Background and purpose Modern descriptions of the percutaneous triple hemisection technique for Achilles tendon lengthening do not take into account the axial twist in the ligament. We were concerned that technical failures of the lengthening technique might occur more often than has been reported, and analyzed the results of the triple hemisection technique in cadaveric tendons in quantitative and qualitative terms, focusing on insufficient or complete tenotomies.

Methods We performed a percutaneous triple hemisection of the Achilles tendon in 20 legs from adult cadavers, and measured the increase in ankle dorsiflexion in degrees, the length of the cuts in mm, and the depth of the cuts as a percentage of the total diameter of the tendon. Failure of the hemisection was defined as a sliding gap of ≤ 2 mm and/or a cut depth of ≤ 25% or < 75%.

Results 21 of the 60 hemisections failed. These failures occurred in 12 of the 20 legs, and included 1 complete tendon rupture and 3 near-ruptures with only a few connecting fibers left.

Interpretation Our findings support our hypothesis that technical failures in the triple hemisection procedure occur more often than acknowledged. Despite the scarce but good clinical results described in children, we suggest performing this technique as an open procedure, especially in cases where the boundaries of the tendon are less easily palpable (adults, obese children), and to use the largest possible distance between the hemisections.