What causes metatarsophalangeal (MTP) joint pain?
Pain in the metatarsophalangeal joint or Metatarsalgia is a common musculoskeletal condition which is usually observed when abnormal foot biomechanics and long-standing stress deteriorates the anatomical balance of foot.
Almost all cases of metatarsal joint pain presents with localized pain, difficulty in walking or just difficulty in maintaining normal day-to-day activities. Patients also report tenderness along the top and bottom surfaces of the foot with limited range of joint motion. Some cases of metatarsophalangeal joint pain are also associated with callus formation underneath the joint surface.
The most common presentation is symptoms of sub-acute or chronic joint inflammation (such as localized warmth, swelling and pain) along with rigidity along the top and bottoml aspects of foot.
Certain risk factors that aggravate the risk of developing metatarsophalangeal joint pain is:
- Anatomical deformities of foot such as pes cavus, ankle equinus and Achilles tendon deformities.
- Chronic inflammatory conditions of metatarsal joints (especially rheumatoid arthritis).
- Poor choice of footwear or unhealthy lifestyle.
What are some common cause of metatarsophalangeal joint pain?
- Calluses – Plantar Keratosis Callosities: This is the most frequent cause
of metatarsalgia and is also referred to as plantar calluses. These are mainly due to abnormal weight bearing and chronic exposure to pressure that results in inflammation of metatarsal head.
- Morton Neuroma: Morton’s neuroma is an entrapment neuroma of the plantar interdigital nerve. The pathophysiology of Morton neuroma revolves around persistent or ongoing irritation due to a narrow or poor choice of footwear leading to fibrosis of interdigital nerve and disturbing symptoms of pain, paresthesia and numbness. Third and
fourth interdigital spaces are usually involved and diagnosis is mainly clinical.
- Mechanical disorders of MTP joint: Metatarsophalangeal joint pain (also referred to as metatarsalgia) can also be due to surface misalignment of connective tissue framework, resulting in a misalignment or subluxation of joints, plate tears or destruction of joint cartilage. The misalignment of joints can also lead to swelling and even permanent destruction of joints. The disease process most frequently involves the second metatarsophalangeal joint.
Most common mechanical cause of MTP joint pain is stress fracture (especially of 3 and 4th metatarsal due to limited mobility). The diagnosis of stress fracture is tricky, since radiological examination is usually inconclusive.
In poorly managed cases, the risk of other musculoskeletal ailments also increases; such as:
- Foot deformities such as hammer toe
- Other less common causes are:
- MTP Arthritis: Morning stiffness, joint rigidity and pain on weight bearing are some signs that are strongly suggestive of early rheumatoid arthritis.
- MTP Synovitis: In osteoarthritic synovitis, patients present with swelling and localized warmth. In cases of inflammatory arthropathies, patients also reports swelling, warmth and redness with severe limitation of joint mobility due to pain and stiffness.
The diagnostic process involve two key elements:
- Clinical evaluation by a clinician experienced in foot pain. This comprises of a careful history taking and clinical examination.
- Squeeze Test: Squeezing all the MTP joints together softly. If this causes pain, it suggests the possibility of underlying joint inflammation.
- XRay, CT or MRI assessment to confirm the clinical diagnosis and to identify concurrent issues.
If infection or inflammation symptoms are present, your doctor may advice additional tests.
The presence of numbness, burning pain and tingling can indicate a neuralgia/neuroma as opposed to a mechanical cause of metatarsophalangeal joint pain. Likewise the presence of redness, warmth, swelling and edema are suggestive of an active infection.
Management and Treatment:
Treatment mainly revolves around the primary disease process. Injecting local anesthetic solution or corticosteroid can help to reduce inflammation.
Management also involves:
- Orthotics: Orthoses are ideally recommended in the long term management of metatarsophalangeal joint pain. Custom-designed orthotics are helpful in relieving stress and pressure from the joints. Doctors recommend orthotics to correct the unusual bone and foot alignment. Modification of orthotics can also improve the motion of metatarsophalangeal joint and relieve pain.
- Rest and relaxation: It is very important to limit the physical motion or activity in order to control the symptoms and to hasten the recovery.
- Physical therapy and rehabilitative exercises: Controlled activity and carefully executed exercises help in tissue remodeling processes and ensure optimal connective tissue conditioning to shorten the duration of ailment.
Surgery is a last resort.
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- Fink, B. R. (2011). Steps to take in managing metatarsalgia. Journal of Musculoskeletal Medicine, 28(9), 346.
- Guimarães, M. C., Yamaguchi, C. K., Aihara, A. Y., Hartmann, L. G., Pröglhöf, J., & Fernandes, A. D. R. C. (2006). Metatarsalgias: differential diagnosis with magnetic resonance imaging. Radiologia Brasileira, 39(4), 297-304.