Introduction Studies suggest that women have worse treatment outcome than men after acute Achilles tendon rupture (ATR). Few studies have assessed the influence of age and comorbidity on treatment outcome after ATR. The aim of the study was to investigate if gender, age and comorbidity affect patient reported outcome following ATR.

Materials and methods The study was performed as a registry study in the Danish Achilles tendon Database. The endpoints were the Achilles tendon rupture score (ATRS) at 4 months, 1 year and 2 years after injury. Variables of interest were gender, age, diabetes, hypertension, rheumatic disease, smoking and previous Achilles tendon disorder.

Results Data were collected from April 2012 to March 2018. 1524 patients participated at 4 months, 1277 at 1 year and 899 at 2 years. Women had statistically significantly lower ATRS at 4 months (mean difference, [confidence interval], p-value) (4.8, [1.78;7.78], p<0.01) and 1 year (9.9, [4.3;15.5], p<0.01), but not after 2 years. Patients with hypertension (7.6, [1.4;13.8], p=0.02) and non-operatively treated patients with rheumatic disease (14.8, [0.4;29.2], p=0.04) had lower ATRS at 1 year. Age showed a weak correlation to ATRS at 1 year (r=0.12; p<0.01).

Conclusion Women scored statistically significantly less than men in ATRS at 4 months and 1 year after ATR. The difference was half the clinically relevant difference at 4 months and peaked at 1 year where it equaled the clinically relevant difference. Hypertension and rheumatic disease led to statistically significantly decreased ATRS. Age did not have clinical relevant influence on ATRS.