Updated: 6/7/2021

MTP Dislocations

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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
  • summary
    • MTP Dislocations are conditions characterized by multiplanar instability of the MTP joint which may present as as a "crossover toe."
    • Diagnosis is made clinically with presence of dorsomedial deviation of the toe in relation to the metatarsal.
    • Treatment consists of a trial of shoe modifications, and taping. Operative management is indicated for patients with progressive pain and fixed deformities.
  • Etiology
    • 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
  • 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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(OBQ11.24) Floating-toe deformity is the most common complication of which of the following surgical procedures used to treat central metatarsalgia?

QID: 3447
1

Dorsal soft-tissue release with pin fixation

2%

(66/2858)

2

Silicone implant arthroplasty

3%

(86/2858)

3

MTP joint excisional arthroplasty

34%

(975/2858)

4

Metatarsal shaft osteotomy (Helal procedure)

11%

(305/2858)

5

Metatarsal neck osteotomy (Weil procedure)

49%

(1409/2858)

L 4 C

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(OBQ09.191) A 40-year-old man has metatarsalgia secondary to a chronically dislocated 2nd metatarsalphalangeal(MTP) joint. Nonoperative modalities including shoe modifications have failed to improve his symptoms. When comparing osteotomy B (Weil osteotomy) to osteotomy A (Helal osteotomy) as shown in Figure A, all of the following are true EXCEPT:

QID: 3004
FIGURES:
1

Higher patient satisfaction rates

5%

(123/2687)

2

Lower incidence of recurrent metatarsalgia

8%

(205/2687)

3

Fewer transfer lesions

6%

(170/2687)

4

Higher percentage of radiographic reduction and maintenance of the MTP joint reduction

12%

(322/2687)

5

Increased rate of malunion or pseudoarthrosis

69%

(1845/2687)

L 2 B

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(OBQ09.61) A 57-year-old man plays 45 holes of golf per week and has foot pain during the toe-off phase of gait. He notes the foot pain started 3 months ago after walking up a hill and falling forward on some wet grass. Your exam shows skin callosities dorsally at the 2nd PIP joint and plantarly at the 2nd MT head. Radiographs show a hyperextension deformity of the 2nd proximal phalanx in relation to the metatarsal. All of the following are true about this patient's condition EXCEPT:

QID: 2874
1

Symptomatic treatment initially includes extra depth shoes, metatarsal pads, and well-padded liners

6%

(134/2129)

2

The MTP drawer test will likely show laxity at the MTP joint in the dorsal-plantar plane

8%

(166/2129)

3

Repeated MTP dorsiflexion weakens the plantar aponeurosis, plantar plate, and capsular stabilizers

6%

(138/2129)

4

Plantar callosities result from dorsal displacement of the fatty cushion underneath the metatarsal head

10%

(208/2129)

5

Condition is a result of repetitive stresses causing microfractures with subsequent compromised blood supply to the metatarsal subchondral bone

69%

(1465/2129)

L 2 D

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(OBQ04.107) A 70-year-old man complains of inability to wear normal shoes on his left foot due to a second and third toe deformities. Radiographs are shown in Figures A and B. He decides to undergo surgical treatment. After intra-operative extensor tendon lengthening and capsular release, the joints continue to subluxate. What is the next step to correct the deformities?

QID: 1212
FIGURES:
1

Flexor tendon resection

10%

(238/2486)

2

Proximal phalangeal crescentic osteotomy

8%

(203/2486)

3

Metatarsophalangeal joint arthrodesis

31%

(765/2486)

4

Distraction osteogenesis of the metatarsal

0%

(11/2486)

5

Metatarsal shortening osteotomy

50%

(1252/2486)

L 4 B

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