Background: Dorsal pain from osteoarthritic midfoot joints is thought to be relayed by branches of the medial and lateral plantar, sural, saphenous, and deep peroneal nerves (DPN). However, there is no consensus on the actual number or pathways of the nervous branches for midfoot joint capsular innervation. This study examined the DPN's terminal branches at the midfoot joint capsules through anatomic dissection and confirmation of their significance in a clinical case series of patients with midfoot pain relief after DPN block.
Methods: Eleven cadaveric lower leg specimens, 6 left and 5 right, were dissected using operative loupe magnification. We preserved the terminal branches and recorded their paths and branching patterns. Joint capsular innervations were individually noted. To confirm our hypothesis of significant dorsal midfoot joint capsular innervation by the DPN, we also performed an institutional review board-approved retrospective chart review of 37 patients with painful dorsal midfoot osteoarthritis who underwent diagnostic local anesthetic injection block of the DPN. The percentage of temporary pain relief after the injection was recorded.
Results: Terminal innervation of the DPN branches showed distribution of the second and third tarsometatarsal joints in all specimens. Inconsistent innervation of the naviculocuneiform (9/11), fourth (7/11), first (6/11), and fifth (4/11) tarsometatarsal and calcaneocuboid joints (1/11) were observed. The retrospective review of pain relief in patients with dorsal midfoot pain due to arthritis after diagnostic injection demonstrated a mean of 92.1% improvement.
Conclusion: Innervation of the dorsal midfoot joint capsule appears to follow a consistent distribution across 3 joints: second and third tarsometatarsal joints and the naviculocuneiform joint. Acute relief of dorsal midfoot arthritic pain after diagnostic injection suggests that dorsal midfoot nociceptive pain is at least partly transmitted by the DPN.
Level of evidence: Level IV, case series.
Keywords: deep peroneal nerve; midfoot arthritis.