This injection procedure is used to diagnose and treat Morton’s metatarsalgia and Morton’s neuroma.
After informed consent is obtained, the patient is positioned for optimal access to the dorsal aspect of the foot. The metatarsal joint interspaces are palpated for swelling and tenderness. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1-in. (2-cm), 25-gauge needle is inserted at the point of maximal tenderness, perpendicular to the skin, and advanced about 1 cm. After negative aspiration, a 2-mL mixture of 5 mg of triamcinolone acetonide (or equivalent) and local anesthetic is injected (Fig. 67-59).
FIGURE 67-59. Metatarsal joint injection. Approach for metatarsal joint aspiration and injection.
Morton’s metatarsalgia often involves the first and second interdigital spaces. Morton’s neuroma is neuritis of the plantar digital nerves located between the third and fourth metatarsal heads and occasionally in the nerve between the second FIGURE 67-59. Metatarsal joint injection. Approach for metatarsal joint aspiration and injection. (From Katz J. Atlas of Regional Anesthesia. Norwalk, CT: Appleton & Lange; 1994:93, with permission.) and third metatarsal heads. This procedure is used to treat postoperative scar pain often present after surgical removal of a Morton’s neuroma.
Serious complications are uncommon with appropriate needle placement.