The “Knot of Henry” was dissected in 16 embalmed cadaveric feet to reveal the complex interconnections between flexor hallucis longus (FHL) and flexor digi-torum longus (FDL) tendons. Three distinct anatomical patterns were observed.

Tension was applied manually to FHL or FDL proximal to the Knot. Digit movement was different depending on the anatomical pattern.

FHL or FDL tendon transfer is an accepted technique to prevent progression of acquired plano-valgus deformity. In order to minimise donor deficit, we suggest the use of either FHL or FDL should be based on assessment of the anatomical pattern at the time of surgery.