Revision Total Knee Research Articles

General vs Spinal Anesthesia for Revision Total Knee Arthroplasty: Do Complication Rates Differ?

BackgroundThe incidence of both primary total knee arthroplasty (TKA) and revision TKA is increasing. Data from primary arthroplasty patients suggest a risk reduction with the use of spinal anesthesia when compared with general anesthesia. However, the same relationship has not been examined in the revision knee arthroplasty patient. MethodsThis is a retrospective cohort study using the American College of Surgeons-National Surgical Quality Improvement database. Patients undergoing revision TKA with either spinal or general anesthesia were identified from the database. Baseline characteristics were compared, and ultimately patients were matched using coarsened exact matching. Multivariate analysis was then performed on matched cohorts controlling for baseline patient and operative characteristics. This model was used to look for any differences in rates of complications, operative time, length of stay, and readmission. ResultsPatients undergoing revision TKA with general anesthesia had increased risk of several postoperative complications, even after controlling for baseline patient characteristics. Specifically, there were significantly increased rates of the following: unplanned readmission (OR = 1.43, 95% confidence interval [CI] = 1.18-1.72, P < .001), nonhome discharge (OR = 1.60, 95% CI = 1.46-1.76, P < .001), transfusion (OR = 1.63, 95% CI = 1.41-1.88, P < .001), deep surgical site infection (OR = 1.43, 95% CI = 1.01-2.03, P = .043), and extended length of stay (OR = 1.22, 95% CI = 1.11-1.34, P < .001). General anesthesia was additionally associated with increased operative time. ConclusionGeneral anesthesia is associated with increased risk of numerous postoperative complications in patients undergoing revision TKA. This study is retrospective in nature, and while causality cannot be definitively determined, the results suggest that spinal anesthesia is preferential to general anesthesia in the revision TKA patient.

Are Joint Surgeons Being Adequately Compensated for Single-Component versus Double-Component Revision TKA? An Analysis of Relative Value Units.

Relative value units (RVUs) are used for ensuring that physicians are appropriately reimbursed based on case complexity. While past research has elucidated that surgeons are reimbursed at a higher rate for primary total knee arthroplasty (TKA) versus revision TKA, no study has explored differences in reimbursements between single-component and double-component revisions, considering a double-component revision is likely to require more effort/skill as compared with single-component revision. The 2015 to 2016 American College of Surgeons National Surgical Quality Improvement Program files were queried using Current Procedural Terminology (CPT) codes for single-component revision TKA (CPT-27486) and double-component revision TKA (CPT-27487). A total of 1,962 single-component and 4,184 double component revisions were performed during this period. Total RVUs, RVU/min, and dollar amount/min were calculated for each case. The mean RVU was 21.12 and 27.11 for single-component and double-component revision TKAs, respectively. A statistically significant difference was noted in mean operative time (single component = 100.44 vs. double component = 144.29; p < 0.001) between the two groups. Single-component revision had a significantly higher mean RVU/min (0.267) versus double-component revision (0.223). The reimbursement amounts calculated for single-component versus double-component revisions were per minute ($9.58/min vs. $8.00/min), per case ($962.22 vs. $1,154.32), and per day ($5,773.32 vs. $4,617.28) with a projected annualized cost difference of $184,966. Orthopaedic surgeons are reimbursed at a higher rate for single-component revision TKAs as compared with double-component revision TKAs, despite the higher complexity and longer operative times required in the latter. The study highlights the need for a change in the RVUs for either double-component or single-component revision to ensure reimbursement per unit time is adequate for performing a complex case such as double-component revision TKA.

Reconsidering Strategies for Managing Chronic Periprosthetic Joint Infection in Total Knee Arthroplasty: Using Decision Analytics to Find the Optimal Strategy Between One-Stage and Two-Stage Total Knee Revision.

Periprosthetic joint infection (PJI) following total knee arthroplasty is a growing concern, as the demand for total knee arthroplasty (TKA) expands annually. Although 2-stage revision is considered the gold standard in management, there is substantial morbidity and mortality associated with this strategy. One-stage revision is associated with lower mortality rates and better quality of life, and there has been increased interest in utilizing the 1-stage strategy. However, surgeons are faced with a difficult decision regarding which strategy to use to treat these infections, considering uncertainty with respect to eradication of infection, quality of life, and societal costs with each strategy. The purpose of the current study was to use decision analysis to determine the optimal decision for the management of PJI following TKA. An expected-value decision tree was constructed to estimate the quality-adjusted life-years (QALYs) and costs associated with 1-stage and 2-stage revision. Two decision trees were created: Decision Tree 1 was constructed for all pathogens, and Decision Tree 2 was constructed solely for difficult-to-treat infections, including methicillin-resistant infections. Values for parameters in the decision model, such as mortality rate, reinfection rate, and need for additional surgeries, were derived from the literature. Medical costs were derived from Medicare data. Sensitivity analysis determined which parameters in the decision model had the most influence on the optimal strategy. In both decision trees, the 1-stage strategy produced greater health utility while also being more cost-effective. In the Monte Carlo simulation for Decision Trees 1 and 2, 1-stage was the dominant strategy in about 85% and 69% of the trials, respectively. Sensitivity analysis showed that the reinfection and 1-year mortality rates were the most sensitive parameters influencing the optimal decision. Despite 2-stage revision being considered the current gold standard for infection eradication in patients with PJI following TKA, the optimal decision that produced the highest quality of life was 1-stage revision. These results should be considered in shared decision-making with patients who experience PJI following TKA. Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

Long-term results of fresh osteochondral allografts and realignment osteotomy for cartilage repair in the knee.

The aim of this study was to report the outcome of femoral condylar fresh osteochondral allografts (FOCA) with concomitant realignment osteotomy with a focus on graft survivorship, complications, reoperation, and function. We identified 60 patients (16 women, 44 men) who underwent unipolar femoral condylar FOCA with concomitant realignment between 1972 and 2012. The mean age of the patients was 28.9 years (10 to 62) and the mean follow-up was 11.4 years (2 to 35). Failure was defined as conversion to total knee arthroplasty, revision allograft, or graft removal. Clinical outcome was evaluated using the modified Hospital for Special Surgery (mHSS) score. A total of 14 grafts (23.3%) failed at a mean of 8.6 years (1.4 to 20.1). Graft survivorship was 87.3% (95% confidence interval (CI) 79.0 to 96.6), 85.0% (95% CI 75.8 to 95.3), 74.8% (95% CI 62.2 to 90.0), 65.2% (95% CI 49.9 to 85.2), and 59.8% (95% CI 43.5 to 82.1) at five, ten, 15, 20, and 25 years, respectively. A total of 23 patients (38.3%) developed complications, and 26 (43.3%) had a further operation. Persistent postoperative malalignment occurred more frequently in failed grafts (28.6% vs 4.3%; p = 0.023), and was a risk factor for graft failure (hazard ratio 6.55; 95% CI 1.61 27.71; p = 0.009). The mean mHSS score improved from 74.1 (40 to 91) preoperatively to 89.0 (66 to 100) at final follow-up (p < 0.001). Femoral condylar FOCA with concomitant realignment osteotomy provides excellent long-term graft survival and reliable functional improvement. Persistent malalignment may increase the risk for graft failure.

Rate of surface contamination in the operating suite during revision total joint arthroplasty.

BackgroundThis study estimated operating room surface contamination rates during aseptic vs septic total joint arthroplasty and evaluated the similarity between clinically infecting organisms and those isolated from contaminated surfaces.MethodsPatients undergoing total hip and knee revision arthroplasties were identified, and surface and tissue samples were collected. Cases were classified aseptic or septic based on Musculoskeletal Infection Society criteria for prosthetic joint infection. Positive surface cultures were compared with intraoperative tissue cultures. Positive cultures were speciated and tested for antimicrobial sensitivity.ResultsSamples were collected from 31 aseptic and 18 septic cases. Patients had similar demographics and time to explantation. Surface contamination rates for septic revisions were greater than those for aseptic revisions (77% vs 13%). During septic revisions, when intraoperative tissue cultures were positive, the surgical field was contaminated in 14 of 15 cases. The kappa correlation statistic for positive surgical cultures matching the surface sample was 0.9 (95% confidence interval: 0.78-1).ConclusionsSeptic revisions had a significantly higher rate of surgical field contamination than aseptic revisions. Cultures suggest that bacteria contaminating the septic revision surgical field likely originated from the infected joint. Although this observation seems obvious, it is an important piece of information when discussing best practices during a single-stage exchange revision. Further clinical studies will demonstrate the use of a preparation and reset period during a single-stage revision to remove contaminated surfaces.

Conversion Knee Arthroplasty Using a Rotating Hinge as a Salvage Prosthesis Following Periprosthetic Joint Infection and Ligamentous Insufficiency: A Case Report

BackgroundIn the event of a complex revision TKA in which there is extensor mechanism involvement and ligamentous instability or insufficiency, non-linked levels of constraint may not be adequate for achieving restoration of patient function. Total knee arthroplasty devices that incorporate a linked level of constraint are successful alternatives to unlinked devices (PS and PS-Constrained) in this clinical context.Case PresentationWe present the case of a 62 year-old male patient that required a non-articulating knee fusion and multiple total knee arthroplasty revisions in conjunction with a ruptured and repaired extensor mechanism, ligamentous instability, bone loss and periprosthetic joint infection. (Revision knee prosthesis that includes a increasing degree of nodularity and physical constraint). The subsequent risk factors associated with the loss of bone and ligamentous insufficiency required performing conversion arthroplasty with a knee prosthesis that includes an increasing degree of modularity and physical constraint not commonly used in revision total knee arthroplasty.DiscussionThe authors report on a patient who underwent multiple operative procedures, we outline the step wise decision making progression that lead to the successful eradication of the PJI and reimplant device strategy based on the confounding factors presented. We assess the use of revision TKA systems that offer extreme degrees of constraint which should be considered in complex revision knee revision procedures.

Similar Outcomes of Two-Stage Revisions for Infection and One-Stage Revisions for Aseptic Revisions of Knee Endoprostheses.

Two-stage revision knee arthroplasty using an antibiotic-loaded spacer is the most widely performed procedure for infected knee arthroplasties. The clinical outcome of this type of surgery compared with aseptic joint revision with exchange of tibial and femoral components is still controversial. Therefore, we analyzed clinical outcomes of septic two-stage revisions compared with aseptic one-stage revision total knee arthroplasties (TKAs). In a retrospective study, we assessed 135 consecutive patients who underwent two-stage revision for septic TKA (52 patients) and one-stage aseptic total knee revision arthroplasty (83 patients). The average follow-up was 26.1 months for the aseptic group and 26.5 months for the septic group. For clinical evaluation, we used the Knee Society Score, Oxford Knee Score, Kujala score, Turba score, and the Short Form 36 (SF-36). Postoperative pain level was determined using the visual analog pain scale. The surgeries were performed 51 months (aseptic group) and 24 months (septic group) after primary TKA on average. The main indications for aseptic revision surgeries were instability (40%), aseptic loosening (22.4%), anterior knee pain due to pathologies of the patella (11.8%), or material wear (5.9%). In the clinical outcome, patients achieved 124.8 points in the aseptic group and 105.4 points in the septic group in the Knee Society Score. The Oxford Knee Score revealed 29.9 points for the aseptic group and 33.9 points for the septic group. For the Kujala score, we found 53.2 points in the aseptic group and 48.5 points in the septic group. For the Turba score, we found 8.4 points in the aseptic group and 10.8 points in the septic group. The SF-36 (psychical) showed 52.2 versus 49.5 points and the SF-36 (physical) showed 36.5 versus 35.4 points. Mean level of persisting pain on the visual analog scale was 3.0 (aseptic group) and 3.5 (septic group). Performing septic two-stage or aseptic one-stage tibial and femoral revision knee arthroplasty showed similar clinical outcomes in relation to objective and subjective outcome measures.

Significant increase of pathogen detection rate by dry arthroscopic biopsies at suspected low-grade infection following total knee arthroplasty: a prospective observational study.

The differentiation between stiff-knee and low-grade periprosthetic joint infection (PJI) is the current diagnostic challenge in total knee (TKA) revision arthroplasty. The aim of this study was to investigate the additional value of dry biopsies, compared to wet biopsies, in patients presenting with knee stiffness following primary TKA. Single center, prospective observational study. Consecutive patients with joint stiffness of unknown origin following primary TKA were enrolled. Patient assessment followed the diagnostic standard algorithm. During diagnostic arthroscopy, synovial fluid (synovial WBC, PMN%) and five dry biopsies (dry) were collected. Then fluid was infused and another five microbiology (wet) and five histological biopsies gathered, all from identical locations. The primary outcome parameter was the difference between the pathogens in wet and dry biopsies. 71 patients (61% females, 67 ± 10years) were eligible. Preoperative blood serology mean CRP (0.7 ± 1.5mg/dl; p = 0.852), WBC (6.6 ± 1.7 G/l; p = 0.056), and synovial fluid mean WBC (1639 ± 2111; p = 0.602), PMN% (38 ± 28; p = 0.738) did not differ between patients with negative, positive wet or dry biopsies. The histology was in 11% positive (p = 0.058). In 32% at least one pathogen was detected, 48% from wet, 44% from dry biopsies. An inhomogeneous distribution was found. Cutibacterium acnes (100%) was solely found in wet, Micrococcus luteus (75%), Staphylococcus capitis (67%), and Micrococcus lylae (100%) were predominantly found in dry biopsies. Additional dry biopsies increased the pathogen detection rate by 49%. The addition of dry biopsies to the current standard diagnostic algorithm for PJI increased the pathogen detection rate by 49%.

Optimal use of stems in revision TKA

Stems supplement the fixation of the femoral and tibial components in revision total knee (TKA) arthroplasty. The type of stem needed varies with the location and amount of bone loss present making no one stem design appropriate for all revision TKAs.Stems of variable lengths, with or with offset options, and supplemented with either/and cement and porous augments have their benefit and must be individualized to the situation present. The pros and cons of each design will be discussed.

The Use of Tantalum Metaphyseal Cones for the Management of Severe Bone Defects in Septic Knee Revision

BackgroundFemoral and tibial massive bone defects are common findings in septic total knee revision and pose considerable challenges for the orthopedic surgeon. The aim of this study was to report the midterm clinical and radiographic outcomes with the use of tantalum cones for the management of massive bone defects after 2-stage knee revision. MethodsWe retrospectively reviewed the medical records of 60 patients (mean age, 67.9 ± 8.8 years) treated with 94 tantalum cones associated with constrained or semiconstrained knee for massive bone loss (mean follow-up, 43.5 ± 17.4 months). In all cases, the indication was a staged revision for periprosthetic knee infection. Functional scores, radiographic outcomes, and implant survivorship were analyzed. ResultsThe mean Knee Society Score and Oxford Knee Score improved from 44.1 ± 7.4 and 19.2 ± 4.1 to 85.4 ± 5.6 and 38.4 ± 3.9 (P < .01), respectively. The mean flexion increased from 60.6° ± 15.5° to 96.8° ± 10.9° at the last evaluation (P < .01). The mean improvement in flexion contracture was 6.2 ± 8.0 (P < .01). Two failures (3.3%) due to periprosthetic knee infection recurrence were observed, but no cone-related mechanical failures were reported. The cone-related survival rate was 97.8%. ConclusionExcellent clinical and radiographic midterm outcomes were achieved with a low complication rate. Tantalum cones may be considered a safe and effective option in the management of massive bone defects also in septic knee revision surgery.

Mortality During Total Knee Periprosthetic Joint Infection

BackgroundPeriprosthetic joint infections (PJIs) are fraught with multiple complications including poor patient-reported outcomes, disability, reinfection, disarticulation, and even death. We sought to perform a systematic review asking the question: (1) What is the mortality rate of a PJI of the knee undergoing 2-stage revision for infection? (2) Has this rate improved over time? (3) How does this compare to a normal cohort of individuals? MethodsWe performed a database search in MEDLINE/EMBASE, PubMed, and all relevant reference studies using the following keywords: “periprosthetic joint infection,” “mortality rates,” “total knee arthroplasty,” and “outcomes after two stage revision.” Two hundred forty-two relevant studies and citations were identified, and 14 studies were extracted and included in the review. ResultsA total of 20,719 patients underwent 2-stage revision for total knee PJI. Average age was 66 years. Mean mortality percentage reported was 14.4% (1.7%-34.0%) with average follow-up 3.8 years (0.25-9 years). One-year mortality rate was 4.33% (3.14%-5.51%) after total knee PJI with an increase of 3.13% per year mortality thereafter (r = 0.76 [0.49, 0.90], P < .001). Five-year mortality was 21.64%. When comparing the national age-adjusted mortality (Actuarial Life Table) and the reported 1-year mortality risk in this meta-analysis, the risk of death after total knee PJI is significantly increased, with an odds ratio of 3.05 (95% confidence interval, 2.69-3.44; P < .001). ConclusionThe mortality rate after 2-stage total knee revision for infection is very high. When counseling a patient regarding complications of this disease, death should be discussed.

Comparison of Research Participation among African American and Caucasian Children with Food Allergy

The purposes of this study were to (1) test the accuracy of α-defensin and combined α-defensin-aspiration cultures in diagnosing periprosthetic joint infection (PJI) before revision total knee and hip arthroplasty and (2) evaluate Musculoskeletal Infection Society (MSIS) criteria and α-defensin as predictors of successful reimplantation (second-stage) at 1 year after surgery.We retrospectively evaluated a total of 97 synovial fluid aspirations performed between August 2014 and September 2016 before revision due to septic or aseptic failures (n = 70) or before second-stage (n = 27) joint arthroplasty. Revisions were categorized as either septic or aseptic according to the MSIS criteria. Synovial fluid was tested for α-defensin, cell count with differential, and cultures. Reimplantations were assessed for success or failure (defined as the need for reoperation due to infection) within 1 year after surgery.For septic and aseptic revision arthroplasty, the sensitivity, specificity, positive predictive value, and negative predicted value of α-defensin was 97% while for the combined α-defensin and aspiration culture, it was 96%, 100%, 100%, and 97%. Despite being performed with negative MSIS criteria and α-defensin test results, 11% (3/27) of reimplantations (second-stage) failed within 1 year postoperatively because of infection.Alpha-defensin is an accurate diagnostic test for the diagnosis of PJI before revision arthroplasty. The combination of α-defensin and aspiration cultures has higher specificity and positive predictive value. MSIS criteria and α-defensin may help predict the success of reimplantations within 1 year after surgery.

Identifying Common Pathogens in Periprosthetic Joint Infection and Testing Drug‐resistance Rate for Different Antibiotics: A Prospective, Single Center Study in Beijing

The aim of this study is to identify the common microorganisms causing PJI as well as the drug-resistant spectrum for each microorganism, to help orthopaedic surgeons to choose appropriate antibiotics. One hundred and sixty patients who suffered from failure of primary or revision total hip or knee arthroplasty for different reasons were prospectively recruited. These patients underwent revision or re-revision total hip or knee arthroplasty in our institution between August 2013 to August 2016. The details of patients' medical history and comprehensive physical examination, as well as demographic data were recorded precisely. Routine blood test results, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6) levels, and synovial leukocyte counts were collected. Additionally, aspiration was conducted during surgery to avoid pollution unless when PJI was strongly suspected, in which case, joint puncture and aspiration were conducted before surgery. Intraoperatively, the implant-surrounding tissue and the prosthesis were collected under aseptic conditions. Postoperatively, the prosthesis, implant-surrounding tissue and synovium were sent to the laboratory immediately. The sonicate extraction (the prosthesis was sent for ultrasound sonication first), implant surrounding tissue and synovium were sent for microbiologic culture, and the implant-surrounding tissue was also sent for pathological examination. The isolated bacteria strains and drug-resistance rates for each pathogen for different antibiotics were presented. There were 59 PJI cases in the infectious group and 101 cases in the non-infectious group (PJI is diagnosed according to the diagnosing criteria from the Workgroup of the Musculoskeletal Infection Society). Of 69 strains of pathogens isolated, Gram-positive bacterium is the most common pathogenic bacteria causing PJI (60, 86.96%). Staphylococcus epidermidis and Staphylococcus aureus played an important role as well, followed by Gram-negative bacteria (8, 11.59%) and fungus (1, 1.45%). Penicillin (78.57%), erythromycin (66.67%) and clindamycin (44.74%) showed high antibiotic resistance rate. In addition, the second-generation cephalosporin, usually as the prophylactic antibiotic, resistance rate was high (20%) as well. Fortunately, no vancomycin-resistant bacteria were discovered in the current study. This study provides some information on the most common pathogens in our institution and the selection of antibiotics in the perioperative period in northern China. Cefuroxime and clindamycin might not be appropriate for use as prophylactic antibiotics in revision total knee or hip arthroplasty. Vancomycin is ideal for empiric antibiotic use in suspected PJI cases because of the low drug-resistance rate.

Tibial Tubercle Osteotomy in Total Knee Arthroplasty: Midterm Results Experience of a Monocentric Study.

Purpose Difficult primary total knee arthroplasty (TKA) and revision TKA may be high demanding, especially during joint exposure. Aim of this article is to evaluate the clinical and radiological outcomes of a series of patients, who underwent TKA and revision TKA, where tibial tubercle osteotomy (TTO) was performed. Methods We retrospectively reviewed a cohort of 79 consecutives TKAs where TTO was performed. Patients were assessed clinically and radiographically at their last follow-up (mean, 7.4 ± 3.7 years). Clinical evaluation included the Knee Society Score (KSS), the pain visual analogue scale (VAS), and range of motion. Radiological assessment included the evaluation of radiolucent lines, osteolysis, cortical bone hypertrophy, time of bone healing of the TTO fragment, and the hardware complication. Results KSS raised from 40.7 ± 3.1 to 75 ± 4.3 ( p < 0.0001). Knee flexion increased from 78.7 ± 9.9° to 95.0 ± 9.5° ( p < 0.0001), and VAS improved from 7.9 ± 0.9 to 3.8 ± 1 ( p < 0.0001). No signs of loosening or evolutive radiolucency lines were found. Osteolytic areas around the stem were detected. No significant association was found between the implant design and the outcomes, while aseptic loosening showed significantly better results. Complications were: 4 painful hardware, 3 late periprosthetic infections, 1 extension lag of 5°, and 3 flexion lag. Conclusion Our experience suggests the use of TTO to improve the surgical approach in difficult primary TKA or revision TKA. A precise surgical technique leads to good results with low risk of complications. Level of Evidence Level IV, therapeutic case series.

A Risk Calculator Using Preoperative Opioids for Prediction of Total Knee Revision Arthroplasty.

Total knee arthroplasty (TKA) is a procedure to improve quality of life. However, some patients require early total knee revision (TKR). Chronic opioid use before TKA is associated with TKR. No risk calculator including opioid use or other risk factors is currently available for predicting TKR. We retrospectively analyzed medical records of Veterans Affairs patients who underwent TKA from January 1, 2006 to January 1, 2012. Patients were followed until January 1, 2013. Chronic opioid use was defined as opioid use for ≥3 months preoperatively. A cross-validated Cox proportional hazards model was created to predict TKR before initial TKA. Model performance was evaluated by the mean absolute error at 1 and 5 years. Totally, 32,297 patients were included. A risk calculator was generated with a mean absolute error of 0.1% at 1 year and 3.6% at 5 years. Chronic opioid use was a significant predictor of TKR (hazard ratio [HR], 1.27; 95% confidence interval, 1.13-1.43; P<0.001). Other model variables were age (HR, 0.95; P<0.001), female sex (HR, 0.77; P=0.020), body mass index (HR, 0.99; P=0.022), diabetes (HR, 1.20; P=0.001), chronic kidney disease (HR, 1.48; P<0.001), and nonchronic opioid use (HR, 1.07; P=0.313). Preoperative chronic opioid use is a predictor of TKR. Using this association and others, a TKA revision risk calculator was generated at http://www.bit.do/tka.

Correlation of tibial bone defect shape with patient demographics following total knee revision

BackgroundBone defects of the proximal tibia following revision total knee arthroplasty (TKA) are challenging to manage, but must be addressed to provide lasting stability. This paper will categorize tibial bone defects into shape groups and correlate resulting groups to patient demographic data. MethodsRetrospective analysis of four hundred and four patients post revision TKA between January 2005 and February 2014 was conducted. One hundred and eighteen met the inclusion criteria and were subcategorized by defect shape on their post-operative lateral and anterior-posterior (AP) radiographs. The subgroups of defect shape were subsequently analyzed with Fisher’s exact test and one way ANOVA. ResultsTrapezoidal shaped defects were the most common in both radiographic views, and the magnitude of the defect at the top joint line varied significantly amongst shape groups in both AP and lateral views. Trapezoid shaped defects were correlated with smaller defect top lengths in both views. There was no statistical correlation between defect shape BMI, TIV and reason for revision in lateral view. However, T-bilateral defect shapes were correlated with higher BMIs in AP view. ConclusionA volumetric classification system of tibial defects is necessary for preoperative planning in revision TKA. Common tibial bone defect shape groups were identified and analyzed in AP and lateral radiographs after revision TKA. Trapezoidal defects were the most common, and all other shapes followed a pattern of proximal enlargement tapering distally. Trapezoidal defects were smaller than other shapes and AP T-bilateral shaped defects were correlated with higher BMIs.

What Is the Optimal Criteria to Use for Detecting Periprosthetic Joint Infections Before Total Joint Arthroplasty?

BackgroundThe purposes of this study were to (1) test the accuracy of α-defensin and combined α-defensin-aspiration cultures in diagnosing periprosthetic joint infection (PJI) before revision total knee and hip arthroplasty and (2) evaluate Musculoskeletal Infection Society (MSIS) criteria and α-defensin as predictors of successful reimplantation (second-stage) at 1 year after surgery. MethodsWe retrospectively evaluated a total of 97 synovial fluid aspirations performed between August 2014 and September 2016 before revision due to septic or aseptic failures (n = 70) or before second-stage (n = 27) joint arthroplasty. Revisions were categorized as either septic or aseptic according to the MSIS criteria. Synovial fluid was tested for α-defensin, cell count with differential, and cultures. Reimplantations were assessed for success or failure (defined as the need for reoperation due to infection) within 1 year after surgery. ResultsFor septic and aseptic revision arthroplasty, the sensitivity, specificity, positive predictive value, and negative predicted value of α-defensin was 97% while for the combined α-defensin and aspiration culture, it was 96%, 100%, 100%, and 97%. Despite being performed with negative MSIS criteria and α-defensin test results, 11% (3/27) of reimplantations (second-stage) failed within 1 year postoperatively because of infection. ConclusionAlpha-defensin is an accurate diagnostic test for the diagnosis of PJI before revision arthroplasty. The combination of α-defensin and aspiration cultures has higher specificity and positive predictive value. MSIS criteria and α-defensin may help predict the success of reimplantations within 1 year after surgery.

Clinical and Functional Outcomes: Primary Constrained Condylar Knee Arthroplasty Compared With Posterior Stabilized Knee Arthroplasty.

Constrained condylar knee (CCK) prostheses are commonly used in difficult primary total knee arthroplasty and revision total knee arthroplasty. We postulate that the use of CCK prostheses in primary knee arthroplasty may result in decreased range of motion but with better patient-reported functional scores compared with primary posterior stabilized (PS) knee prostheses because of increased varus and valgus stability from increased constraint. We conducted a case-control study using prospectively collected data on functional outcome scores and range of motion preoperatively and at 6 months and at 2 years. Thirty-eight patients with primary CCK arthroplasty were matched with 38 patients with primary PS knee arthroplasty treated by a single surgeon. Institutional review board approval was obtained. Analysis was done using the independent t-test. Total 76 patients with 61 (80.3%) female patients, 30 (39.5%) left knees, and 9 (11.8%) valgus knees. There was no significant difference in preoperative age (CCK arthroplasty 70.7 ± 6.0 years versus PS knee arthroplasty 68.5 ± 5.2 years; P < 0.085), body mass index (27.2 ± 4.4 versus 26.3 ± 5.2; P < 0.44), Oxford Knee Score (35.8 ± 7.8 versus 36.0 ± 7.6; P < 0.92), and Medical Outcomes Study 12-Item Short Form (SF-36) scores and knee extension (8.0° ± 6.7° versus 7.7° ± 7.6°; P < 0.84). There was no significant difference in preoperative knee flexion (106.0° ± 22.9° versus 117.3° ± 20.1°; P < 0.026). There was no significant difference in 6-month knee extension (4.5° ± 6.8° versus 4.1° ± 4.5°; P < 0.80), knee flexion (110.5° ± 15.8° versus 110.9° ± 15.5°; P < 0.92), Oxford Knee Score (18.9° ± 3.4° versus 20.1° ± 5.3°; P < 0.27), and SF-36 scores. There was no significant difference in 2-year knee extension (1.8° ± 5.7° versus 1.5° ± 4.0°; P < 0.82), knee flexion (111.3° ± 13.6° versus 115.0° ± 16.5°; P < 0.30), Oxford Knee Score (18.5° ± 3.7° versus 18.2° ± 4.2°; P < 0.77), and SF-36 scores. The use of CCK prostheses in primary knee arthroplasty gives similar clinical and functional outcomes at 2 years as those of PS knee prostheses, despite increased constraint.

Treatment options and prognosis of infection after total knee arthroplasty

Objective To investigate surgical interventions for periprosthetic joint infection (PJI) after total knee arthroplasty and characteristics of prognosis. Methods Sixty-two patients with PJI after total knee arthroplasty from January 2000 to November 2016 were reviewed retrospectively, included with 17 males and 45 females. The mean age was 66.0±10.2 years old (37-85). Fourty-nine patients were diagnosed with osteoarthritis, 9 with rheumatoid arthritis, 2 with secondary ankyloses after suppurative arthritis and 2 with hemophilia arthritis. Forty-one patients underwent unilateral total knee arthroplasties, and 21 bilateral total knee arthroplasties. Characteristics of PJI, including infection types, existence of sinus tract, infectious pathogen, surgical intervention and patients' prognosis, were collected. Results Twenty-four patients underwent open debridement with prothesis retention. In the 14 successful cases, medial time interval between primary total knee arthroplasty and debridement was 33 days. One case of positive Methicillin resistant Staphylococcus aureus culture of joint aspiration, and 1 case formed sinus tract. In 10 cases of failed debridement, the medial time interval was 270 d. Intra-articular culture presented 4 cases of antibiotic resistant bacteria, and 6 cases formed sinus tract. Except for one patient gave up treatment and another received arthrodesis, the other 8 failed cases were all treated with revisions. In 46 revisions, nine patients underwent one-stage revisions. The mean time interval between primary total knee arthroplasty and revision was 15.9±14.5 d. Intra-articular culture presented 3 cases of antibiotic resistant bacteria, and 1 case formed sinus tract. In the other 37 two-stage revisions, the mean time interval was 1 045.7±1 044.1 d. Intra-articular culture showed 15 cases of antibiotic resistant bacteria, and 12 cases formed sinus tract. The mean follow-up duration was 73.9±48.2 months. At the last follow-up, all patients were free of antibiotics treatment. The mean Knee Society Score (KSS) was 85.9±4.3 after successful open debridement with prothesis retention. The KSS of one-stage revision patients was 78.5±3.3, while that of two stage revision patients was 65.7±7.4. Statistical difference was found among groups (P<0.05). Conclusion For PJI within 3 weeks after total knee arthroplasty without sinus tract or intra-articular culture of antibiotic resistant bacteria, open debridement with prosthesis retention could be recommended. One stage revision could be applied in infectious cases which appeared between 3 weeks to 1 month after primary surgery or in cases with unstable prostheses found in open debridement. For infectious cases longer than 1 month after primary procedure or those with sinus tract, severe soft tissue deficiency, intra-articular culture of antibiotic resistant bacteria, two-stage revision could be recommended. Key words: Arthroplasty, replacement, knee; Prosthesis-related infections; Reoperation; Debridement

Tibial tubercle osteotomy (TTO) in total knee arthroplasty, is it worth it? A review of the literature.

Tibial tubercle osteotomy (TTO) is a well-established extensile approach to improve joint visualization and implant removal. Despite this, TTO is a challenging technique with a long learning curve and potential pitfalls. Complications are not infrequent, even if performing the correct surgical steps. Aim of this paper is to review the current literature about TTO, its safeness and reliability, and finally the complications rate. We performed a systematic review of the available English literature, considering the outcomes and the complications of TTO. The combinations of keyword were "tibial tubercle osteotomy", "total knee arthroplasty", "total knee revision", "outcomes", "complication" and "surgical approach". From the starting 322 papers available, 26 manuscripts were finally included. Most of the papers show significant improvements in clinical outcomes, both in primary and in revision procedures. Radiographic fragment healing is close to 100%. Related complications can range from 3.8-20%. TTO may be necessary to correct pathological tuberosity position or patella tracking. However, TTO is a challenging technique to improve the surgical approach during total knee arthroplasty. A strict surgical technique can lead to better results and to minimize complications. However, it is not clear if the improved outcome can outweigh the longer surgery and the higher risk of pitfalls.