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Chronic Achilles tendon lesions (CATLs) ensue from a neglected acute rupture or a degenerated tendon. Surgical treatment is usually required. The current English literature (PubMed) about CATLs was revised, and particular emphasis was given to articles depicting CATL classification. The available treatment algorithms are based on defect size. We propose the inclusion of other parameters, such as tendon degeneration, etiology, and time from injury to surgery. Partial lesions affecting less than (I stage) or more than (II stage) half of the tendon should be treated conservatively for healthy tendons, within 12 weeks of injury. In II stage complex cases, an end-to-end anastomosis is required. Complete lesions inferior to 2 cm should be addressed by an end-to-end anastomosis, with a tendon transfer in the case of tendon degeneration. Lesions measuring 2 to 5 cm require a turndown flap and a V-Y tendinous flap in the case of a good-quality tendon; degenerated tendons may require a tendon transfer. Lesions larger than 5 cm should be treated using two tendon transfers and V-Y tendinous flaps. A proper algorithm should be introduced to calibrate the surgical procedures. In addition to tendon defect size, tendon degeneration, etiology of the lesion, and time from injury to surgery are crucial factors that should be considered in the surgical planning.