Heel width as a simple parameter to prevent sural nerve entrapment during percutaneous Achilles tendon repair

Background. The aim of the research was to evaluate a simple parameter that could prevent sural nerve (SN) entrapment during percutaneous acute Achilles tendon (AT) repair. The parameter could be easily introduced during surgery, would not raise the costs of procedure and could be universally used by any orthopedic surgeon. Methods. A number of 28 fresh male cadavers were used to identify the crossing point between the medial margin of the SN and the lateral margin of the AT, proximally from the calcaneal tuberosity (CT). The following measurements were taken: shin length, heel width, foot length and AT width 16 cm from CT. Results. A significant relationship was found between heel width and the crossing point of CT with AT (p = 0.04). The distance from the crossing point was not related to shin length, foot length, AT width 16 cm from CT, shin length/foot length index, shin length/heel width index, or foot length/heel width index. The linear regression model found only the estimated regression coefficient at heel width to be significant (p < 0.05), i.e. if the heel width increases by a unit (1 mm), the AT and SN crossing point increases by an average of two units (2 mm). Conclusion. Of the tested parameters, heel width appears to be the best predictor of SN and AT crossing point location, both with regard to significance and simplicity of use in the operation. The SN-AT junction point is located two heel widths proximal from the most prominent aspect of the CT. Level of evidence II b