The purpose of the present study is to measure whether a new technique of double row suturing of a ruptured Achilles tendon will result in a normalization of the length of the Soleus part (primary outcome) and of the superficial Gastrocnemius part of the tendon (secondary outcome) one-week post-operative. Results will be compared to that of a participants group that underwent the same operation but with a standard operative technique and the same rehabilitation regime recently completed (NCT04263493).

The investigators hypothesize that the new suturing technique will result in an elongation of the Soleus part of the Achilles tendon (primary outcome) by 8.9 mm or less relative to the uninjured contralateral side one week (primary endpoint) after surgery compared to retrospective data from a recently completed randomized controlled trial

This study is an ambidirectional cohort study with a retrospective part based on a recently completed trial (NCT04263493) and this prospective registered trial.

Inclusion Criteria:

• Diagnosed with a traumatic, complete mid-substance Achilles tendon rupture
• Manages transportation to/from the hospital on their own
• Presented within 14 days from injury
• Adult (18 to 60 years)
• Understands Danish

Exclusion Criteria:

• Other injuries affecting their lower limb functions
• Prior Achilles contralateral tendon rupture
• Contraindications for MRI
• Re-rupture
• Smoking
• Systemic diseases influencing tendon healing
• Anticoagulation treatment
• Inability to follow rehabilitation or complete follow-ups
• Immunosuppressive treatment including systemic corticosteroid treatment.

Patients with diagnosed acute Achilles tendon rupture