Laboratory Studies
Although appearing clinically different from traumatic injuries to the first metatarsophalangeal joint, gout commonly presents with pain at the base of the first toe. Testing of uric acid levels, the erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) may be helpful in excluding gouty arthritis and other rheumatologic conditions in subtle cases. Otherwise, laboratory studies are of little benefit in the evaluation of metatarsalgia. (See also the Medscape Reference article Gout and Pseudogout.)
Imaging Studies
A radiographic foot survey is indicated as an initial imaging test and may be helpful in excluding other etiologies of forefoot pain.
Order repeat radiographs and a bone scan to assist the physician with diagnosing or excluding a metatarsal stress fracture. (See also the Medscape Reference article Metatarsal Stress Fracture.)
Ultrasonography provides useful information about possible pathologic conditions that may be responsible for pain in the metatarsal region of the foot, including bursitis, Morton neuroma, and joint effusions. [10, 11] (See also the Medscape Reference article Bursitis in Emergency Medicine.)
Yu and Tanner demonstrated that magnetic resonance imaging (MRI) is a powerful, noninvasive method for detecting and diagnosing many causes of pain in the metatarsal and midfoot regions, including conditions caused by trauma, circulatory disorders, arthritides, neuroarthropathies, and those that result in biomechanic imbalance. [12]
Other Tests
F-Scan (Tekscan, Inc, South Boston, Mass) is an objective measurement system that is used to assess plantar pressures, identify the location of peak pressures, and help with the molding and placement of orthotic devices that can be most effective in dispersing excessive localized forces.
Procedures
A local digital nerve block just below the transverse tarsal ligament may be helpful in the diagnosis of an interdigital neuroma. Patients with an interdigital neuroma should receive relief after the injection.
