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Background Surgery is a major transient risk factor for venous thromboembolism (VTE). However, the impact of major surgery as a VTE trigger has been scarcely investigated using a case-crossover design. Aim To investigate the role of major surgery as a trigger for incident VTE in a population-based case-crossover study while adjusting for other concomitant VTE triggers. Methods We conducted a case-crossover study with 531 cancer-free VTE cases derived from the Tromsø Study cohort. Triggers were registered during the 90 days before a VTE event (hazard period) and in four preceding 90-day control periods. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for VTE according to major surgery and after adjustment for other VTE triggers. Results Surgery was registered in 85 of the 531 (16.0%) hazard periods and in 38 of the 2,124 (1.8%) control periods, yielding an OR for VTE of 11.40 (95% CI: 7.42-17.51). The OR decreased to 4.10 (95% CI: 2.40-6.94) after adjustment for immobilization and infection and was further attenuated to 3.31 (95% CI: 1.83-5.96) when additionally adjusted for trauma, blood transfusion, and central venous catheter. In a mediation analysis, 51.4% (95% CI: 35.5-79.7%) of the effect of surgery on VTE risk could be mediated through immobilization and infection. Conclusions Major surgery was a trigger for VTE, but the association between surgery and VTE risk was in part explained by other VTE triggers often coexisting with surgery, particularly immobilization and infection.
RESUMO
BACKGROUND: Achilles tendinopathy is a painful disorder, and various treatment options are available. Bipolar radiofrequency microtenotomy (RFM) has shown promising results in treating tendinosis. PURPOSE/HYPOTHESIS: The purpose was to compare the results between treatment with bipolar RFM and physical therapy (PT) for patients with midportion Achilles tendinopathy. It was hypothesized that RFM would be equivalent or superior to PT. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 38 patients with midportion Achilles tendinopathy were evaluated for 2 years. The patients were randomized to receive either RFM or PT. There were 20 patients in the RFM group and 18 patients in the PT group. Clinical outcomes were assessed using the visual analog scale (VAS) for pain and the Foot and Ankle Outcome Score (FAOS). The degree of tendinosis was evaluated with magnetic resonance imaging (MRI) of the affected ankle performed before intervention and 2 years after intervention. RESULTS: In both groups, the VAS scores at the 2-year follow-up were significantly improved compared with preintervention: from 7.2 ± 1.5 to 1.0 ± 1.4 for the RFM group and from 5.9 ± 1.3 to 3.1 ± 1.8 for the PT group (P < .01 for both). Compared with the PT group, the RFM group had significantly better VAS scores at both the 1- and 2-year follow-ups (P < .01 for both) and better scores on 4 of the 5 FAOS subscales at the 2-year follow-up (P < .01 for all). MRI revealed an improvement in the tendinosis score in both groups, without any significant difference between the groups. CONCLUSION: In this randomized study, the clinical assessments revealed significant improvements in the VAS, FAOS, and tendinosis score as seen on MRI 2 years after intervention with either RFM or PT in patients with midportion Achilles tendinopathy. The improvement was significantly better in the RFM group with regard to VAS and FAOS, but not in the MRI appearance. REGISTRATION: NCT03274557 (ClinicalTrials.gov identifier).