Abstract
Plantar plate degeneration and tear is a common cause of forefoot pain, typically
involving the second metatarsophalangeal joint at the proximal phalangeal insertion
laterally, frequently confused with the second web space Morton neuroma. The condition
has received increased attention with the development of surgical techniques that
can result in successful repair of the plantar plate and substantial improvement in
patient symptoms. High-resolution MRI or ultrasound can confirm a diagnosis of plantar
plate degeneration and tear and exclude other pathologies, particularly Morton neuroma.
The normal plantar plate is a mildly hyperechoic structure on ultrasound and is hypointense
on all conventional MR sequences. Plantar plate degeneration manifests on ultrasound
as hypoechoic echotextural change and on MRI as mild signal hyperintensity on short
TE sequences, becoming less conspicuous on long TE sequences. Adjacent entheseal bony
irregularity is commonly present. Plantar plate tears on ultrasound may be seen as
an anechoic cleft defect or area of heterogeneous echotexture, sometimes more conspicuous
with dorsiflexion stress. Plantar plate tears demonstrate greater signal hyperintensity
on proton-density sequences, becoming more conspicuous on fat-suppressed proton density
and T2-weighted sequences. Edema and fibrotic change in the pericapsular fat plane
is commonly seen in the setting of an adjacent plantar plate tear and should not be
misinterpreted as reflecting a Morton neuroma.
Keywords
plantar plate - forefoot - ultrasound - MRI - metatarsalgia
