Background. Two-stage revision arthroplasty is the standard treatment for chronic hip and knee periprosthetic joint infections (PJI). Accurate diagnosis of persistent infections at 2nd stage using established biomarkers and diagnostic criteria is of paramount importance. This study aimed to evaluate the diagnostic value of synovial calprotectin and alpha-defensin, and compare established diagnostic criteria from the International Consensus Meeting (ICM 2018) and the European Bone and Joint Infection Society (EBJIS 2021) to determine persistent PJI at the 2nd stage of a two-stage revision arthroplasty. Methods. We retrospectively analyzed 97 patients who underwent 100 two-stage revisions (hip: 39, knee: 61). Synovial fluid samples were assessed for calprotectin and alpha-defensin levels. ICM 2018 and EBJIS 2021 were applied to all patients undergoing 2nd stage revision. Receiver operating characteristic (ROC) curves and Youden Index were utilized to determine optimal cut-off values, and correlations between biomarkers were evaluated. The microbiological spectrum was analyzed at 2nd stage and re-revision surgery. Results. Calprotectin levels showed a sensitivity of 66.7%, specificity of 32.9%, and accuracy of 38.0% in predicting septic failure. Alpha-defensin showed sensitivity of 28.6%, specificity of 87.8%, and accuracy of 79.2%. Significant correlations included: calprotectin with PMN% (r = 0.471, p = 0.05) and alpha-defensin with WBC (r = 0.830, p < 0.01) in the successful cohort. For septic re-revisions, calprotectin and alpha-defensin were highly correlated (r = 0.969, p < 0.01). ICM correctly diagnosed persistent PJI in 26.7%, while EBJIS diagnosed 24.2%. The microbial spectrum shifted from gram-positive to gram-negative bacteria between reimplantation and re-revision surgeries. Conclusion. Synovial calprotectin and alpha-defensin demonstrated limited accuracy in ruling out persistent PJI at reimplantation. The low sensitivity of current diagnostic criteria, combined with the observed shift in microbial spectrum, underscores the challenges in diagnosing persistent PJI during 2nd stage of a two-stage revisions arthroplasty

Aim. Periprosthetic joint infection (PJI) is a feared complication of total joint arthroplasty of hip (THA) or knee (TKA). Debridement, antibiotic treatment, and implant retention (DAIR) is an effective treatment of early PJI. In the Netherlands, cefazolin resistance in early PJI after primary arthroplasty is low. Little is known about causative micro-organisms and resistance patterns in PJI after revision arthroplasty. No recommendations for empirical treatment are described in the current guidelines. The aim of this study is to describe the characteristics of PJI after revision arthroplasty and to evaluate whether the used empirical treatment regimens are adequate, based on microbiology data. Method. In this retrospective study we included patients with early PJI after aseptic revision of THA or TKA, treated with DAIR between 2012 and 2020. Success rate was defined as implant retention and no persistent or recurrent infection during one year follow-up. Results. We identified 96 patients with PJI. PJI was most frequently caused by Staphylococcus spp. (n=73), Gram-negative bacilli (n=31) or Enterococcus spp. (n=13). Polymicrobial infection was diagnosed in 38 PJIs. Mismatches were present in 72 (75%) of the PJIs (95% CI: 0.66–0.84). Table 1 shows the number of mismatches per empirical treatment regimen. Figure 1 shows the responsible micro-organisms for the mismatches. Success rate of PJI treatment was significant reduced for patients with mismatching compared to matching empirical therapy: 62% vs. 95% respectively (OR: 0.09, 95% CI: 0.01–0.68, p=0.004). If vancomycin would have been the empirical treatment, mismatches would have been reduced to 31 (32%) (95% CI: 0.23–0.42). With vancomycin-ciprofloxacin combination therapy the mismatches would have been reduced to 1% (95% CI: −0.01–0.03). Conclusions. There is a high number of mismatches in empirical treatment in early PJI after revision arthroplasty, which have significant influence on the outcome. Based on our data cefazolin should not be recommended as empirical treatment for this specific group. Our data shows that review of local data is necessary to improve treatment strategies, that eventually might improve outcome. Besides changing Gram-positive coverage, a prospective study is needed to assess the benefits of broader spectrum empiric antimicrobial treatment taken into account toxicity and other side effects such as antimicrobial resistance. For any tables or figures, please contact the authors directly

Aim. Success rate of debridement, antimicrobial and implant retention (DAIR) in high suspicion of early PJI after primary arthroplasty is 70–80%. No studies have been performed focusing on outcome of DAIR after revision arthroplasty of the hip (THA) or knee (TKA). The aim of this study is to investigate the outcome of DAIR in suspected early PJI after revision THA or TKA and to identify risk factors for failure. Method. In this retrospective study, we identified early DAIRs after revision THA or TKA performed between January 2012 and August 2019. All patients received empirical antibiotics directly after the DAIR procedure. Antimicrobial treatment was adjusted to the tissue culture results. Success was defined as: 1) implant retention; 2) no repeated revision arthroplasty or supervised neglect after treatment; 3) no persistent or recurrent PJI after treatment and no administration of suppressive antimicrobial therapy; 4) survival of the patient. Infection free success was defined as: 1) no persistent or recurrent PJI after treatment; 2) no administration of suppressive antimicrobial therapy. Results. The overall success rate after one year of 100 cases with early DAIR after revision THA or TKA was 79% and infection free success rate was 85%. In PJI cases, empirical antimicrobial mismatch with causative micro-organisms was associated with lower success rate (70%) than non-mismatch (95%) (p=0.02). No patients from the non-PJI group failed after one year versus 13 failures within the PJI group. A consecutive DAIR within 90 days after the first DAIR was warranted in 24 cases. Only 4 of 20 PJI cases failed despite the consecutive DAIR. Conclusions. In high suspicion of early PJI after revision arthroplasty, DAIR is a good treatment option with comparable outcome with DAIR after primary arthroplasty. A consecutive DAIR should not be avoided when infection control fails within 90 days after the first DAIR to prevent explantation of the prosthesis. Antimicrobial mismatch is associated with failure and should be avoided

Aim. Perioperative myocardial infarction/injury (PMI) is a common complication in noncardiac surgery, contributing to postoperative morbidity and mortality. We aimed to identify the risk for PMI in periprosthetic joint infection (PJI) in comparison to primary hip (THA) and knee arthroplasty (TKA) and to non-PJI revision surgery. Methods. Patients undergoing primary/revision THA/TKA at a University Hospital who were eligible for the institutional PMI screening and response program were prospectively included. Revision arthroplasties were divided into 2 groups (PJI revision and non-PJI revision). PJI was defined according to the EBJIS criteria, and included DAIR, one-stage and two-stage revisions. Non-PJI revisions included partial and/or complete exchange of components. The primary endpoint was PMI, secondary endpoints were major adverse cardiovascular events (MACE) and all-cause mortality within 120 days. Results. The study population included 673 patients (443 primary THA/TKA, 119 PJI revision, 111 Non-PJI revision) enrolled from 05/2014 to 06/2018. The median age in all groups was 75 years. In primary, non-PJI and PJI revision surgery, 39%, 41% and 50%, respectively were male. PMI occurred in 12% of patients with primary arthroplasty compared to 20% and 35% in non-PJI and PJI revision, respectively (p<0.001 overall), with PJI having a significantly elevated risk over non-PJI revisions (p=0.014). Conversely, in MACE (4% primary vs 9% non-PJI vs 12% PJI, p=0.002) an all-cause mortality (2% primary vs 4% non-PJI vs 9% PJI, p<0.001) no significant difference between PJI and non-PJI revisions was observed. We found no difference for the risk of PMI comparing DAIR vs one-/two-stage PJI revision (p=0.88). In multivariable analysis (primary arthroplasty as reference), significant odds ratios for PMI included PJI (3, 1.7–5.3), coronary artery disease (2.9, 1.9–4.4), chronic heart faiure (1.3, 1.1–1.7) and age (1.1, 1.0–1.1 per each year age). Urgency of surgery, duration of surgery, to the presence of Staphylococcus aureus were not significant. impact on PMI. Conclusion. In PJI, PMI and MACE were 3-times, and death 4.5 times, respectively, more frequently observed than in primary arthroplasty. Also, PJI had the highest odds for PMI (3.0). Orthopaedic surgeons should be aware of the high PMI risk when performing revision surgery. This work confirms the importance of a peri-/postpoperative PMI screening and response program in the field of septic surgery

Aim. Synovial fluid investigation is the best alternative to diagnose prosthetic joint infection (PJI) before adequate microbiological/histology sampling during revision surgery. Although accurate preoperative diagnosis is certainly recommended, puncturing every patient before revision arthroplasty raises concerns about safety and feasibility issues especially in difficult to access joint (e.g., hip), that often require OR time and fluoroscopy/ultrasound guidance. Currently there is no clear guidelines regarding optimal indications to perform preoperative joint aspiration to diagnose PJI before revision surgery. The main goal of this study is to determine the accuracy of our institutional criteria using the new European Bone and Joint Infection Society (EBJIS) PJI definition. Method. We retrospectively evaluated every single- or first-stage for presumed aseptic or known infected revision total hip/knee arthroplasty procedures between 2013–2020. Preoperative clinical and laboratory features were systematically scrutinized. Cases with insufficient information for accurate final PJI diagnosis (i.e., no perioperative synovial fluid examination or no multiple cultures including sonication of removed implant) were excluded. Preoperative joint aspiration is recommended in our institution if any of the following criteria are met: 1) elevated CRP and/or ESR; 2) early failure (<2 years) or repeat failure; 3) high clinical suspicion/risk factors are present. Performance of such criteria were compared against final postoperative EBJIS definition PJI diagnosis. Results. A total of 364 revision THAs or TKAs were performed during the study period. After excluding 258 cases with insufficient information, a total of 106 patients were ultimately included. 38 (35,8 %) were classified as confirmed infections, 10 (9.4 %) as likely infected and 58 (54.7%) as infection unlikely. Of those, 37 confirmed infection cases, 9 likely infected cases and 32 infection unlikely cases did have indication for preoperative synovial fluid collection before revision surgery. Institutional criteria showed 95.8 % Sensitivity, 44.83 % Specificity, 92.9 % Negative Predictive Value (NPV) and 59 % Positive Predictive Value (PPV). Conclusions. Sensitivity and NPV of the aforementioned institutional criteria are very high even with the use of the more sensitive EBJIS PJI definition. As such they seem to be a valid alternative in selecting patients that should be punctured before revision arthroplasty. They identify the vast majority of infected patients while saving a significant number of patients from unnecessary procedures

Aim. Dissolvable antibiotic-loaded calcium sulphate beads have been utilized for management of periprosthetic joint infection (PJI) and for aseptic revision arthroplasty. However, wound drainage and toxic reactive synovitis have been substantial problems in prior studies. Currently a commercially pure, physiologic product has been introduced that may reduce complications associated with this treatment modality. We aim to answer the question: does a commercially pure, physiologic version of antibiotic-loaded calcium sulfate beads reduce wound drainage and provide efficacious treatment for PJI and aseptic revision arthroplasty?. Method. Starting January 2010, 756 consecutive procedures were performed utilizing a set protocol of Vancomycin and Tobramycin antibiotics in commercially pure dissolvable antibiotic beads. There were 8 designated study groups:. Aseptic Revision TKA. N = 216. Aseptic Revision THA. N = 185. DECRA. *. TKA. N = 44. DECRA. *. THA. N = 16. 1. st. Stage Resection TKA. N = 103. 1. st. Stage Resection THA. N = 62. Reimplant TKA. N = 81. Reimplant THA. N = 49. *. DECRA = Debridement, modular Exchange, Component Retention, iv Antibiotics for acute PJI. Results. Wound drainage in the entire series was 4.2%. Wound drainage was generally seen in cases using higher bead volumes (≥30cc). The rate of heterotopic ossification was 1.6%. With bead volumes of ≥30cc, we did notice transient hypercalcemia in 12% of the study group (14% hips, 10% knees). The overall rate of infection failure was 2.5%. In the DECRA groups, reinfection failure rate was encouraging, measuring 9.1% in knees and 6.3% in hips. The non-DECRA group with the highest infection rate was Reimplant TKA (6.2%). Conclusions. We utilized a large series of commercially pure dissolvable antibiotic-loaded beads in a wide variety of clinical scenarios in patients with substantial comorbidities. Our rate of wound drainage, compared to prior studies utilizing gypsum products, was reasonably good. Additionally, our infection failure rates were encouraging. Over-stuffing knee joints with too many beads, in our clinical review, does affect wound drainage rates. By removing impurities from calcium sulfate, we do not see the substantial toxic synovial reaction compared to the traditional gypsum-washed products. We feel that commercially pure, physiologic antibiotic-loaded dissolvable beads are an acceptable delivery tool for local antibiotic delivery in aseptic and septic revision joint arthroplasty of the hip and knee. In our opinion, further study is warranted. We advocate future randomized studies to examine the potential of improving outcomes of PJI and aseptic revision arthroplasty

We present the indications and outcomes of a series of custom 3D printed titanium acetabular implants used over a 9 year period at our institution (Sydney, Australia), in the setting of revision total hip arthroplasty.

Individualised image-based case planning with additive manufacturing of pelvic components was combined with screw fixation and off-the-shelf femoral components to treat patients presenting with failed hip arthroplasty involving acetabular bone loss. Retrospective chart review was performed on the practices of three contributing surgeons, with an initial search by item number of the Medicare Benefits Scheme linked to a case list maintained by the manufacturer. An analysis of indications, patient demographics and clinical outcome was performed.

The cohort comprised 65.2% female with a median age of 70 years (interquartile range 61–77) and a median follow up of 32.9 months (IQR 13.1 - 49.7). The indications for surgery were infection (12.5%); aseptic loosening (78.1%) and fracture (9.4%), with 65.7% of cases undergoing previous revision hip arthroplasty. A tumour prosthesis was implanted into the proximal femur in 21.9% of cases. Complications were observed in 31.3% of cases, with four cases requiring revision procedures and no deaths reported in this series. Kaplan-Meier analysis of all-cause revision revealed an overall procedure survival of 88.7% at two years (95%confidence interval 69 - 96.2) and 83.8% (95%CI 62 - 93.7) at five years, with pelvic implant-specific survival of 98% (95%CI 86.6 - 99.7) at two and five year follow up.

We conclude that an individualised planning approach for custom 3D printed titanium acetabular implants can provide high overall and implant-specific survival at up to five years follow up in complex cases of failed hip arthroplasty and acetabular bone loss.

Introduction. Acute infection following Total Hip Arthroplasty (THA) is a serious complication. It is commonly treated by irrigation and debridement (I&D) with component retention (exchange only the mobile parts of the joint - head and liner). However, the reported re-infection rate with the use of this approach remains high. We are reporting our experience in using single - stage revision arthroplasty in treating acute infection of THA. We hypothesized that the infection control rate after immediate early revision for acute infection of cementless implants is better than has been reported for I&D with exchange of mobile parts. Methods. From our infection arthroplasty database, we reviewed the outcome of 19 patients who had an acute infection (within 6 weeks) of cementless THA. Our management strategy includes I&D and single-stage (direct-exchange) revision arthroplasty followed by 6 weeks course of culture specific oral antibiotics. Results. Patients' average age was 64 year (39–85), M:F = 11:8. There were 13 primary and 6 revision cementless THAs. Average time from the index operation to the development of clinical symptoms of infection was 18 days (4–41). 14 patients (73.7%) were successfully treated with single stage revision strategy with no evidence of re-infection at 64.3 (32–89) months of follow up. 5 patients (26.3%) developed re-infection requiring two stage-revision surgery. Discussion. Our results showed that single stage revision strategy has a better outcome in treating acute infection after THR than the outcomes reported for I&D with component retention. When faced with acute infection of a cementless implant, early implant exchange prior to ingrowth should be considered

Aim

Prosthetic joint infection (PJI) is a devastating and costly complication of total joint arthroplasty (TJA). Use of extended oral antibiotic prophylaxis (EOAP) has become increasingly popular in the United States following a highly publicized study (Inabathula et al) from a single center demonstrating a significant protective effect (81% reduction) against PJI in ‘high-risk’ patients. However, these results have not been reproduced elsewhere and EOAP use directly conflicts with current antibiotic stewardship efforts. In order to study the role of EOAP in PJI prevention, consensus is needed for what defines ‘high-risk’ patients. The revision TJA (rTJA) population is an appropriate group to study due to having a higher incidence of PJI. The purpose of the current study was to rigorously determine which preoperative conditions described by Inabathula et al. (referred to as Inabathula criteria (IBC)) confer a higher rate of PJI in patients undergoing aseptic rTJA.

Background. KAR™ prosthesis was introduced following the success of Corail® femoral stem to tackle difficult revision cases (Paprosky type1, 2a, 2b and 3a). The ARTO group reported a success rate of 94% at 17 years follow-up. Only two independent studies reported similar success rate to date. Purpose. To analyse the short-term performance of the KAR™ prosthesis used in our unit. Methods. This was a retrospective study of all KAR™ prosthesis between 2005 and 2013. Basic demographic, stem size, indications, failures and complications were recorded. X-rays were analysed for evidence of implant failure and distal cortical hypertrophy. Results. A total of 83 cases were analysed. The mean age was 68 (range 38–88 years) with an average follow-up was 3 years (range 1–8 years). The main indications for revision were aseptic loosening (83.7%), and periprosthetic fractures (7%). Kaplan-Meier Survival Rate for ‘all reasons of failure’ and ‘stem loosening’ was 93.83% and 100% respectively at 3 years follow-up. The most common reason for failure following KAR™ revision was periprosthetic fracture (3 cases). All three cases had radiographic evidence of proximal bone loss prior to index revision. Two patients developed deep infection and one patient had stem subsidence requiring revision. One patient sustained dislocation but revision surgery was not required. When comparing the effect of cortical hypertrophy, there were no significant differences in the measured distal canal/cortical diameter over the entire period of follow-up. Discussion. KAR™ prosthesis offers respectable clinical performance over a short-term period. Revision rate for this system was comparable to other ‘independent non-designer’ study. The three patients that sustained periprosthetic fracture may have been better served with a distally locked stem revision system. We believe that this HA coated implant encourages consistent osseointegration around the metaphysis region when there is evidence of a sound distal fixation. Conclusion. This study confirms that this fully coated hydroxyapatite titanium stem offers reliable clinical performance in revision arthroplasty

Aims

The aim of this study was to assess the incidence the microbiological spectrum and clinical outcome of hip and knee revision arthroplasties with unexpected-positive-intraoperative-cultures (UPIC) at a single center with minimum follow up of 2 years.

Introduction

Dual mobility (DM) total hip arthroplasty (THA) prostheses are designed to increase stability. In the setting of primary and revision THA, DM THA are used most frequently for dysplasia and instability diagnoses, respectively. As the use of DM THA continues to increase, with 8,031 cases logged in the American Joint Replacement Registry from 2012–2018, characterizing in vivo damage and clinical failure modes are important to report.

Introduction

Revision total hip arthroplasty is a complex procedure and becoming more common. Acetabular implant loosening or fracture has previously been treated with a cup and cage construct. Recent studies have shown significant failure rates with Cup Cage constructs in more complex 3B and 3C Acetabular revisions. As a result the use of 3D printed custom made acetabular components has become more common.

Introduction

A stiff total knee arthroplasty (TKA) is an uncommon but disabling problem because it causes pain and limited function. Revision surgery has been reported as a satisfactory treatment option for stiffness with modest benefits. The aim of this study was to evaluate the results of revision surgery for the treatment of stiffness after TKA.

Joint replacement is a highly effective intervention to treat osteoarthritis of the hip, relieving pain and improving mobility and quality of life.(1) Periprosthetic joint infection (PJI) is a devastating complication after arthroplasty. Debridement, antibiotics and implant retention are treatment of first choice in case of early infection after total hip arthroplasty (THA).(2) In case of persisting infection, one- or two-stage revision needs to be performed.(3) The use of different kinds of spacers has been widely debated in the past years.(4)

The aim of this study was to determine which type of spacer should be used during the interval of two-stage revision of an infected THA.

A search term with Boolean operators was constructed. We extracted all information regarding study and patient characteristics and baseline clinical and laboratory findings. Data regarding type of spacer and antibiotics used, timing of second stage surgery, tissue culture results, postoperative regimen, functional outcome and patient satisfaction were extracted.

A total of twenty-six studies met our inclusion criteria and were included for data analysis. Ten studies described various preformed spacers, six studies described functional spacers and eleven studies described custom made spacers. See Table 1 for results.

Research should focus on finding the preferred type of treatment and type of spacer to combine a high success rate of infection treatment with a good functional and patient reported outcome. There is a need for a prospective study evaluating patient satisfaction and functional outcome after two-stage revision THA comparing various spacers. Secondly, research should focus on the optimal timing of the second stage procedure.

Functional spacers achieve a comparable rate of infection eradication in the treatment of periprosthetic hip joint infections as compared to preformed spacers. There is insufficient evidence concerning rehabilitation and functional outcome after two-stage revisionTHA to advocate or discourage the use of either kind of interval spacer.

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.

There is no doubt that peri-prosthetic joint infection (PJI) is one the most terrible complications of joint arthroplasty. There has been a surge of interest in PJI in recent years as this problem moves to be the last frontier in joint arthroplasty.

There are a number of strategies employed for prevention of PJI. Irrigation of the surgical site with various irrigation solutions is one such strategy as it helps reduce bioburden in the wound and reduce the potential for subsequent infection.

Although the irrigation solution may work by dilution phenomenon alone, some believe that bactericidal or bacteriostatic agents may be added to the irrigation solution to increase its efficacy. Addition of antibiotics (Abx) to the irrigation solution stems from the same reasoning.

There are a number of serious issues related to the addition of Abx to the irrigation solution or in fact, for pouring into the wound (like the vancomycin powder).

Efficacy: There are no randomised prospective studies to demonstrate that addition of Abx to the irrigation solution improves “kill”. To do such a study would be logistically challenging. Basic science studies and other clinical studies with a small number of patients have failed to prove the efficacy of Abx in the irrigation solution. In fact, I would argue that the use of agents like dilute betadine is much more likely to be effective in reduction of bioburden without having many of the issues related to the use of Abx in irrigation solution.

Emergence of Resistance: Some may argue what would one lose by adding Abx to the wound or the irrigation solution. The modern society is facing an emerging catastrophe. Antimicrobial Resistance (AMR), if it persists, will kill more people than cancer by the year 2050. Annually 1000s of patients die of ESKAPE or AMR related issues. A recent task force convened by the British government produced a report about AMR which is sobering. The main finding of the task force was that continued liberal use of Abx will lead to further escalation of the AMR crisis that threatens the modern society. The guidelines by the CDC, that are about to be published, will discourage clinicians from pouring Abx into wounds and asks clinicians to exercise Abx stewardship.

Expense: There are costs associated with the use of Abx in any circumstance including their addition to irrigation solution. With over 1 million joint arthroplasties being done in the US alone, this cost can be substantial.

Hypersensitivity reactions: The use of Abx is not without problems. There have been a few fatalities associated with the use of Abx in patients with recognised and possibly unrecognised hypersensitivity to antibiotics.

Infection is still a major problem in implant surgery. Most infections are caused by bacteria that enter the wound at the time of the operation. Although prophylactic antibiotics given intravenously have been shown to be effective if given during the correct time frame, the concentration of local antibiotics in the knee in response to intravenous antibiotics is about 1/3 that achieved in the serum, and the level is transient. The concentration of antibiotics in the joint fluid achieved with antibiotics applied locally during surgery is 1000 times higher, and can be maintained throughout the procedure. High concentration persists in drainage fluid for 24 hours after surgery.

Studies done with use of local antibiotics in spinal implant surgery indicate a major reduction in the rate of infection, and cost analysis shows a remarkable monetary benefit to this effect.

Local antibiotic irrigation during implant surgery is inexpensive, easy, and effective.

Background. The aim of this study was to evaluate causes and results of revision surgery in unstable total knee arthroplasties. Methods. We retrospectively reviewed 24 knees that underwent a revision arthroplasty for unstable total knee arthroplasty. The average follow-up period was 33.8 months. We classified the instability and analyzed the treatment according to its cases. Stress radiographs, postoperative component position and joint level were measured. Clinical outcomes were assessed using the score and range of motion of the Hospital for Special Surgery (HSS). Results. Causes of instability included coronal instability with posteromedial polyethylene wear and lateral laxity in 13 knees(Fig. 1) and coronal instability with posteromedial polyethylene wear in 6 knees(Fig. 2), coronal and sagittal instability in 3 knees including post breakage in 1 knee(Fig. 3), global instability in 1 knee(Fig. 4) and flexion instability in 1 knee. Mean preoperative/postoperative varus and valgus angles were 5.8°/3.2° (p = 0.713) and 22.5°/5.6° (p = 0.032). Mean postoperative α, β, γ, δ angle were 5.34°, 89.65°, 2.74°, 6.77°. Mean changes of joint levels were from 14.1 mm to 13.6 mm from fibular head (p = 0.82). The mean HSS score improved from 53.4 to 89.2 (p = 0.04). The average range of motion was changed from 123° to 122° (p = 0.82). Conclusions. Revision total knee arthroplasty with or without a more constrained prosthesis will be a definite solution for an unstable total knee arthroplasty. The solution according to the causes is very important and seems to have a chance of avoidance of unnecessary over-constrained implant selection in revision surgery for total knee instability

Aim. Periprosthetic fractures are usually observed in patients aged over 65 years. The incidence of postoperative periprosthetic femur and tibia fractures is rising with increasing number of hip and knee joint replacements and the increasing life expectancy. The aetiology of periprosthetic fractures is multifactorial. Minimal trauma is causal for the fracture in most cases. Other risk factors are: generalized osteoporosis, loosening of the prosthesis and revision arthroplasty. Our aim is restoration of the patient's pre-fracture functional status. Method. Between 2004 and 2009 in the Asklepios Orthopedic Clinic Hohwald 118 patients (82 women, 36 men) were operated because of periprosthetic fractures. Mean patient age at surgery was 71 years (range 60-87). The right treatment depends on the location of the fracture and the stability of the implant. Very important is also the quality of bone and the patient's general state of health. Results. A successful surgical treatment requires a careful preoperative planning. The type of the fracture with or without prostheses instability and with or without bone defect all have influence on the type of patients surgery. Two patients died within one year. There were 2 cases of infection and cases of 5 late healing. Fixation with different plates was used for 67 fractures, at intact and undamaged endoprosthesis was used usually osteosynthesis with “Less Invasive Stabilisation System” plate (LISS, NCB). It combines high primary stability with the biological advantages of a slide-insertion plate osteosynthesis. Retrograde nailing was possible in 5 patients and 8 further with screws and cerclage wiring. In 38 cases we changed the endoprosthesis partially or completely. We reconstructed prosthetic damage or periprosthetic fractures with bone defect using modular prostheses. This system allows a large number of additional components and their combination with cone blocks for reconstruction of severe bone defects. Conclusion. Periprosthetic fractures have such a range of clinical presentations that they need to be managed on individual basis. The best functional results for stable implants gived internal fixation with a plate. Alternative osteosynthetic techniques and additive minimal osteosynthesis can work better in special cases. Modular prostheses for bone replacement are a method of choice for fractures with extensive bone loss. Nonoperative treatment should only be performed in exceptional cases. Periprosthetic fractures are serious complications because of the mortality and the difficulty in achieving functional recovery after treatment. Our primary aim is remobilization as early as possible-that is the best prevention of secondary complications