Edited by Vinod Panchbhavi, MD
Metatarsalgia is characterized by pain in the forefoot. The term literally means “pain on the metatarsal” (there are 5 metatarsal bones in the forefoot). Metatarsalgia is not a true diagnosis, but rather it is a symptom. Patients with metatarsalgia present with pain in their forefoot, usually in the ball of the foot (Figure 1). The pain is often described as aching, and it is typically aggravated by standing and walking. In general, metatarsalgia is caused by repetitive overloading of the forefoot, leading to chronic localized tissue injury. Often the most symptomatic area is at the base of the 2nd or 3rd toe. Factors that may predispose to the development of metatarsalgia include: a bunion deformity, arthritis of the great toe, ligament instability of the midfoot, an excessively tight calf muscle, a congenital foot deformity, and claw toe deformities.
Non-operative treatment of metatarsalgia is often successful. Treatment principles include:
- Making the correct diagnosis and addressing the underlying cause of the symptom.
- Diminishing the repetitive loading through the forefoot.
- Dispersing the loading on the forefoot over a wider area.
Figure 1: Typical Pain location
Figure 2: Localized forefoot load
The pain that is experienced in metatarsalagia typically occurs in the forefoot, at the base of the second or third toes (under the second or third metatarsal head). It often feels like walking “on stones or pebbles” or on “a rolled up sock” at the base of the involved toes. The pain is often described as aching, and it is aggravated by standing and walking, particularly on hard surfaces. There may also be a burning sensation extending into the tips of the toes.
As the condition progresses, it may be associated with increased clawing of the toes. This can cause the fatty tissue that provides shock absorption to the forefoot to no longer be located under the weight-bearing bones of the forefoot (distal migration of the plantar fat pad leaving the metatarsal heads and the metatarso-phalangeal joints (MTP) joints without the padding or “uncovered”). This results in less protection for the metatarsal heads; less shock absorption as they bear weight, callus formation, and worsening of the symptoms.
Unfortunately for some patients, the cause of metatarsalagia is hidden by the secondary clawtoe deformity that develops and worsens the symptoms. If an ink imprint of the weight bearing sole of the foot is obtained, such as with a Harris mat (a device that assesses how force is distributed throughout the foot), there is often an intense uptake in the area corresponding to the involved metatarsal head(s) (Figure 2). Continued, localized, repetitive loading to the involved area will predispose to chronic injury to the structures being loaded. The structures that are commonly injured include the MTP joint capsule, the plantar plate, and the metatarsal bone (head and/or neck). The irritation of the MTP joint is due to repetitive overload, and can lead to swelling of the joint itself. Patients are unable to bend the toes completely and show the ‘knuckles’ on the top. Often in early stages the toes start separating. This condition is called as MTP joint synovitis.
X-rays in patients with metatarsalgia often demonstrate a long second or third metatarsal, relative to the first and the fourth metatarsalgia. In rare instances, the MTP joint may actually be subluxed (partially out of joint) or even dislocated. Deformities of the 1st metatarsal, such as those present with a Bunion or with midfoot instability, may also be observed on x-ray.
Patients respond well to non-operative treatment. If the underlying cause can be addressed, non-operative treatment will be successful in the longterm. 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, calf stretching, foot muscle strengthening, and NSAIDS (Non-steroidal anti-inflammatory drugs).
- Comfort shoes: Unfortunately, heels and pointed toe shoes will worsen the symptoms, by concentrating weight bearing on the forefoot. Shoes that are characterized by a stiff sole and a slight rocker bottom contour can help disperse force away from the forefoot. Orthopaedic shoes of the past carry a negative connotation of an ugly, unstylish, men’s Oxford which are rejected by many patients. Currently, many women’s and men’s dress and athletic shoe manufacturers carry lines with more style and the same features.
- Metatarsal pads: 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. As noted in Figure 3 to be effective a metatarsal pad needs to be positioned before the main area of loading.
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: A calf muscle contracture (equinus contracture) will increase stress on the forefoot. Stretching the calf will help eliminate this cause of pain. After the joints become irritated, the small muscles (intrinsic muscles) of the foot often become weak, which serves to spreads the symptoms. Strengthening these muscles through foot specific exercises will improve the contraction, and lead to better more tolerated loading through the foot.
- Non-steroidal anti-inflammatory drugs: NSAIDs can be very helpful if symptoms are moderate or severe, as they can modify the perception of symptoms, giving other non-operative treatments time to allow the overloaded area to heal.
- Corticosteroid Injection: Injecting corticosteroids into the involved joint can give temporary relief (1-3 months) in certain cases. If performed repetitively, cortisone may cause ligament degeneration and precipitate a toe deformity.
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.
It is essential that the primary cause of the metatarsalgia be addressed. If a “clawtoe” is present, it may be necessary to address this deformity surgically. By successfully correcting the toe deformity, the shock-absorbing plantar fat pad can be reduced under the metatarsal heads. There are a variety of different ways to surgically correct a clawtoe deformity. The technique chosen will depend on the extent of the deformity, the stiffness of the toe, and the preference of the surgeon. If the joint at the base of the involved toe (MTP joint) is swollen and inflamed, it may be helpful to remove the inflamed synovial lining (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. If a Bunion deformity is present, this deformity may need to be corrected in order to address the abnormal weight bearing of the forefoot. If a tight calf muscle is present and does not resolve with stretching, lengthening of the gastrocnemius muscle (Strayer procedure) may be beneficial.
General Potential Complications
The usual list of general post-surgical complications may occur with various procedures that are used to address metatarsalgia. This includes the potential for:
- Wound healing problems
- 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
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.
- 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, balancing 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 to part or all of the toe may be lost following surgery, as the small nerves that supply sensation to the toe are close to the 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.
- Loss of blood supply to the tip of the toe In rare instances, the blood supply to the tip of the toe is severely attenuated. There are two small arteries (one on either side of the toe) which supply blood to the tip of the toe. In some patients, one of these vessels may 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.
Edited on December 28, 2016