Soft tissue micro-circulation in the healthy hindfoot: a cross-sectional study with focus on lateral surgical approaches to the calcaneus.

PURPOSE

Open reduction and internal fixation (ORIF) using an extended lateral approach combined with plate osteosynthesis represents the current gold standard in calcaneal fracture treatment, but it is associated with a wound complication rate of up to 30%. Literature suggests that micro-circulation is one of the key factors for sufficient wound healing. The aim of this study was to evaluate soft tissue micro-circulation of the hindfoot in healthy volunteers to determine influencing factors and to identify hypoxic or hypoperfused areas in non-trauma situations, with special attention to surgical approaches.

METHODS

Micro-circulation of the lateral hindfoot of 125 participants was non-invasively measured at 2 and 8 mm depths, utilizing a Micro-Lightguide O2C® spectrophotometer. Blood flow (BF [AU]) and oxygen saturation (SO2 [%]) of ten measurement points (MPs) were documented. Demographic factors (age, gender, body mass index [BMI], systolic/diastolic blood pressure, smoking, and pack-years) and regional differences with special regard to surgical approaches (extended lateral approach, Palmer approach, Ollier approach, and a self-modified extended lateral approach) were analyzed.

RESULTS

The SO2 assessments at 2- and 8-mm depths revealed higher values in males (p = 0.043; p = 0.025). There was a correlation between higher age and lower 2 mm BF (p = 0.044). Smoking history and number of pack-years did not predict micro-circulation. BF at the 2 mm depth was highest in the regions of Palmer and Ollier approach (p < 0.001). The MP at the distal calcaneal tuberosity showed significantly higher values regarding all parameters (SO2 (2 mm), p < 0.001; SO2 (8 mm), p = 0.001; BF (2 mm), p < 0.001; BF (8 mm), p < 0.001), compared to the surrounding area.

CONCLUSIONS

In non-trauma situations, young males were associated with better micro-circulatory supply of the lateral hindfoot. There was a trend for higher blood flow in regions of the Palmer and Ollier approach. The distal calcaneal tuberosity was clearly superior in all micro-circulatory parameters when compared to the surrounding area.