Passive Ankle Plantarflexion Position and Skin Surface Blood Flow Adjacent to the Achilles Tendon

Open repair of the Achilles tendon carries a risk of wound complications and infection. The Achilles tendon is covered by a thin layer of skin and subcutaneous tissue, which has a fragile blood supply. The full plantarflexion position may cause sustained blanching of the skin above the Achilles tendon. However, no reports have described the in vivo blood flow (BF) changes at the skin surface with ankle position. This study aimed to use laser Doppler flowmetry to evaluate the in vivo BF at the skin surface and thereby clarify the changes in BF with ankle position.The study cohort comprised 30 feet in 15 participants with no history of Achilles tendon rupture. Laser Doppler flowmetry was used to measure the BF at the skin surface above the medial Achilles tendon in the natural plantarflexion (NP) and full plantarflexion (FP) positions.In the NP and FP positions, the BF at 5 cm proximal to the calcaneal insertion (frequent site of Achilles tendon rupture) was 1.50 ± 0.32 and 0.97 ± 0.28 mL/min/100 g, respectively (P < .0001).The BF at the skin surface adjacent to the medial Achilles tendon at 5 cm proximal to the calcaneal insertion was significantly less in the FP position than the NP position.