What Is a Plantar Plate Tear or Injury?
An injury or damage to the plantar plate is called a plantar plate tear. The plantar plate is a thick strong ligament that runs along the underside of the foot. It is a fibrocartilagenous structure that maintains the stability of the metatarsophalangeal (MTP) joint, the region where toes are connected to the foot. Therefore, damage to the plantar plate leads to MTP joint instability. As a result, the toes may move out of their normal alignment, and the connection with the bone becomes unstable. The tears are most commonly seen on the second toe.
What Are the Causes?
A plantar plate tear is commonly seen in three scenarios;
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Acute traumatic injury.
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Chronic attritional rupture.
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Rheumatoid pathology of the plantar plate.
Of the above scenarios, chronic attritional rupture is seen in most cases of plantar plate injury. It is most commonly prevalent in females over 50 years old.
The risk factors for developing chronic attritional rupture of the plantar plate are:
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Halux vagus or bunions (Bunions are painful bony projections at the base of the big toe joint that develop when the big toes lean towards the remaining toes).
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Hallux rigidus (a condition characterized by stiffening of the joint at the base of the big toe).
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An elongated second metatarsal may lead to its protrusion from the metatarsal parabola.
Acute traumatic rupture is uncommon in less than 10 percent of cases.
Inflammation of the synovial membrane (synovitis) associated with rheumatoid arthritis also increases the risk of developing a plantar plate tear.
What Are the Clinical Features?
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The affected individual presents with gradual onset pain.
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Pain gets worse during weight-bearing or when walking on hard surfaces.
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The patient may complain of a feeling of “walking on marbles”.
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Swelling may be present.
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The second MTP is the most common site; however, in rheumatoid arthritis patients, the fifth and fourth MTP are the most common sites.
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Tenderness on the plantar aspect of the affected MTP.
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Sometimes callus formation (calluses are areas of thickened or hardened skin on the foot that develop due to friction or pressure) may be seen in the affected region.
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“V-sign” is present, characterized by a gap between adjacent toes.
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With the condition's progression, hyperextension of the MTPJ region is seen. In this condition, the toes fail to touch the ground while standing.
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In the later stages of the disease, a crosstie deformity is seen. This condition occurs when one toe is either over or under-riding the adjacent toe.
A plantar plate tear has been classified both anatomically and clinically.
The clinical grading system for MTPJ instability is as follows:
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Grade 0 - MTPJ swelling, and pain is present. Prodromal phase with no deformity. Normal joint alignment.
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Grade 1 - Mild joint malalignment. MTPJ swelling and pain are present. “V-sign” present.
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Grade 2 - Moderate joint malalignment.
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Grade 3 - Severe joint malalignment.
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Grade 4 - Severe deformity. Crossover toe or fixed hammertoe (Hammertoes are conditions in which the toes curl downward due to the toe's middle joint pocking out) deformity present.
What Are the Diagnostic Tests?
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Radiographs - X-rays or radiographs are used to confirm the diagnosis, plan pre-operative planning, rule out other foot issues, and analyze the extent of the condition.
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Ultrasound - Ultrasound helps in confirming synovitis in the affected MTPJ region.
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MRI (Magnetic Resonance Imaging) - As MRI provides high-definition static images, it is considered the most sensitive imaging study for plantar plate tears.
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Plantar-Grip Test or Pullout Test - In this text, the affected person is asked to flex their toes and grip a piece of paper on the ground. The physician tries to pull out the paper strip, but a diminished or absent ability to hold the paper suggests a plantar plate pathology.
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Metatarsophalangeal Drawer Test - In this test, a vertical shear force is applied on the proximal phalanx, with the MTPJ held in a neutral position, comparison with the adjacent toe is done.
What Are the Treatment Options?
1. Conservative Treatment Options:
Conservation treatment options mainly aim to provide symptomatic relief and slow disease progression. They are the first line of treatment and are most beneficial in the initial stages of the disease.
These include:
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Activity modification is beneficial; it includes limiting the pain-inducing activity for a definite period. High-impact activities should be avoided.
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Orthotics aid in slowing the progression of the condition. Over-the-counter orthotics or prescription shoe inserts can be used. Orthotics help with even weight distribution across the feet and reduce pressure on the big toe.
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Analgesics like NSAIDs (non-steroidal anti-inflammatory drugs) can be used as ointments or tablets to reduce pain and swelling. Tablets should be avoided for a longer period due to the potential side effects associated with them.
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Stiff-soled shoes should be used to protect the MTPJ.
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In the acute stage, cold therapy with ice packs may be useful.
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The toe can be positioned in neutral alignment by taping or strapping. These help provide stability to the joint and reduce symptoms.
2. Surgical Treatment Options:
Realignment and stabilization of the MTP joint is the main goal of surgical therapy. Surgery is indicated in cases where the non-surgical options fail or the deformity is severe and cannot be corrected non-surgically.
Mostly, the surgical options are of the following types:
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Anatomic Plantar Plate Repair: Plantar plate repair is done either through a plantar (underfoot) approach or a dorsal (top of the foot or toe) approach. The plantar approach results in painful scarring. The orthopedic surgeon cuts the metatarsal bone to correct the alignment; sometimes, the metatarsal bone may be shortened.
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Tendon Transfer: These are mostly indicated in the case of grade 4 irreparable plantar fascia tears. Various types of tendon transfers are available. However, in most cases, the patient complains of joint stiffness post-operatively.
Conclusion
A plantar plate tear leads to MTPJ instability. Pain and swelling are initially present, but as the condition progresses, the malalignment becomes severe, resulting in deformities like fixed hammertoes or crossover toes. The condition can be managed by conservative options if diagnosed early. However, later stages require surgical correction.
