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BACKGROUND - Experimental data indicate that reducing factor XI levels attenuates thrombosis without causing bleeding, but the role of factor XI in the prevention of postoperative venous thrombosis in humans is unknown. FXI-ASO (ISIS 416858) is a second-generation antisense oligonucleotide that specifically reduces factor XI levels. We compared the efficacy and safety of FXI-ASO with those of enoxaparin in patients undergoing total knee arthroplasty.
METHODS - In this open-label, parallel-group study, we randomly assigned 300 patients who were undergoing elective primary unilateral total knee arthroplasty to receive one of two doses of FXI-ASO (200 mg or 300 mg) or 40 mg of enoxaparin once daily. The primary efficacy outcome was the incidence of venous thromboembolism (assessed by mandatory bilateral venography or report of symptomatic events). The principal safety outcome was major or clinically relevant nonmajor bleeding.
RESULTS - Around the time of surgery, the mean (±SE) factor XI levels were 0.38±0.01 units per milliliter in the 200-mg FXI-ASO group, 0.20±0.01 units per milliliter in the 300-mg FXI-ASO group, and 0.93±0.02 units per milliliter in the enoxaparin group. The primary efficacy outcome occurred in 36 of 134 patients (27%) who received the 200-mg dose of FXI-ASO and in 3 of 71 patients (4%) who received the 300-mg dose of FXI-ASO, as compared with 21 of 69 patients (30%) who received enoxaparin. The 200-mg regimen was noninferior, and the 300-mg regimen was superior, to enoxaparin (P<0.001). Bleeding occurred in 3%, 3%, and 8% of the patients in the three study groups, respectively.
CONCLUSIONS - This study showed that factor XI contributes to postoperative venous thromboembolism; reducing factor XI levels in patients undergoing elective primary unilateral total knee arthroplasty was an effective method for its prevention and appeared to be safe with respect to the risk of bleeding. (Funded by Isis Pharmaceuticals; FXI-ASO TKA ClinicalTrials.gov number, NCT01713361.).
Black race has been associated with a higher rate of complications following total joint arthroplasty, such as infection, deep vein thrombosis, pulmonary embolism, and death. We hypothesized that there would be no significant association between black race and adverse outcome when medical conditions were adjusted for. Data on 585,269 patients from the Nationwide Inpatient Samples were assessed by multivariable logistic regression analysis. Black race was significantly associated with postoperative complication and death. Comorbidities do not account for racial differences in adverse events. Black race was an independent predictive factor for increased complications and death following hip and knee arthroplasty.
Copyright © 2013 Elsevier Inc. All rights reserved.
We performed a retrospective cohort study of 84 patients to determine the incidence and predictors of acute kidney injury after antibiotic-impregnated cement spacer (ACS) placement for infected total knee arthroplasties. Acute kidney injury was defined as a more than 50% rise in serum creatinine from a preoperative baseline to a level greater than 1.4 mg/dL within 90 days postoperatively. Total incidence was 17% (n = 14; 95% confidence interval [CI], 10%-26%), and acute kidney injury was significantly associated with ACS tobramycin dose as both a dichotomous variable (>4.8 g; odds ratio, 5.87; 95% CI, 1.43-24.19; P = .01) and linear variable (odds ratio, 1.24 for every 1-g increase; 95% CI, 1.00-1.52; P = .049). Routine monitoring of serum creatinine and measurement of serum aminoglycoside levels in response to a threshold creatinine rise may be warranted after the placement of an aminoglycoside-containing ACS.
Copyright © 2012 Elsevier Inc. All rights reserved.
In megaprostheses, the tibial component is rarely a source of failure. The evolution of these implants has followed standard arthroplasty trends moving from majority use of all-polyethylene tibias (APT) to high volume use of metal-backed tibial (MBT) components. We report the results of 72 endoprostheses using either MBT (n = 42) or APT (n = 30) implanted between 1994 and 2006. Failures of the implant related to the tibial component were isolated, and 5-year survival of the tibial implant of the MBT cohort was 94%, and for the APT cohort, 87% (P = .39). The difference in tibial component failures between the 2 groups was not statistically significant (Pearson χ(2) = 0.1535, P = .6952). Revision rates for the entire implant and infection rates were not significantly different between the 2 groups.
Copyright © 2011 Elsevier Inc. All rights reserved.
Concerned by a perceived high revision rate, we retrospectively reviewed the survivorship of a series of 43 cemented, medial, mobile-bearing Preservation unicompartmental knee replacements implanted during a 2-year period at a single institution. The initial post-operative AP and lateral radiographs were independently assessed to test the hypothesis that suboptimal implantation of the prosthesis was responsible for early failure. An X-ray scoring system based on the criteria for assessing the Oxford mobile-bearing unicompartmental knee replacement was devised. The components of this score included assessment of prosthesis alignment, sizing and cementation. Nine (21%) LCS Preservation mobile-bearings prostheses had required revision at a mean of 22 months post-implantation. The commonest causes for failure were pain (44%) and tibial component loosening (33%). Analysis of post-operative radiographs showed no difference (n.s.) between the compound error scores for the revised and the surviving prostheses. No particular surgical error was identifiable leading to subsequent need for revision. The high failure rates shown in this study have led us to cease using this implant. The clinical relevance of this study is that the captive running track of the LCS mobile-bearing prosthesis may over constrain the meniscal component leading to early failure.
Currently, porous tantalum (trabecular metal) implants are widely accepted and frequently used for primary and revision hip and knee replacement surgery. This study examines the results of porous tantalum endoprostheses used to reconstruct large skeletal defects following resection of bone tumors. Seven custom tantalum implants were used to reconstruct 7 patients following resection for skeletal sarcomas in the femur and proximal tibia. Patient ages ranged from 13 to 71, with a mean of 34 years. Minimum patient follow-up was 6 years. The average Musculoskeletal Tumor Society functional evaluation score was 95 % of normal. There were no infections, hardware failures, or adverse events. One implant was revised 98 months post insertion because of fibrosis, loss of motion and loosening. In this small clinical series, the use of porous tantalum for limb salvage reconstruction is shown to be safe, to successfully provide osteointegration and soft tissue ingrowth, and to facilitate return of limb girdle muscle function.
We hypothesized that preoperative emotional distress and pain intensity would predict the occurrence of signs and symptoms of complex regional pain syndrome (CRPS) following total knee arthroplasty (TKA). Depression (Beck Depression Inventory, BDI), anxiety (State Trait Anxiety Inventory, STAI), pain (McGill Pain Questionnaire-Short Form, MPQ), and signs/symptoms meeting IASP criteria for CRPS were assessed preoperatively, and at 1-, 3-, and 6-months postoperatively in 77 patients undergoing TKA. The prevalence of subjects fulfilling CRPS criteria was 21.0% at 1 month, 13.0% at 3 months, and 12.7% at 6 months postoperative. Higher preoperative scores on the STAI predicted positive CRPS status at 1-month follow-up (P<0.05), with a similar non-significant trend for preoperative BDI scores (P<0.10). Diagnostic sensitivity for the STAI was good (0.73), with moderate specificity (0.56). Neither measure predicted CRPS at later follow-up (P>0.10). Greater preoperative pain intensity predicted positive CRPS status at 3-month (MPQ-Sensory and MPQ-Affective; P<0.01) and 6-month (MPQ-Sensory) follow-up (P<0.01), but not at 1-month (P>0.10). Diagnostic sensitivity was high (0.83-1.00), with moderate specificity (0.53-0.60). Post-TKA patients with CRPS were more depressed at 1-month follow-up (P<0.05) and more anxious at 6-month follow-up (P<0.05) than patients with ongoing non-CRPS pain (all other comparisons non-significant, P>0.10). Overall, results indicate that CRPS-like phenomena occur in a significant number of patients early post-TKA; however, it is not associated with significantly greater complaints of postoperative pain. There appears to be a modest utility for preoperative distress and pain in predicting CRPS signs and symptoms following TKA, although false positive rates are relatively high.
To describe the natural history of pain after total knee arthroplasty and to identify factors predicting excessive postoperative pain, we used a prospective, observational study assessing clinical and radiographic variables preoperatively and at 1, 3, 6, and 12 months after knee replacement. Data sources included the visual analog pain scale and other measures of patient health, psychologic state, and component reliability. Regression analyses were conducted to identify specific factors predictive of postoperative pain, controlling for inequality of variables, and confirmed using regression diagnostics. For 116 patients (149 knees; mean age, 66 years; 55.2% women), significant pain was reported by 72.3%, 44.4%, 22.6%, 18.4%, and 13.1%, respectively. No intergroup differences existed for anesthesia, weight, age, or gender. Patients with greater preoperative pain had more postoperative pain, used more home therapy, and postoperative manipulations. Preoperative depression and anxiety were associated with heightened pain at 1 year. Pain after knee replacement resolves quickly, declining to approximately (1/2) by 3 months. However, one in eight patients report moderate to severe pain 1 year after surgery despite an absence of clinical or radiographic abnormalities. Development of office-based preoperative screening tools and interventions for these patients may reduce postoperative costs and improve patient-perceived outcomes.
OBJECTIVE - To characterize the production and regulation of acidic fibroblast growth factor (aFGF) in type B (fibroblast-like) synoviocytes cultured from both inflammatory and noninflammatory synovial lesions.
METHODS - Immunohistochemistry, Western blotting, and reverse transcriptase-polymerase chain reaction were used to examine the expression of aFGF by synovial cells in vitro. Incorporation of 3H-thymidine by NIH3T3 cells in the presence or absence of neutralizing antibody to aFGF was used to measure bioactive aFGF levels in culture media.
RESULTS - Acidic FGF was detected in all synovial cell lines during growth in vitro; however, synoviocytes from rheumatoid arthritis (RA) patients sustained more abundant production of cytoplasmic and nuclear aFGF. Acidic FGF production persisted after multiple passages and did not depend on the presence of serum. Both RA and noninflammatory synovial cells were competent to release aFGF into the media, even though aFGF lacks a signal peptide. Tumor necrosis factor alpha, interleukin-6, and epidermal growth factor did not increase aFGF expression in vitro; in contrast, transforming growth factor beta1 (TGFbeta1) was found to markedly increase aFGF production by cultured synovial cells.
CONCLUSION - Acidic FGF synthesis and release is a component of synovial cell growth that is markedly increased in RA. TGFbeta1, and not proinflammatory cytokines, is a potent inducer of aFGF production by synoviocytes in vitro. These findings suggest that in RA, interactions between TGFbeta1 and aFGF may contribute to angiogenesis and fibroblast proliferation, potentially independently of inflammatory mediators.