The Role of Highly Selective Implant Retention in the Infected Hip Arthroplasty

Two-stage Partial Component Retention and Interim Cemented Liner for Infected Total Hip Arthroplasty: A Case Report

Introduction

There is interest in partial exchange for infected total hip arthroplasty, as an alternative to complete removal of components in a traditional two-stage revision. Partial exchange avoids the difficulty of removing a well-fixed component and its associated bone loss.

Case Report

We report a case of a 61-year-old male patient with an infected total hip arthroplasty, who underwent a two-stage partial exchange, with retention of the well-fixed femoral stem, and an interim cemented liner. He had excellent function and no infection recurrence at 4 years of follow-up.

Conclusion

Two-stage partial exchange with interim cemented liner could be an effective option for infected total hip arthroplasty.

Partial Two-Stage Exchange for Infected Total Hip Arthroplasty: A Treatment to Take into Account

INTRODUCTION

Two-stage revision is the gold standard for chronic periprosthetic joint infection (PJI). The removal of well-fixed implants, especially the femoral component, can be extremely difficult and additional osteotomies may be needed, which is time-consuming and results in bone stock loss. When the femoral stem is osseointegrated, there is no clear indication for the use of partial two-stage revision. The primary objective was to assess infection eradication after surgery.

METHODS

Retrospective study of specific case series. A total of eight patients with a chronic uncemented PJI, in the setting of complex revision surgeries, were treated with partial two-stage revision, which included selective retention of the well-fixed femoral component and complete acetabular removal. Stem retention was carried out regardless of the bacteria or associated comorbidities.

RESULTS

All patients were re-revision cases with at least two previous surgeries (range, 2-4). Complex revisions were performed in five cases (non-articulated spacer) and simple revisions in three cases (articulated spacer). The minimum follow-up time was 24 months (range, 24-132 months). The infection eradication rate at final follow-up was 100%.

CONCLUSION

Partial two-stage reconstruction is a promising technique for the treatment of chronic PJI in patients with a well-fixed stem and complex re-revision acetabular procedures. Further prospective studies and prolonged follow-ups are required to confirm our results.

Management of Periprosthetic Joint Infections After Hemiarthroplasty of the Hip: A Critical Analysis Review

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Periprosthetic joint infection (PJI) following hip hemiarthroplasty (HA) is a devastating complication, incurring immense health-care costs associated with its treatment and placing considerable burden on patients and their families. These patients often require multiple surgical procedures, extended hospitalization, and prolonged antimicrobial therapy.

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Notable risk factors include older age, higher American Society of Anesthesiologists (ASA) score, inadequate antibiotic prophylaxis, non-antibiotic-loaded cementation of the femoral implant, longer duration of the surgical procedure, and postoperative drainage and hematoma.

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Although the most frequent infecting organisms are gram-positive cocci such as Staphylococcus aureus, there is a higher proportion of patients with gram-negative and polymicrobial infections after hip HA compared with patients who underwent total hip arthroplasty.

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Several surgical strategies exist. Regardless of the preferred surgical treatment, successful management of these infections requires a comprehensive surgical debridement focused on eradicating the biofilm followed by appropriate antibiotic therapy.

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A multidisciplinary approach led by surgeons familiar with PJI treatment and infectious disease specialists is recommended for all cases of PJI after hip HA to increase the likelihood of treatment success.

A Decision Support Framework for Periprosthetic Joint Infection Treatment: A Cost-Effectiveness Analysis Using Two Modeling Approaches

Today, periprosthetic joint infection (PJI) is one of the leading indications for revision surgery and the most ominous complication in artificial joint patients. The current state of the art for treating PJI requires the development of methods for planning the costs at different scales to facilitate the selection of the best treatment methods. In this paper, we perform a cost-effectiveness assessment for strategies related to the treatment of PJI using a composite decision support modeling framework. Within the framework, two models are implemented: a detailed discrete-event probabilistic model based on the decision tree approach and a dynamic Markov model with generalized states. The application of the framework is demonstrated on the dataset which was provided by the Russian Scientific Research Institute of Traumatology and Orthopedics named after R.R. Vreden. The analyzed dataset contains 600 patient records divided into two groups (retrospective group, based on old records, and prospective group, based on real-time follow-up). The cost-effectiveness of treatment methods was compared based on associated costs and QALY units gained, with the mentioned two indicators calculated using two models independently from each other. As a result, two comparative rankings of cost-effectiveness of PJI treatment methods were presented based on the model output.

Classification and management options for prosthetic joint infection

Periprosthetic joint infection (PJI) is one of the major complications following arthroplasty implantation. Management of PJIs is a challenge for surgeons and various classification systems have been introduced, which consider variables such as onset of symptoms, pathogenesis and clinical manifestation. In an attempt to overcome the shortcomings which may limit their usefulness in borderline cases, a new classification system focusing on the topography of the infectious process has been proposed. This theory relies on the identification of the exact location of the bacterial colonization thus allowing to decide between a conservative or a more radical intervention irrespectively of the timing. The use of nuclear medicine device like radiolabelled white blood cells (WBC) scan could lead the path in identifying pathogenetic processes and their exact location thus guiding orthopaedic surgeons to the most appropriate diagnosis and treatment options. Currently management relies on debridement, antibiotics and implant retention (DAIR), which is traditionally performed at early stages, 1- or 2-stage revision arthroplasty which is commonly limited to chronic cases. Reports have demonstrated similar rates of infection recurrence following one and two-stage revisions, and the use of one-stage revision surgery is gaining popularity. More recently, satisfying results following partial implant retention during revision total arthroplasty for septic failures have been reported. In addition, in severe cases, definitive articulating antibiotic spacer, excision arthroplasty, arthrodesis or amputation can be performed.

Prognosis of unexpected positive intraoperative cultures in arthroplasty revision: A large multicenter cohort

BACKGROUND

The positive-intraoperative-cultures-type prosthetic joint infection (PIOC-PJI) is considered when surgical cultures yield microorganisms in presumed aseptic arthroplasty revisions. Herein we assess the risk factors for failure in the largest cohort of PIOC-PJI patients reported to date.

METHODS

A retrospective, observational, multicenter study was performed during 2007-2017. Surgeries leading to diagnose PIOC-PJI included only one-stage procedures with either complete or partial prosthesis revision. Failure was defined as recurrence caused by the same microorganism.

RESULTS

203 cases were included (age 72 years, 52% females). Coagulase-negative staphylococci (n = 125, 62%) was the main etiology, but some episodes were caused by virulent bacteria (n = 51, 25%). Prosthesis complete and partial revision was performed in 93 (46%) and 110 (54%) cases, respectively. After a median of 3.4 years, failure occurred in 17 episodes (8.4%, 95%CI 5.3-13.1). Partial revision was an independent predictor of failure (HR 3.63; 95%CI 1.03-12.8), adjusted for gram-negative bacilli (GNB) infection (HR 2.68; 95%CI 0.91-7.89) and chronic renal impairment (HR 2.40; 95%CI 0.90-6.44). Treatment with biofilm-active antibiotics (rifampin/fluoroquinolones) had a favorable impact on infections caused by staphylococci and GNB.

CONCLUSION

Overall prognosis of PIOC-PJI is good, but close follow-up is required in cases of partial revision and in infections caused by GNB.

Adherence to a reliable PJI diagnostic protocol minimizes unsuspected positive cultures rate

Background

The aim of the present study was to evaluate the incidence of unsuspected PJI when prosthetic revisions are thoroughly evaluated by PJI dedicated orthopedic surgeon before surgery. The hypothesis is that the incidence of unsuspected PJI is reduced by applying this protocol.

Methods

This is a historical cohort study carried out in one university hospital. The prosthetic revision assessment was carried out in January 2019. From that date on, all patients that were programmed for hip or knee revision (either by an orthopedic surgeon specialized or not in septic revisions) were scheduled for a preoperative visit with the same orthopedic surgeon specialized in septic revisions. The diagnostic algorithm applied was based on the Pro-Implant Foundation diagnostic criteria. Prior to the revision assessment, the indication for joint aspiration was done at the surgeons’ discretion (non-specialized in septic revisions) and the preoperative identification of PJI was also done by a hip or knee surgeon (not specialized in septic surgery).

Results

Based on the PIF criteria, there were 15 infections among the revisions in group 1 and 18 PJI in group 2 (p > 0.05). The most interesting finding was that there were 7 patients with unsuspected positive cultures in group 1. That represents 11% of all revisions. No patient in group 2 was found with unsuspected positive cultures (p < 0.001).

Conclusion

A thorough PJI diagnostic algorithm should be implemented before prosthetic revision to avoid unsuspected positive cultures.

Does the retention of osseointegrated prosthetic implants during the surgical management of chronic infections following reverse total shoulder arthroplasty (RTSA) influence functional outcomes without impacting the efficacy of the infection treatment?

INTRODUCTION

The gold standard (GS) for treating chronic infections following reverse total shoulder arthroplasty (RTSA) is a complete exchange of the prosthesis carried out in one or two stages. This surgical procedure, which may damage the bone stock, can result in poor functional outcomes due to intraoperative complications. The purpose of this study was to compare the GS to a surgical technique that retained osseointegrated implants: the partial one-stage exchange.

HYPOTHESIS

Partial one-stage exchange was effective in treating chronic infections after RTSA (no recurrent infection) and resulted in better functional outcomes than the GS.

MATERIALS AND METHODS

This retrospective single-center study included 18 patients with chronic infection after a primary RTSA. Two treatments were compared in a non-randomized fashion. The first included 11 patients who underwent a partial one-stage exchange with implant retention in case of macroscopic osseointegration. The second included seven patients who were treated with the GS: six patients with a complete one-stage exchange and one patient with a two-stage surgical approach. The absence of recurrent infection and functional outcomes were assessed after a minimum of two years.

RESULTS

There were no statistically significant differences in treatment efficacy between the two strategies: 91% vs. 100%, respectively. The partial one-stage exchange resulted in a significantly improved shoulder function compared to the GS with postoperative Constant scores of 55±14.58 vs. 44±14.45, respectively (p=.03). In the partial one-stage exchange group, there was a significantly improved shoulder function with a preoperative Constant score of 40 [28-55]±9.04 preoperatively vs. 55 [25-75]±14.58 postoperatively (p=.01). The GS treatment did not significantly improve the postoperative function (p=.09).

DISCUSSION

Partial one-stage exchange does not compromise treatment efficacy of chronic infections after RTSA. This technique resulted in better shoulder function than a conventional GS-type management. A study with greater statistical power is required.

LEVEL OF EVIDENCE

III; clinical series, retrospective, single-center.

Partial Single Stage Exchange Arthroplasty With Retention of a Well Fixed Cemented Femoral Stem for the Treatment of Culture Negative Infection in a Bipolar Hemiarthroplasty: A Case Report

Background:

Prosthetic joint infection (PJI) is the second most common cause for revision following hip hemiarthroplasty (HHA) resulting in a mortality rate of 5.6%. The treatment of PJI is both challenging and controversial, without general consensus on best practice. In an attempt to avoid surgery, patients are commonly prescribed antibiotics, reducing the chance of detecting a microorganism, and culture negative infections are reported to occur in up to 21% of all PJI. Two stage revision is arguably the gold standard treatment but frequently these patients are too frail to undergo such extensive procedures. Some surgeons have attempted to avoid this by leaving well fixed implants undisturbed, effectively performing a partial single-stage revision.

Case Presentation:

A previously well 83 -year-old female patient presented with a gradual onset of increasing pain and difficulty walking. Just over 1 year prior to this presentation she fell at home and underwent an uncomplicated bipolar hemiarthroplasty. Clinical examination as well as serological and radiological investigations were suspicious for a periprosthetic infection. Her rapidly deteriorating clinical picture required prompt surgical intervention. In theater the patient underwent a single stage partial exchange arthroplasty leaving the well cemented femoral stem undisturbed. Although multiple samples were taken, no microorganism was identified. The patient has been followed up for 1 year and remains well, with no recurrence of infection. Her inflammatory markers have returned to normal and radiographs demonstrate no evidence of loosening of the total hip replacement.

Conclusion:

The burden of infection following hip hemiarthroplasty is likely to parallel the predicted increase in hip fractures. The combination of physiologic frailty, osteoporosis and multiple medical comorbidities are pertinent factors for consideration in the development of a treatment strategy. A partial single stage revision THR performed by an experienced arthroplasty surgeon, along with expertly led antimicrobial therapy may be considered in carefully selected patients.

Selective Component Retainment in the Treatment of Chronic Periprosthetic Infection After Total Hip Arthroplasty: A Systematic Review

INTRODUCTION

Chronic infections after a total hip arthroplasty (THA) are a devastating complication and are usually treated by a complete revision of components. Selective revision, with preservation of well-fixed components, has been previously reported. We did a systematic review to report on success rates of selective revision in chronic infections after THA.

METHODS

PubMed, Web of Science, and the Cochrane Database were systematically searched for studies reporting on partial-retaining revision for chronically infected THA. These were reviewed to determine success rates based on component revised, as well as infectious organism.

RESULTS

Nine studies reported on 134 patients. The majority of the patients underwent femoral-retaining procedures (118), and the rest of the patients underwent acetabular-retaining procedures (16). Average follow-up was 60.56 months, and the success rates were 80% for femoral revision, 90.43% for acetabular revision, and overall success rate was 89.41%.

DISCUSSION

In select patients, retainment of well-fixed components in chronically infected THA may be considered. Although reported success rates are high, and comparable with complete revision arthroplasty in cases of chronic infections, the quality of the studies included is poor. The studies lacked sufficient internal validity, sample size, methodological consistency, and standardization of protocols and outcomes.

LEVEL OF EVIDENCE

Systematic review of level IV studies.

Dual Surgical Setup May Improve Infection Control Rate of Debridement and Implant Retention Procedures for Periprosthetic Infections of the Hip and Knee

BACKGROUND

Debridement, antibiotics, and implant retention (DAIR) is an appealing treatment option for periprosthetic joint infection (PJI) due to its low cost and low morbidity. There are many nonmodifiable risk factors for DAIR failure that have previously been established. A dual DAIR setup constitutes establishing a new, sterile field after the initial debridement. The purpose of this study is to determine whether the modifiable surgical technique of a dual setup improves the infection control rate following PJI.

METHODS

A retrospective study was conducted from January 1, 2000 to December 31, 2017 to identify patients who underwent a DAIR procedure as initial surgical treatment for PJI of the hip or knee. Patients were divided between 2 groups, failed and successful DAIR procedures. Failure was defined as infection recurrence requiring surgical intervention. Demographic (age, gender, body mass index, smoking status, American Society of Anesthesiologists status), preoperative comorbidity (hypertension, cardiac disease, diabetes status, depression or anxiety diagnosis, pulmonary disease), operating surgeon, single vs dual setup, hospital, use of long-term antibiotics postoperatively (greater than 6 weeks of intravenous antibiotics), joint, and laterality data were compared between cohorts using multivariate regression analysis.

RESULTS

Two hundred sixty-three patients were identified who underwent DAIR as the exclusive and initial treatment for PJI. Single vs dual setup, knee vs hip joint, cardiac or vascular disease diagnosis, major depressive disorder or generalized anxiety disorder diagnosis, and staphylococcal infections were found to be independent predictive variables for DAIR failure.

CONCLUSION

In our series, the dual setup DAIR was a modifiable surgical technique that significantly decreased the risk of infection recurrence compared to single setup DAIR.

Prevalence and Impact of Positive Intraoperative Cultures in Partial Hip or Knee Revision

BACKGROUND

Our aim is to investigate the impact of unexpected positive cultures on the outcome of partial prosthetic revisions.

METHODS

Data regarding patients who underwent a partial hip or knee revision from 2003 and 2012 with the preoperative diagnosis of aseptic loosening was retrospectively reviewed. The protocol of revision included at least 3 intraoperative cultures. Failure was defined as the need for re-revision due to aseptic or septic loosening at 5 years.

RESULTS

A total of 99 hip and 46 knee partial revisions were included. All cases had at least 5 years of follow-up. Ninety-seven cases (66.9%) had all cultures negative, 35 (24.1%) a single positive culture and 13 (9.0%) ≥2 positive cultures for the same microorganism. The median time from primary arthroplasty to partial revision was significantly shorter for patients with ≥2 positive cultures (26 months) than in those with all cultures negative (48 months) or with a single positive culture (51 months). Partial revisions performed within the first 5 years of implantation had a higher 5-year re-revision rate. The presence of a single positive culture during the partial exchange was not associated with a higher re-revision rate (2 of 35, 5.7%) than in those with negative cultures (3 of 97, 3.1%). On the contrary, re-revision rate was significantly higher in cases with ≥2 positive cultures (3 of 13, 23.1%) than in those with negative cultures (P = .02).

CONCLUSION

Partial revisions performed within the first 5 years from implantation and ≥2 intraoperative positive cultures were associated with a higher re-revision risk at 5 years.

Mid-term outcomes of a partial 2-stage approach in late chronic periprosthetic hip infections

INTRODUCTION

Late chronic periprosthetic infections (LCPIs) are worrisome complications of primary hip arthroplasties. The gold standard procedure is the 2-stage revision. 1-stage exchange is gaining popularity in order to reduce the invasivity of the former technique. A partial 2-stage exchange technique, retaining fixed components, may overcome some of the drawbacks of the previous techniques, allowing a much easier reconstruction step.

METHODS

28 patients with a LCPI after a primary total hip arthroplasty underwent a first removal stage: the loosened component was removed (23 cups and 5 stems) and the fixed component, with no local signs of infection, was retained. An antibiotic hand molded spacer was positioned in 16 cases. After a mean time of 8 months and a tailored antimicrobial therapy, the spacer was removed and the implant was revised.

RESULTS

The mean follow-up was 5 years. The HHS score was 82.7. 4 cases failed (2 patients presenting a septic relapse after revision and 2 patients undergoing Girdlestone arthroplasty), achieving a survival rate of 83.4% at 5 years. 2 patients were unwilling to perform a further procedure and did not proceed to the second stage. All the other patients had no clinical, radiological, laboratory signs of septic relapse.

CONCLUSIONS

The partial 2-stage approach seems a promising technique for LCPI in selected cases, with good infection control. It allows an easier revision by sparing the fixed components. Larger case series and longer follow-ups are needed to confirm the results and identify the limits of this approach.

Partial implant retention in two-stage exchange for chronic infected total hip arthroplasty

BACKGROUND

The efficacy of partial retention of well-fixed components during two-stage exchange for chronic total hip arthroplasty (THA) infection has remained unknown.

METHODS

A total of 14 patients with chronic infected THA were treated with damage control two-stage revision, including selective retention of the well-fixed femoral or acetabular component, aggressive debridement, antibiotic-laden cement spacer, antibiotic therapy, and delayed reimplantation. Indications for this treatment included chronic infected THAs with ingrown femoral or acetabular component and positive microbial growth with sensitive antibiotics. We excluded patients with acute infection; negative microbial growth; positive pathogen with high-virulence bacterial infections and multiple drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, fungi, and Mycobacterium tuberculosis; sinus formation; a prior failure for periprosthetic joint infection (PJI) treatment; and obvious bone resorption in both femoral and acetabulum side. During the study period, this represented 3.3% (14/425) of the patients treated for infected THA. Minimum follow-up was three  years. None of the 14 patients in this series were lost to follow-up. Successful treatment was defined according to a modified Delphi-based international multidisciplinary consensus.

RESULTS

No repeated debridement and recurrence of infection occurred during the study period; no patient need chronic antibiotic suppression. Successful treatment of chronic PJI was achieved in all patients. Despite the high peri-operative complication rate, no severe consequences were observed. The mean Harris Hip Score was 86 (range, 82-92; SD, 3.3).

CONCLUSIONS

The selective partial implant retention two-stage revision for chronic PJI may be a treatment option in properly selected patients with low virulence bugs.

Partial Component-Retained 2-Stage Reconstruction in the Treatment of Infected Hip Arthroplasty

BACKGROUND

It is considered the gold standard treatment for infected hip arthroplasty to remove and reimplant the corresponding whole set of implant components before and after infection control, but it usually causes substantial bone loss to remove the well-fixed cup or stem, which may increase the difficulty in reconstruction. We would like to determine whether infected hip arthroplasty can be treated without removal of a well-fixed cup or stem.

METHODS

Patients with infected hip arthroplasty and a radiographically well-fixed, cementless cup or stem were selected. During the first surgical stage, we retained the stem or cup if these cannot be removed using a stem or cup extractor. We performed the reimplantation surgery after control of infection.

RESULTS

From January 2008 to December 2016, 26 patients underwent partial component-retained 2-stage reconstruction. All the patients were free of infection with a mean follow-up time of 43.85 months.

CONCLUSION

Partial component-retained 2-stage reconstruction may be a treatment option for infected total hip arthroplasty with a well-fixed component in patients.

Twenty common errors in the diagnosis and treatment of periprosthetic joint infection

Background

Misconceptions and errors in the management of periprosthetic joint infection (PJI) can compromise the treatment success. The goal of this paper is to systematically describe twenty common mistakes in the diagnosis and management of PJI, to help surgeons avoid these pitfalls.

Materials and methods

Common diagnostic and treatment errors are described, analyzed and interpreted.

Results

Diagnostic errors include the use of serum inflammatory biomarkers (such as C-reactive protein) to rule out PJI, incomplete evaluation of joint aspirate, and suboptimal microbiological procedures (such as using swabs or collection of insufficient number of periprosthetic samples). Further errors are missing possible sources of distant infection in hematogenous PJI or overreliance on suboptimal diagnostic criteria which can hinder or delay the diagnosis of PJI or mislabel infections as aseptic failure. Insufficient surgical treatment or inadequate antibiotic treatment are further reasons for treatment failure and emergence of antimicrobial resistance. Finally, wrong surgical indication, both underdebridement and overdebridement or failure to individualize treatment can jeopardize surgical results.

Conclusion

Multidisciplinary teamwork with infectious disease specialists and microbiologists in collaboration with orthopedic surgeons have a synergistic effect on the management of PJI. An awareness of the possible pitfalls can improve diagnosis and treatment results.

Treatment of periprosthetic hip infection with retention of a well-fixed stem: six to 13-year outcomes

Background

Treatment of periprosthetic joint infection (PJI) is challenging, generally requiring complete implant removal. However, recently reported treatments involve partial retention of implants because of the severe local and systemic burden on the patients and difficulties in functional preservation. Long-term results should be evaluated because of the risk of residual biofilm on the retained implant and late infection recurrence. We evaluated 6 to 13-year clinical outcomes of two-stage treatment of chronic PJI retaining well-fixed cementless stems.

Methods

Among 36 surgeries for deep infection following hip arthroplasty performed from 2004 to 2011, six hips had a well-fixed and well-functioning cementless stem. These six hips were all chronic PJI and were treated without stem removal. The first-stage surgery involved acetabular cup removal and reconstruction by filling the acetabular defect with antibiotic-loaded acrylic cement, creating a socket-like hemispherical dent, and reducing the retained femoral head to this dent. After confirming infection eradication the second-stage acetabular reconstruction was performed. One patient died of an unrelated noninfective cause 1 year after the operation. Clinical outcomes of the remaining five patients were followed for 6 to 13 years.

Results

Between the two surgeries (range; 2–5 months), patients underwent active range-of-motion and ambulation exercises. No dislocation was found during the interval. No recurrence of infection was found and good functional outcomes and radiographic findings were observed during the average follow-up of 109 months in all five patients.

Conclusions

Two-stage treatment with retention of a well-fixed stem may minimize local and systemic burden of the patient and enhance functional preservation while obtaining long-term infection control. Although further study could establish the effectiveness and indications for this treatment option, currently used indications should be carefully evaluated considering factors including local and systemic conditions of the patient, implant fixation status, and type of bacteria.

Partial two-stage exchange at the site of periprosthetic hip joint infections

INTRODUCTION

In the past 10 years an increasing number of studies about partial two-stage exchange arthroplasty in the management of periprosthetic hip infections have been published. The aim of the present work was to systematically review the current knowledge about this procedure, and critically verify the success as well as the complications of this treatment option.

MATERIALS-METHODS

A literature search was performed through PubMed until June 2018. Search terms were "partial two stage hip" and "partial retention hip", and "retaining well fixed hip".

RESULTS

A total of 7 studies reporting on a total of 80 patients could be identified. All studies had a level of evidence IV. The great majority of the studies reported on the isolated removal of the acetabular cup and placement of an antibiotic-loaded cement spacer head onto the retained, well-fixed stem. Most of the periprosthetic infections were caused by staphylococci. The infection eradication rate varied between 81.3 and 100% at a mean follow-up between 19 and 70 months. Poor outcome was observed at the site of MRSA infections.

CONCLUSIONS

The partial two-stage exchange arthroplasty appears to be a possible option in the management of PJI when one prosthetic component is well-fixed so that their removal might result in significant bone loss and compromise of fixation at the time of the later prosthesis reimplantation, and the causative organisms are not multiresistant. The small numbers published about this protocol does not allow for a generalization of application and should be only applied in highly selected patients. Future studies with larger collectives and longer follow-ups are welcome to evaluate the clinical success of this option and its possible role in the management of PJI.

A new perspective on current prosthetic joint infection classifications: introducing topography as a key factor affecting treatment strategy

Periprosthetic joint infection (PJI) is a relatively frequent and devastating complication following prosthetic joint implantation. Several classification systems have been presented by various authors and are routinely used in clinical practice to help in early diagnosis and treatment. The most widely accepted classifications of periprosthetic infections rely on the timing of clinical presentation. Unfortunately, these schemes possess important shortcomings which limit their usefulness in clinical practice, as data reported in literature are contrasting, with success rate ranging from 60 to 80%, irrespectively of prosthetic infection timing. An attempt is made by us to update the current knowledge on PJIs by looking them from a different perspective, introducing a topographic principle in their classification. Our approach is based on the theory that identifying the exact location of the bacterial colonization may allow to decide whether to conservatively treat the patient or to perform a more radical intervention. The aim is to improve the understanding of the aetiology of this serious complication, lead to the appropriate treatment strategy according to the stage of the disease thus enhancing the outcomes of surgical management. Such a strategy, if widely accepted, could guide research studies on the management of PJIs. The availability of investigations like scintigraphy could aid in identifying pathogenetic processes and their exact location, which may be missed on conventional radiographs, and could enable orthopaedic surgeons to have a better understanding of PJI patterns.

Retention of the well-fixed implant in the single-stage exchange for chronic infected total hip arthroplasty: an average of five years of follow-up

PURPOSE

Removal of an infected prosthesis was considered the gold standard for eradication of infection. However, removal of well-fixed components can result in structural bone damage and compromised reconstruction. In these situations we questioned whether the infection after the total hip arthroplasty could be treated effectively and retain the well-fixed implant in a single-stage exchange.

METHODS

A retrospective analysis which included 31 patients with chronic infected THA who underwent major partial single-stage revision, including routinely exchanged femoral head and liner components, aggressive soft tissue debridement, removal of the femoral stem or acetabular cup and retention of the well-fixed component, thorough exposed component brushing, and adequate surgical soaking. Powdered Vancomycin was poured into the surgical area and the infection control rate and clinical outcomes were evaluated. The failure to treat the infection was defined as a recurrence of infection in the same hip. The average follow-up was five years (2-15 years).

RESULT

There were four (12.9 %) failures during the study period at an average of 15 months (9-21 months) after partial single-stage revision. Of the 31 patients, 27 (87.1 %) patients had a satisfactory outcome and required no additional surgical or medical treatment for recurrence of infection. Acetabular cups were revised in 22 patients and femoral stems in nine patients. The mean post-operative Harris hip score at the most recent assessment was 74.6 (68-82).

CONCLUSIONS

Treatment of chronic infected THA with retention of the well-fixed implant in a single-stage exchange can be fairly effective in the treatment of infection and achieving acceptable functional outcomes, which indicated that this may be an attractive alternative in highly selected patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study.