Infected Total Knee Replacement Research Articles

The Safety of Glycopeptide-Impregnated Calcium Sulphate Following Debridement, Antibiotics and Implant Retention (DAIR) for Infected Total Knee Replacement.

Background and objective The impact of prosthetic joint infection (PJI) stretches far beyond the physical nature of the disease. It can result in psychological and social consequences, with significant morbidity and mortality for patients. Calcium sulphate-based delivery agents are effective in the management of PJI, yet with associated risks of systemic adverse events. This study aims to evaluate the risk of systemic adverse events when using calcium-sulphate-based local antibiotic delivery agents in the management of PJIs. Methodology We identified 43 patients who underwent debridement, antibiotics and implant retention (DAIR) for infected total knee arthroplasty (TKA) between 2008 and 2014. Patients in the control groupunderwent conventional intravenous and then oral antibiotic administration, while those in the intervention groupunderwent additional local antibiotic therapy via a calcium sulphate alpha hemihydrate matrix. Case notes and laboratory results data were compiled to establish the safety and efficacy of local glycopeptide delivery. Results Serum vancomycin levels were within the safe therapeutic range for all patients in the intervention group with no difference in serum assays between treatment groups (intervention 7.7 mg/L; control 8.0 mg/L; P = 0.85). Renal function for the study cohort improved at every time point post-operatively when referenced against pre-operative renal function (P < 0.05). There was no difference in renal function between intervention and control groups on day 1, one week, six weeks or 12 weeks post-operatively (P = 0.78, 0.89, 0.20 and 0.50). Conclusions Local glycopeptide delivery via a calcium sulphate alpha hemihydrate matrix did not result in systemic adverse consequences specifically not raising the systemic level of glycopeptide, nor reducing renal function. Implications for future research Although demonstrates a safety profile and potential therapeutic benefit, the long-term efficacy of this approach needs to be established. Importantly, selection bias may contribute to masking clinically significant differences in post-operative outcomes.

Circular external fixation for knee fusion in complex indications.

Reconstructive surgery for complex knee problems is limited and challenging. The aim of this study is to report the technique, outcomes and complications of circular external fixation for knee fusion in complex indications. Retrospective review of a prospectively collected database of a complex limb reconstruction unit was done during December 2022. Patients with complex knee problems who underwent knee fusion with circular external fixator were included. Fourteen patients met the inclusion criteria. The mean age of the patients was 63 ± 16.8years. Deep infection was the indication for surgery in 11 patients (78.5%), of which 10 cases were related to previously failed revision arthroplasty. The mean duration of treatment in frame was 13 ± 4.1months, while the mean follow-up duration following frame removal was 7.1 ± 4.2years. Fusion was achieved in 13 patients (92.9%). The most common complication was pin site infection (6; 42.9%), of which three (21.4%) required pin/wire revision. One (7.1%) patient had fracture at the fusion site following frame removal that was treated with reapplication of the frame. Knee fusion using circular external fixation is a reliable surgical option for complex knee problems especially in infected failed revision total knee replacements.

Osseointegration Following Transfemoral Amputation After Infected Total Knee Replacement: A Case Series of 10 Patients With a Mean Follow-up of 5 Years.

BackgroundManagement of total knee replacement (TKR) infection may sometimes prompt knee fusion (KF) or transfemoral amputation (TFA), both associated with low mobility and quality of life (QOL). Transcutaneous osseointegration for amputees provides superior mobility and QOL vs traditional socket prostheses but has not been studied for patients with a history of infected TKR. This study investigates the following hypothesis: Patients who have had TFA or KF following infected TKR achieve better mobility and QOL following transfemoral osseointegration.Material and methodsA retrospective evaluation of the prospectively maintained registry identified 10 patients who had prior infected TKR. The mobility assessments (patient daily prosthesis wear time, K-level, Timed Up and Go, 6-Minute Walk Test) and QOL surveys (Questionnaire for Persons with a Transfemoral Amputation Global, Mobility, and Problem scores) were compared preoperatively and after at least 2 years. Complications requiring an additional surgery were also evaluated.ResultsDaily wear hours, K-level, and 6-Minute Walk Test and Questionnaire for Persons with a Transfemoral Amputation Global and Problem scores significantly improved (P < .05). Through 1 year, 4 patients (40%) had additional surgeries. After several years, 7 patients (70%) had at least 1 additional surgery, and 5 (50%) had multiple, for an average of 1 debridement and 1.3 soft-tissue refashionings per patient. One patient died of newly diagnosed cancer 1 year after transcutaneous osseointegration for amputees.ConclusionTransfemoral osseointegration confers significantly better mobility and QOL vs KF or a TFA with traditional socket prostheses following infected TKR. Technique improvements to prevent subsequent surgeries may provide an increasingly streamlined experience.

Diagnosis and management of the infected total knee replacement: a practical surgical guide

PurposeProsthetic joint infection (PJI) after total knee arthroplasty (TKA) is a significant burden in health care. Diagnosis and proper management are challenging. A standardised procedure for the diagnostic workup and surgical management provides clear benefits in outcome.MethodsSeveral diagnostic protocols and definitions for PJI were established in recent years. Proper PJI diagnosis remains critical for success and for choosing the optimal treatment option. A distinct workup of diagnostic steps, the evaluation of the results in a multidisciplinary setup and the meticulous surgical management of the infection are the key factors of successful treatment.ResultsThe management of PJI after TKA consists of early revision with debridement and implant retention (DAIR) in early cases or staged revision in late infections beyond 30 days postoperative or after onset of acute symptoms. The revision is performed as a two-stage procedure with the use of a fixed or mobile antibiotic spacer, or in selected cases as a single-stage operation with the use of local and systemic antibiotic treatment.ConclusionsThis paper reflects the opinion of two revision surgeons who follow the same protocol for diagnosis and treatment of PJI after TKA, highlighting the key steps in diagnosis and management.Level of evidenceExpert’s opinion

Amputation as a Complication after Total Knee Replacement, is it a Real Concern to be Discussed?: A Systematic Review.

Total knee replacement (TKR) is a growing attractive treatment for a degenerative knee disease. However, there remain some certain devastating complications to be discussed with patients preoperatively, including limb amputation. This systematic review aimed to determine the rate of amputation following TKR. In this study, the literature was searched up to 2019. The papers were included in which knee amputation was reported following TKR. The primary search concluded the articles from EMBASE, SCOPUS, PubMed, Web of Science, MEDLINE, OvidSP, CINAHL, EBSCO, Web of Science™, and CENTRAL. After screening and excluding case reports, 40 papers were included in the present study. The present review showed that amputation is a real end result of knee replacements either in primary or revision knee arthroplasties, which needs to be discussed with patients for their decision-making. Prevalence of amputation in terms of failure or complications after TKR procedures was estimated between 0.1-10% in different studies , with 5.1% amputation rate in infected TKR and 0.025% amputation rate in primary TKR as a result of infection in our review. Deep infection was the main cause of amputation. Vascular complications and fractures associated with bone loss and compartment syndrome were other reasons for amputation.

Infected total knee replacement: How I do a one-stage revision

BackgroundAs part of a session on the infected knee replacement at the British Orthopaedic Association congress in Liverpool, 2019, this topic was delivered as a lecture. The content and ideas of the lecture have been expanded to produce this article. MethodsOne-stage revision total knee replacement is not a new concept but remains controversial. This article is not written to persuade any surgeon to undertake the procedure but to simply give a working framework for how one surgeon performs the operation. We will cover the philosophy underpinning the rationale for single-stage revision (not 2-in-1 revision) including extensile exposure, a defined debridement protocol, reconstruction and fixation, antibiotic delivery and exclusion criteria. ResultsNone. ConclusionThe techniques outlined in this article should give confidence that one-stage revision knee replacement is a viable option when working within a multi-disciplinary team structure.

High Rate of Fusion but High Complication Rate After Knee Arthrodesis for Infected Revision Total Knee Replacement.

Knee arthrodesis is a demanding technique regarding difficulties to achieve bone fusion, control of infection and its associated complications. The purpose of this study was to evaluate if knee arthrodesis should still be indicated after failed revision total knee replacement. This was a retrospective study of 45 patients. Age, gender, follow-up, pathogens, Charlson comorbidity index, time from primary arthroplasty to arthrodesis, number of previous procedures, surgical technique, functional capability assessed by the SF-12 score, limb-length discrepancy after arthrodesis, presence of radiographic knee fusion, and complications were recorded. The mean age at the time of operation was 72years. 29% of patients were men, 71% were women, and the mean follow-up was 8.5years. The average Charlson comorbidity index was 4.5. The most common microorganisms isolated were Staphylococcus epidermidis (29%), Staphylococcus aureus (22%), and Pseudomonas aeruginosa (15%). In 20% of patients, no microorganism was identified, and in 37% of patients the infection was polymicrobial. Time from primary total knee arthroplasty to arthrodesis was 55months, and patients underwent a mean of 3.9 previous surgeries. The surgical technique used was an intramedullary long nail in 95.5%. Functionally, 93.3% of patients walked with weight bearing. The SF-12 was higher after arthrodesis (p < 0.05). Mean limb length discrepancy was 2.4cm. Among the group treated with long intramedullary nailing, 91.1% obtained tibiofemoral fusion. Complications occurred in 37.6% of patients. Knee arthrodesis with a long intramedullary nail after failed infected revision total knee replacement has a high rate of fusion, but the complication rate is high.

Symptomatic Hypercalcaemia Following the Use of Dissolvable Antibiotic Beads in Infected Total Knee Arthroplasty

The gold standard treatment for periprosthetic joint infections is currently a 2-stage revision procedure with the use of antibiotic beads or cement spacer. We report the case of an elderly lady who had an infected total knee replacement and underwent a prosthesis retaining procedure with the use of antibiotic loaded calcium sulphate beads (stimulan in this case). Postoperatively, she became profoundly hypercalcaemic and lethargic. After other causes were excluded, she was taken for surgical washout of the knee joint. This led to prompt normalisation of serum calcium levels and resolution of her symptoms. We recommend the need for routine pre- and postoperative serial calcium measurements when using antibiotic impregnated calcium sulphate beads and that all doctors have an increased awareness of this risk.

Loading capacity of dynamic knee spacers: a comparison between hand-moulded and COPAL spacers

BackgroundThe two-stage revision protocol represents the current gold standard for treating infected total knee replacement implants. Allowing early mobility with weight-bearing between staged procedures will enable early restoration to knee function. So, the mechanical performance of knee spacers is a key issue. Commercially available moulds are often used as they are easy to prepare and produce smoother surfaces of the articulating parts. However, they are costly, and only for single use. A cost-effective alternative is the surgeon-made hand-moulded spacers. In this study, we wanted to determine how the hand-moulded spacers will compare biomechanically with the commercially available COPAL spacers.MethodsSeven cadaveric knees were implanted with knee spacers fabricated using COPAL knee moulds. The same surgeon implanted eight cadaveric knees with hand-moulded spacers. In the first test protocol, an axial load was applied at 200 mm/min till failure. In the second test protocol, the knees were cyclically loaded in five steps of 1000 cycles each from 30-400 N, 30-600 N, 30-800 N, 30-1000 N, 30-1200 N at 1.5 Hz.ResultsCOPAL knee spacers demonstrated a maximum load and mean stiffness of 5202 (± 486.9) N and 1098 (± 201.5) N/mm respectively. The hand-moulded knee spacers demonstrated a mean stiffness of 4509 (± 1092.6) N and 1008.7 (± 275.4) N/mm respectively. The maximum axial displacement was 1.19 ± 0.57 mm and 0.89 ± 0.30 mm for specimens implanted with COPAL knee spacers and hand-moulded spacers respectively. The differences between COPAL and hand-moulded knee spacers were not statistically different.ConclusionsOur study demonstrated that dynamic knee spacers may be able to withstand more than the touch-down load permitted in previous studies, and this may allow more weight-bearing during ambulation. Previous studies have demonstrated that hand-moulded knee spacers have similar advantages to commercially available dynamic spacers with respect to mobility, pain, bone loss, and reinfection rate. Given that ambulation with weight-bearing up to 1200 N is permitted during rehabilitation, it may be more cost-effective to fabricate hand-moulded spacers in revision total knee arthroplasty.

Abstract 128: Potential Virulence of MRSA and Enterococcus in Patients Undergoing Free Tissue Transfer for Chronic, Non-healing Lower Extremity Wounds

PURPOSE: Chronic wounds in the lower extremity (LE) often fail to heal, necessitating free tissue transfer (FTT) for limb salvage. Patients in whom microsurgical LE reconstruction is indicated are often highly comorbid and prone to infection. In LE free flap studies, Hashimoto et al.1 and Corten et al.2 reported common wound colonization with Staphylococcus and Enterococcus, findings similar to those within patients of our tertiary-care center. While larger studies have investigated the microsurgical significance of Staphylococcus, few, if any, have investigated Enterococcus. The purpose of this study was to investigate the potential virulence of bacterial colonization on microsurgical limb-salvage outcomes. METHODS: Between April 2011 and May 2018, 140 LE FTT procedures were performed by the corresponding author for reconstruction of chronic wounds. The average patient age was 54.2yrs, the average BMI 29, and 50.3% of patients had diabetes. An average of 2.65 wound-bed debridements were performed per patient prior to FTT. Deep, intra-operative qualitative tissue cultures were obtained. Average follow-up after FTT was 17 months. Using multivariate analysis we studied the implications of wound colonization with Methicillin-resistant Staphylococcus aureus (MRSA) or Enterococcus on microsurgical success and limb-status after closure was attempted via FTT. RESULTS: Overall microsurgical success and limb-salvage rates were 91.4% (128/140) and 85% (119/140), respectively. Flaps contaminated with Enterococcus at the time of surgery were at increased risk for failure (OR6.21, p=0.05). In addition, risk for flap infection was greater in patients with wounds contaminated with Enterococcus during preoperative debridement (OR4.3; 95%CI, 1.518–11.997; p=0.006). Major amputation risk was increased in patients with wounds previously contaminated with MRSA (OR9.08; 95%CI, 2.721–30.320; p=0.0003), patients with positive Enterococcus cultures at the time of surgery (OR6.4; 95%CI, 1.21–34.43; p=0.03), and patients who developed flap infection with Enterococcus (OR19.7; 95%CI, 1.9–199.5; p=0.01). CONCLUSION: FTT can salvage the limb that has otherwise failed all other attempts at wound closure, obviating the need for major amputation. However, the medical demographics of this patient population and technical complexity of FTT make microsurgical outcomes vulnerable to many factors. Thus, part of restoring limb function in these patients is optimizing patient condition by mitigating perioperative risk factors. The negative impact of colonization of chronic wounds with bacteria, including MRSA, has been described. However, studies placing primary focus on individual pathogens in this population are lacking. Our results indicate potential adverse outcomes associated with noninfectious MRSA and Enterococcus colonization of chronic leg wounds. With this information, microsurgeons could stratify patients by infectious etiology for risk of adverse events, potentially allowing for earlier, mitigating treatment in the preoperative course. CITATIONS 1. Hashimoto I, Abe Y, Morimoto A, Kashiwagi K, Goishi K, Nakanishi H. Limb salvage and vascular augmentation by microsurgical free flap transfer for treatment of neuropathic diabetic foot ulcers. J Med Investig. 2014. doi:10.2152/jmi.61.325 2. Corten K, Struelens B, Evans B, Graham E, Bourne RB, MacDonald SJ. Gastrocnemius flap reconstruction of soft-tissue defects following infected total knee replacement. Bone Jt J. 2013. doi:10.1302/0301-620X.95B9

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.

CHEMICAL DEBRIDEMENT USING ACETIC ACID DURING REVISION ARTHROPLASTY

A common step to revision surgery for infected total knee replacement (TKR) is a thorough debridement. Whilst surgical and mechanical debridement are established as the gold standard, we investigate a novel adjuvant chemical debridement using an Acetic Acid (AA) soak that seeks to create a hostile environment for organisms, further degradation of biofilm and death of the bacteria. We report the first orthopaedic in vivo series using AA soak as an intra-operative chemical debridement agent for treating infected TKR's. We also investigate the in vitro efficacy of AA against bacteria isolated from infected TKR's. A prospective single surgeon consecutive series of patients with infected TKR were treated according to a standard debridement protocol. Patients in the series received sequential debridement of surgical, mechanical and finally chemical debridement with a 10 minute 3% AA soak. In parallel, we isolated, cultured and identified bacteria from infected TKR's and assessed the in vitro efficacy of AA. Susceptibility testing was performed with AA solutions of different concentrations as well as with a control of a gentamicin sulphate disc. The effect of AA on the pH of tryptone soya was also monitored in an attempt to understand its potential mechanism of action. Physiological responses during the AA soak were unremarkable. Intraoperatively, there were no tachycardic or arrythmic responses, any increase in respiratory rate or changes in blood pressure. This was also the case when the tourniquet was released. In addition, during the post-operative period no increase in analgesic requirements or wound complications was noted. Wound and soft tissue healing was excellent and there have not been any early recurrent infections at mean of 18 months follow up. In vitro, zones of inhibition were formed on less than 40% of the organisms, demonstrating that AA was not directly bactericidal against the majority of the clinical isolates. However, when cultured in a bacterial suspension, AA completely inhibited the growth of the isolates at concentrations as low as 0.19%v/v. This study has shown that the use of 3% AA soak, as part of a debridement protocol, is safe. Whilst the exact mechanism of action of acetic acid is yet to be determined, we have demonstrated that concentrations as low as 0.19%v/v in solution in vitro is sufficient to completely inhibit bacterial growth from infected TKR's.

Two-stage revision surgery for infected total knee replacements: reasonable function and high success rate with the use of primary knee replacement implants as temporary spacers.

Two-stage revision surgery for infected total knee replacements remains the gold standard treatment. Articulating spacers are preferred to static spacers for improved functional outcome. Articulating spacers made of cement can be prone to fracture, may not be suitable for full weight bearing, create abrasion debris and necessitate second-stage revision surgery. An alternative is the use of primary knee replacement implants as temporary spacers. With this technique, implants are loosely cemented into place at time of revision, allow the patient reasonable mobility and an ability to fully weight bear and can obviate the need for second-stage surgery. A retrospective review of all patients undergoing revision for infection over two years was conducted. Patients were clinically assigned to single- or two-stage revision. Patients who had a temporary knee replacement, that is, a primary knee replacement used as an articulating spacer, were identified and contacted to complete an Oxford Knee Score. Time to second stage and recurrence was identified from the notes 23 patients received temporary knee replacements. Of these, one patient died, 13 proceeded to a second-stage revision and nine remain in situ. Median time to second-stage revision was 19weeks [range 11-27]. No patients had re-infection. Median follow-up for ongoing temporary knee replacements was 43weeks [range 24-90]. Four temporary implants had survived for longer than 1year. Median Oxford Knee Score was 26 [23-32] and satisfaction score was 8 out of 10 [8-8]. These early results show that knee replacement implants used as spacers provide a good alternative to cement-based articulating spacers with low re-infection rates. Their additional cost when compared with cement spacers is offset by the fact that many patients achieve adequate function and frail patients can avoid a revision procedure. Level of evidence Case series, Level IV.

Review of Clinical and Functional Outcome of Prosthetic Salvage for Infected Total Knee Replacement

We have retrospectively studied the infected total knee replacement cases treated by open irrigation and debridement from 1996 to 2006 at NHS Tayside hospitals. Case notes of 18 (17 patients) were reviewed and looked into factors such as criteria chosen for surgery, timing of debridement, organism cultured and antibiotic duration. A success rate of 94% was noted (only 1 case of failure). Failure of the procedure included those which were re-infected or underwent some other treatment after initial debridement. The clinical and functional outcome amongst the successful cases was noted to be good as evidenced by knee society scores. The median follow-up was 3 years. The commonest organism found was staphylococcus aureus (27%). The single case of failure was a 77 year old female with no significant co-morbidities and had mixed organisms in culture. No relation was found between success and failure with regard to age, sex, pre-operative diagnosis and co-morbidity. However, timing of surgery and the length of antibiotic administration were considered relevant to the success of this method. Despite the hesitant and not so encouraging results of some previous studies concerning prosthetic salvage by this method, we believe that this procedure has a role in immediate post-operative period in carefully chosen cases within 4 weeks of index surgery.

The DAIR (debridement, antibiotics and implant retention) procedure for infected total knee replacement - a literature review.

Prosthetic joint infection (PJI) is a devastating complication in total knee arthroplasty (TKA) and third most common cause of revision of TKA with significant morbidity and surgical challenges. Treatment options include non-operative measures with long term antibiotic suppression, debridement and implant retention (DAIR), one- or two-stage revision arthroplasty, arthrodesis and amputation. Implant retention without infection is ideal and DAIR has been reported to have variable success rates depending on patient factors, duration of infection, infecting micro-organisms, choice of procedure, single or multiple debridement procedures, arthroscopic or open, antibiotic choice and duration of antibiotic use. We present a thorough literature review of DAIR for infected TKA. The important factors contributing to failure are presence of sinus, immunocompromised patient, delay between onset of infection and debridement procedure, Staphylococcal infection in particular Meticillin Resistant Staphylococcal aureus, multiple debridement procedures, retention of exchangeable components and short antibiotic duration. In conclusion DAIR can be successful procedure to eradicate infection in TKA in selective patients with factors contributing to failure taken into account.

Can Teicoplanin Be an Effective Choice for Antibiotic-Impregnated Cement Spacer in Two-Stage Revision Total Knee Arthroplasty?

The main purpose of this study was to evaluate the clinical results of two-stage revision total knee arthroplasty using a teicoplanin-impregnated cement spacer for infected primary total knee replacements. Twenty-five patients operated between 2005 and 2012 were included in this study. At the clinical status analysis, rate of infection eradication was assessed, physical examination was performed, Knee Society Score (KSS) was noted, isolated microorganisms were recorded, and the radiographic evaluation was performed. The mean KSS improved from 40 (range, 25-69) preoperatively to 77 (range, 32-96) at the latest follow-up (p < 0.05). Methicillin-resistant Staphylococcus epidermidis was isolated in 9 of 25 patients as the most frequently isolated pathogen, and the other isolated pathogens were methicillin-susceptible S. epidermidis, methicillin-resistant Staphylococcus aureus, and methicillin-susceptible S. aureus. Infection was successfully eradicated in 24 of 25 patients. Two-stage revision of the infected primary knee replacement is a time-consuming but a reliable procedure with high rates of success. Teicoplanin was found to be an effective choice for antibiotic-impregnated cement spacer applied for the eradication of the infection.

Management of infected TKR (total knee replacement) and results of two stage surgery for infected TKR

Background: Total knee Replacement is one of the common surgery for knee Osteoarthritis. Infection after total knee replacement is uncommon but disastrous complication. Purpose: Main purpose of study is to determine functional results of two stage surgery in infected TKR, compare the results of two stage surgery with other modalities of treatment, risk factors for infections, role of laboratory and clinical markers for early diagnosis of infection in TKR. Methods: This is retrospective study of 40 patients who operated for infected TKR through two stage revision arthroplasty. Inclusion criteria: All patients operated for infected TKR by two stage revision arthroplasty. Exclusion criteria: · Less than 12 months follow up · Expired patients Results: The average age of patients was 62.1 years. With youngest patient were being 40 years old and the oldest being 82. Average BMI in our series was 27.07. It varied with a range from 19.9 to 38.67. 15 patients had diabetes mellitus (DM), 7 patients had hypertension and 1 patient had hypothyroidism. The average WOMAC score improved from 37.525 to 56.3 with a minimum pre op score of 30 and maximum of 45. The mean clinical knee society score (KSS score) improved from from 50.1 to 69.325. 97% of patients showed improvement in their preoperative pain. The mean range of movement improved from 53.75 to 90.375. Pre op minimum ROM was 30 and maximum was 100. The average extensor lag preoperatively was 6.65 degrees with a range of 0-15 degrees. Patients showed improvement with average extensor lag reducing to 2.75 degree, with range of 0-10 degrees. The failure rate of our study was 8% with persistent infection after treatment. Conclusion: ·

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

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. 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. 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. 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. III.

Patella tendon injuries secondary to cement spacers used at first-stage revision of infected total knee replacement.

We describe a series of three patients who sustained patella tendon injuries in infected total knee arthroplasties following the use of a static cement spacer at first-stage knee revision. The patella tendon injuries resulted in significant compromise to wound healing and knee stability requiring multiple surgeries. The mid-term function was poor with an Oxford score at 24 months ranging from 12 to 20. Based on our experience, we advise caution in the use of static cement spacer blocks. If they are to be used, we recommend that they should be keyed in the bone to prevent patella tendon injuries.

Preventing Deep Infection in Total Knee Replacement

BACKGROUND: The rate of infection following primary total knee replacement (TKR) ranges between 1 and 2%. The medical community has implemented many practices with the intention of preventing infection after TKR. QUESTION: What are the prevention measures to reduce infection risk after TKR? METHODS: A PubMed (MEDLINE) search and a Cochrane Library search were performed until 31 March 2014. Six hundred and fifty-seven articles were found but only 42 were finally analysed. The main criteria for selection were that the articles addressed the aforementioned question. RESULTS: Rheumatoid arthritis, diabetes mellitus, immunosuppression treatment, psoriasis, and previous infections in the knee are the risk factors most clearly related with TKR infection. Appropriate patient selection is fundamental. Staphylococcus Aureus is the most common organism in infected TKRs. Systematic preoperative screening by swab is very important. Prevention of MRSA-positive cases by means of nasal decontamination (mupirocin 3 days) is advisable. Preoperative antibiotic prophylaxis has shown to be an efficient method to lower infection rates. Appropriate surgeon´s preparation and clean air in the operating room (OR) also seem to be important. Many authors have used ORs equipped with laminar air flow (LAF) although some authors have recently found that the incidence of infection decreased after abandoning the LAF in ORs. Adequate skin preparation and dressings also appear to be very important. Prolonged operative time seems to correlate with increased infection rate after TKR. The correlation between antibiotic-loaded cement and the risk of infection is still controversial. CONCLUSIONS: Prevention measures could help diminish the infection rate in patients undergoing TKR but the efficacy of some preventive practices is still controversial.