The aim of this work was to revise the current guidelines and to propose a new, comprehensive treatment algorithm for chronic achilles tendon lesions (CATL)s.
For this purpose, the electronic database PubMed was investigated for articles on CATLs in the English language.
All of the classifications were largely based on defect size.
The end-to-end anastomosis was suggested for small defects, whereas larger gaps
required tendon transfer or augmentation techniques.
Considering the limits of the previous classifications and the other parameters related to CATLs, the authors propose a new algorithm that includes a comprehensive assessment of the defect size and the other parameters (comorbidities, MRI evaluation, time from injury to surgery).
Comorbidities include all of the medical conditions that could affect tendon quality, causing degeneration.
Magnetic resonance imaging is important for evaluating the degree of tendinopathy, assessing paratenonitis or tendinitis.
Time from injury to surgery seems to affect the scar tissue between the two stumps: when the surgery is performed within 12 weeks of the injury, a soft debridement could be advised to spare as much tissue as possible.
Partial lesions affecting less than (I stage) or more than (II stage) half of the tendon should be treated conservatively in the case of modest degeneration in a healthy patient within 12 weeks of injury.
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.
In addition to tendon defect size, tendon degeneration, aetiology of the lesion, and time from injury to surgery are crucial factors that should be considered in the surgical planning.