Metatarsalgia in the Foot: Definition and Possible Treatments

Metatarsalgia: The causes

What is metatarsalgia?

Metatarsalgia is pain on the sole of the foot under the metatarsal head. This pain is mechanical; it appears and increases with weight-bearing on the forefoot. Metatarsalgia can affect one or more metatarsals; it is a pain in the plantar pads.

Frequently observed symptoms

The main symptom is pain in the plantar pads. This pain is generally mechanical and subsides with rest.

Depending on how long the condition has lasted, some neurological sensations may be described by patients as a result of excessive pressure and compression of nerve fibers in the forefoot. Some patients describe the sensation of having a rolled-up sock under their toe, for example.

Certain toe deformities may be associated with metatarsalgia. Lesions of the plantar plates, which are real safety belts for the toes allowing proper contact with the ground, can also appear; they lead to poor toe support when walking, potentially worsening metatarsalgia.

The progression of plantar plate lesions can lead to the rupture of a plantar plate, causing elevation of the affected toe, which may result in a claw deformity of that toe. Overlapping toes can also be observed in the case of plantar plate lesions, as well as metatarsophalangeal dislocations.

The most common causes

The main cause of metatarsalgia is probably the shortening of the posterior muscle chains, especially the gastrocnemius (calf muscles). The calf muscles are connected to the Achilles tendon and the plantar fascia, which inserts at the base of the toes. Shortening of the system leads to excess pressure on the forefoot, which may cause metatarsalgia.

Morphological causes can also be responsible for metatarsalgia.

It is essential to have weight-bearing X-rays of the feet from the front and side for an analysis of metatarsalgia. The relative length of the metatarsals can be assessed, and some disharmonies in length may be noted. There are radiographic criteria for analyzing the relative length of the metatarsals, known as the Maestro criteria, described by Dr. Maestro. These criteria make it possible to determine morphotypes with relatively long central metatarsals and relatively short lateral metatarsals. The longer a metatarsal is, the more pressure it will undergo when the foot rolls during walking.

The length of the big toe should also be taken into account. When the big toe is relatively long, this is called hallomegaly; its push-off strength while walking is lower, thus overloading the lateral metatarsal row. If the big toe is relatively short, propulsion while walking is also managed by the lateral toes, which can lead to metatarsalgia.

In cases of hallux valgus, or hallux rigidus, pain and joint instability can lead to poor propulsion during walking by the long flexor of the hallux (big toe).

High-arched feet are a source of metatarsalgia, due to the pressure on the metatarsals and the often associated shortening of the posterior muscle chains.

Hypotrophy or atrophy of the plantar fat pad can also promote metatarsalgia. If the plantar pads are thin, patients may describe the sensation of literally walking on their bones.

Treatments for metatarsalgias

Conservative treatments

Stretching, physiotherapy sessions, and wearing shock-absorbing insoles.

The retraction of the posterior muscle chains should be checked during the clinical examination and should be addressed with self-rehabilitation exercises or physiotherapy. Stretching the calf muscles, or gastrocnemius, will help relieve pressure on the forefoot. The calf muscles are part of the sural Achilles-plantar system, and this is the only structure within the system that can be stretched. Self-rehabilitation exercises are demonstrated to patients during consultation.

Rehabilitation exercises consist of performing additional stretches according to a specific rehabilitation method, the Mézières method.

Strengthening sessions for the intrinsic muscles of the foot help improve toe suspension and limit pressure under the metatarsal heads.

Wearing shock-absorbing insoles made of foam, gel, or noene can provide additional cushioning for the plantar pads.

Joint injections

Intra-articular injections should be avoided. Cortisone injections can weaken the peri-articular tissues, especially the plantar plates. Ruptures of the plantar plate can cause metatarsophalangeal dislocations.

Cortisone injections can also cause small fat atrophies called lipodystrophy or lipoatrophy, which can further weaken the quality of the plantar pad.

Surgical treatments

Indications and Criteria

Surgical treatment for metatarsalgia is considered in cases of disabling pain after the failure of functional and medical treatments.

In cases of atrophy of the plantar pad, percutaneous elevation osteotomies of the metatarsal heads are proposed. The aim is to elevate the metatarsal heads in order to thicken the plantar pad.

In cases of plantar plate injury and abnormal length of the metatarsal parabola, open decompression metatarsal osteotomies of the Weil type are proposed. These may be combined with tendon lengthenings or tendon transfers to increase the plantar flexion strength of the toe.

The surgical correction of a propulsive first ray should be performed at the same time. Thus a hallux valgus can be corrected during the same operation even if it is asymptomatic, as its surgical treatment will help restore its propulsion force and thereby limit stress on the lateral metatarsals.

Plantar plate repair can be performed; however, Weil osteotomies allow the metatarsal head to be repositioned on a healthier area of the plantar plate.

Arthroscopy

Arthroscopy may be used on the lateral rays. Some surgeons have described plantar plate repairs under arthroscopic guidance.

Total metatarsophalangeal prosthesis

In cases of metatarsalgia associated with joint instabilities that can damage the cartilage, it may be necessary to treat the associated osteoarthritis.

Silicone metatarsophalangeal prostheses can be used to stabilize the joint. Spherical pyrocarbon prostheses may also be suggested in cases of metatarsophalangeal osteoarthritis of the lateral rays.

Treatment of fracture sequelae

Metatarsalgia can be a sequela of a fracture in the foot, particularly in the forefoot.

This frequently involves disharmony in the length of the metatarsals. It may be necessary to propose a global harmonization of the metatarsal length, based on the most severe deformity.

Conclusion

The analysis of factors that promote or worsen metatarsalgia is crucial because they need to be corrected to relieve metatarsalgia.