"Safe incision" in calcaneal sliding osteotomies reduces the incidence of sural nerve injury.

PURPOSE: The purpose of this study was to demonstrate whether application of the so-called safe incision when performing calcaneal sliding osteotomies reduces the risk of sural nerve injury.
METHODS: Patients who underwent either medial or lateral sliding calcaneal osteotomies between 2010 and 2018 were analysed retrospectively. A thorough neurological examination was performed, and the location of the surgical wound and the type of wound closure were recorded. The European Foot and Ankle Surgery (EFAS) score and 12-item Short Form Survey (SF-12) were also documented.
RESULTS: A total of 57 patients were included, of which 20 (35.1%) had a sural nerve injury. Five patients had a neurapraxia (8.8%), while 15 patients had a permanent injury (26.3%). Respecting the "safe incision" decreased sural nerve injury (p = 0.02). The type of osteotomy and closure was not significant. No significant differences were found in the functional tests between the different techniques, or between patients who presented sural nerve injury and those who did not.
CONCLUSION: Sural nerve injury after calcaneal sliding osteotomies is higher than previously reported in the scientific literature, with an incidence of 35.1% (20/57 patients). Respecting the so-called safe zone (oblique incision that runs through the point that is > 1/3 of the distance from the tip of the lateral malleolus to the posteroinferior margin of the calcaneus) clearly decreases the incidence of sural nerve injury. Finally, the majority of patients remained asymptomatic despite the neurological injury.