The aim of the present study was to compare repaired Achilles tendon (AT) remodelling, whether its function was restored and what effects the surgery had on our patients’ gait cycle in a long-term follow-up study. The study population comprised 30 human subjects treated acutely and chronically for AT ruptures, using the same surgical technique in all cases. The study group was divided into two subgroups regarding the age of their AT injury, i.e., how much time elapsed between the injury and when a correct diagnosis was made and when adequate treatment was applied. Following these criteria, persons presenting at less than 4 weeks postinjury were classified as acute rupture (AR) patients and those presenting at more than 4 weeks after injury were grouped as chronic rupture (CR) patients. Both patient groups were operated on using a surgical method favoured at least a decade ago, i.e., open repair through a posteromedial approach. The AT was augmented with a plantaris longus tendon autograft, followed by suturing using the pull-out suture technique. The results were measured using clinical, ultrasonographic (US) and pedobarographic methods. Our ultrasonographic and pedobarographic findings revealed differences between both patient groups, thus indicating that delayed surgery had negative impacts on treatment success, however, with good long-term functional score outcomes in both patient groups. Nevertheless, delayed treatment of AT ruptures did not leave individual gait phases unaffected, as it also affected the plantar surface and balance performance of the affected limb. As per the results, the Achilles tendon manifested decreased capacity following delayed treatment; however, its long-term functional outcomes were favourable, irrespective of whether it was for acute or chronic patients.