Distributions of local anesthetics injected into the distal interphalangeal joint and podotrochlear bursa: An experimental study

Abstract

Local anesthetic injections into the distal interphalangeal (DIP) joint and the podotrochlear bursa have variable clinical results. The current study evaluates the anatomy of these structures and the diffusion of dye-local anesthetic solution to surrounding structures. The abaxial portions of the collateral sesamoidean ligament (CSL) were nearly encircled by the synovial cavities of the DIP joint. Dye-anesthetic solution diffused from the DIP joint via the distal sesamoidean impar ligament (DSIL) and deep digital flexor tendon. Diffusion of dye-anesthetic solution from the podotrochlear bursa involved portions of the neurovascular bundle, similar to DIP joint injections. From our knowledge of work detailing the sensory nerves in the CSL and DSIL, we believe that the local anesthetic injections into these two synovial cavities are not selective for only their exposed surfaces.