Duplication of the Plantaris Tendon and Its Clinical Significance: A Case Report

The plantaris tendon may be absent in some individuals, indicating its unclear function. Anatomically, the plantaris tendon originates from the lateral femoral condyle and has a variable course and insertion point at the calcaneal tuberosity. The plantaris tendon may influence conditions such as Achilles tendinopathy, particularly in its midportion, whether by its close relation to the calcaneal tendon or adhesions between both tendons. This case study involves a 38-year-old male patient with an Achilles tendon rupture; two plantaris tendons were discovered during surgical exploration. An anatomical variation was described before in a cadaveric study, where two plantaris muscles were encountered during specimen dissection, and the accessory tendon was inserted in the crural fascia proximal to the calcaneal tendon. The relationship between anatomical variations of the plantaris tendon and Achilles tendon injuries remains an area of ongoing research, and current findings suggest that while there may be a correlation, definitive conclusions cannot be drawn. This case reports a rare anatomical variation encountered during routine surgery, and despite not establishing a relation to tendon rupture, it can alert other surgeons to the anatomic variability of the plantar tendon and its possible role in the treatment of Achilles tendinopathy.