Plantar Plate Tear / Metatarsalgia

Pre-Dislocation Syndrome with Hammertoe Formation

1pplatetearOn the bottom of each lesser toe joint there is a ligament between the base of the toe and the metatarsal behind the joint. This ligament is called the plantar plate. This ligament acts to keep the toe in the joint and keep the toe from elevating out of the joint. In the gait cycle, the toes will bend at the base of the toe joint just before the foot pushes off the ground. The plantar plate holds the toe in place and brings the toe back straight. There is no muscle associated with this ligament. In some cases this ligament can become overstretched or tear causing pain and deformity to the toe leading to a dislocation of the toe. It is often misdiagnosed as a neuroma.

Causes:

A plantar plate tear is caused by a specific injury to the toe and the joint, or overuse over time.

Symptoms:

A plantar plate tear will present with pain on the ball of the foot and in the joint of the toe. In mild cases, there may be little to no deformity to the toe that can be seen. A patient may describe the pain as a dull ache or a sharp pain the ball of the foot. It may feel as though there is not enough cushion between the bone and the ground. It usually only involves one toe at a time, and usually involves the 2nd toe. Over time as the tear increases the toe will begin to shift upwards and or shift to one side or the other. When the foot is placed on the ground the toe may not touch the ground and may shift to one side as well. When the toe is elevated in this way, more pressure in placed onto the head of the metatarsal from the ground forces, causing bone bruising and pain. When the ligament tear becomes chronic, the deformity can be greater, leading to a severely deformed toe and hammer toe. As the deformity progresses, the cartilage in the joint can become eroded from the misaligned joint leading to arthritis of the joint and increased pain.

Diagnosis:

2pplatetearClinical evaluation and manipulation of the toe is performed. The toe joint will be moved and manipulated into several different positions to evaluate the amount of deformity and the location of the pain. Plain x-rays will show the degree and angles of the deformity. They will also show if there is any associated arthritis in the joint. Often an MRI will be needed in order to evaluate the extent of the damage to the plantar plate ligament. In some cases a special x-ray with a dye can be injected into the joint to find the tear in the ligament. It is important to distinguish the areas of pain on the ball of the foot from the examination, from those that would be caused by a neuroma.

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MRI showing inflammation around the torn ligament under the toe joint. X-ray showing injection of fluid into the joint. Notice the leaking of the fluid out of the joint from the tear of the ligament.

Treatment:

In the early stages of the disruption of the ligament, conservative treatments can be successful. It is important first to remove the deforming force or activity. In acute cases, there will be a need to be in a special shoe or boot to take weight off the ball of the foot. Special tapping will be placed onto the toe for a number of weeks. This is done by strapping it into a downward position. If there is any deformity from side to side, the tape can hold the toe in the opposite direction. This will allow the ligament to heal without continued strain. Custom molded orthotics with support under the ball of the foot will aid in keeping the deformity from returning. In chronic cases and those with more severe deformity, surgical correction is indicated. The toe will need to be realigned into the joint and stabilized. The plantar plate will be tightened and repaired. The surgical correction for a plantar plate tear is similar to the correction of a hammertoe deformity. In such cases, a hammertoe correction with a tendon transfer is needed to reconstruct the torn plantar plate area. Simple hammertoe correction will not result in an ideal outcome as the tendon transfer is necessary to stabilize the toe at the ball of the foot. This is a simple surgery with limited to no downtime. A pin is used to hold the area during healing and a boot is worn for 5-6 weeks during the healing period. With proper care, patients return to full activity with little to no pain. If left untreated, the toe will often dislocate and a more involved surgery is necessary to correct the problem.

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Picture showing harvesting of the tendon before the transfer. The extra bone from the toe has been removed already. Picture showing the tendon transferred from the bottom of the toe to now the top of the toe. Notice the pin out the end of the toe holding the toe in the proper position.
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Picture showing the toe straightened before closure. Notice the screw at the top of the wound. The metatarsal has been shortened as well to make room for the toe to be straightened. Final postoperative photo.
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X-ray showing the dislocated toe before surgery. X-ray showing the final result after surgery.