PurposeThe aim of this study was to investigate whether patient subjective and functional outcomes after Achilles tendon rupture (ATR) are related to deep venous thrombosis (DVT) during leg immobilization.MethodsA cohort study with prospectively collected randomized data was conducted between 2010 and 2017. Two-hundred and fifty-one Patients with an Achilles tendon rupture (mean age = 41 ± 8), treated with uniform surgical techniques, were retrospectively analyzed. DVT incidence at 2 and 6 weeks was assessed using compression duplex ultrasound. At 12 months patient-reported outcomes were assessed using the Achilles tendon Total Rupture Score (ATRS), Foot- and Ankle Outcome Score (FAOS), Physical Activity Scale (PAS) and functional outcome with the calf-muscle endurance test. ANOVA analyses were used and adjusted for assumed confounding factors (patient age, sex, BMI and rehabilitation).ResultsThe total DVT incidence was 122 out of 251 (49%). Patients suffering a DVT exhibited significantly lower ATRS at 1 year compared to patients without DVT (mean 76 vs 83, 95% CI 71–79 vs 80–87; p < 0.01). Sixty-seven percent (95% CI 57–77%) of the patients devoid of DVT reported a good outcome (ATRS > 80) compared to 51% (95% CI 41–61%) of the patients sustaining a DVT (p < 0.05). Quality of life displayed significantly better outcome in the non-DVT versus DVT patients (mean = 75 (95% CI 71–79) vs. mean = 68 (95% CI 64–72); p < 0.05). A significant difference in total concentric work was observed between non-DVT and DVT patients (median = 1.9 kJ (IQR = 0.9 kJ) vs. median = 1.6 kJ (IQR = 1.0 kJ); p < 0.01).ConclusionSustaining a DVT during leg immobilization significantly impairs patient-reported outcome at 1 year after surgical repair of ATR.Level of evidenceIII.