The plantar plate is a thick, fibrous structure at the base of each metatarsal phalangeal joint. This fibrous band stabilizes the toe, preventing it from elevating or deviating. A tear of the plantar plate will cause joint instability along with pain and swelling around the joint. This tends to be common at the 2nd metatarsal-phalangeal joint, which is shown in the image to the left.
Traumatic injuries can cause plantar plate tears. These result in immediate pain and swelling to the ball of the foot and destabilization of the joint. Chronic problems are more common as the plantar plate may be subject to repetitive microtrauma and slowly elongate, causing a gradual joint destabilization and rising of the toe. Chronic development is due to faulty foot mechanics, most commonly hypermobility of the 1st ray (click here for a discussion of hypermobility & 2nd metatarsal overload syndrome). A plantar plate injury will not show on X-ray, but arthrography, MRI or ultrasound can help with the diagnosis.
Other problems which may mimic a plantar plate tear include synovitis (joint tissue inflammation), neuromas (inflamed nerve), hammertoe (crooked toe pressing back on the joint) and 2nd metatarsal overload syndrome which results in joint inflammation, pain and can lead to plantar plate tears.
Conservative treatments include taping and stabilizing the toe, taping, rigid shoes, orthotics and physical therapy. Steroid injections are controversial and with pre-dislocation syndrome, injections can be done in association with taping, bracing and/or a rigid shoe or cast boot for 2 weeks. The injection will decrease the inflammation and pain, but also increases the risk for further tearing and instability of the toe. When a plantar plate tear is suspected, steroid injections are not recommended. Surgery is considered when conservative therapy fails.