Metatarsalgia – The Clinical Syndrome
Along with sesamoiditis, metatarsalgia is another painful condition of the forefoot being seen with increasing frequency in clinical practice because of the increased interest in jogging and long-distance running. Metatarsalgia is characterized by tenderness and pain over the metatarsal heads. The patient often feels as if he or she is walking with a stone in the shoe. The pain of metatarsalgia worsens with prolonged standing or walking for long distances and is exacerbated by improperly fitting or padded shoes. Often a patient with metatarsalgia develops hard callus over the heads of the second and third metatarsals when trying to shift the weight off the head of the first metatarsal to relieve the pain. This callus increases the pressure on the metatarsal heads and exacerbates the patient’s pain and disability.
What are the Symptoms of Metatarsalgia
On physical examination, pain can be reproduced by pressure on the metatarsal heads. Callus often is present over the heads of the second and third metatarsal heads and can be distinguished from plantar warts by the lack of thrombosed blood vessels that appear as small dark spots through the substance of the wart when the surface is trimmed. A patient with metatarsalgia often exhibits an antalgic gait in an effort to reduce weight bearing during the static stance phase of walking. Ligamentous laxity and flattening of the transverse arch also may be present, giving the foot a splayed-out appearance.
How is Metatarsalgia diagnosed
Plain radiographs are indicated in all patients with metatarsalgia to rule out fractures and to identify sesamoid bones that may have become inflamed. Based on the patient’s clinical presentation, additional tests, including complete blood cell count, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated. Magnetic resonance imaging (MRI) and ultrasound imaging of the metatarsal bones is indicated if joint instability, occult mass, or tumor is suspected. Radionucleotide bone scanning may be useful in identifying stress fractures that may be missed on plain radiographs of the foot.
Primary pathology of the foot, including gout and occult fractures, may mimic the pain and disability associated with metatarsalgia. Entrapment neuropathies such as tarsal tunnel syndrome, bursitis, and plantar fasciitis of the foot also may confuse the diagnosis; bursitis and plantar fasciitis may coexist with sesamoiditis. Sesamoid bones beneath the heads of the metatarsal bones are present in some individuals and are subject to the development of inflammation termed sesamoiditis. Sesamoiditis is another common cause of forefoot pain and may be distinguished from metatarsalgia by the fact that the pain of metatarsalgia is centered over the patient’s metatarsal heads and does not move when the patient actively flexes his or her toes, as is the case with sesamoiditis. The muscles of the metatarsal joints and their attaching tendons are susceptible to trauma and wear and tear from overuse and misuse and may contribute to forefoot pain. Primary and metastatic tumors of the foot also may manifest in a manner analogous to that of arthritis of the midtarsal joints.
Initial treatment of the pain and functional disability associated with metatarsalgia should include a careful evaluation of the patient’s footwear. Shoes should be well fitting with adequate length and a wide toe box. A firm rocker bottom sole may provide symptomatic relief. A combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy may provide relief from the pain of metatarsalalgia. Local application of heat and cold may be beneficial. Avoidance of repetitive activities that aggravate the patient’s symptoms and short-term immobilization of the midtarsal joint also may provide relief. For patients who do not respond to these treatment modalities, injection of the affected metatarsal heads with a local anesthetic and steroid may be a reasonable next step. Ultrasound guidance may improve the accuracy of needle placement and decrease the incidence of needle-related complications.
Complications and Pitfalls
The major complication of injection of the metatarsal heads is infection. This complication should be exceedingly rare if strict aseptic technique is followed. Approximately 25% of patients report a transient increase in pain after injection of the metatarsal heads, and patients should be warned of this possibility. Another potential risk of this injection technique is trauma to the associated tendons from the injection.
Pain emanating from the forefoot is a common problem encountered in clinical practice. Metatarsalgia must be distinguished from stress fractures of the metatarsal bones, Morton neuroma, and sesamoiditis. Although the previously mentioned injection technique provides palliation of the pain of metatarsalgia, the patient often also requires shoe orthoses, including metatarsal bars and padded insoles, to help remove pressure from the metatarsal heads. Coexistent bursitis and tendinitis may contribute to metatarsal pain and may require additional treatment with more localized injection of a local anesthetic and depot steroid. Injection of the metatarsal heads with a local anesthetic and steroid is a safe procedure if careful attention is paid to the clinically relevant anatomy in the areas to be injected. The use of physical modalities, including local heat and gentle range-of-motion exercises, should be introduced several days after the patient undergoes this injection technique for metatarsalgia pain. Vigorous exercises should be avoided because they would exacerbate the patient’s symptoms. Simple analgesics and NSAIDs may be used concurrently with this injection technique.