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https://upload.orthobullets.com/topic/7053/images/crossover toe.jpg
https://upload.orthobullets.com/topic/7053/images/plantar plate.jpg
https://upload.orthobullets.com/topic/7053/images/mri plantar plate.jpg
Introduction
  • A condition characterized by multiplanar instability of MTP joint
    • often seen with "crossover toe"
    • dorsomedial subluxation
  • Pathoanatomic stages
    • plantar plate disrupted 
      • can be caused by
        • traumatic rupture 
        • chronic inflammation (more common)
    • lateral collateral ligament fails 
      • leads to medial deviation of the second toe
      • plantar plate, with its flexor tendon attachments, displace medially
      • medial displacement of the proximal phalanx relative to the metatarsal
    • medial structures become contracted
      • lumbrical and interosseous tendons, medial collateral ligament (MCL), and medial capsule become tight and contracted creating adduction force
    • plantar plate subsequently fails
      • hyperextension forces on the proximal phalanx result in dorsal instability
  • Associated conditions
    • MTP synovitis, deformity often accelerated by cortisone injection done for either misdiagnosed Morton's neuroma or into the MPJ for synovitis.
Anatomy
  • Plantar plate 
    • anatomy
      • broad, thick ligamentous structure that spans the plantar aspect of the MTP joint 
      • origin
        • on the metatarsal head via a thin synovial attachment, just proximal to the metatarsal articular surface
      • insertion
        • plantar base of the proximal phalanx
    • function
      • resists tensile loads in the sagittal plane (particularly in dorsiflexion of the joint)
      • cushion the joint and support weightbearing forces
Presentation
  • Symptoms
    • pain
    • walking on “marble in the ball of their foot”
    • early instability (prior to deformity) may be confused with Morton's neuroma, deformity often follows cortisone injection for presumed neuroma
  • Physical exam
    • callus under the metatarsal head
    • dorsomedial deviation of the toe in relation to the metatarsal
    • hammertoe (flexion at the PIPJ, extension at the MPJ)
    • dorsal instability found on "drawer test "
      • grip toe (proximal phalanx) with one hand and the metatarsal head with the other and move toe dorsally
Imaging
  • Radiographs
    • recommended views
      • weightbearing AP, oblique, and lateral
    • findings
      • AP shows dislocation of the proximal phalanx (medial more often than lateral)
      • weightbearing lateral shows hyperextension and dorsal dislocation of the proximal phalanx
  • MRI
    • indications
      • rule out other pathology
      • elucidate pathology of surrounding structures
    • used in early stages of MTP synovitis to evaluate plantar plate but not necessarily useful in dislocation
Treatment
  • Nonoperative
    • taping, shoe modification, metatarsal pads, Budin splint, and NSAIDS 
      • indications
        • first line of treatment
      • will not correct deformity
  • Operative
    • distal oblique shortening MT osteotomy (Weil procedure)  
      • indications
        • significant pain and loss of function
        • fixed deformity 
    • plantar plate repair
      • performed with metatarsal osteotomy
      • sutures passed through distal plantar plate and then through drill holes in proximal phalanx
    • flexor to extensor tendon transfer
      • FDL split and brought over top of proximal phalanx to stabilize joint
    • EDB transfer under intermetatarsal ligament
Surgical Techniques
  • Distal oblique shortening MT osteotomy (Weil procedure)
    • soft tissue balancing
      • dorsal and medial capsular release with lateral capsular reefing can be used in combination with Weil osteotomy
      • EDB tendon transfer after rerouting tendon through transverse intermetatarsal ligament results in a dynamic stabilizer of incompetent lateral structures
      • flexor digitorum longus (FDL)–to–extensor digitorum longus (EDL) tendon transfer (Girdlestone-Taylor procedure)
      • resection arthroplasty of the metatarsal head (DuVries)
      • plantar plate repair as above
    • osteotomy
      • intra-articular osteotomy that achieves longitudinal decompression through shortening and allows joint reduction.
      • metatarsal (MT) is exposed and the direction of shortening in the original Weil procedure runs mostly parallel to the plantar aspect of the foot. 
    • fixation
      • osteotomy is fixed by means of a screw running perpendicular to the osteotomy line.
Complications
  • Floating toe deformity
    • inability to flex MTP joint causing 2nd digit dorsiflexion deformity (ie. floating toe) 
    • most common complication 
  • Toe vascular compromise
    • if correcting a chronic dislocation, the soft tissue (including vasculature) can contract
    • stretching of the vasculature can compromise flow
    • procedure may need to be reversed to save digit
 

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