METATARSALGIA
Summary
Patients with metatarsalgia present with pain in their forefoot (Figure #1). The pain is usually in the "ball" of the foot, under the second or third metatarsal head. This is right at the base of their involved toes. The pain is often described as aching and it is aggravated by standing and walking. There may also be a burning sensation extending into the tips of the toes. Symptoms are aggravated by walking on hard surfaces. Many patients and physicians mix up or interchange a Morton’s neuroma with Metatarsagia. In fact a Morton’s neuroma is a type of metatarsalgia. Successfully treating metatarsalgia involves:
- 1. decreasing the repetetive loading through the forefoot (for example, less standing and walking), and
- 2. Dispersing the loading on the forefoot over a wider area.
Figure 1: Typical Pain location | Figure 2: Localized forefoot load |
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Clinical Presentation
Patients usually have tenderness at the base of the involved toes (metatarsal head region). As well, there can be swelling at the metatarsophalangeal (MTP) joints. In addition, it is not uncommon to have some clawing of the toes with distal migration of the plantar fat pad (the fatty tissue that provides shock absorption to the forefoot) leaving the MTP joints “uncovered”. This provides less covering for the metatarsal heads and therefore, less shock absorption as they bear weight. If a Harris mat (a device that assesses how force is distributed throughout the foot) is performed, it is quite common to see an intense uptake over the involved metatarsal head (Figure 2). Essentially, this is a condition characterized by a localized, repetitive loading (and therefore chronic injury) to the involved area. Structures that are injured include the digital nerve (Morton’s nerve), the MTP joint capsule, the plantar plate, and the metatarsal bone (head and/or neck)
Imaging Studies
Radiographs may demonstrate a relatively long second or third metatarsal relative to the first and the fourth. In rare instances, the MTP joint may actually be subluxed (partially out of joint) or even dislocated.
Treatment
Non-Operative Treatment
Most patients respond well to non-operative treatment. The principle of non-operative treatment is to off load the involved area. This can be done with a combination of comfort shoes, metatarsal pads, soft accommodative orthotics, activity modifications, and possibly anti-inflammatory medications.
These are shoes that are characterized by a stiff sole and a slight rocker bottom contour can help disperse force away from the forefoot. In addition, the toebox should be wide and accommodative.
Metatarsal pads can be very helpful in this condition (Figure 3). When metatarsal pads are fitted appropriately they will help bear weight away from the metatarsal heads that are involved.
Figure 3: Metatarsal Pad
Soft Orthotics
Soft accommodative orthotics can also help to cushion the localized force and thereby decrease the tendency for repetitive injury to the involved area.
Hammertoe crest pad.
For patients with an associated clawtoe deformity, it may be helpful to use a hammertoe crest pad or toe taping to help bring the toe back into an improved position. This may serve to help reposition the thick plantar fat pad under the prominent metatarsal head.
Activity modification
Limiting the amount of standing and walking and thereby decreasing the number of repetitive blows to the involved area of the foot can also help limit symptoms.
NSAIDs can be very helpful if symptoms are moderate or severe.
Corticosteroid Injections
Injecting corticosteroids into the involved metatarsal phalangeal joint can give temporary relief (1-3 months) in certain cases.
Operative Treatment
In a small percentage of patients, non-operative treatment will fail. In these patients, surgery may be helpful. There are a variety of procedures that have been proposed either in isolation or in combination.
If a clawtoe is present, it may be necessary to address this deformity surgically. By repositioning the clawtoe either with an extensor tendon lengthening, flexor to extensor transfer, and/or a PIP joint resection, the plantar fat pad can be reduced under the metatarsal heads.
If the MTP joint is swollen and inflamed it may be helpful to perform a localized synovectomy. This is often done in conjunction with other procedures.
If the second and/or third metatarsal heads are long, it may be beneficial to perform a metatarsal shortening osteotomy such as a Weil osteotomy. By shortening the metatarsal between 3 mm and 6 mm the loading characteristics can be changed and the tendency to load one or more of the metatarsal heads can be altered.
General Potential Complications
The usual list of general post-surgical complications may occur with a various procedures that are used to address metatarsalgia. This includes the potential for
- -wound healing problems
- -Infection
- -Nonunion (if the PIP joint is fused)
- -Nerve injury to the local nerves that provide sensation to the tips of the toes
- -Deep Vein Thrombosis (DVT) -uncommon
- -Pulmonary Embolism (PE) -very uncommon
Specific Complications
Surgery on the toes and forefoot is not as predictable or as easy as patients think. Specific complications depend on the procedure(s) that are performed but can include:
- Continued symptoms. It is often difficult to eradicate all or even most of the symptoms because metatarsalgia is typically a chronic problem. There is a certain amount of tissue damage that has already been done and can not be undone. In some instances patients are made worse by surgery.
- Loss of blood supply to the tip of the toe. The blood supply to the tip of the toe can be tenuous. There are two small arteries (one on either side of the toe) which supply blood to the tip of the toe. It is not uncommon for one of these vessels to be absent. If the blood supply to the tip of the toe is lost the tissue will die and it may be necessary to amputate part, or all of the toe.
- Stiffness of the toe. Toes that have been operated on almost invariably lose some flexibility. Usually this is not a major problem, but in some instances it can lead to discomfort.
- Recurrent deformity of the toe. Toe surgery is performed in an attempt to correct or improve the deformity and associated symptoms. However, balacing and positioning the toe can be tricky and a recurrent cock-up deformity of the toe can occur.
- Numbness to all or part of the toe. Although unlikely it is possible that the sensation topart or all of the toe may be lost following surgery as the small nerves that supply sensation to the toe are close to thte operative site.
- Transfer metatarsalgia. Surgery that corrects a claw toe or moves one of the metatarsal bones may alter the loading characteristics of the front of the foot. This may lead to increase pain in another, previously less symptomatic part of the foot.
Edited July 5th, 2009