The results of our trials showed that prophylaxis with low-molecular-weight heparin for the 8 days after knee arthroscopy or during the full period of immobilization due to casting was not effective for the prevention of symptomatic venous thromboembolism. (Funded by the Netherlands Organization for Health Research and Development; POT-KAST and POT-CAST ClinicalTrials.gov numbers, NCT01542723 and NCT01542762 , respectively.).

To cite this article: van Adrichem RA, Debeij J, Nelissen RGHH, Schipper IB, Rosendaal FR, Cannegieter SC. Below-knee cast immobilization and the risk of venous thrombosis: results from a large population based case-control study. J Thromb Haemost 2014; 12: 1461-9.Summary. Background: From the available evidence, the risk of venous thrombosis in patients with below-knee cast immobilization remains unclear. Objectives: To estimate the risk of venous thrombosis after below-knee cast immobilization and to identify high-risk groups. Patients and methods: We used data from a large populationbased case-control study (MEGA study) on the etiology of venous thrombosis (4418 cases; 6149 controls). Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated, and adjusted for age, sex, body mass index, and regular exercise. Absolute risks were estimated from the ORs. Results: One hundred and thirty-four patients and 23 controls had below-knee plaster cast immobilization in the year before the index date, resulting in an eight-fold increased risk ). Traumatic indications led to a higher risk than non-traumatic indications: OR 12.7 (95% CI 6.6-24.6) vs. OR 7.6 (95% CI 0.9-66.4). An additionally increased risk was found for combinations with genetic or acquired risk factors: oral contraceptives (OR 18.2 [95% CI 6.2-53.4]); obesity (OR 17.2 [95% CI 5.4-55.2]); factor V Leiden, factor II 20210A mutation, and/or non-O blood group ); all for a period of 1 year. Ninety per cent of the events occurred in the first 3 months after cast application. This led to a 56-fold increased risk ) in this period. Conclusions: Below-knee cast immobilization strongly increases the risk of venous thrombosis. We found distinct differences in intrinsic risk between individuals with respect to indication for cast immobilization and the presence of genetic or acquired risk factors.

BackgroundGuidelines and clinical practice vary considerably with respect to thrombosis prophylaxis during plaster cast immobilization of the lower extremity. Identifying patients at high risk for the development of venous thromboembolism (VTE) would provide a basis for considering individual thromboprophylaxis use and planning treatment studies.The aims of this study were (1) to investigate the predictive value of genetic and environmental risk factors, levels of coagulation factors, and other biomarkers for the occurrence of VTE after cast immobilization of the lower extremity and (2) to develop a clinical prediction tool for the prediction of VTE in plaster cast patients.Methods and FindingsWe used data from a large population-based case–control study (MEGA study, 4,446 cases with VTE, 6,118 controls without) designed to identify risk factors for a first VTE. Cases were recruited from six anticoagulation clinics in the Netherlands between 1999 and 2004; controls were their partners or individuals identified via random digit dialing. Identification of predictor variables to be included in the model was based on reported associations in the literature or on a relative risk (odds ratio) > 1.2 and p ≤ 0.25 in the univariate analysis of all participants. Using multivariate logistic regression, a full prediction model was created. In addition to the full model (all variables), a restricted model (minimum number of predictors with a maximum predictive value) and a clinical model (environmental risk factors only, no blood draw or assays required) were created. To determine the discriminatory power in patients with cast immobilization (n = 230), the area under the curve (AUC) was calculated by means of a receiver operating characteristic. Validation was performed in two other case–control studies of the etiology of VTE: (1) the THE-VTE study, a two-center, population-based case–control study (conducted in Leiden, the Netherlands, and Cambridge, United Kingdom) with 784 cases and 523 controls included between March 2003 and December 2008 and (2) the Milan study, a population-based case–control study with 2,117 cases and 2,088 controls selected between December 1993 and December 2010 at the Thrombosis Center, Fondazione IRCCS Ca’ Granda–Ospedale Maggiore Policlinico, Milan, Italy.The full model consisted of 32 predictors, including three genetic factors and six biomarkers. For this model, an AUC of 0.85 (95% CI 0.77–0.92) was found in individuals with plaster cast immobilization of the lower extremity. The AUC for the restricted model (containing 11 predictors, including two genetic factors and one biomarker) was 0.84 (95% CI 0.77–0.92). The clinical model (consisting of 14 environmental predictors) resulted in an AUC of 0.77 (95% CI 0.66–0.87). The clinical model was converted into a risk score, the L-TRiP(cast) score (Leiden–Thrombosis Risk Prediction for patients with cast immobilization score), which showed an AUC of 0.76 (95% CI 0.66–0.86). Validation in the THE-VTE study data resulted in an AUC of 0.77 (95% CI 0.58...

ObjectivesKnowledge on the epidemiology and long-term course of rotator cuff calcific tendinitis (RCCT) is scarce. We assessed demographics, radiological characteristics, and their association with long-term outcomes in a large patient group.MethodsBaseline demographics, radiological characteristics and treatment were recorded in 342 patients. Interobserver agreement of radiological measures was analyzed. Long-term outcome was evaluated with questionnaires (WORC, DASH). The association of baseline characteristics with outcome was assessed.ResultsMean age was 49.0 (SD = 10.0), and 59.5 % were female. The dominant arm was affected in 66.0 %, and 21.3 % had bilateral disease. Calcifications were on average 18.7 mm (SD = 10.1, ICC = 0.84 (p < 0.001)) and located 10.1 mm (SD = 11.8) medially to the acromion (ICC = 0.77 (p < 0.001)). Gärtner type I calcifications were found in 32.1 % (Kappa = 0.47 (p < 0.001)). After 14 years (SD = 7.1) of follow-up, median WORC was 72.5 (range, 3.0-100.0; WORC < 60 in 42 %) and median DASH 17.0 (range, 0.0-82.0). Female gender, dominant arm involvement, bilateral disease, longer duration of symptoms, and multiple calcifications were associated with inferior WORC. DASH results were similar.ConclusionsMany subjects have persisting shoulder complaints years after diagnosis, regardless of treatment. Female gender, dominant arm involvement, bilateral disease, longer duration of symptoms, and multiple calcifications were associated with inferior outcome. Radiological measures had moderate-to-good reliability and no prognostic value.Key Points• Most RCCT studies report on short-term outcome and/or small patients groups.• In this large, long-term observational study, RCCT appeared to not be self-limiting in many subjects.• Negative prognostic factors included female gender, more calcifications, dominant arm affected, and longer duration of symptoms.• Interobserver agreement of general radiological RCCT measures is moderate to good.• More rigorous diagnostics and treatment might be needed in specific RCCT cases.Electronic supplementary materialThe online version of this article (doi:10.1007/s00330-016-4224-7) contains supplementary material, which is available to authorized users.

To cite this article: van Adrichem RA, Nelissen RGHH, Schipper IB, Rosendaal FR, Cannegieter SC. Risk of venous thrombosis after arthroscopy of the knee: results from a large population-based case-control study. J Thromb Haemost 2015; 13: 1441-8.Summary. Background: From the currently available evidence, the risk of venous thrombosis after knee arthroscopy remains unclear. Objectives: To estimate the risk of venous thrombosis after arthroscopy of the knee, and to identify high-risk groups. Patients and Methods: We used data from a large population-based case-control study (the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis [MEGA] study) on the etiology of venous thrombosis (4416 cases; 6150 controls). Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for age, sex, body mass index, rheumatic disease, and regular exercise, were calculated. Results: One hundred and three patients and 24 controls had a knee arthroscopy in the year before the index date, resulting in a six-fold increased risk (OR 5.9, 95% CI 3.7-9.3). Ligament reconstructions led to a higher risk (OR 17.2, 95% CI 2.2-136) than meniscal surgery, diagnostic arthroscopy, or chondroplasty (OR 5.4,). An additionally increased risk was found for combinations with genetic and acquired risk factors: with oral contraceptives (OR 46.6, 95% CI 6.1-353); and with factor V Leiden, factor II G20210A mutation, or non-O blood type (OR 15.3,). The risk of venous thrombosis was particularly high in the first 3 months after knee arthroscopy, with an 18-fold increased risk (OR 16.2, 95% CI 7.8-33.7). Conclusions: We observed a strongly increased risk of venous thrombosis after knee arthroscopy, especially in the first months after the procedure. The risk was particularly high in the presence of other acquired or genetic risk factors, making knee arthroscopy a high-risk intervention in certain individuals.