Soluble Urokinase Plasminogen Activator Receptor (SuPAR) Analysis for Diagnosis of Periprosthetic Joint Infection.

Soluble urokinase plasminogen activator receptors (suPARs) are a biomarker for inflammatory diseases. This study aims to investigate its diagnostic properties regarding periprosthetic joint infections (PJI). This retrospective cohort study included adult patients who underwent joint puncture for suspected PJI. The presence of PJI was determined according to the criteria of the European Bone and Joint Infection Society (EBJIS). Laboratory study analyses included the determination of white blood cells (WBC) in whole blood, C-reactive protein (CRP) in blood plasma, and suPAR in both blood plasma and synovial fluid. Appropriate diagnostic cut-off values were identified utilizing Youden's J, and their diagnostic performance was determined by calculating the positive (PPV) and negative predictive value (NPV) for each marker. Sixty-seven cases were included in the final analysis. Forty-three samples (64%) were identified as periprosthetic joint infection (PJI) and twenty-four specimen (36%) were PJI negative cases. The PPV and NPV were 0.80 and 0.70 for synovial suPAR, 0.86 and 0.55 for CRP, 0.84 and 0.31 for WBC and 1.00 and 0.31 for plasma suPAR. Synovial suPAR showed a solid diagnostic performance in this study and has the potential to be an alternative or complementary biomarker for PJI. Further investigations in larger patient collectives are indicated.

Vancomycin Elution Kinetics of Four Antibiotic Carriers Used in Orthopaedic Surgery: In Vitro Study over 42 Days.

This study aimed to analyse and compare the vancomycin elution kinetics of four biodegradable, osteoconductive antibiotic carriers used in clinical practice within a 42-day in vitro setting. Carriers A and D already contained vancomycin (1.1 g and 0.247 g), whereas carriers B and C were mixed with vancomycin according to the manufacturer's recommendations (B: 0.83 g and C: 0.305 g). At nine time points, 50% (4.5 mL) of the elution sample was removed and substituted with the same amount of PBS. Probes were analysed with a kinetic microparticle immunoassay. Time-dependent changes in vancomycin concentrations for each carrier and differences between carriers were analysed. Mean initial antibiotic levels were highest for carrier A (37.5 mg/mL) and lowest for carrier B (5.4 mg/mL). We observed time-dependent, strongly negative linear elution kinetics for carriers A (-0.835; p < 0.001), C (-0.793; p < 0.001), and D (-0.853; p < 0.001). Vancomycin concentrations increased from 48 h to 7 d and dropped thereafter in carriers C and D whilst constantly decreasing at any time point for carrier A. Carrier B showed a shallower decrease. Mean antibiotics levels at 42 d were 1.5 mg/mL, 2.6 mg/mL, 0.1 mg/mL, and 0.1 mg/mL for carriers A, B, C, and D. Differences in mean initial and final vancomycin concentrations for carrier A were significantly larger in comparison to C (p = 0.040). A carrier consisting of allogenic bone chips showed the highest vancomycin-to-carrier ratio and the largest elution over the study period. Whilst vancomycin concentrations were still measurable at 42 days for all carriers, carrier A provided a higher drug-to-carrier ratio and a more consistent antibiotic-releasing profile.

The Sinus Tract in Bone and Joint Infection: Minimally Invasive Salvation or Prolonged Suffering? A Multicenter Study.

This study assessed the quality of life (QOL) and the functional outcome in daily living in patients with a chronic, treatment-resistant periprosthetic joint infection (PJI) or osteomyelitis, living with a natural or iatrogenic sinus tract. METHODS: A follow-up examination in three national reference centers for septic bone and joint surgery was performed utilizing the Hospital Anxiety and Depression Scale (HADS-D/A), the Visual Analogue Scale (VAS), and the Short Form-36 (SF-36) score, including patients with a chronic sinus tract due to treatment-resistant PJI or osteomyelitis. RESULTS: In total, 48 patients were included, with a mean follow-up time of 43.1 ± 23.9 months. The mean SF-36 Mental Component Summary (MCS) was 50.2 (±12.3) and the Physical Component Summary (PCS) was 33.9 (±11.3). The mean HADS-D was 6.6 (±4.4) and HADS-A was 6.2 (±4.6), and the VAS was 3.4 (±2.6). The SF-36 MCS showed no significant differences between the study group and the standard population (47.0, p = 0.10), as well as the HADS-A. The PCS in the study population was significantly worse (50.0, p < 0.001), as was the HADS-D. CONCLUSIONS: A sinus tract represents a treatment option in selected cases with an acceptable QOL. The treatment should be considered for multimorbid patients with a high perioperative risk or if the bone or soft tissue quality prevents surgery.

Total joint arthroplasty versus resection-interposition arthroplasty for thumb carpometacarpal arthritis: a randomized controlled trial.

BACKGROUND AND PURPOSE: Thumb carpometacarpal (TCMC) osteoarthritis is a common condition that causes pain and functional limitations. We compared the outcomes of 2 surgical procedures for TCMC osteoarthritis, the Epping resection-suspension arthroplasty and the double-mobility TCMC prosthesis, and focused on pain relief, functional outcomes, and patient quality of life. PATIENTS AND METHODS: Over a 7-year period a randomized controlled trial including 183 cases of TCMC osteoarthritis was conducted comparing a double mobility TCMC prosthesis (Moovis, Stryker, Kalamazoo, MI, USA) with the Epping resection-suspension arthroplasty. Pre- and postoperative examinations included the range of motion (ROM), SFMcGill score, visual analogue scale (VAS), the disabilities of the arm, shoulder and hand questionnaire (DASH), and the hospital anxiety and depression scale (HADS). RESULTS: At the 6-week postoperative follow-up, significant differences were found in VAS: Epping median 4.0 (interquartile range [IQR] 2.0-5.0) vs. TCMC prosthesis 2.0 (IQR 0.25-4.0), p = 0.03, effect size (area under the curve [AUC]) 0.64 (95% confidence interval [CI] 0.55-0.73), in DASH score: Epping 61 (IQR 43-75) vs. TCMC prosthesis 45 (IQR 29-57), p < 0.001, AUC 0.69 (CI 0.61- 0.78), and in radial abduction: Epping 55 (IQR 50-60) vs. TCMC prosthesis 62 (IQR 60-70), p = 0.001, AUC 0.70 (CI 0.61-0.79). No significant group differences were found at the 6- and 12-months follow-up. During the follow-up period, 3 of 82 prostheses had to be revised but there was no revision in the Epping group. CONCLUSION: The double mobility TCMC prosthesis had superior outcomes compared with the Epping procedure at 6 weeks; however, there were no significant differences in outcomes at 6 months and 1 year postoperatively. The implant survival rate of 96% after 12 months was acceptable.

Long-term changes in serum silver concentrations after extremity reconstruction with silver-coated megaprostheses.

Silver-coated megaprostheses are considered to reduce infection rate following reconstruction of bone defects in tumour surgery or revision arthroplasty. However, little is known about systemic silver exposure and possible side effects. The aim of this study was to analyse serum silver concentrations in patients with silver-coated megaprostheses over a prolonged time period. Between 2004 and 2016, 46 patients (52.2% female, mean age at surgery 47.1 ± 24.2 years) received silver-coated megaprostheses for septic (n = 26) or oncological (n = 17; main implant since 2013) indications, or aseptic loosening (n = 3). Blood was drawn from all patients within the first few days following surgery (without silver ion levels) and thereafter every 6 months at the outpatient department (with silver ion levels). Inductively coupled plasma mass spectrometry was used to determine silver ion levels. Median follow-up was 47.3 months (IQR: 16.1-78.9). Overall, 29 revision surgeries became necessary in 20 patients, equivalent to a cumulative complication rate of 63.0%. Revisions were most commonly for periprosthetic joint infections (PJIs, n = 12) and instability/soft tissue problems (n = 10). Revision-free implant survival was 81.4%, 42.3% and 35.2% at one, 5 and 10 years. Incidence of local argyria was 8.7% (n = 4). Silver ion levels at two or more consecutive time points during follow-up were available for 26 patients. An increment of silver levels within the first months ("run-in") was observed, followed by an unspecific undulating course. Median initial and latest follow-up (median, 49.5 months) serum silver ion levels were 16.0 ppb (IQR: 9.1-29.1) and 7.4 ppb (IQR: 2.7-14.1), respectively. According to the multivariate mixed linear random-effects model, development of PJI was associated with significantly higher silver ion levels over time (p = 0.002), irrespective of time from surgery (p = 0.274). In the current series, a cumulative complication rate of 63.0% was observed for patients receiving silver-coated megaprostheses for septic of oncological indications. An overall unspecific course of silver ion concentration was present. Development of PJI was significantly associated with increased silver ion levels over time. Yet, no systemic complication associated to high silver levels occurred. It can be concluded that silver-coated implants constitute a safe solution for megaprosthetic reconstruction, but monitoring of silver concentrations is recommended.

Fracture, nonunion and postoperative infection risk in the smoking orthopaedic patient: a systematic review and meta-analysis.

This systematic review and meta-analysis aimed to analyse negative effects of smoking in orthopaedic and trauma patients.A PubMed search was carried out for studies published until July 2020 regarding effects of smoking on fracture risk, nonunion, infection after orthopaedic surgery, and persisting nonunion after scaphoid nonunion surgery. Random effects models calculated for outcome parameters, and relative risks (RR) with 95% confidence intervals are provided. No adjustments for covariates were made. Heterogeneity was assessed with Higgins' I2, publication bias with Harbord's p (Hp), sensitivity analysis performed on funnel plots and quality of studies was analysed using the Newcastle-Ottawa Scale.Of 3362 retrieved entries, 69 were included in the final analysis. Unadjusted RR for smokers to develop vertebral (six studies, seven entries; RR: 1.61; p = 0.008; I2 = 89.4%), hip (11 studies, 15 entries; RR: 1.28; p = 0.007; I2 = 84.1%), and other fractures (eight studies, 10 entries; RR: 1.75; p = 0.019; I2 = 89.3%) was significantly higher. Postoperative infection risk was generally higher for smokers (21 studies; RR: 2.20; p < 0.001; I2 = 58.9%), and remained upon subgroup analysis for elective spinal (two studies; RR: 4.38; p < 0.001; I2 = 0.0%) and fracture surgery (19 studies; RR: 2.10; p < 0.001; I2 = 58.5%). Nonunion risk after orthopaedic (eight studies; RR: 2.15; p < 0.001; I2 = 35.9%) and fracture surgery (11 studies; RR: 1.85; p < 0.001; I2 = 39.9%) was significantly higher for smokers, as was persisting nonunion risk after surgery for scaphoid nonunion (five studies; RR: 3.52; p < 0.001; I2 = 0.0%). Sensitivity analysis for each model reduced heterogeneity whilst maintaining significance (all I2 < 20.0%).Smoking has a deleterious impact on fracture incidence, and (subsequent) development of nonunions and postoperative infections. Cite this article: EFORT Open Rev 2021;6:1006-1019. DOI: 10.1302/2058-5241.6.210058.

Cat at home? Cat scratch disease with atypical presentations and aggressive radiological findings mimicking sarcoma, a potential diagnostic pitfall.

Background and purpose - Cat scratch disease (CSD) is a self-limiting disease caused by Bartonella (B.) henselae. It is characterized by granulomatous infection, most frequently involving lymph nodes. However, it can present with atypical symptoms including musculoskeletal manifestations, posing a diagnostic challenge. We describe the prevalence and demographics of CSD cases referred to a sarcoma center, and describe the radiological, histological, and molecular findings.Patients and methods - Our cohort comprised 10 patients, median age 27 years (12-74) with clinical and radiological findings suspicious of sarcoma.Results - 7 cases involved the upper extremities, and 1 case each involved the axilla, groin, and knee. B. henselae was found in 6 cases tested using polymerase chain reaction and serology in 5 cases. 9 cases were soft tissue lesions and 1 lesion involved the bone. 1 patient had concomitant CSD with melanoma metastasis in enlarged axillary lymph nodes. On MRI, 5 soft tissue lesions were categorized as probably inflammatory. In 3 cases, with still detectable lymph node structure and absent or initial liquefaction, the differential diagnosis included lymph node metastasis. A sarcoma diagnosis was suggested in 4 cases. The MRI imaging features of the bone lesion were suspicious of a bone tumor or osteomyelitis.Interpretation - Atypical imaging findings cause a diagnostic challenge and the differential diagnosis includes malignant neoplasms (such as sarcoma or carcinoma metastasis) and other infections. The distinction between these possibilities is crucial for treatment and prognosis.

Comparison of elution characteristics and mechanical properties of acrylic bone cements with and without superficial vancomycin coating (SVC) in the late phase of polymerization.

INTRODUCTION: Antibiotic-loaded bone cements (ALBCs) are used as spacers in two-stage revision arthroplasty for periprosthetic joint infection. We previously described a new technique applying vancomycin powder coating to custom-made cements. To our best knowledge, this method of superficial vancomycin coating (SVC) has not been assessed before. We therefore performed an in-vitro study to determine: (1) whether manually applied SVC strengthened the cements' antibiotic effect; and (2) whether the mechanical requirements for the cements were fulfilled. HYPOTHESIS: SVC increases the antibiotic effect of cement within the first 24hours. METHODS: Cuboid blocks were produced from two commercially available acrylic ALBCs (Palacos R+G and Copal G+V) with and without SVC. Each block was eluted in phosphate-buffered saline at 37°C. Eluates obtained at 1, 2, 3, 4, 5, 10, 15, 30 and 60minutes and 3, 6 and 24hours were evaluated against Staphylococcus aureus (Palacos, Copal) and methicillin-resistant Staphylococcus aureus (MRSA) (Copal) using zone of inhibition tests. Mechanical test results (bending modulus, bending strength) were compared to ISO requirements (≥1800MPa, ≥50MPa). RESULTS: Palacos with SVC produced significantly greater zones of inhibition against Staphylococcus aureus than Palacos without SVC (p=0.002). Copal with SVC showed greater zones of inhibition against both Staphylococcus aureus and MRSA (p=0.002). The antibiotic effect was enhanced by SVC in both cements at every time point within 24hours. The bending modulus and bending strength of Palacos with SVC (2089±166MPa, 60.8±2.6 MPA) and Copal with SVC (2283±195MPa, 56.9±2.4MPa) were significantly above ISO requirements. CONCLUSION: SVC boosts the antibiotic effect of ALBCs in the first 24hours, while maintaining sufficient stability. These findings endorse SVC as a promising additive in septic revision surgery. LEVEL OF EVIDENCE: III; case control study.

Successful Two-Stage Exchange Arthroplasty for Periprosthetic Infection Following Total Knee Arthroplasty: The Impact of Timing on Eradication of Infection.

Background: Periprosthetic joint infection (PJI) represents a serious complication following total knee arthroplasty. In the setting of chronic infections, the two-staged approach has traditionally been the preferred treatment method. The aim of this study was to determine the optimal period of rest between the first and second stage. Furthermore, we analyzed potentially outcome-relevant parameters, such as general and local conditions and the presence of difficult-to-treat or unidentified microorganisms, with regard to their impact on successful treatment of PJI. Patients and Methods: We performed a retrospective analysis of prospectively collected data for all patients treated for PJI at our institution. Seventy-seven patients who had undergone two-stage revision arthroplasty for PJI of the knee were included into the study. Antibiotic-loaded cement spacers were used for all patients. Results: After a median follow-up time of 24.5 months, infection had reoccurred in 14 (18.7%) patients. A prolonged spacer-retention period of more than 83 days was related to a significantly higher proportion of reinfections. Furthermore, significant compromising local conditions of the prosthetic tissue and surrounding skin, as well as repeated spacer-exchanges between first- and second-stage surgery, negatively influenced the outcome. Neither the patients' age nor gender exerted a significant influence on the outcome regarding reinfection rates for patients' age or gender. Conclusions: We observed the best outcome regarding infection control in patients who had undergone second-stage surgery within 12 weeks after first-stage surgery. Nearly 90% of these patients stayed free from infection until the final follow-up. An increased number of performed spacer-exchanges and a bad local extremity grade also had a negative impact on the outcome.

Risk of reinfection after two- or multiple-stage knee revision surgery using superficial vancomycin coating and conventional spacers.

This study investigates the effect of superficial vancomycin coating (SVC) in two- or more-stage exchange procedures of prosthetic knee joint infections. We hypothesized that spacer treatment with SVC result in lower reinfection rates than conventional spacers after prosthetic reimplantation. Our secondary aim was to determine the demographic and treatment factors associated with reinfection rates. This retrospective cohort study compromised 96 cases with prosthetic knee infections. Twenty-four cases were treated with a temporary SVC spacer and 72 cases with conventional spacers. Prosthetic reinfection occurred after a median observation period of 1.7 ± 4.0 years in 24 cases (25%). The prevalence of having a reinfection was not significantly different between the two treatment groups (13% [3 cases] in the SVC group vs. 29% [21 cases] in the conventional spacer group [p = .104]). In seven cases (7.3%), two in the SVC group (8.3%) and five (6.9%) in the conventional spacer group (p ≥ .999), histological, respectively microbiological evaluations from the intraoperative specimens revealed persistent infection at the second stage. Nevertheless, in all seven cases no significant higher risk of periprosthetic reinfection was observed during follow-up (p = .750). Our secondary investigation of cofactors revealed that spacers additionally stabilized by nails were significantly associated with a 3.9-fold higher hazard ratio of sustaining a reinfection of revision prosthesis (p = .005).

Mid-term results show no significant difference in postoperative clinical outcome, pain and range of motion between a well-established total knee arthroplasty design and its successor: a prospective, randomized, controlled trial.

PURPOSE: The purpose of this study was to compare the clinical and functional outcome scores following total knee arthroplasty (TKA) with two different systems. The hypothesis was that there is a difference between patients receiving the newer design than those receiving the predecessor. METHODS: Two hundred patients who underwent TKA were randomized into two groups: patients received either Attune TKA or PFC Sigma (both DePuy Synthes, Warsaw, IN). Clinically, the Knee Society Knee and Function Scores (KS and FS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Range of Motion (ROM) and Visual Analogue Scale (VAS) were evaluated and compared between the groups 2 years after surgery. 158 patients (80 in the Attune group and 78 in the PFC Sigma group) were available for follow-up. RESULTS: Through bivariate analysis using parametric and non-parametric statistical tests, no significant differences in postoperative KS, FS, WOMAC, ROM or VAS between the two groups were detected. Both groups significantly improved regarding all evaluated endpoints 2 years after surgery. CONCLUSIONS: In the current study population, no difference in clinical outcome between the two systems was found. The expected benefits of design modifications could not be observed in clinical outcome scores 2 years postoperatively. Both designs are effective options for improving pain and function in end-stage osteoarthritis. LEVEL OF EVIDENCE: I.

Residents' Learning Curve of Total Knee Arthroplasty Based on Radiological Outcome Parameters: A Retrospective Comparative Study.

BACKGROUND: This study aimed to plot the impact of a learning curve for a resident's first 103 total knee arthroplasties (TKAs) based on radiological deviations and incision to closure time (ICT), and to compare it to 103 matched TKAs performed by a senior surgeon. METHODS: This is a retrospective comparative study comprising a total of 206 TKAs and evaluated the results based on radiographic outcome and ICT. Radiological evaluation was performed according to a predefined implemented radiological grading system (RGS). t-Tests compared ICT and RGS; data of mechanical axis were observed with Man-Whitey U-tests and Wilcoxon signed-rank-tests. RESULTS: The study included 206 patients (mean age 73 years, mean body mass index of 30). Determining all the deviation points (DP) with the RGS, the deviation ratio for resident vs senior surgeon was 0.96:0.5 DP (P = .0002). The learning curve based on DP showed a decrease over time with statistical significance in the first (26 DP, P = .0001), second (21 DP, P = .0059), and fourth (20 DP, P = .0187) quintiles of implanted cases. The ICT of the resident showed a decrease within the quintiles from 79.45 minutes (first quintile) to 65.17 minutes (fifth quintile), for an improvement of 14.28 minutes. When the quintiles are viewed in relation to the mean operation time of the senior surgeon (mean ICT 66.04 minutes), the mean values of the first and the second quintiles remain statistically significant. CONCLUSION: Supervised TKA showed statistical significance in the learning curves according to deviations documented with a predefined radiological outcome assessment system as well as to ICTs. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

The Dark Side of Arthroplasty: Competing Risk Analysis of Failed Hip and Knee Arthroplasty With Periprosthetic Joint Infection.

BACKGROUND: Increasing total hip (THA) and knee (TKA) arthroplasties inevitably lead to accumulating failed arthroplasty (FA) with periprosthetic joint infections (PJI) and definite treatment recommendations are scarce. Our aims were to evaluate patient and infection site specific risk factors, and to identify case-dependent salvage procedure recommendations. METHODS: Retrospective analysis was conducted of salvage procedures for FA after PJI (amputation, Girdlestone resection arthroplasty [GRA], arthrodesis, or chronic fistulation [CF]) from 2008 to 2018. Univariable and multivariable modeling of revision and mortality rates, using cumulative incidence competing risk analysis, and Cox proportional hazards models were calculated. RESULTS: In total, 135 patients (THA 62%; TKA 38%) were diagnosed for FA after PJI, having undergone an average of 3 [1-4] revisions at a mean follow-up of 12.8 [7.8-20.9] years. Forty-four percent of THAs and 55% of TKAs had to be revised following FA, 44% deceased during follow-up, and 16% could be reconverted to an infection-free arthroplasty. GRA revealed significantly higher revision rates than CF (P = .015) for THA. Lower age (P = .003), higher number of revisions before FA (P = .007), more than one microorganism at infection site (P = .034), and GRA (P = .037, only THA) prevailed independent risk factors for revision. Patients' age remained an independent mortality risk factor (P = .001). CONCLUSION: High-risk patients suffering from FA after THA with poor constitution profit from controlled constitution of CF, reducing the risk for revision surgeries and hospitalization. In case of FA after TKA, data did not allow definite treatment recommendations. We believe that education concerning amputation should be considered early after multiple TKA revisions.

Excellent mid-term osseointegration and implant survival using metaphyseal sleeves in revision total knee arthroplasty.

PURPOSE: Metaphyseal fixation in revision total knee arthroplasty (RTKA) is a very promising treatment option for extended bone defects. Currently published mid-term results remain limited. The purpose was to analyse the implant durability, the clinical and the radiological mid-term results in RTKA when using metaphyseal sleeves. METHODS: Clinical and radiological follow-up examinations were performed in 92 patients (93 knees) with RTKA using hybrid fixation technique (cementless sleeves and stem). Radiographic measurements regarding osseointegration at the bone-sleeve interface were performed and the range of motion (ROM), a subjective satisfaction score (SSS), the American Knee Society Score (KSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) as well as the SF-36 Health survey were examined. Bone defects were analysed using the Anderson Orthopaedic Research Institute (AORI) classification. RESULTS: No knee had to be revised due to aseptic loosening at the time of the follow-up (mean 6.3 years ± 2.3, minimum 2 years). Satisfactory radiographic osseointegration at the sleeve/bone interface was detected in 96.1% of cases. 17 knees (18.2%) had to be re-revised, 15 of them due to a recurrent infection and 2 due to aseptic reasons (mediolateral instability and a periprosthetic fracture). The median of the ROM (96°), SSS (8), KSS (87), WOMAC (9), SF-36 MCS (55) and SF-36 PCS (38) showed very satisfying results. CONCLUSION: No case of aseptic loosening was found in this large series of RTKA with extended bone defects using metaphyseal sleeve fixation. In this large retrospective series, it has been shown that this technique is an excellent treatment option for extended bone defects in RTKA surgery. LEVEL OF EVIDENCE: Retrospective cohort study, level III.

Septic Revision Total Knee Arthroplasty: Treatment of Metaphyseal Bone Defects Using Metaphyseal Sleeves.

BACKGROUND: Bone loss is a severe problem in septic revision total knee arthroplasty (RTKA). The use of porous coated metaphyseal sleeves is a promising treatment option for metaphyseal bone defects. The currently published midterm results remain limited and no study has been focused exclusively on septic cases. Our aim was to determine the implant survivorship (with special focus on osseointegration) and the clinical and radiological midterm outcome of metaphyseal sleeve fixation in septic RTKA surgery (minimum follow-up of 2 years). METHODS: We performed a clinical and radiographic examination of 56 patients with a history of prosthetic joint infection who underwent 2-stage RTKA with the use of porous coated metaphyseal sleeves. These examinations included evaluation of the American Knee Society Score, the Western Ontario and McMaster Universities Osteoarthritis Index, the Short Form (SF-36) Health survey as well as radiographic measurement to determine whether successful osseointegration had been achieved. RESULTS: Nine patients (16%) had to be re-revised at the time of follow-up (mean, 5.3 years; range, 2-11.2), all due to reinfection. We did not encounter any cases of aseptic loosening. The mean range of motion (92°, SD ± 21°), subjective satisfaction score (7, SD ± 2), American Knee Society Score (76, SD ± 19), Western Ontario and McMaster Universities Osteoarthritis Index (70, SD ± 20), SF-36 mental component summary (55, SD ± 14), and SF-36 physical component summary (35, SD ± 9) have shown satisfying results. CONCLUSION: Metaphyseal sleeves have shown very promising midterm results regarding clinical scores, osseointegration, and aseptic loosening. Our results are the first analyzing exclusively septic indications and indicate that they are a reliable fixation option in all bone defect types in septic RTKA patients.

Pedicle screw loosening is correlated to chronic subclinical deep implant infection: a retrospective database analysis.

PURPOSE: Spinal fusion is used for treatment of spinal deformities, degeneration, infection, malignancy, and trauma. Reduction of motion enables osseous fusion and permanent stabilization of segments, compromised by loosening of the pedicle screws (PS). Deep implant infection, biomechanical, and chemical mechanisms are suspected reasons for loosening of PS. Study objective was to investigate the frequency and impact of deep implant infection on PS loosening. METHODS: Intraoperative infection screening from wound and explanted material sonication was performed during revision surgeries following dorsal stabilization. Case history events and factors, which might promote implant infections, were included in this retrospective survey. RESULTS: 110 cases of spinal metal explantation were included. In 29.1% of revision cases, infection screening identified a germ, most commonly Staphylococcus (53.1%) and Propionibacterium (40.6%) genus. Patients screened positive had a significant higher number of previous spinal operations and radiologic loosening of screws. Patients revised for adjacent segment failure had a significantly lower rate of positive infection screening than patients revised for directly implant associated reasons. Removal of implants that revealed positive screening effected significant pain relief. CONCLUSIONS: Chronic implant infection seems to play a role in PS loosening and ongoing pain, causing revision surgery after spinal fusion. Screw loosening and multiple prior spinal operations should be suspicious for implant infection after spinal fusion when it comes to revision surgery. These slides can be retrieved under Electronic Supplementary Material.

Impact of a new cryotherapy device on early rehabilitation after primary total knee arthroplasty (TKA): a prospective randomised controlled trial.

BACKGROUND: The aim of this prospective, randomised and single blinded study was to evaluate the efficiency and safety of a new cryotherapy device in patients undergoing unilateral, primary total knee arthroplasty (TKA). Our hypothesis was that patients administered to the new cryotherapy device would perform better than patients receiving a conventional standard cold therapy regimen. METHODS: Ninety-seven patients were randomised into two groups receiving either the cTreatment® (new cryotherapy device) or the standard cold therapy protocol (including cold pack application for six days after the surgical intervention). We evaluated the following endpoints consisting of range of motion (ROM), pain intensity, and knee girth on admission day and the second, fourth, and sixth post-operative day (POD). RESULTS: A statistically significant benefit of the new cryotherapy device was detected regarding the ROM on the sixth POD with an average gain of 7 degrees (p = 0.021). Pain in the numeric rating scale (NRS) score in motion was significantly lower in the cTreatment® group on the second POD (p = 0.034). There were no statistically significant differences between groups regarding the NRS in rest, patient controlled analgesia (PCA) consumption, and girth measurements. No adverse effects were observed in both study groups. CONCLUSION: The new computer-controlled cooling therapy device provides benefits in terms of early post-operative remobilisation with respect to ROM and pain, which might be attributed to a reduced inflammatory response, as well as reduced secretion and bleeding. The cTreatment® system appears to be a safe and efficient procedure.

Superficial Vancomycin Coating of Bone Cement in Orthopedic Revision Surgery: A Safe Technique to Enhance Local Antibiotic Concentrations.

BACKGROUND: The use of antibiotic-loaded cement has become a well-accepted method to develop high local antibiotic concentrations in revision surgery of infected arthroplasty. A new surgical technique has been established to further increase the local antibiotic concentration and thereby minimizes the risk of reinfection. Our study aim was to investigate the safety of additional superficial vancomycin coating (SVC) by analyzing postoperative joint and serum vancomycin concentrations, as well as the creatinine levels of patients with orthopedic revision surgery. METHODS: A longitudinal case series was performed by reviewing collected data of patients who were treated by SVC during revision surgery (1- or 2-stage exchange) because of prosthetic joint infections. Vancomycin levels were obtained, local from drains and systemic from blood samples, on postoperative days 1 to 5. Furthermore, preoperative and postoperative serum creatinine levels were analyzed. RESULTS: Highest median local vancomycin levels were documented on postoperative day 1 with 546.8 µg/mL (range, 44.4-1485 µg/mL) in the reimplantation group and 408.7 µg/mL (range, 24.7-1650 µg/mL) in the spacer group. Median serum vancomycin level was 4.4 µg/mL (range, <2.0-11.7 µg/mL) on the first postoperative day in the reimplantation group and <2.0 µg/mL (range, <2.0-3.9 µg/mL) in the spacer group, and lower than 2.0 µg/mL (range, <2.0-7.5 µg/mL) from postoperative day 2 to 5 in both groups. Neither an anaphylactic reaction nor other side effects to SVC were observed. CONCLUSION: Our data showed that SVC of bone cement is an effective technique to enhance local concentrations of vancomycin without leading to systemic side effects.

Similar rate of infection eradication for functional articulating, prefabricated and custom-made spacers in 2-stage revision of the infected total hip: a literature review.

BACKGROUND: 2-stage revision with the use of an antibiotic-loaded interval spacer is therapy of choice in late periprosthetic joint infection for most surgeons. For the spacer, either a prefabricated, functional articulating or custom-made spacer can be used. Little is known about which type of spacer provides optimal outcome after 2-stage revision. The aim of this study was to determine which type of spacer provides the best results, when used in 2-stage revision of an infected THA. METHODS: We performed a systematic review of the literature to analyse which type of interval spacer provides highest infection eradication rate and best functional outcome after a minimum 2 year follow-up. Exclusion criteria were follow-up of less than 2 years, single-stage revision, or 2-stage revision without use of a spacer. RESULTS: 25 studies were included. Infection eradication rate was similar with rates of 96%, 93% and 95% for the prefabricated-, functional articulating- and custom-made spacers respectively. Functional outcome was scarcely described. Postoperative HHS was 81, 90 and 83 respectively. CONCLUSIONS: Functional articulating spacers achieve a comparable rate of infection eradication in the treatment of periprosthetic hip joint infections as compared to preformed or custom-made antibiotic-loaded spacers. There is insufficient evidence concerning rehabilitation and functional outcome after 2-stage revision hip arthroplasty to advocate or discourage the use of either kind of interval spacer.

Effect of Laminin-A4 inhibition on cluster formation of human osteoarthritic chondrocytes.

Formation of chondrocyte clusters is not only a morphological sign of osteoarthritis but it is also observed in cell culture. Active locomotion of chondrocytes is controlled by integrins in vitro. Integrins bind to Laminin-A4 (LAMA4), a protein that is highly expressed in vivo in clusters of hypertrophic chondrocytes. We tested if LAMA4 is relevant for cluster formation. Human chondrocytes were cultured in a 2D matrigel model and treated with different concentrations of a monoclonal inhibitory anti-LAMA4-antibody. Migration and cluster formation was analysed using live cell imaging technique. Full genome gene expression analysis was performed to assess the effect of LAMA4 inhibition. The data set were screened for genes relevant to cell motility. F-actin staining was performed to document cytoskeletal changes. Anti-LAMA4 treatment significantly reduced the rate of cluster formation in human chondrocytes. Cells changed their surface morphology and exhibited fewer protrusions. Expression of genes associated with cellular motility and migration was affected by anti-LAMA4 treatment. LAMA4-integrin signalling affects chondrocyte morphology and gene expression in vitro, thereby contributing to cluster formation in human osteoarthritic chondrocytes.