Soft tissue microcirculation around the healthy Achilles tendon: a cross-sectional study focusing on the Achilles tendon and dorsal surgical approaches to the hindfoot

BACKGROUND: Dorsal approaches to the hindfoot are frequently used. Furthermore, the vascular supply is discussed as a possible cause for ruptures and degeneration of the Achilles tendon. The aim of this study was to evaluate the microperfusion of three possible posterior approaches to the hindfoot and different areas of the Achilles tendon. METHODS: In 111 subjects, a laser Doppler/white light spectroscopy was used to measure microperfusion in terms of blood flow (Flow) and capillary venous oxygen saturation (SO2) in the hindfoot and Achilles tendon. Measurements were performed at two measurement points (MP, proximal and distal) of three dorsal approaches (medial, lateral and central) and inside the Achilles tendon. RESULTS: Microperfusion differed partially between the surgical approaches. The medial and the lateral approaches were significantly superior to the central approach with regard to Flow in both MP (p < 0.001), while SO2 was significantly higher at the proximal measurement point (MP 1; p < 0.001). In this area, the lateral approach was significantly superior to the medial approach regarding Flow (MP 1; p = 0.012). The Achilles tendon exhibited a significantly reduced microperfusion 5 cm proximal to the calcaneal tubercle (SO2 p = 0.001; Flow p = 0.048). Demographic factors, such as body mass index and age, had different effects. Microcirculation was partially superior in men and negatively affected by smoking. CONCLUSIONS: Soft tissue microcirculation on the lateral and medial side of the healthy Achilles tendon was better than centrally on the tendon. Proximally, the lateral approach was better than the medial approach. These circumstances could provide advantages regarding the surgical approach. The Achilles tendon exhibited significantly reduced microperfusion at the typical side of degeneration and rupture. This circumstance could be a possible cause of degenerative processes.