The lateral dorsal cutaneous branch of the sural nerve: clinical importance of the surgical approach to proximal fifth metatarsal fracture fixation.

BACKGROUND

Fractures of the proximal fifth metatarsal are one of the most common forefoot injuries encountered by orthopaedic surgeons in sports medicine. The percutaneous surgical approach to Jones fracture fixation and corresponding anatomy has received little attention in the literature to date.

PURPOSE

To describe in detail the location of the lateral dorsal cutaneous nerve (LDCN) and its branches relative to the base of the fifth metatarsal and to the standard lateral approach.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ten fresh-frozen cadaveric foot specimens were used for this study. Specimens were dissected at the lateral aspect of the foot over the proximal fifth metatarsal, and the LDCN and its branches were identified. The distance of the LDCN to the superior border of the peroneus brevis tendon (PBT) was measured relative to standard reference points in all specimens, and the presence of an anastomotic branch was noted. A set of vertical and horizontal reference lines were also constructed to determine whether the LDCN or its branches would be compromised by a standard lateral approach.

RESULTS

The LDCN was superficial (ie, lateral) and inferior to the superior border of the PBT in all specimens and at all reference points. A bifurcation of the LDCN was present in 8 specimens, located an average of 18 mm posterior and 11 mm dorsal to the base of the fifth metatarsal. The dorsolateral branch and dorsomedial branch of the LDCN each intersected with the base of the fifth metatarsal horizontal line and vertical line, respectively, indicating potential compromise of the nerve with a standard lateral surgical approach.

CONCLUSION

The standard lateral approach to the base of the fifth metatarsal carries a higher risk for surgical injury to the LDCN. A "high and inside" approach that remains superior to the superior border of the PBT is anatomically safe and may decrease the chance of intraoperative nerve injury and irritation postoperatively.