Increased risk of deep venous thrombosis in patients with poor ankle dorsiflexion after lower limb immobilization

OBJECTIVE: Many trauma patients are at risk of pulmonary embolism due to unrecognized deep vein thrombosis (DVT). Restricted ankle dorsiflexion (AD) range of motion during leg immobilization is known to cause reduced venous blood flow. The aim of the present study was to assess whether AD at plaster cast removal is related to the incidence of DVT and to patient outcome. DESIGN: Prospective observational cohort study. SETTING: Level 1 Trauma Center. PATIENTS: A total of 124 patients (97 men, 27 women; mean age 40.3 years) with plaster cast leg immobilization after surgical repair of Achilles tendon rupture were assessed. MAIN OUTCOME MEASURES: At 2 weeks postoperatively, assessments of AD and the incidence of DVT using compression duplex ultrasound were performed with observers blinded to patient grouping. Patients were dichotomized into 2 groups; poor or good AD, according to the mean AD, −7°. At 3- and 12 months patient-reported outcome was examined using validated questionnaires (ATRS and FAOS), and functional outcome using the heel-rise test. RESULTS: Patients with poor AD sustained 42% DVTs, while patients with good AD exhibited a DVT-rate of 23% (P = .036). Logistic regression analysis corroborated this finding (OR = 2.62, P = .036; 95% CI = 1.06–6.44). AD was not linked to any long-term functional or patient-reported outcome. CONCLUSIONS: Reduced AD after plaster cast removal is associated with a higher risk of DVT. The results of this observational study warrant further prospective studies to confirm the effects of ankle dorsiflexion on the risk of developing venous thromboses. Level of evidence: II