Palmar/plantar approach for radiographic-guided injection of the equine distal interphalangeal joint collateral ligament insertion

There are limited radiographic-guided injection techniques of the insertion of the distal interphalangeal joint (DIPJ) collateral ligaments. The objective of this study was to develop and evaluate a palmar/plantar radiographic-guided injection of the collateral ligament insertion in cadavers. Fifty limbs were used to develop the technique and 24 additional limbs were used to evaluate accuracy. An 18 G, 9 cm spinal needle was placed in the depression between the palmar digital neurovascular bundle and arch of the ungular cartilage with dorsodistal advancement towards the distal phalanx collateral fossa. Radiographs verified ideal needle location on the proximal border of the distal phalanx at the collateral fossa. Dye was injected. Hoof walls were partially removed and collateral ligaments were dissected with needles in place to determine needle and dye location. Accuracy of needle placement into the insertion of the DIPJ collateral ligament was 41/48 (85 per cent), with lower accuracy of dye within the ligament (34/48; 71 per cent). Dye entered the DIPJ in 2/48 injections, but dye entered periligamentous structures in 22/48 (46 per cent) injections. A palmar/plantar radiographic-guided injection of the insertion of the DIPJ collateral ligament had high accuracy rate with low injection rate of the DIPJ in cadavers.