Impact of thromboprophylaxis guidelines on clinical outcomes following total hip and total knee replacement

A Comparison of the Periprosthetic Fracture Rate of Cemented and Cementless Mobile Bearing Unicompartmental Knee Arthroplasties: An Analysis of Data From the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man

BACKGROUND

Periprosthetic fractures are rare but serious complications of unicompartmental knee arthroplasty (UKA). Although cementless UKA has a lower risk of loosening than cemented, there are concerns that tibial fracture risk may be higher given the reliance on interference fit for primary stability. The risk of fracture and the effect of surgical fixation are currently unknown. We compared the periprosthetic fracture rate following cemented and cementless UKA surgery.

METHODS

A total of 14,122 medial mobile-bearing UKAs (7,061 cemented and 7,061 cementless) from the National Joint Registry and Hospital Episodes Statistics database were propensity score-matched. Cumulative fracture rates were calculated and Cox regressions were used to compare fixation groups.

RESULTS

The three-month periprosthetic fracture rates were similar (P = .80), being 0.10% in the cemented group and 0.11% in the cementless group. The fracture rates were highest during the first three months postoperatively, but then decreased and remained constant between one and 10 years after surgery. The one-year cumulative fracture rates were 0.2% (confidence interval [CI]: 0.1 to 0.3) for cemented and 0.2% (CI: 0.1 to 0.3) for cementless cases. The 10-year cumulative fracture rates were 0.8% (CI: 0.2 to 1.3) and 0.8% (CI: 0.3 to 1.3), respectively. The hazard ratio during the whole study period was 1.06 (CI: 0.64 to 1.77; P = .79).

CONCLUSIONS

The periprosthetic fracture rate following mobile bearing UKA surgery is low, being about 1% at 10 years. There were no significant differences in fracture rates between cemented and cementless implants after matching. We surmise that surgeons are aware of the higher theoretical risk of early fracture with cementless components and take care with tibial preparation.

LEVELS OF EVIDENCE

III.

A Comparison of the Periprosthetic Fracture Rate of Cemented and Cementless Total Knee Arthroplasties: An Analysis of Data From the National Joint Registry

BACKGROUND

Periprosthetic fractures are serious complications of knee arthroplasty often requiring complex surgery. There is concern of increased periprosthetic fracture risk with cementless components given the reliance on interference fit for primary stability. It is unknown how the periprosthetic fracture risk compares between cemented and cementless total knee arthroplasties (TKAs).

METHODS

A total of 22,477 cemented and 22,477 cementless TKAs from the National Joint Registry and Hospital Episodes Statistics database were propensity score matched on patient and surgical factors. Cumulative periprosthetic fracture rates were calculated using Kaplan-Meier analyses and compared with Cox regressions. Subgroup analyses were performed in different age, body mass index, and sex groups.

RESULTS

The 3-month fracture rate in the cemented and cementless TKA groups were 0.02% and 0.04%, respectively. At 10 years, the cumulative fracture rate after cemented TKA was 1.2%, and after cementless was 1.4%. During the study period, there were no significant differences in fracture rates between cemented and cementless TKAs with a hazards ratio 1.14 (confidence interval 0.94 to 1.37, P = .20) at 10 years postoperatively. There were no significant differences in fracture rates between fixation types on subgroup analyses of sex, body mass index, and age groups. Female sex was a risk factor for fracture in both cemented (odds ratio 2.35, P < .001) and cementless TKAs (odds ratio 2.97, P < .001).

CONCLUSIONS

The periprosthetic fracture rates following cemented and cementless TKA surgery are low being approximately 1.2% and 1.4%, respectively at 10 years. There were no significant differences in periprosthetic fracture rates requiring readmission between cemented and cementless TKAs.

LEVEL OF EVIDENCE

III.

A Comparison of the Periprosthetic Fracture Rate of Unicompartmental and Total Knee Replacements: An Analysis of Data of >100,000 Knee Replacements from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man and Hospital Episode Statistics

BACKGROUND

Periprosthetic fractures are rare but devastating complications of knee replacement, often requiring complex surgery with substantial morbidity and mortality. It is not known how the fracture rates after total knee replacement (TKR) and unicompartmental knee replacement (UKR) compare. We performed the first matched study comparing TKR and UKR periprosthetic fracture rates.

METHODS

This study involved 54,215 UKRs and 54,215 TKRs, identified in the National Joint Registry and Hospital Episodes Statistics database, which were propensity score-matched on patient and surgical factors. The International Classification of Diseases, Tenth Revision, (ICD-10) code M96.6 was used to identify periprosthetic fractures at ≤3 and >3 months postoperatively, as well as estimate rates at up to 10 years. Subgroup analyses were performed in different age groups (<55, 55 to 64, 65 to 74, and ≥75 years), body mass index (BMI) categories (normal, 18.5 to <25 kg/m 2 ; overweight, 25 to <30 kg/m 2 ; obese, 30 to <40 kg/m 2 ; and morbidly obese, ≥40 kg/m 2 ), and sexes.

RESULTS

The 3-month fracture rate was 0.09% (n = 50) in the UKR group and 0.05% (n = 25) in the TKR group, with this difference being significant (odds ratio [OR], 2.0; p = 0.004). The rate of fractures occurring at >3 months was 0.32% (n = 171) in the UKR group and 0.61% (n = 329) in the TKR group (OR, 0.51; p < 0.001). At 10 years, the cumulative incidence of fractures was 0.6% after UKR versus 1% after TKR (OR, 0.68; p < 0.001). Fracture rates increased with increasing age, decreasing BMI, and female sex for both UKRs and TKRs.

CONCLUSIONS

The fracture risk was small after both UKR and TKR, with small absolute differences between implant types. During the first 3 postoperative months, the fracture rate after UKR was 0.1% and was about twice as high as that after TKR. However, over the first 10 years, the cumulative fracture rate after TKR was 1% and was almost twice as high as that after UKR. Fracture rates after both UKR and TKR were higher in women, patients ≥75 years of age, and patients with normal weight.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

The Effect of Body Mass Index on the Relative Revision Rates of Cemented and Cementless Unicompartmental Knee Replacements: An Analysis of Over 10,000 Knee Replacements from National Databases

BACKGROUND

Unicompartmental knee replacements (UKRs) are being performed in an increasingly overweight population. There are concerns that cemented fixation will not last. Cementless fixation may offer a solution, but the relative performance in different body mass index (BMI) groups remains unknown.

METHODS

Ten thousand, four hundred and forty cemented and cementless UKRs were propensity matched. Patients were stratified into 4 BMI groups: underweight (<18.5 kg/m2), normal weight (18.5 to <25 kg/m2), overweight (25 to <30 kg/m2), and obese (≥30 kg/m2). The effect of BMI on the relative performance of UKR fixation groups was studied. Cox regression was used to compare revision and reoperation rates.

RESULTS

The revision rate per 100 component-years significantly increased (p < 0.001) with BMI for the cemented UKRs. Revision rates per 100 component-years for the normal, overweight, and obese groups were 0.92 (95% confidence interval [CI], 0.91 to 0.93), 1.15 (95% CI, 1.14 to 1.16), and 1.31 (95% CI, 1.30 to 1.33), respectively. This was not observed for the cementless UKR, with revision rates of 1.09 (95% CI, 1.08 to 1.11), 0.70 (95% CI, 0.68 to 0.71), and 0.96 (95% CI, 0.95 to 0.97), respectively. The 10-year implant survival rates for the matched cemented and cementless UKRs in the normal, overweight, and obese groups were 93.8% (95% CI, 89.1% to 96.5%) and 94.3% (95% CI, 90.9% to 96.5%) (hazard ratio [HR], 1.17; p = 0.63), 88.5% (95% CI, 84.2% to 91.7%) and 93.8% (95% CI, 90.2% to 96.2%) (HR, 0.61; p = 0.005), and 90.7% (95% CI, 88.2% to 92.6%) and 91.8% (95% CI, 88.9% to 94.0%) (HR, 0.74; p = 0.02), respectively. There were insufficient numbers in the underweight group for analysis (n = 13). Obese patients had less than half the rates of aseptic loosening (0.46% vs. 1.31%; p = 0.001) and pain (0.60% vs. 1.20%; p = 0.02) in the cementless group as compared with the cemented group.

CONCLUSIONS

Higher-BMI groups had higher revision rates for the cemented UKRs but not for the cementless UKRs. Cementless fixation was associated with reduced long-term revision rates compared with cement fixation in the overweight and obese groups. In the obese group, the rates of aseptic loosening and pain were at least 50% lower in the cementless UKR group.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Effect of Age on the Relative Outcomes of Cemented and Cementless Mobile-Bearing Unicompartmental Knee Arthroplasty, Based on Data From National Databases

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is an effective treatment for medial compartment arthritis. A challenge is that patients requiring knee arthroplasty are becoming younger. It is currently unknown what the relative performances of cemented and cementless UKAs are, in different age groups.

METHODS

A total of 12,882 cemented and cementless UKAs from the National Joint Registry and Hospital Episodes Statistics databases were matched on patient and surgical factors. Patients were stratified into 3 groups: (1) <60 years; (2) 60-69 years; and (3) ≥70 years. Revision and reoperation rates were compared using Cox regression analyses.

RESULTS

The 10-year implant survival for the matched cemented and cementless UKAs for (1) <60 years were 81.4% (CI 73.6-87.0) and 86.7% (CI 80.7-90.9) (hazard ratio [HR] 0.73, CI 0.56-0.94, P = .02); (2) for 60-69 years were 91.8% (CI 88.9-94.0) and 94.5% (CI 92.9-95.7) (HR 0.90, CI 0.67-1.22, P = .51); and (3) ≥70 years were 93.5% (CI 91.1-95.3) and 94.2% (CI 92.0-95.8) (HR 1.0, CI 0.71-1.40, P = .99). The same trend was observed for reoperations. In the <60 years and 60-69 years groups there were significantly fewer revisions for aseptic loosening in the cementless group (0.5% versus 1.6% [P < .001] and 0.4% versus 1.3% [P = .002], respectively).

CONCLUSION

Younger ages were associated with higher revision rates in both cemented and cementless UKA groups. Cementless fixation has reduced long-term revision rates compared to cemented fixation in the <60 years group with aseptic loosening rates 3 times lower.

LEVEL OF EVIDENCE

III.

A Matched Comparison of the Long-Term Outcomes of Cemented and Cementless Total Knee Replacements: An Analysis from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man

BACKGROUND

Total knee replacements (TKRs) can be implanted with or without the use of cement. It is currently uncertain how cemented and cementless TKRs compare overall and in different age groups of the population in the long term.

METHODS

The National Joint Registry collects information on knee replacements inserted in England, Wales, Northern Ireland, and the Isle of Man and was linked for multiple confounders to the National Health Service Hospital Episode Statistics database. With use of propensity score matching techniques, 44,954 cemented and cementless TKRs were compared. Regression models were used to compare the outcomes of revision, reoperation, and mortality both overall and in different age strata.

RESULTS

The 10-year implant survival rate with revision as the end point for cemented and cementless TKRs was 96.0% and 95.5%, respectively (hazard ratio [HR] = 1.14; p = 0.01). The 10-year survival rate with reoperation as the end point was 82.7% and 81.4%, respectively (HR = 1.08; p = 0.001). The rate of revision for pain was higher for cementless TKRs (0.5% [cemented] compared with 0.7% [cementless]; p = 0.002), but the rate of revision for infection was lower (0.7% [cemented] compared with 0.5% [cementless]; p = 0.003). No significant interactions with age existed for the outcomes of revision (p = 0.24), reoperation (p = 0.30), or mortality (p = 0.58).

CONCLUSIONS

We found that matched cemented and cementless TKRs both have 10-year implant survival rates of >95%. Cementless TKRs had a higher revision rate (absolute difference, 0.5%) and reoperation rate (absolute difference, 1.3%). The rate of revision for infection was lower in the cementless group, although the rate of revision for pain was higher. Age did not significantly affect the relative performances.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

A matched comparison of revision rates of cemented Oxford Unicompartmental Knee Replacements with Single and Twin Peg femoral components, based on data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

Background and purpose - Registries report high revision rates after unicompartmental knee replacement (UKR) due, in part, to aseptic loosing. In an attempt to improve Oxford UKR femoral component fixation a new design was introduced with a Twin rather than a Single peg. We used the National Joint Registry (NJR) to compare the 5-year outcomes of the Single and Twin Peg cemented Oxford UKRs.Patients and methods - We performed a retrospective observational study using NJR data on propensity score matched Single and Twin Peg UKRs (matched for patient, implant and surgical factors). Data on 2,834 Single Peg and 2,834 Twin Peg were analyzed. Cumulative implant survival was calculated using the Kaplan-Meier method and comparisons between groups performed using Cox regression models.Results - In the matched cohort, the mean follow up for both Single and Twin Peg UKRs was 3.3 (SD 2) and 3.4 years (SD 2) respectively. The 5-year cumulative implant survival rates for Single Peg and Twin Peg were 94.8% (95% CI 93.6-95.8) and 96.2% (CI 95.1-97.1) respectively. Implant revision rates were statistically significantly lower in the Twin Peg (hazard ratio [HR)] = 0.74; p = 0.04). The revision rate for femoral component aseptic loosening decreased significantly (p = 0.03) from 0.4% (n = 11) with the Single Peg to 0.1% (n = 3) with the Twin Peg. The revision rate for pain decreased significantly (p = 0.01) from 0.8% (n = 23) with the Single Peg to 0.3% (n = 9) with the Twin Peg. No other reasons for revision had significant differences in revision rates.Interpretation - The revision rate for the cemented Twin Peg Oxford UKR was 26% less than the Single Peg Oxford UKR. This was mainly because the revision rates for femoral loosening and pain more than halved. This suggests that the Twin Peg component should be used in preference to the Single Peg design.

Thromboprophylaxis After Hospitalization for Joint Replacement Surgery

Venous thromboembolism (VTE) is a leading cause of mortality during the perioperative period, with individuals who have undergone hip and knee arthroplasty at the highest risk for VTE. The American College of Chest Physicians recommends 35 days of postoperative thromboprophylaxis and the use of intermittent pneumatic compression (IPC) therapy for mechanical compression after major orthopedic surgery. However, little research has described adherence to these recommendations during recovery at home. The purpose of this cross-sectional descriptive study was to describe thromboprophylaxis prescription, use, and education among patients discharged home after major orthopedic surgery. We surveyed patients within 2 years of major orthopedic surgery. A total of 388 subjects completed the survey. More than three-quarters of respondents reported a thromboprophylaxis duration <35 days. Most (93.8%) respondents were prescribed a pharmacologic agent, while 55.9% were prescribed mechanical compression therapy. Of the respondents who were prescribed mechanical compression therapy, 13.4% were prescribed IPC. Adherence to mechanical compression therapy was moderate, with 63% of respondents wearing mechanical compression therapy ≥75% of the time. The results of this study suggest a need for increased duration of thromboprophylaxis and increased use of IPC in the outpatient setting. Additional research describing prescribers' perceptions of thromboprophylaxis is also needed.

New surgical instrumentation reduces the revision rate of unicompartmental knee replacement: A propensity score matched comparison of 15,906 knees from the National Joint Registry

BACKGROUND

Unicompartmental knee replacement (UKR) offers advantages over total knee replacement but has higher revision rates. New instrumentation known as Microplasty was introduced to address this. The aim was to compare the revision rates of UKRs implanted with Microplasty and traditional instrumentation (Non-Microplasty).

METHODS

National Joint Registry (NJR) data was used to propensity score match 15,906 UKRs (7953 Microplasty and 7953 Non-Microplasty) for important patient, implant and surgical factors. Implant survival rates were determined using the Kaplan-Meier method and compared using Cox regression models in a multilevel model.

RESULTS

The five-year implant survival for Microplasty and Non-Microplasty UKRs were 96.7% (95% CI: 96.0%-97.2%) and 94.5% (CI: 93.8-95.1%), respectively. The revision rate for Microplasty UKR was significantly lower than that of Non-Microplasty UKRs (hazard ratio [HR] = 0.77, p = 0.008). Compared with Non-Microplasty UKRs, the revision rate of Microplasty UKRs implanted during the year after the introduction of Microplasty was lower, but the difference was not significant (HR: 0.86, CI: 0.67-1.10, p = 0.23), whereas for those implanted more than a year after introduction, the difference was significant (HR: 0.69, CI: 0.54-0.89, p = 0.004).

CONCLUSION

The use of Microplasty instrumentation has resulted in an improved five-year UKR survival. Microplasty UKR implanted during the first year after introduction had a small, non-significant decrease in revision rate. As the revision rate did not increase, this suggests that there is no adverse learning curve effect. Microplasty UKRs implanted after this transition period had a revision rate 31% lower than the Non-Microplasty group.

LEVEL OF EVIDENCE

II.

The Effect of Surgeon Caseload on the Relative Revision Rate of Cemented and Cementless Unicompartmental Knee Replacements: An Analysis from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

BACKGROUND

Unicompartmental knee replacement (UKR) offers substantial benefits compared with total knee replacement (TKR) but is associated with higher revision rates. Data from registries suggest that revision rates for cementless UKR implants are lower than those for cemented implants. It is not known how much of this difference is due to the implant or to other factors, such as a greater proportion of high-volume surgeons using cementless implants. We aimed to determine the effect of surgeon caseload on the revision rate of matched cemented and cementless UKRs.

METHODS

From a group of 40,522 Oxford (Zimmer Biomet) UKR implants (30,814 cemented, 9,708 cementless) recorded in the National Joint Registry, 14,814 (7,407 cemented, 7,407 cementless) were propensity-score matched. Surgeons were categorized into 3 groups: low volume (<10 cases/year), medium volume (10 to <30 cases/year), and high volume (≥30 cases/year). The effect of caseload on the relative risk of revision was assessed with use of Cox regression.

RESULTS

The 10-year survival rates for unmatched cementless and cemented UKR implants were 93.3% (95% confidence interval [CI] = 89.8% to 95.7%) and 89.1% (95% CI = 88.6% to 89.6%), respectively, with the difference being significant (hazard ratio [HR] = 0.59; p < 0.001). Cementless UKR implants had a greater proportion of high-volume surgeon users than cemented implants (30.4% compared with 15.1%). Following matching, the 10-year survival rates were 93.2% (95% CI = 89.7% to 95.6%) and 90.2% (95% CI = 87.5% to 92.3%), which were still significantly different (HR = 0.76; p = 0.002). The 10-year survival rates for matched cementless and cemented UKR implants were 86.8% (95% CI = 73.6% to 93.7%) and 81.8% (95% CI = 73.0% to 88.0%) for low-volume surgeons, 94.3% (95% CI = 92.2% to 95.9%) and 92.5% (95% CI = 89.9% to 94.5%) for medium-volume surgeons, and 97.5% (95% CI = 96.5% to 98.2%) and 94.2% (95% CI = 90.8% to 96.4%) for high-volume surgeons. The revision rate for cementless implants was lower for surgeons in all 3 caseload groups (HR = 0.74, 0.79, 0.80, respectively).

CONCLUSIONS

Cementless fixation decreased the revision rate by about a quarter, whatever the surgeon caseload. Caseload had a profound effect on implant survival. Low-volume surgeons had a high revision rate with cemented or cementless fixation and therefore should consider either stopping or doing more UKR procedures. High-volume surgeons performing cementless UKR demonstrated a 10-year survival rate of 97.5%, which was similar to that reported in registries for the best-performing TKRs.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Comparison of the 10-year outcomes of cemented and cementless unicompartmental knee replacements: data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

Background and purpose - Unicompartmental knee replacement (UKR) offers advantages over total replacement but has higher revision rates, particularly for aseptic loosening. The cementless Oxford UKR was introduced to address this. We undertook a registry-based matched comparison of cementless and cemented UKRs.Patients and methods - From 40,552 Oxford UKRs identified by the National Joint Registry for England, Wales, Northern Ireland and Isle of Man (NJR) we propensity score matched, based on patient, surgical, and implant factors, 7,407 cemented and 7,407 cementless UKRs (total = 14,814).Results - The 10-year cumulative implant survival rates for cementless and cemented UKRs was 93% (95% CI 90-96) and 90% (CI 88-92) respectively, with this difference being significant (HR 0.76; p = 0.002). The risk of revision for aseptic loosening was less than half (p < 0.001) in the cementless (0.42%) compared with the cemented group (1.00%), and the risk of revision also decreased for unexplained pain (to 0.46% from 0.74%; p = 0.03) and lysis (to 0.04% from 0.15%; p = 0.03). However, the risk of revision for periprosthetic fracture increased significantly (p = 0.01) in the cementless (0.26%) compared with the cemented group (0.09%). 10-year patient survival rates were similar (HR 1.2; p = 0.1).Interpretation - The cementless UKR has improved 10-year implant survival compared with the cemented UKR, independent of patient, implant, and surgical factors. This improved survival in the cementless group was primarily the result of lower revision rate for aseptic loosening, unexplained pain, and lysis, suggesting the fixation of the cementless was superior. However, there was a small increased risk of revision for periprosthetic fracture with the cementless implant.

Thromboprophylaxis for Hip Revision Arthroplasty: Can We Use the Recommendations for Primary Hip Surgery? A Cohort Study

The risk of thromboembolic events after hip revision arthroplasty might be higher than in primary hip arthroplasty. However, evidence regarding the use of thromboprophylaxis in revisions is scarce. The purpose of this study is to determine whether thromboprophylaxis recommendations for primary arthroplasty produce similar results in hip revision arthroplasty. This comparative cohort study retrospectively analyzed consecutive patients undergoing primary hip arthroplasty and hip revision surgery between March 2004 and December 2015, who received thromboprophylaxis according to local clinical practice guidelines for primary hip arthroplasty. The prevalence of deep vein thrombosis and pulmonary embolism and the presence of major bleeding events were assessed during hospitalization and at 3 months after discharge and compared between groups. The overall prevalence of thromboembolic events in the hip revision surgery cohort and in the primary hip cohort was 1.62% and 1.35%, respectively (P = .801). The 38.4% of hip revision patients and 20.3% of primary hip patients presented major bleeding events. Thromboembolic disease outcomes with the use of a standardized thromboprophylaxis regimen were similar in both cohorts, regardless of the high variability of hip revision surgery and the increased risk of complications. Implementation of this regimen is recommended in patients requiring joint replacement revision surgery.

Oral Contraceptive Pills Are Not a Risk Factor for Deep Vein Thrombosis or Pulmonary Embolism After Arthroscopic Shoulder Surgery

Background:

Worldwide, more than 100 million women between the ages of 15 and 49 years take oral contraceptive pills (OCPs). OCP use increases the risk of venous thromboembolism (VTE) through its primary drug, ethinylestradiol, which slows liver metabolism, promotes tissue retention, and ultimately favors fibrinolysis inhibition and thrombosis.

Purpose:

To evaluate the effects of OCP use on VTE after arthroscopic shoulder surgery.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A large national payer database (PearlDiver) was queried for patients undergoing arthroscopic shoulder surgery. The incidence of VTE was evaluated in female patients taking OCPs and those not taking OCPs. A matched group was subsequently created to evaluate the incidence of VTE in similar patients with and without OCP use.

Results:

A total of 57,727 patients underwent arthroscopic shoulder surgery from 2007 to 2016, and 26,365 patients (45.7%) were female. At the time of surgery, 924 female patients (3.5%) were taking OCPs. The incidence of vascular thrombosis was 0.57% (n = 328) after arthroscopic shoulder surgery, and there was no significant difference in the rate of vascular thrombosis in male or female patients (0.57% vs 0.57%, respectively; P > .99). The incidence of VTE in female patients taking and not taking OCPs was 0.22% and 0.57%, respectively (P = .2). In a matched-group analysis, no significant difference existed in VTE incidence between patients with versus without OCP use (0.22% vs 0.56%, respectively; P = .2). On multivariate analysis, hypertension (odds ratio [OR], 2.00; P < .001) and obesity (OR, 1.43; P = .002) were risk factors for VTE.

Conclusion:

OCP use at the time of arthroscopic shoulder surgery is not associated with an increased risk of VTE. Obesity and hypertension are associated with a greater risk for thrombolic events, although the risk remains very low. Our findings suggest that patients taking OCPs should be managed according to the surgeon’s standard prophylaxis protocol for arthroscopic shoulder surgery.

Delphi-RAND consensus of the Spanish Society of Internal Medicine on the controversies in anticoagulant therapy and prophylaxis in medical diseases. INTROMBIN Project (Uncertainty in thromboprophylaxis in internal medicine)

The aim of this study was to determine the opinion of internists on the management of anticoagulation and thromboembolism prophylaxis in complex clinical scenarios in which the risk-benefit ratio of surgery is narrow and to develop a consensus document on the use of drugs anticoagulant therapy in this patient group. To this end, we identified by consensus the clinical areas of greatest uncertainty, a survey was created with 20 scenarios laid out in 40 clinical questions, and we reviewed the specific literature. The survey was distributed among the internists of the Spanish Society of Internal Medicine (SEMI) and was completed by 290 of its members. The consensus process was implemented by changing the Delphi-RAND appropriateness method in an anonymous, double-round process that enabled an expert panel to identify the areas of agreement and uncertainty. In our case, we also added the survey results to the panel, a methodological innovation that helps provide additional information on the standard clinical practice. The result of the process is a set of 19 recommendations formulated by SEMI experts, which helps establish guidelines for action on anticoagulant therapy in complex scenarios (high risk or active haemorrhage, short life expectancy, coexistence of antiplatelet therapy or comorbidities such as kidney disease and liver disease), which are not uncommon in standard clinical practice.

Evaluation of Appropriate Venous Thromboembolism Prophylaxis in Patients With Orthopaedic Trauma With Symptom-Driven Vascular and Radiographic Studies

OBJECTIVE

To evaluate venous thromboembolism (VTE) prophylaxis adherence and effectiveness in orthopaedic trauma patients who had vascular or radiographic studies showing deep vein thromboses or pulmonary emboli.

DESIGN

Retrospective review.

SETTING

A level I trauma center that independently services a 5-state region.

PATIENTS

Four hundred seventy-six patients with orthopaedic trauma who underwent operative treatments for orthopaedic injuries and had symptom-driven diagnostic VTE studies.

INTERVENTION

The medical records of patients treated surgically between July 2010 and March 2013 were interrogated using a technical tool that electronically captures thrombotic event data from vascular and radiologic imaging studies by natural language processing.

MAIN OUTCOME MEASUREMENTS

Patients were evaluated for hospital guideline-directed VTE prophylaxis adherence with mechanical or chemical prophylaxis. Patient demographics, associated injuries, mechanism of injury, and symptoms that led to imaging for a VTE were also assessed.

RESULTS

Of the 476 orthopaedic patients who met inclusion criteria, 100 (mean age 52.3 median 52, SD 18.3, 70% men) had positive VTE studies. Three hundred seventy-six (age 47.3, SD 17.3, 69% men) had negative VTE studies. Of the 100 patients with VTE, 63 deep vein thromboses, and 49 pulmonary emboli were found. Eight-five percent of all patients met hospital guideline-VTE prophylaxis standards.

CONCLUSION

The study population had better than previously reported VTE prophylaxis adherence, however, patients still developed VTEs.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Geriatric Patient Safety Indicators Based on Linked Administrative Health Data to Assess Anticoagulant-Related Thromboembolic and Hemorrhagic Adverse Events in Older Inpatients: A Study Proposal

Background

Frail older people with multiple interacting conditions, polypharmacy, and complex care needs are particularly exposed to health care-related adverse events. Among these, anticoagulant-related thromboembolic and hemorrhagic events are particularly frequent and serious in older inpatients. The growing use of anticoagulants in this population and their substantial risk of toxicity and inefficacy have therefore become an important patient safety and public health concern worldwide. Anticoagulant-related adverse events and the quality of anticoagulation management should thus be routinely assessed to improve patient safety in vulnerable older inpatients.

Objective

This project aims to develop and validate a set of outcome and process indicators based on linked administrative health data (ie, insurance claims data linked to hospital discharge data) assessing older inpatient safety related to anticoagulation in both Switzerland and France, and enabling comparisons across time and among hospitals, health territories, and countries. Geriatric patient safety indicators (GPSIs) will assess anticoagulant-related adverse events. Geriatric quality indicators (GQIs) will evaluate the management of anticoagulants for the prevention and treatment of arterial or venous thromboembolism in older inpatients.

Methods

GPSIs will measure cumulative incidences of thromboembolic and bleeding adverse events based on hospital discharge data linked to insurance claims data. Using linked administrative health data will improve GPSI risk adjustment on patients’ conditions that are present at admission and will capture in-hospital and postdischarge adverse events. GQIs will estimate the proportion of index hospital stays resulting in recommended anticoagulation at discharge and up to various time frames based on the same electronic health data. The GPSI and GQI development and validation process will comprise 6 stages: (1) selection and specification of candidate indicators, (2) definition of administrative data-based algorithms, (3) empirical measurement of indicators using linked administrative health data, (4) validation of indicators, (5) analyses of geographic and temporal variations for reliable and valid indicators, and (6) data visualization.

Results

Study populations will consist of 166,670 Swiss and 5,902,037 French residents aged 65 years and older admitted to an acute care hospital at least once during the 2012-2014 period and insured for at least 1 year before admission and 1 year after discharge. We will extract Swiss data from the Helsana Group data warehouse and French data from the national health insurance information system (SNIIR-AM). The study has been approved by Swiss and French ethics committees and regulatory organizations for data protection.

Conclusions

Validated GPSIs and GQIs should help support and drive quality and safety improvement in older inpatients, inform health care stakeholders, and enable international comparisons. We discuss several limitations relating to the representativeness of study populations, accuracy of administrative health data, methods used for GPSI criterion validity assessment, and potential confounding bias in comparisons based on GQIs, and we address these limitations to strengthen study feasibility and validity.

Venous thromboembolism: identifying patients at risk and establishing prophylaxis

Venous thromboembolism (VTE) is a major cause of morbidity and mortality and is associated with substantial healthcare costs. Identification of patients at risk of developing VTE enables appropriate thromboprophylaxis to be implemented. Although no predisposing risk factors can be identified in many patients in whom VTE develops, most have at least one underlying risk factor which can be categorized according to whether it confers low, moderate, or high risk. Clinical trials have demonstrated the effectiveness of thromboprophylaxis, both non-pharmacological and pharmacological, in a host of medical settings and there is sufficient evidence to support routine prophylaxis in many groups of patients. The implementation of decision making tools based on risk factor assessment improves the prescription of appropriate VTE prophylaxis. Nonetheless, thromboprophylaxis is often inadequate, with haphazard risk assessment and application of guidelines, leading to easily preventable instances of VTE. The most commonly used agents for pharmacological thromboprophylaxis of VTE are low dose unfractionated heparin; a low molecular weight heparin such as dalteparin, enoxaparin or tinzaparin; fondaparinux; warfarin; or aspirin. However, these have a number of drawbacks, principally the need for parenteral administration (with heparins) and frequent coagulation monitoring (with warfarin). The optimal anticoagulant would be orally administered, with a wide therapeutic window, rapid onset of action, predictable pharmacodynamics and pharmacokinetics, minimal interactions with food and other drugs, an ability to inhibit free and clot-bound coagulation factors, low, non-specific binding, and no requirement for routine coagulation monitoring or dose adjustment. A number of novel, single-target oral anticoagulants have been developed that appear to fulfill many of these requirements. This narrative review discusses the use of guidelines and risk assessment tools to identify patients at risk of VTE; it provides an overview of appropriate prophylaxis strategies in these patients with a summary of clinical trial results with novel oral anticoagulants.

Real life thromboprophylaxis in orthopedic surgery in Italy. Results of the GIOTTO study

INTRODUCTION

Data from a prospective, multicentre observational study (Studio GIOTTO) were analyzed to determine, in clinical practice, the pattern of VTE prophylaxis and adherence to international guidelines recommendations in major orthopedic surgery (MOS) - including total hip arthroplasty (THA), total knee arthroplasty (TKA) and hip fracture surgery (HFS) - and knee arthroscopic surgery (KAS).

METHODS

In 2010, the first consecutive 30 patients hospitalized in Italian centers for MOS and the first 15 for KAS were enrolled and treated according to the usual practice.

RESULTS

2010 patients were admitted for MOS (577 TKA, 787 THA and 646 HFS) and 993 for KAS; mean ± SD age was 71.7 ± 8 and 43.0 ± 15 years, and female prevalence was 65.6% and 31.1% in MOS and KAS, respectively. Most (66.7%; 95% CI: 65-69%) patients admitted for MOS received a combined VTE prophylaxis, consisting of both pharmacological and physical tools, and 33.2% (95% CI: 31-35%) only pharmacological. For KAS figures were 23.7 (95% CI: 21-26%) and 75.3% (95% CI: 72-77%). Most MOS (91%; 95% CI: 89-92%) and KAS (95% CI: 98-100%) patients receiving pharmacological thromboprophylaxis were treated with low molecular weight heparin (LMWH), for (median) 40 days in TKR, 39 days in THR, 44 in HFS, and 16 in KAS. Patients receiving <35 days of LMWH prophylaxis among those undergoing THR and HFS were 8.9% and 5.9%, respectively.

CONCLUSION

Although most patients undergoing orthopedic surgery received VTE prophylaxis, a gap between clinical practice and international guideline recommendations was observed. The reduced adherence to guideline recommendations is relevant for certain choices like type and duration of VTE, and physicians' behavior may reflect the changing approach of guidelines in their different editions.

Opportunities for improvement: anticoagulation in patients undergoing total knee or hip replacement

BACKGROUND

According to guidelines, initiation of pharmacological thromboprophylaxis after total knee or hip replacement is recommended and associated with improved patient outcomes. However, data on how these recommendations are followed in clinical practice are sparse.

METHODS

All patients undergoing first-time total knee or hip replacement in Denmark 2008-2011 were identified. By cross-referencing Danish nationwide registries, quantitative use of anticoagulants administered orally and subcutaneously post-discharge was assessed by number of claimed prescriptions after surgery. Logistic regression analysis was used to identify factors associated with initiation of prophylaxis.

RESULTS

A total of 50,389 patients were included in the study (median age 69, inter-quartile range 62-76). Novel oral anticoagulants were initiated in 14.7 % of the patients and heparins/fondaparinux in 2.3 % of the patients. The use of anticoagulants increased from 6.3 % in 2008 to 30.0 % of patients in 2011. Among patients initiating prophylaxis with a novel oral anticoagulant post-discharge, almost all were treated according to guidelines in terms of treatment duration. Factors significantly associated with an increased chance of prophylaxis among total hip replacement patients were: age (per 10-year increments) and female gender.

CONCLUSIONS

Use of pharmacological thromboprophylaxis after total knee or hip replacement was low, but increasing during the study period. This is probably due to increased availability of novel oral anticoagulants. Further initiatives to increase guideline recommended use of prophylactic anticoagulation after orthopaedic surgery are warranted.

Risk factors for venous thromboembolism of total hip arthroplasty and total knee arthroplasty: a systematic review of evidences in ten years

Background

Risk factors for venous thromboembolism (VTE) of total joint arthroplasty (TJA) have been examined by many studies. A comprehensive systematic review of recent findings of high evidence level in this topic is needed.

Methods

We conducted a PubMed search for papers published between 2003 and 2013 that provided level-I and level-II evidences on risk factors for VTE of TJA. For each potential factors examined in at least three papers, we summarize the the number of the papers and confirmed the direction of statistically significant associations, e.g. “risk factor” “protective factor” or “controversial factor”.

Results

Fifty-four papers were included in the systematic review. Risk factors found to be associated with VTE of both total hip arthroplasty and total knee arthroplasty included older age, female sex, higher BMI, bilateral surgery, surgery time > 2 hours. VTE history was found as a VTE risk factor of THA but an controversial factor of TKA. Cemented fixation as compared to cementless fixation was found as a risk factor for VTE only of TKA. TKA surgery itself was confirmed as a VTE risk factor compared with THA surgery.

Conclusions

This systematic review of high level evidences published in recent ten years identified a range of potential factors associated with VTE risk of total joint arthroplasty. These results can provide informations in this topic for doctors, patients and researchers.

Effectiveness and safety of different duration of thromboprophylaxis in 16,865 hip replacement patients--a real-word, prospective observational study

INTRODUCTION

Clinical trials have provided evidence about efficacy and safety of extended thromboprophylaxis among total hip replacement (THR) patients. There is a lack of evidence on effectiveness and safety of extended treatment in unselected patients from routine clinical practice. We examined the effectiveness and safety of short (1-6 days) and standard (7-27 days) compared with extended (≥28 days) thromboprophylaxis using population-based design.

MATERIAL AND METHODS

Among all primary THR procedures performed in Denmark from 2010 through 2012 (n=16,865), we calculated adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) for risk of symptomatic venous thromboembolism (VTE) and major bleeding, in addition to net clinical benefit, defined as the number of VTE avoided minus the number of excess bleeding events occurring among patients prescribed short-term and standard versus extended treatment.

RESULTS

The 90-day risks of VTE were 1.1% (short), 1.4% (standard), and 1.0% (extended), yielding aHRs of 0.83 (95% CI: 0.52-1.31) and 0.82 (95% CI: 0.50-1.33) for short and standard versus extended treatment. The risk of major bleeding was 1.1% (short), 1.0% (standard), and 0.7% (extended), resulting in aHRs of 1.64 (95% CI: 0.83-3.21) and 1.24 (95%CI: 0.61-2.51) for short and standard versus extended thromboprophylaxis. Direct comparison between benefits and harms using net clinical benefit analyses did not favor any of the three treatment durations. The same results were found for VTE or death.

CONCLUSIONS

In a real-word observational cohort of unselected THR patients, we observed no difference in the risks of symptomatic VTE, VTE/ death or bleeding with respect to thromboprophylaxis duration.

Review article: Perioperative care in enhanced recovery for total hip and knee arthroplasty

Enhanced recovery pathways for total hip and knee arthroplasty can reduce length of hospital stay and perioperative morbidity. 22 studies were reviewed for identification of perioperative care interventions, including preoperative (n=4), intra-operative (n=8), and postoperative (n=4) care interventions. Factors that improve outcomes included use of pre-emptive and multimodal analgesia regimens to reduce opioid consumption, identification of patients with poor nutritional status and provision of supplements preoperatively to improve wound healing and reduce length of hospital stay, use of warming systems and tranexamic acid, avoidance of drains to reduce operative blood loss and subsequent transfusion, and early ambulation with pharmacological and mechanical prophylaxis to reduce venous thromboembolism and to speed recovery.

Venous thromboembolism prophylaxis in acutely ill hospitalized medical patients. A retrospective multicenter study

OBJECTIVE

To analyze the incidence of VTE in hospitalized medical patients and prophylaxis applied in accordance with the 8th ACCP guidelines and the National PRETEMED guide for thromboprophylaxis.

METHODS

Discharge lists were reviewed to select the first consecutive 20 patients, aged ≥ 40 years and admitted ≥ 4 days to the Internal Medicine Departments of 79 Spanish hospitals. Exclusion criteria were: admission for diagnostic procedures, VTE or surgical illness, or care during hospitalization provided by the local investigator.

RESULTS

From September 2011 to July 2012, 2845 discharge reports were evaluated and 1623 were considered eligible for the study. Overall 930 (57.3%) patients of this group were at risk of VTE according to the ACCP guidelines, 759 (81.6%) received VTE prophylaxis (mechanical or pharmacological) and 159 (17.1%) had at least one risk factor that might contraindicate anticoagulant use. The proportion of patients at VTE risk according to the ACCP and National PRETEMED guidelines with no risk factors of bleeding that did not receive prophylaxis was 16.3% and 17.2%, respectively. During hospitalization, there were 14 (0.9%) episodes of symptomatic VTE, 12 (86%) of which occurred in patients receiving prophylaxis. VTE rate was 1.3% among patients with VTE risk that received prophylaxis and 3.5% in patients that also had one risk factor that might contraindicate anticoagulant use.

CONCLUSIONS

In a setting characterized by high thromboprophylaxis compliance most of the episodes occurred in patients receiving pharmacological prophylaxis. Patients with combined VTE and bleeding risk factors showed the highest rate of both symptomatic VTE and prophylaxis failure.

Venous thromboembolism after total joint arthroplasty: results from a Japanese multicenter cohort study

Introduction

Real-world evidence of the effectiveness of pharmacological thromboprophylaxis for venous thromboembolism (VTE) is limited. Our objective was to assess the effectiveness and safety of thromboprophylactic regimens in Japanese patients undergoing joint replacement in a real-world setting.

Method

Overall, 1,294 patients (1,073 females and 221 males) who underwent total knee arthroplasty (TKA) and 868 patients (740 females and 128 males) who underwent total hip arthroplasty (THA) in 34 Japanese national hospital organization (NHO) hospitals were enrolled. The primary efficacy outcome was the incidence of deep vein thrombosis (DVT) detected by mandatory bilateral ultrasonography up to post-operative day (POD) 10 and pulmonary embolism (PE) up to POD28. The main safety outcomes were bleeding (major or minor) and death from any cause up to POD28.

Results

Patients undergoing TKA (n = 1,294) received fondaparinux (n = 360), enoxaparin (n = 223), unfractionated heparin (n = 72), anti-platelet agents (n = 45), or no medication (n = 594). Patients undergoing THA (n = 868) received fondaparinux (n = 261), enoxaparin (n = 148), unfractionated heparin (n = 32), anti-platelet agents (n = 44), or no medication (n = 383). The incidence rates of sonographically diagnosed DVTs up to POD10 were 24.3% in patients undergoing TKA and 12.6% in patients undergoing THA, and the incidence rates of major bleeding up to POD28 were 1.2% and 2.3%, respectively. Neither fatal bleeding nor fatal pulmonary embolism occurred. Significant risk factors for postoperative VTE identified by multivariate analysis included gender (female) in both TKA and THA groups and use of a foot pump in the TKA group. Only prophylaxis with fondaparinux reduced the occurrence of VTE significantly in both groups. Propensity score matching analysis (fondaparinux versus enoxaparin) showed that the incidence of DVT was lower (relative risk 0.70, 95% confidence interval (CI) 0.58 to 0.85, P = 0.002 in TKA and relative risk 0.73, 95% CI 0.53 to 0.99, P = 0.134 in THA) but that the incidence of major bleeding was higher in the fondaparinux than in the enoxaparin group (3.4% versus 0.5%, P = 0.062 in TKA and 4.9% versus 0%, P = 0.022 in THA).

Conclusions

These findings indicate that prophylaxis with fondaparinux, not enoxaparin, reduces the risk of DVT but increases bleeding tendency in patients undergoing TKA and THA.

Trial registration

University Hospital Medical Information Network Clinical Trials Registry: UMIN000001366. Registered 11 September 2008.

The effect of body mass index on the risk of post-operative complications during the 6 months following total hip replacement or total knee replacement surgery

OBJECTIVE

To assess the effect of obesity on 6-month post-operative complications following total knee (TKR) or hip (THR) replacement.

DESIGN

Data for patients undergoing first THR or TKR between 1995 and 2011 was taken from the Clinical Practice Research Datalink. Logistic regression was used to assess whether body mass index (BMI) was associated with 6-month post-operative complications [deep vein thrombosis or pulmonary embolism (DVT/PE), myocardial infarction (MI), stroke, respiratory infection, anaemia, wound infection, urinary tract infection or death] after controlling for the effects of age, gender, smoking, drinking, socio-economic status (SES), co-morbidities and medications.

RESULTS

31,817 THR patients and 32,485 TKR patients were identified for inclusion. Increasing BMI was associated with a significantly higher risk of wound infections, from 1.6% to 3.5% in THR patients (adjusted P < 0.01), and from 3% to 4.1% (adjusted P < 0.05) in TKR patients. DVT/PE risk also increased with obesity from 2.2% to 3.3% (adjusted P < 0.01) in THR patients and from 2.0% to 3.3% (adjusted P < 0.01) in TKR patients. Obesity was not associated with increased risk of other complications.

CONCLUSION

Whilst an increased risk of wound infection and DVT/PE was observed amongst obese patients, absolute risks remain low and no such association was observed for MI, stroke and mortality. However this is a selected cohort (eligible for surgery according to judgement of NHS GPs and surgeons) and as such these results do not advocate surgery be given without consideration of BMI, but indicate that universal denial of surgery based on BMI is unwarranted.

Use of rivaroxaban in Germany: a database drug utilization study of a drug started in hospital

PURPOSE

The purpose of this drug utilization study was to describe the use of rivaroxaban in Germany during a time period in which approval was limited to the prevention of venous thromboembolism following hip or knee replacement. Additionally, we explored the feasibility of reconstructing inpatient drug use of rivaroxaban in a database where with a few exceptions inpatient prescribing information is not available.

METHODS

Source of data was one statutory health insurance providing data on about seven million insurants throughout Germany. Analyses were based on a cohort of rivaroxaban users from launch (October 2008) to December 2009 and encompassed potential indications for rivaroxaban use, treatment duration, and co-prescribing of potentially interacting drugs. Start of rivaroxaban treatment was defined by the date of surgery.

RESULTS

During the study period, 425 rivaroxaban users were identified contributing 440 treatment periods. For more than 82% of these episodes labelled indications could be determined. Treatment durations exceeded recommendations in 95% of the episodes following knee replacement whereas rivaroxaban use after elective hip surgery was found to be longer than recommended in 56%. Prescribing of potentially interacting medication was rare except for non-steroidal anti-inflammatory drugs.

CONCLUSIONS

Overall, no important off-label use of rivaroxaban was identified. Based on several assumptions that have to be considered in the interpretation of the results our study describes a database approach to reconstruct inpatient drug use for a drug started after a coded hospital procedure, when treatment continues after hospital discharge and no change in drug use is expected in the outpatient setting.

Venous Thromboembolism (VTE) Prophylaxis for Hip and Knee Arthroplasty: Changing Trends

Venous thromboembolism (VTE) has been identified as an immediate threat to patients undergoing major orthopedic procedures such as total hip arthroplasty (THA) and total knee arthroplasty (TKA). Given the known dangers of VTE, arthroplasty surgeons are sensitive to the need for VTE thromboprophylaxis. However, the modalities of thromboprophylaxis used to minimize the risks to patients have been variable. Clinical practice guidelines have been published by several professional organizations, while some hospitals have established their own protocols. The 2 most popular guidelines are those published by the Academy of Orthopaedic Surgeons (AAOS) and American College of Chest Physicians (ACCP), both from North America. Prior to 2012, these recommendations varied depending on underlying definitions, methodology, and goals of the 2 groups. For the first time, both groups have similar recommendations that focus on minimizing symptomatic VTE and bleeding complications. The key to determining the appropriate chemoprophylaxis for patients is to balance efficacy of a prophylactic agent, while being safe in regards to bleeding complications. However, a multimodal approach that focuses on early postoperative mobilization and the use of mechanical prophylaxis, in addition to chemoprophylaxis, is essential.

DVT prophylaxis after TKA: routine anticoagulation vs risk screening approach - a randomized study

The American College of Chest Physicians (ACCP) recommended routine anticoagulation for thromboprophylaxis in patients undergoing lower limb arthroplasty. We compared results of routine anticoagulation Vs risk stratified approach for Deep Venous Thrombosis (DVT) prophylaxis after TKA in terms of symptomatic DVT and wound complications. Nine hundred TKAs done in 673 patients were randomized after DVT risk screening to routine anticoagulation (n = 450) or to risk stratification (n = 450) and selective anticoagulation. 194 patients in the risk screening group received only Aspirin. Primary outcome was symptomatic DVT and wound complication. This randomized study showed that the symptomatic DVT rates after TKA were similar whether patients were routinely anticoagulated or selectively anticoagulated after risk screening. However there was a significantly higher incidence of wound complications (P < 0.014) after routine anticoagulation.

Should we follow the 9th ACCP guidelines for VTE prevention in surgical patients?

The 9th edition of the American College of Chest Physicians (ACCP) guidelines on antithrombotic therapy and prevention, includes relevant changes compared to previous versions. In the 9th ACCP, leadership of most chapters was given to methodologists who were familiar with the GRADE methodology. All topic panelists underwent a selection process paying particular attention to their financial and intellectual conflicts of interests. In the 9th ACCP guidelines, evidence has been explicitly presented in many evidence profiles and summary of evidence tables. In order to get a more balanced trade-off between desirable and undesirable effects of the alternative prevention and therapeutic interventions, there has been an increased emphasis on clinically relevant events, as opposed to previous surrogate asymptomatic outcomes. In addition, there has been a systematic review and survey on patient values and preferences for thrombotic and bleeding outcomes. As a result of the above changes, the strength of most recommendations has been downgraded compared to previous editions. The main changes regarding prevention on nonorthopedic surgical patients include the adoption of two risk assessment models. The only recommendation that has been upgraded is to extend prophylaxis with low molecular weight heparins (LMWH) for four weeks after abdominal or pelvic cancer surgery. A controversial modification in orthopedic patients is recommendation in favor of the use of aspirin after hip or knee arthroplasty. New oral anticoagulants are recommended, but LMWH are suggested as the preferred option. Extending pharmacological prophylaxis for up to 35days rather than 10-14days is now suggested for patients undergoing major orthopedic surgery.