The best management is still highly debating, whereas many treatment options are available. These include suppressive antibiotics, arthroscopic irrigation and debridement, open debridement with insert exchange, single-stage reimplantation and two-stage reimplantation. The choice of the treatment depends on many variables, including integrity of implant, timing of the infection, host factors (age, health, immunologic status), virulence of the infecting organism and wishes of the patient. The aim of this review is to provide a comprehensive understaning of the different options for knee PJIs.

Total Joint Replacement of Ankle, Knee, and Hip: How Do Patients Perceive Their Operative Outcomes at 10 Years?

Background:

Patient-reported outcomes (PROMs) are an integral part of national joint registers in measuring outcomes of operative procedures and improving quality of care. There is lack of literature comparing outcomes of total ankle replacement (TAR) to total knee replacement (TKR) and total hip replacement (THR). The aim of this study was to compare PROMs between TAR, TKR, and THR patient groups at 1, 5, and 10 years.

Methods:

Prospective PROMs from patients who underwent a TAR, TKR, or THR procedure between 2003 and 2010 were studied. Patients were divided into 3 groups based on their index joint replacement (hip, knee, or ankle). Patient demographics (age, gender, body mass index), patient-reported outcome scores (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], 36-Item Short Form Health Survey [SF-36]) and patient satisfaction scores (4-point Likert scale) at follow-up were compared between the 3 groups.

Results:

Data was available on 1797 THR, 2475 TKR, and 146 TAR patients. TAR patients were younger and reported fewer number of comorbidities. All 3 groups improved significantly from preoperative to 10 years for WOMAC scores (P < .001). For SF-36 scores at 10 years, the THR group (32.2% follow-up) scored the highest for 3 domains (P = .031) when compared to the TKR group (29.1% follow-up). All 3 groups had similar outcomes for 5 of 8 domains; P < .05). For patient satisfaction, the THR group reported overall 95.1% satisfaction followed by 89.8% for the TKR group and 83.9% in the TAR group (42.4% follow-up).

Conclusion:

In this cohort with diminishing numbers over the decade of time the patients were followed up we found that patients are equally happy with functional and general health outcomes from total ankle replacement vs other major lower extremity joint replacement. TAR surgery should be considered as a viable treatment option in this patient group.

Level of Evidence:

Level III, retrospective case series.

Revision knee replacement for prosthetic joint infection: Epidemiology, clinical outcomes and health-economic considerations

Prosthetic joint infection (PJI) is a devastating complication of knee replacement surgery. Recent evidence has shown that the burden of disease is increasing as more and more knee replacement procedures are performed. The current incidence of revision total knee replacement (TKR) for PJI is estimated at 7.5 cases per 1000 primary joint replacement procedures at 10 years. Revision TKR for PJI is complex surgery, and is associated to a high rate of post-operative complications. The 5-year patient mortality is comparable to some common cancer diagnoses, and more than 15% of patients require re-revision by 10 years. Patient-reported outcome measures (PROMs) including joint function may be worse following revision TKR for PJI than for aseptic indications. The complexity and extended length of the treatment pathway for PJI places a significant burden on the healthcare system, highlighting it as an area for future research to identify the most clinically and cost-effective interventions.

Outcome of Revision Surgery for Infection After Total Knee Arthroplasty: Results of 3 Surgical Strategies

BACKGROUND

Periprosthetic joint infection (PJI) after knee arthroplasty surgery remains a serious complication, yet there is no international consensus regarding the surgical treatment of PJI. This study aimed to assess prosthesis survival rates, risk of revision, and mortality rate following different surgical strategies (1-stage versus 2-stage implant revision and irrigation and debridement with implant retention) that are used to treat PJI.

METHODS

The study was based on 644 total knee arthroplasties (TKAs) that were revised because of a deep infection (i.e., surgically treated PJI) and reported to the Norwegian Arthroplasty Register (NAR) from 1994 to 2016. Kaplan-Meier and multiple Cox regression analyses were performed to assess implant survival rate and risk of revision. We also studied mortality rates at 90 days and 1 year after revision for PJI.

RESULTS

During the follow-up period, 19% of the irrigation and debridement cases, 14% of the 1-stage revision cases, and 12% of the 2-stage revision cases underwent a subsequent revision because of a PJI. The 5-year Kaplan-Meier survival rate with revision for infection as the end point was 79% after irrigation and debridement, 87% after 1-stage revision, and 87% after 2-stage revision. There were no significant differences between 1-stage and 2-stage revisions with subsequent revision for any reason as the end point (relative risk [RR], 1.7; 95% confidence interval [CI], 0.9 to 3.5) and no difference with revision because of infection as the end point (RR, 1.6; 95% CI, 0.7 to 3.7). In an age-stratified analysis, however, the risk of revision for any reason was 4 times greater after 1-stage revision than after 2-stage revision in patients over the age of 70 years (RR, 4.3; 95% CI, 1.3 to 14.8). Age had no significant effect on the risk of subsequent revision for knees that had been revised with the irrigation and debridement procedure. The 90-day and 1-year mortality rates after revision for PJI were 1.2% and 2.5%, respectively.

CONCLUSIONS

Irrigation and debridement yielded good results compared with previous published studies. Although the 1-stage revisions resulted in a fourfold increase in risk of subsequent revision compared with the 2-stage revisions in older patients, the overall outcomes after 1-stage and 2-stage revisions were similar.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Role of Poly(Methyl Methacrylate) in Management of Bone Loss and Infection in Revision Total Knee Arthroplasty: A Review

Poly(methyl methacrylate) (PMMA) is widely used in joint arthroplasty to secure an implant to the host bone. Complications including fracture, bone loss and infection might cause failure of total knee arthroplasty (TKA), resulting in the need for revision total knee arthroplasty (rTKA). The goals of this paper are: (1) to identify the most common complications, outside of sepsis, arising from the application of PMMA following rTKA, (2) to discuss the current applications and drawbacks of employing PMMA in managing bone loss, (3) to review the role of PMMA in addressing bone infection following complications in rTKA. Papers published between 1970 to 2018 have been considered through searching in Springer, Google Scholar, IEEE Xplore, Engineering village, PubMed and weblinks. This review considers the use of PMMA as both a bone void filler and as a spacer material in two-stage revision. To manage bone loss, PMMA is widely used to fill peripheral bone defects whose depth is less than 5 mm and covers less than 50% of the bone surface. Treatment of bone infections with PMMA is mainly for two-stage rTKA where antibiotic-loaded PMMA is inserted as a spacer. This review also shows that using antibiotic-loaded PMMA might cause complications such as toxicity to surrounding tissue, incomplete antibiotic agent release from the PMMA, roughness and bacterial colonization on the surface of PMMA. Although PMMA is the only commercial bone cement used in rTKA, there are concerns associated with using PMMA following rTKA. More research and clinical studies are needed to address these complications.

Outcome of single-stage versus two-stage exchange for revision knee arthroplasty for chronic periprosthetic infection

The gold standard for treating chronic periprosthetic joint infection is still considered to be double-stage exchange revision. The purpose of this review is to analyse the difference in terms of eradication rates and functional outcome after single- and double-stage prosthetic exchange for chronic periprosthetic joint infection around the knee.

We reviewed full text articles written in English from 1992 to 2018 reporting the success rates and functional outcomes of either single-stage exchange or double-stage exchange for knee arthroplasty revision performed for chronic infection. In the case of double-stage exchange, particular attention was paid to the type of spacer: articulating or static.

In all, 32 articles were analysed: 14 articles for single-stage including 687 patients and 18 articles for double-stage including 1086 patients. The average eradication rate was 87.1% for the one-stage procedure and 84.8% for the two-stage procedure. The functional outcomes were similar in both groups: the average Knee Society Knee Score was 80.0 in the single-stage exchange group and 77.8 in the double-stage exchange. The average range of motion was 91.4° in the single-stage exchange group and 97.8° in the double-stage exchange group.

Single-stage exchange appears to be a viable alternative to two -stage exchange in cases of chronic periprosthetic joint infection around the knee, provided there are no contra-indications, producing similar results in terms of eradication rates and functional outcomes, and offering the advantage of a unique surgical procedure, lower morbidity and reduced costs.

Cite this article: EFORT Open Rev 2019;4:495-502. DOI: 10.1302/2058-5241.4.190003

Evolving concepts in bone infection: redefining "biofilm", "acute vs. chronic osteomyelitis", "the immune proteome" and "local antibiotic therapy"

Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone. In contrast, S. aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.

Higher failure rate of two-stage revision for infected knee arthroplasties in significantly compromised (host-C) patients

PURPOSE

To evaluate clinical outcomes of two-stage revision arthroplasty for managing infected knee arthroplasties in significantly compromised patients (host-C).

METHODS

This was a prospective consecutive series of two-stage revisions of infected total knee arthroplasties in host-C-type patients with a minimum 2-year follow-up using objective and patient-reported outcome measures. Thirteen consecutive patients were included and prospectively followed with a median 5-year follow-up (range 2-10). Median age was 68 years (range 59-73) at time of initial presentation. All patients were type-C host using McPherson classification system. All patients had primary arthroplasties in situ with confirmed chronic infections; the infecting pathogens were Staphylococcus aureus in 5/13 patients, coagulase-negative Staphylococci in 5/13, and the remaining three patients had mixed growth. All patients underwent two-stage revision protocol.

RESULTS

At the final follow-up, 9/13 patients were infection free achieving satisfactory outcomes. Two patients had recurrent infections with different organisms and treated with suppressive antibiotics and salvage knee arthrodesis, respectively. Furthermore, two patients had chronic pain and poor functional outcomes with deficient extensor mechanism and significant bone loss; later underwent salvage knee arthrodesis. The preoperative knee society score (median 35.5; range 22-51; n = 10) showed a statistically significant improvement at the final follow-up (median 79.5; range 49-87; n = 10) p < 0.05. Patients reported outcome scores at the final follow-up were WOMAC-knee (median 59.1; range 47.7-94.7; n = 13) and Oxford knee score (median 26; range 11 to 43; n = 13).

CONCLUSION

This study highlights the challenge of treating infected knee arthroplasties in physiologically compromised patients with 9/13 (69%) having satisfactory clinical outcomes.

LEVEL OF EVIDENCE

Case series, level IV.

Single-Stage Revision Surgery in Infected Total Knee Arthroplasty: A PRISMA Systematic Review

Periprosthetic joint infection in total knee arthroplasty is a significant complication that is a common reason for revision surgery. The current standard of care is two-stage revision surgery. There is however increasing evidence to support the use of single-stage revision surgery. We conducted a PRISMA systematic review of the current evidence on the use of single-stage revision for infected total knee arthroplasty. Four databases (PubMed, Embase, Science Direct, and Cochrane Library) were systematically screened for eligible studies. The risk bias of each study was identified using ROBINS-I tool, and the quality of evidence was assessed using the GRADE criteria. Sixteen articles were retained after applying the inclusion and exclusion criteria that evaluated 3645 knee single-stage revision surgeries. Our review reveals satisfactory outcomes for single-stage revision in the management of infected total knee arthroplasty. The reinfection rates in the studies included in our review varied however the majority reported low reinfection rates and good functional outcomes. Although strict patient selection criteria have yielded successful results, good results were also reported when these criteria were not applied. The greater use of risk factors in identifying patients likely to have a successful outcome needs to be balanced with the practical benefits of performing a single stage procedure in higher risk patients. Future large clinical randomized control trials are required to confirm our results.

Assessment and management of infected total knee replacements

Infection following total knee replacement surgery is a challenging and devastating complication. Clinical assessment including history, examination, radiographs, blood tests and knee aspirations helps to establish the diagnosis. Revision surgery is typically required to eradicate infection and restore function. This has traditionally been performed through two-stage revision surgery, although single-stage revision surgery is gaining popularity with comparable results in carefully selected patients. This article reviews the clinical assessment and principles of surgical management of infected total knee replacements.

The Role of One-Stage Exchange for Prosthetic Joint Infection

PURPOSE OF REVIEW

In an era of increasing numbers of hip and knee replacements, strategies to manage prosthetic joint infection (PJI) that are effective at infection control with good patient-reported outcomes and cost containment for health systems are needed. Interest in single-stage exchange for PJI is rising and we assess evidence from the last 5 years related to this treatment strategy.

RECENT FINDINGS

Only five series for total knee replacement and ten series for total hip replacement have been reported in the last five years. More review articles and opinion pieces have been written. Reinfection rates in these recent studies range from 0 to 65%, but a meta-analysis and systematic review of all studies showed a reinfection rate of 7.6% (95% CI 3.4-13.1) and 8.8% (95% CI 7.2-10.6) for single-stage and two-stage revisions respectively. There is emerging evidence to support single-stage revision in the setting of significant bony deficiency and atypical PJIs such as fungal infections. Prospective randomised studies are recruiting and are necessary to guide the direction of single-stage revision selection criteria. The onus of surgical excellence in mechanical removal of implants, necrotic tissue, and biofilms lies with the arthroplasty surgeon and must remain the cornerstone of treatment. Single-stage revision may be considered the first-line treatment for all PJIs unless the organism is unknown, the patient is systemically septic, or there is a poor tissue envelope.

Clinical Outcome of Massive Endoprostheses Used for Managing Periprosthetic Joint Infections of the Hip and Knee

BACKGROUND

Endoprosthetic replacement (EPR) is an option for management of massive bone loss resulting from infection around failed lower limb implants. The aim of this study is to determine the mid-term outcome of EPRs performed in the treatment of periprosthetic joint infection (PJI) and infected failed osteosyntheses around the hip and knee joint and identify factors that influence it.

METHODS

We retrospectively reviewed all hip and knee EPRs performed between 2007 and 2014 for the management of chronic infection following complex arthroplasty or fracture fixation. Data recorded included indication for EPR, number of previous surgeries, comorbidities, and organism identified. Outcome measures included PJI eradication rate, complications, implant survival, mortality, and functional outcome (Oxford Hip or Knee Score).

RESULTS

Sixty-nine EPRs (29 knees and 40 hips) were performed with a mean age of 68 years (43-92). Polymicrobial growth was detected in 36% of cases, followed by coagulase-negative staphylococci (28%) and Staphylococcus aureus (10%). Recurrence of infection occurred in 19 patients (28%): 5 were treated with irrigation and debridement, 5 with revision, 1 with above-knee amputation, and 8 remain on long-term antibiotics. PJI eradication was achieved in 50 patients (72%); the chance of PJI eradication was greater in hips (83%) than in knees (59%) (P = .038). The 5-year implant survivorship was 81% (95% confidence interval 74-88). The mean Oxford Hip Score and Oxford Knee Score were 22 (4-39) and 21 (6-43), respectively.

CONCLUSION

This study supports the use of EPRs for eradication of PJI in complex, multiply revised cases. We describe PJI eradication rate of 72% with acceptable functional outcome.

Is Single-stage Revision Safe Following Infected Total Knee Arthroplasty? A Critical Review

With the improvement in outcomes and modern prosthesis design, total knee arthroplasty (TKA) has now become a commonly performed surgery. It is postulated that a total of 2-5% of the primary and revision TKA becomes infected every year, requiring a revision procedure which to date is the conventional two-stage revision. The diagnosis and treatment of these periprosthetic infections is a major and challenging task, as it requires precise identification of the pathogen, meticulous debridement, and postoperative rehabilitation. To date, there have been very few studies in existing literature comparing the outcomes of single-stage versus two-stage procedure in infected TKA. The aim of the review was to provide the clinicians an insight into the outcome of the single-stage procedure compared to two-stage procedures and to suggest ways to improve the results further. In the following critical review, a total of 669 cases that underwent either a single or two-stage revision for infected TKA were studied. The postoperative functional scores were comparable in most studies during the early postoperative period. Our data supports the use of a single-stage revision surgery in infected TKA as an alternative to a conventional two-stage procedure. However, larger prospective and multicentric trials are required to validate our findings.

3D printed liner for treatment of periprosthetic joint infections

In the United States, long standing deep infections of joint arthroplasty, such as total knee and total hip replacements, are treated with two-stage exchange. This requires the removal of the prior implant, placement of an antibiotic eluting spacer block made of polymethylmethacrylate (PMMA), followed by re-implantation of a new implant after treatment with intravenous antibiotics for six to eight weeks. Unfortunately, the use of PMMA as a spacer material has limitations in terms of mechanical and drug-eluting properties. PMMA is brittle and elutes most of the antibiotics within the first few days. Furthermore, the polymerization reaction for PMMA is highly exothermic, thereby limiting the use to heat-stable antibiotics. We hypothesize that the use of a 3D printed polymeric liner made of polylactic acid (PLA) would overcome the limitations of PMMA because it is a stronger and a less brittle material than PMMA. Furthermore, the liner can also act as a controlled drug delivery vehicle by using built in reservoirs and a network of micro-channels as well as by incorporating antibiotics directly into the polymer during manufacturing stage. Finally, the liner can be 3D printed according to the anatomy of the patient and thereby has the potential to transform the manner in which periprosthetic joint infections are currently treated.

Analysis of causative microorganism in 248 primary hip arthroplasties revised for infection: a study using the NJR dataset

INTRODUCTION

This study aimed to describe the epidemiology of the causative organism in a series of primary hip arthroplasties revised for a diagnosis of periprosthetic joint infection (PJI) in England and Wales.

METHODS

Patient data from the National Joint Registry (NJR) was linked to microbiology data held by Public Health England (PHE) which identified a series of 248 primary hip arthroplasties revised for PJI between 2003 and 2014. Definitive cultures, isolated at time of revision surgery, were available for all cases. Total hip arthroplasty (n = 239, 96%) and hip resurfacing (n = 5, 2%) were the most commonly performed primary procedures. A two-stage revision was the most common operative management (n = 174, 70%).

RESULTS

202 (81%) cases were infected with a single genus microorganism and the most commonly implicated genus was Staphylococcus species (70% of all single genus infections). Staphylococcus species were also the most commonly identified microorganism in mixed genus infections (74% of patient's cultures). There was a significant difference in microorganism distribution when comparing uncemented vs cement implant fixation, with a higher incidence of Gram-negative infection observed in the uncemented group (p = 0.048, Chi-square).

CONCLUSIONS

Both prophylactic and therapeutic antibiotic regimes should be focused on targeting Staphylococci.

Two-stage Revision for Periprosthetic Hip and Knee Joint Infections

Background:

Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following hip and knee surgery. The diagnostic workflow of PJI includes detailed clinical examination, serum markers, imaging and aspiration/biopsy of the affected joint. The goals of treatment are eradication of the infection, alleviation of pain, and restoration of joint function. Surgical management of PJI consists of debridement, antibiotics and implant retention (DAIR) and single or two-stage revision procedures. Two-stage revision remains the gold standard for treatment of PJIs. We aim to discuss the two stage procedure in this article and report the outcomes.

Methods:

The first stage of the two stages consists of removal of all components and associated cement with aggressive debridement and placement of an antibiotic-loaded cement spacer. Patients are then treated with variable periods of parenteral antibiotics, followed by an antibiotic free period to help ensure the infection has been eradicated. If the clinical evaluation and serum inflammatory markers suggest infection control, then the second stage can be undertaken and this involves removal of the cement spacer, repeat debridement, and placement of a new prosthesis.

Results:

Common themes around the two-stage revision procedure include timing of the second stage, antibiotics used in the interim period, length of the interim period before consideration of reimplantation and close liaising with microbiologists.

Conclusion:

Successful eradication of infection and good functional outcome using the two stage procedure is dependent on a multidisciplinary approach and having a standard reproducible startegy.

Infection recurrence factors in one- and two-stage total knee prosthesis exchanges

PURPOSE

Revision of infected total knee replacements (TKR) is usually delayed for a period in which the joint space is filled with an antibiotic-loaded acrylic spacer. In contrast, one-stage re-implantation supposes immediate re-implantation. Formal comparisons between the two methods are scarce. A retrospective multi-centre study was conducted to investigate the effects of surgery type (one-stage vs. two-stage) on cure rates. It was hypothesised that this parameter would not influence the results.

METHOD

All infected TKR, treated consecutively between 2005 and 2010 by senior surgeons working in six referral hospitals, were included retrospectively. Two hundred and eighty-five patients, undergoing one-stage or two-stage TKR, with more than 2-year follow-up (clinical and radiological) were eligible for data collection and analysis. Of them, 108 underwent one-stage and 177 received two-stage TKR. Failure was defined as infection recurrence or persistence of the same or unknown pathogens. Factors linked with infection recurrence were analysed by uni- and multi-variate logistic regression with random intercept.

RESULTS

Factors associated with infection recurrence were fistulae (odds ratio (OR) 3.4 [1.2-10.2], p = 0.03), infection by gram-negative bacteria (OR 3.3 [1.0-10.6], p = 0.05), and two-stage surgery with static spacers (OR 4.4 [1.1-17.9], p = 0.04). Gender and type of surgery interacted (p = 0.05). In men (133 patients), type of surgery showed no significant linkage with infection recurrence. In women (152 patients), two-stage surgery with static spacers was associated independently with infection recurrence (OR 5.9 [1.5-23.6], p = 0.01). Among patients without infection recurrence, International Knee Society scores were similar between those undergoing one-stage or two-stage exchanges.

CONCLUSION

Two-stage procedures offered less benefit to female patients. It suggests that one-stage procedures are preferable, because they offer greater comfort without increasing the risk of recurrence. Routine one-stage procedures may be a reasonable option in the treatment of infected TKR.

LEVEL OF EVIDENCE

III.

One-stage versus two-stage exchange arthroplasty for infected total knee arthroplasty: a systematic review

PURPOSE

Infection complicating total knee arthroplasty (TKA) has serious implications. Traditionally the debate on whether one- or two-stage exchange arthroplasty is the optimum management of infected TKA has favoured two-stage procedures; however, a paradigm shift in opinion is emerging. This study aimed to establish whether current evidence supports one-stage revision for managing infected TKA based on reinfection rates and functional outcomes post-surgery.

METHODS

MEDLINE/PubMed and CENTRAL databases were reviewed for studies that compared one- and two-stage exchange arthroplasty TKA in more than ten patients with a minimum 2-year follow-up.

RESULTS

From an initial sample of 796, five cohort studies with a total of 231 patients (46 single-stage/185 two-stage; median patient age 66 years, range 61-71 years) met inclusion criteria. Overall, there were no significant differences in risk of reinfection following one- or two-stage exchange arthroplasty (OR -0.06, 95 % confidence interval -0.13, 0.01). Subgroup analysis revealed that in studies published since 2000, one-stage procedures have a significantly lower reinfection rate. One study investigated functional outcomes and reported that one-stage surgery was associated with superior functional outcomes. Scarcity of data, inconsistent study designs, surgical technique and antibiotic regime disparities limit recommendations that can be made.

CONCLUSION

Recent studies suggest one-stage exchange arthroplasty may provide superior outcomes, including lower reinfection rates and superior function, in select patients. Clinically, for some patients, one-stage exchange arthroplasty may represent optimum treatment; however, patient selection criteria and key components of surgical and post-operative anti-microbial management remain to be defined.

LEVEL OF EVIDENCE

III.

Microorganisms responsible for periprosthetic knee infections in England and Wales

PURPOSE

This study aimed to delineate epidemiology of infecting microorganism genus in first-time revision knee arthroplasty for indication of periprosthetic joint infection in England and Wales using linked registry data.

METHODS

From the National Joint Registry database for England and Wales, a consecutive series of primary knee arthroplasties performed between April 2003 and January 2014 that went on to have a revision for periprosthetic infection were identified (n = 2810). Each case was then linked to microbiology data held by Public Health England in order to identify infecting microorganism at time of revision surgery established from intra-operative cultures. Following data linkage, 403 culture results at time of revision surgery were identified in a group of 331 patients. The demographic characteristics of five microorganism groups were compared: pure staphylococcus (single genus), pure streptococcus (single genus), other gram-positive infections (single genus), gram-negative infections (single genus) and mixed genus infections.

RESULTS

Staphylococcus species was the most common organism genus isolated after revision of a primary implant for infection and present in 72 % of cases overall (71.3 % of patients with a single-genus infection and 76.8 % of patients with mixed genus infection). A pure staphylococcal infection was present in 59 % of all cases. A single-genus infection was responsible for infection in 83.1 % of cases, and mixed genera were responsible in 16.9 % of cases. A significant difference was observed for mean age at primary procedure in the cohort of patients where there was an isolated pure streptococcal infection (73.2 years) when compared to gram-negative infections (65.0 years). No other significant differences were observed between microorganism groups in terms of BMI, gender, ASA grade, indication for primary procedure and primary implant characteristics.

CONCLUSION

Staphylococci were the most commonly isolated organism species responsible for periprosthetic infection of primary arthroplasty in England and Wales. This information can be used by surgeons to benchmark and audit their own practice against national, publicly available data. Furthermore, this study has shown that even when using the largest national databases available, there is a substantial volume of missing data. Antimicrobial resistance represents a growing clinical problem with significant health and social costs. In order to counteract this threat, this study would advocate the consolidation of national microbial data in order to guide effective strategies towards targeting and combating the threat of antimicrobial resistance.

LEVEL OF EVIDENCE

IV.

Does pre-operative sampling predict intra-operative cultures and antibiotic sensitivities in knee replacements revised for infection?: a study using the NJR dataset

PURPOSE

This study examined a cohort of primary knee arthroplasties revised for peri-prosthetic infection to (1) determine whether the microorganisms isolated by sampling (up to 6 months pre-operatively) are representative of the microorganisms encountered at the time of knee revision, (2) determine whether the antibiotic sensitivity profiles of matching organisms correlate and (3) determine whether the proportion of organism and antibiotic sensitivity matches is influenced by the type of infection, timing of sample collection and the type of microorganism isolated.

METHODS

From the National Joint Registry database for England and Wales, a consecutive series of primary knee arthroplasties performed between 2003 and 2014 that went on to have a revision for peri-prosthetic infection were identified. Each case was then linked to a national microbiology database held by Public Health England. Following data linkage, intra-operative and pre-operative cultures were identified and compared in a group of 75 patients.

RESULTS

Pre-operative genus matched intra-operative genus in 56 of 75 cases (75 %). Of those 56, the corresponding antimicrobial sensitivities matched in 37 (66 % of cases). Overall, 37 of 75 cases (49 %) matched for both microorganism and antimicrobial sensitivity. The proportion of matches was highest in the pure Staphylococcal genus infections (genus match 88 %, sensitivity match 62 %, genus and sensitivity match 55 %) and lowest in those patients with mixed organism infections (genus match 29 %, sensitivity match 14 %).

CONCLUSION

Pre-operative joint sampling obtained by either aspiration or tissue biopsy is advocated in cases where peri-prosthetic infection is suspected and provides the only means of determining infecting organism prior to revision. Overall, only half of all pre-operative cultures matched completely the findings of intra-operative samples in terms of both the microorganism(s) encountered and their corresponding antimicrobial sensitivity profile. Clinicians should be vigilant regarding the possibility of the patient acquiring further microorganisms or the development of new antibiotic resistance by the time of revision, especially in historic pre-operative cultures. Broad spectrum antibiotic therapies should therefore be employed until final microorganisms and antimicrobial sensitivities are confirmed from intra-operative samples.

LEVEL OF EVIDENCE

IV.

Risk of Reinfection After Treatment of Infected Total Knee Arthroplasty

BACKGROUND

The purpose of this study was to determine the incidence of subsequent reinfections after initial treatment of an infected total knee arthroplasty, identify risk factors leading to reinfection, and compare results among the varying treatment modalities.

METHODS

A total of 1,493,924 primary TKA patients were identified from the Medicare data between October 1, 2005, and December 31, 2011. Patients who encountered periprosthetic joint infection (PJI) after TKA were identified using International Classification of Diseases, Ninth Revision, Clinical Modification code 996.66. The risk of subsequent PJI was stratified based on the first-line treatment and compared between the various first-line treatment groups.

RESULTS

A total of 16,622 patients (1.1%) were diagnosed with PJI. The Kaplan-Meier risk of PJI was 0.77% at 1 year and 1.58% at 6 years. Age (P < .001), Charlson score (P < .001), hospital control (P < .001), race (P = .036), census region (P = .031), gender (P < .001) were identified as risk factors for PJI. Of the PJI patients, 20.8% (n = 2806) were treated with incision and drainage (I&D), 15.9% (n = 2150) treated with I&D and liner exchange, 22.7% (n = 3069) treated with 1-stage revision, 39.7% (n = 5364) treated with 2-stage revision, and 0.98% (n = 132) treated with amputation. After first-line treatment, 26% of patients with PJI had a subsequent PJI. Patients undergoing I&D as a first-line treatment had the highest risk of reinfection, with risks of 28.2% at 1 year and 43.2% at 6 years. One-stage revision patients had 33.9% greater adjusted risk of reinfection than 2-stage revision patients (P < .001).

CONCLUSION

Two-stage reimplantation, despite 19% recurrence, had the highest success rate. Given the higher failure rates of I&D and single-stage revisions, guidelines need to be established for their specific indications.

Temporary arthrodesis using fixator rods in two-stage revision of septic knee prothesis with severe bone and tissue defects

PURPOSE

The present study describes a new temporary arthrodesis procedure, which aims for septic knee prosthesis replacement, in particular for larger bone and soft tissue defects. Our technique offers high stability and full weight-bearing capacity of the knee joint.

METHODS

The study included 16 patients with major bone defects (AORI type IIb or greater) after receiving a radical debridement and a septic two-stage revision total knee arthroplasty. After removing the infected prosthesis and debridement, two AO fixator rods were positioned into the intramedullary space of the femur and tibia. Subsequently, both rods were joined tube-to-tube and adjusted in the center of the knee joint. Finally, the whole cavity of the knee joint was filled with PMMA. The number of previous surgeries, bacterial spectrum, risk factors for further infection and reinfection rates was recorded. Immediately after the temporary arthrodesis, radiographs of the knee with the enclosed spacers were taken in order to compare to previous radiographs and avoiding to miss possible spacer loosening.

RESULTS

Nine of sixteen patients underwent more than two revision surgeries before receiving our new arthrodesis technique. No cases of spacer loosening were observed in all 16 patients; further, there were no peri-implant fractures, and four persistent infections were noted.

CONCLUSIONS

Temporary arthrodesis using AO fixator rods offers a high stability without loosening. Its potential to replace conventional augmentation techniques should be taken into account, particularly in the case of larger bone and tissue defects. In clinical practice, the cemented spacer using AO fixator rods could be an alternative technique for temporary knee arthrodesis after septic debridement.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Single Stage Knee Arthroplasty Revision Surgery: A Systematic Review of the Literature

Total Knee Arthroplasty is an increasingly common procedure and revision surgery, particularly for infection, is associated with significant morbidity and healthcare costs. The current gold standard is a two stage revision procedure but single stage revision is increasingly being used in some departments to improve patient outcomes. We conducted a systematic review of the literature to determine the up-to-date evidence underlying the use of a single stage knee approach in revision surgery. A total of 12 studies were included in this review amounting to 433 revision surgeries. This is the largest review of single stage knee revision surgery. The procedures described were heterogenous and included the 'two-in-one' technique as well as other single stage revision procedures. There were also differences in implants and antibiotic regimens. The mean re-infection rates described in 10 studies was 9.4% (range 0-19.2%) after a mean follow-up of 40.3 months (range 7-180 months). The re-infection rates in the studies published over the last 30 years are falling, and this is not accounted for by any significant change in duration of follow-up during this period. The outcome scores varied, but patients generally showed an improvement. The Knee Society Score and the Oxford Knee Score were the most commonly used in five and three studies respectively. We conclude that the current evidence for single stage revision is variable and there is a lack of good quality evidence to address whether single stage revisions is thorough enough to eradicate deep infection and is able to restore adequate function. There is a need for larger prospective studies with standardised procedures and protocol, and with adequate follow-up. Till then, patients considered for a single stage approach should be thoroughly assessed and the surgery should be performed by a senior surgeon with experience in single stage knee revisions.

Unsatisfactory outcome of arthrodesis performed after septic failure of revision total knee arthroplasty

BACKGROUND

Periprosthetic infection is one of the most dreaded orthopaedic complications. Current treatment procedures include one-stage or two-stage revision total knee arthroplasty. If the periprosthetic infection is no longer controllable after several revision total knee arthroplasties, many surgeons regard knee arthrodesis as a promising option. The aim of our study was to ascertain whether intramedullary nailing results in the suppression or eradication of an infection and to identify risk factors for persistent infection.

METHODS

All patients who had undergone intramedullary nailing following septic failure of revision total knee arthroplasty between 1997 and 2013 were included in the study. Pathogens, risk factors predisposing to persistent infection, and the rate of persistent infections were recorded. In addition, a visual analog scale (VAS) and Knee injury Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS), Lysholm, Short Form-36 (SF-36), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaires were completed to assess clinical outcomes and quality of life.

RESULTS

Twenty-six patients were included in the study. Thirteen (50%) had a persistent infection requiring additional revision surgery. Nineteen patients (73%) reported persistent pain (VAS score of >3). All scores showed marked impairment of quality of life.

CONCLUSIONS

Intramedullary nailing following septic failure of revision total knee arthroplasty must be regarded with skepticism, and we cannot recommend it. Repeat revision total knee arthroplasty or amputation should be considered as an alternative in such difficult cases.

Arthrodesis should be strongly considered after failed two-stage reimplantation TKA

BACKGROUND

A two-stage reimplantation procedure is a well-accepted procedure for management of first-time infected total knee arthroplasty (TKA). However, there is a lack of consensus on the treatment of subsequent reinfections.

QUESTIONS/PURPOSES

The purpose of this study was to perform a decision analysis to determine the treatment method likely to yield the highest quality of life for a patient after a failed two-stage reimplantation.

METHODS

We performed a systematic review to estimate the expected success rates of a two-stage reimplantation procedure, chronic suppression, arthrodesis, and amputation for treatment of infected TKA. To determine utility values of the various possible health states that could arise after two-stage revision, we used previously published values and methods to determine the utility and disutility tolls for each treatment option and performed a decision tree analysis using the TreeAgePro 2012 software suite (Williamstown, MA, USA). These values were subsequently varied to perform sensitivity analyses, determining thresholds at which different treatment options prevailed.

RESULTS

Overall, the composite success rate for two-stage reimplantation was 79.1% (range, 33.3%-100%). The utility (successful outcome) and disutility toll (cost for treatment) for two-stage reimplantation were determined to be 0.473 and 0.20, respectively; the toll for undergoing chronic suppression was set at 0.05; the utility for arthrodesis was 0.740 and for amputation 0.423. We set the utilities for subsequent two-stage revision and other surgical procedures by subtracting the disutility toll from the utility each time another procedure was performed. The two-way sensitivity analysis varied the utility status after an additional two-stage reimplantation (0.47-0.99) and chance of a successful two-stage reimplantation (45%-95%). The model was then extended to a three-way sensitivity analysis twice: once by setting the variable arthrodesis utility at a value of 0.47 and once more by setting utility of two-stage reimplantation at 0.05 over the same range of values on both axes. Knee arthrodesis emerged as the treatment most likely to yield the highest expected utility (quality of life) after initially failing a two-stage revision. For a repeat two-stage revision to be favored, the utility of that second two-stage revision had to substantially exceed the published utility of primary TKA of 0.84 and the probability of achieving infection control had to exceed 90%.

CONCLUSIONS

Based on best available evidence, knee arthrodesis should be strongly considered as the treatment of choice for patients who have persistent infected TKA after a failed two-stage reimplantation procedure. We recognize that particular circumstances such as severe bone loss can preclude or limit the applicability of fusion as an option and that individual clinical circumstances must always dictate the best treatment, but where arthrodesis is practical, our model supports it as the best approach.

Evidence-base for aspirin as venous thromboembolic prophylaxis following joint replacement

The National Institute for Health and Clinical Excellence (NICE) has thus far relied on historical data and predominantly industry-sponsored trials to provide evidence for venous thromboembolic (VTE) prophylaxis in joint replacement patients. We argue that the NICE guidelines may be reliant on assumptions that are in need of revision. Following the publication of large scale, independent observational studies showing little difference between low-molecular-weight heparins and aspirin, and recent changes to the guidance provided by other international bodies, should NICE reconsider their recommendations?

Cite this article: Bone Joint Res 2014;3:146–9.

Low-grade periprosthetic knee infection: diagnosis and management

Diagnosis and management of low-grade periprosthetic knee infection are still controversial and debatable. The diagnosis of low-grade infection after total knee arthroplasty is often complex, as clinical symptomatology and diagnostic studies are highly conflicting and knees often exhibit well-fixed components. Although the criterion standard for staged reimplantation is interim placement of an antibiotic-loaded spacer, less-invasive surgical procedures have been advocated for managing infections caused by low-virulence bacteria. Debridement with polyethylene exchange and single-stage reimplantation could offer advantages, such as fewer surgeries, reduced potential for intraoperative complications, and lower direct social costs. The aim of this narrative review was to analyze the literature to evaluate the effectiveness of different surgical procedures in managing low-grade periprosthetic knee infections. Additionally, the most reliable investigations for diagnosing total knee infection caused by low-virulence bacteria were reviewed.

Level of evidence Level V.

A systematic review of the evidence for single stage and two stage revision of infected knee replacement

BACKGROUND

Periprosthetic infection about the knee is a devastating complication that may affect between 1% and 5% of knee replacement. With over 79 000 knee replacements being implanted each year in the UK, periprosthetic infection (PJI) is set to become an important burden of disease and cost to the healthcare economy. One of the important controversies in treatment of PJI is whether a single stage revision operation is superior to a two-stage procedure. This study sought to systematically evaluate the published evidence to determine which technique had lowest reinfection rates.

METHODS

A systematic review of the literature was undertaken using the MEDLINE and EMBASE databases with the aim to identify existing studies that present the outcomes of each surgical technique. Reinfection rate was the primary outcome measure. Studies of specific subsets of patients such as resistant organisms were excluded.

RESULTS

63 studies were identified that met the inclusion criteria. The majority of which (58) were reports of two-stage revision. Reinfection rated varied between 0% and 41% in two-stage studies, and 0% and 11% in single stage studies. No clinical trials were identified and the majority of studies were observational studies.

CONCLUSIONS

Evidence for both one-stage and two-stage revision is largely of low quality. The evidence basis for two-stage revision is significantly larger, and further work into direct comparison between the two techniques should be undertaken as a priority.

Articulating antibiotic impregnated spacers in two-stage revision of infected total knee arthroplasty

Antibiotic impregnated articulating spacers are used in two-stage revision total knee arthroplasty to deliver local antibiotic therapy while preserving function. We have observed infection control in greater than 95% of cases with functional outcomes approaching those seen in revision for aseptic loosening. Higher failure has been observed with methicillin resistant organisms.

Titanium-tethered vancomycin prevents resistance to rifampicin in Staphylococcus aureus in vitro

Rifampicin is currently recognized as the most potent drug against Gram positive implant related infections. The use of rifampicin is limited by the emergence of bacterial resistance, which is often managed by coadministration of a second antibiotic. The purpose of this study was to determine the effectiveness of soluble rifampicin in combination with vancomycin tethered to titanium metal as a means to control bacterial growth and resistance in vitro. Bacterial growth was inhibited when the vancomycin-tethered titanium discs were treated with Staphylococcus aureus inocula of ≤2×10⁶ CFU, however inocula greater than 2×10⁶ CFU/disc adhered and survived. The combination of surface-tethered vancomycin with soluble rifampicin enhanced the inhibitory effect of rifampicin for an inoculum of 10⁶ CFU/cm² by one dilution (combination MIC of 0.008 mg/L versus 0.015 mg/L for rifampicin alone). Moreover, surface tethered vancomycin prevented the emergence of a rifampicin resistant population in an inoculum of 2×10⁸ CFU.