Metatarsalgia is pain on the metatarsal side of the metatarsophalangeal joint of the forefoot. Metatarsalgia is not a diagnosis; it can be caused by a variety of reasons. Since metatarsalgia in both the bunion and the little toe have their own specific diagnoses, metatarsalgia is usually referred to as pain on the metatarsal side of the 2-4 metatarsophalangeal joints, also known as intermediate metatarsalgia.
I. Etiology
(a) Various causes of forefoot biomechanical changes, so that the middle metatarsal bone is under greater stress.
1. Various bunion lesions cause a decrease in the weight-bearing capacity of the bunion, causing the weight to shift to the lateral toes. Such as bunion, bunion stiffness, 1st metatarsophalangeal joint arthritis, etc.
2, the middle three metatarsals are less mobile and more stable. If the inner and outer columns of the foot are overly active, it will put the middle metatarsals under greater stress.
3, various causes of toe hammer toe and other deformities, so that the proximal phalanges dorsal extension, to the metatarsal side extrusion of the metatarsal head, so that the metatarsal bone under greater stress.
4, Achilles tendon or gastrocnemius tendon contracture, so that the foot in gait advancement, can not be enough dorsal extension, the forefoot will be subject to greater stress.
(B) Variation or change of anatomical structure
1. Congenital over-shortening of the 1st metatarsal. Also known as Morton’s foot. The bunion has a lower weight-bearing capacity and the stress is shifted to the lateral toes.
2. Congenital overgrowth of the 2nd metatarsal. During the advancement period of gait, the overlong 2nd metatarsal bone becomes a “lever” and is subjected to greater stress.
3.High arch foot. The stiff foot structure does not allow the foot to absorb and cushion the stress well; the metatarsal head often becomes the stress concentration point.
4.Previous trauma and surgery, excessive shortening or elevation of the 1st metatarsal.
5, lowering of the middle metatarsal bone. Such as fracture or hyperplasia of the metatarsal head lesion.
(C) Inflammation of the metatarsophalangeal joint
1, rheumatoid arthritis. Synovial lesions can damage the ligaments and tendons around the joint. In advanced stages, the metatarsophalangeal joint often becomes dorsally dislocated and the metatarsal heads protrude to the metatarsal side, causing pain.
2, other causes of synovitis.
3.Osteoarthritis of the metatarsophalangeal joint.
(D) Injury
1, metatarsal head cartilage injury.
2. Ischemic necrosis of the metatarsal head.
3, instability of the metatarsophalangeal joint.
(E) Other causes
1.Intermetatarsal neuroma. The common toe nerve is squeezed, causing pain around the metatarsal head.
2.Fatigue fracture of the metatarsal bone.
3. Skin hyperkeratosis.
II. Clinical manifestations and diagnosis
The patient feels pain on the metatarsal side of the forefoot, which is aggravated by walking and can mostly be relieved after non-weight-bearing. They cannot wear thin, hard-soled shoes or high-heeled shoes. Sometimes, there may be swelling of the metatarsophalangeal joint. Painful callus on the metatarsal side of the metatarsal head is often present.
Examination should note the presence of hammertoe, excessive forefoot rotation forward, instability of the medial and lateral columns, arch condition, contracture of the Achilles tendon and gastrocnemius tendon, etc. Swelling of the metatarsophalangeal joint, mobility and stability of the joint. The site of pressure pain, most patients have pressure pain located on the metatarsal side of the metatarsal head. Injury to the tendons and metatarsal plates, the pressure pain may be located distal to the metatarsophalangeal joint. Intermetatarsal neuroma pressure pain is located between the metatarsal heads. Direct pressure pain of the metatarsals should be suspected for fatigue fractures. The forefoot of a patient with rheumatoid arthritis usually presents with a bunion and hammertoe deformity of the other toes. For instability of the metatarsophalangeal joint, the Lachman test of the metatarsophalangeal joint is positive.
X-rays are important for diagnosis. The length of the metatarsal bones and the presence of lesions and injuries to the metatarsophalangeal joint can be determined. For some patients who are unable to identify the site of the lesion, markers can be placed on the painful area and then x-rayed to help determine the cause. For fatigue fractures of the metatarsal bones, they often do not show up on X-rays within the first 2 weeks of symptoms and need to be reexamined.
Laboratory tests: blood sedimentation, rheumatoid factor, C-reactive protein, blood uric acid, etc.
Metatarsalgia is not a diagnosis and should be examined carefully to determine the cause of metatarsalgia.
III. Treatment
1.Non-surgical treatment
(1) Reduce activities. Avoid wearing thin-soled shoes to walk on hard surfaces for a long time.
(2) For simple painful callus, you can go to the bath or use special scissors to cut or grind away the thickened callus, which can reduce the pain. However, it cannot cure metatarsalgia, but can only relieve the symptoms and trim every 2-3 months.
(3) Foot pads. For most of the metatarsalgia to due to increased local stress on the bottom of the foot. The use of soft foot pads can cushion the local stress. Another type of foot pad is to prop up the proximal end of the metatarsal head, thereby reducing the stress on the metatarsal head.
(4) Wear hard, curved-soled shoes with soft insoles. This can reduce the stress on the forefoot during walking and alleviate the symptoms.
(5) For hammertoe deformity, orthoses can be used to correct interphalangeal joint flexion and metatarsophalangeal joint dorsiflexion. To reduce the compression of the metatarsal head by the proximal phalanx.
(6) Inflammation caused by tendon, joint capsule and ligament injuries and synovitis of the joint can be treated with physical therapy and closure.
(7) Use of non-steroidal anti-inflammatory and pain-relieving drugs.
(8) Intermetatarsal neuroma can also be treated with hormone injections into the periapical nerve between the two metatarsal heads.
(9) In case of fatigue fracture, wear forefoot load-free shoes for 2 months.
2.Surgical treatment
If non-surgical treatment is ineffective and the symptoms are more severe and affect life and work, surgical treatment can be considered.
(1) For metatarsalgia caused by increased local stress, the most commonly used surgery is to osteotomize the corresponding metatarsal bone to lift the metatarsal head or shorten the metatarsal bone. For example, Weil osteotomy at the neck of the metatarsal head.
(2) For hammertoe, soft tissues around the metatarsophalangeal joint need to be released, such as lengthening of the extensor tendon, release of the lateral collateral ligament and metatarsal plate. Flexion deformity of the interphalangeal joint requires plication, or joint fusion or artificial joint replacement.
(3) Synovitis caused by damage to the cartilage of the metatarsal head can be cleared of synovial membrane and fragmented cartilage. Severe deformation of the metatarsal head requires removal of the metatarsal head and artificial joint replacement.
(4) Intermetatarsal neuroma can be treated by releasing or removing the common toe nerve.
(5) In severe rheumatoid arthritis, the forefoot often has significant metatarsalgia and often requires forefoot reconstruction surgery. The first metatarsophalangeal joint fusion or joint replacement, 2-5 metatarsal head resection.