Deep venous thrombosis and pulmonary embolism after anterior cruciate ligament reconstruction: incidence, outcome, and risk factors.

AIMS: The aim of this study was to investigate the incidence, risk factors, and outcome of venous thromboembolism (VTE) following anterior cruciate ligament (ACL) reconstruction in a nationwide cohort. PATIENTS AND METHODS: All ACL reconstructions, primary and revision, that were recorded in the Swedish Knee Ligament Register (SKLR) between 2006 and 2013 were linked with data from the Swedish National Board of Health and Welfare. The incidence of VTE was determined by entries between the day of surgery until 90 days postoperatively based on diagnosis codes and the prescription of anticoagulants. Risk factors, outcome, and the use of thromboprophylaxis were analyzed. Descriptive statistics with multivariate analysis were used to describe the findings. RESULTS: The cohort consisted of 26 014 primary and revision ACL reconstructions. There were 89 deep venous thromboses (DVTs) and 12 pulmonary emboli (PEs) with a total of 95 VTEs (0.4 %). Six patients with a PE had a simultaneous DVT. The only independent risk factor for VTE was age greater than or equal to 40 years (odds ratio 2.31, 95% confidence interval 1.45 to 3.70; p < 0.001). Thromboprophylaxis was prescribed to 9461 patients (36%) and was equally distributed between those with and those without a VTE (37.9% vs 36.4%). All patient-reported outcome measures (PROMs) one and two years postoperatively were significantly lower in those with VTE. CONCLUSION: The incidence of VTE following ACL reconstruction is 0.4%, and the only significant risk factor is age. Patients with VTE had worse postoperative clinical outcome than patients without VTE. We recommend against the routine use of thromboprophylaxis, but it should be considered in older patients.

Chemokine expression of CCL2, CCL3, CCL5 and CXCL10 during early inflammatory tendon healing precedes nerve regeneration: an immunohistochemical study in the rat.

PURPOSE: Chemokines are major promoters of repair and may regulate nerve ingrowth that is essential in tendon healing. The purpose of this study was to assess the temporal occurrence of different chemokines during Achilles tendon healing in relation to sensory nerve regeneration. Chemokine presence in tendon healing has not been studied previously. METHODS: Chemokine expression, nerve regeneration, angiogenesis and inflammatory cell occurrence during healing of Achilles tendon rupture in the rat were studied by immunohistochemistry and histology including semiquantitative assessment. Markers for chemokines (CCL5, CCL2, CCL3, CXCL10), nerves (PGP-9.5) and sensory neuropeptide substance P (SP) were analysed at different time points (1 day-16 weeks) post-rupture. RESULTS: In intact tendons (controls) immunoreactivity to all chemokines, PGP-9.5 and SP were confined to the tendon surroundings. After rupture, there was rapid increase in the tendon proper of the chemokines studied, all exhibiting their peak expression at week 1. Subsequently, at weeks 2-6, emerging inflammatory cells and maximum sprouting of PGP-/SP-positive nerves were observed close to newly formed blood vessels within the tendon proper, while chemokine expression already decreased. During weeks 6-8, PGP-/SP-positive nerves withdrew from the rupture site and relocated together with the chemokines in the surrounding tendon. CONCLUSIONS: Early chemokine expression in the healing tendon precedes ingrowth of new nerves, angiogenesis and emergence of inflammatory cells. The fine-tuned temporal and spatial appearance of chemokines suggests a chemoattractant role for inflammatory cell migration and possibly also a role in angiogenesis and neurogenesis. Chemokines may thus exhibit vital targets for biological modulation of tendon repair.