41: MPJ Pathology - Feilmeier Flashcards
what is turf toe?***
- classic: hyperextension (dorsiflexion) of 1st MTPJ
- now: refers to just about any injury involving the 1st MPJ
“sand toe”
- hyperflexion of 1st MPJ
- might be seen in dancers, gymnasts
how does hyperextension of first MPJ occur?***
- axial load is delivered to foot fixed in equinus/plantarflexion
- hyperextension can tear the plantar plate
- allows increased ROM of the hallux
- proximal phalanx compresses agianst met head and can even separate the sesamoids (OCD osteochondral defect of met head)
causative factors of turf toe
shoes
- Soft soled shoes- “the need for speed”
- Traditional football cleats had a metal plate in the forefoot which limited dorsiflexion of the 1st MTPJ
- Newer shoes lack this and allow exaggerated dorsiflexion of 1st MTPJ
surface
- Synthetic surfaces have a higher coefficient of friction and limited shock absorption * (may not contribute as much as once thought)
- Foot becomes “fixed” to playing surface and can’t adapt to external forces and absorbs all the shock
grade I turf toe ***
- attenuation, swelling, minimal ecchymosis
- tx is symptomatic, carbon fiber plate
return to play for different turf toe classification
grade 1 - as tolerated
grade 2 - up to 2 wk, may need taping/carbon fiber plate on return
grade 2 - 10-16 wk depending on sport, likely to need taping, may need surgery
grade II turf toe
- partial tear, moderate swelling, restricted motion due to pain
- walking boot/crutches as needed
grade III turf toe
- complete disruption, significant swelling/bruising. obvious instability, cartilage damage
- tx with long term immobilization or surgery
conservative tx for turf toe
- Orthotic (Carbon fiber plate, Morton’s extension)
- Stiff soled shoe
- Taping (hold in plantarflexion)
- Offloading with crutches/boot
- NSAIDS- tx pain only
when is surgery indicated for turf toe?
- large capsular avulsion with usntable joint
- diastasis of bipartite sesamoid
- diastasis of sesamoid fracture
- retraction of sesamomids
- traumatic hallux valgus deformity
- verticaly instability (positive lachman’s test)
- loose body
- chondral injury
- failed conservative
what is predislocation syndrome?
early stage damage to plantar plate that if not addressed can lead to … instability, elevation (hammertoe)
is predislocation syndrome an acute injury?
no, usually progressive onset
but can be acute
ddx predislocation syndrome
- neuroma ***
- stress fx
- hammertoe
- advential bursitis
- submetarsal bursa
describe the normal plantar plate
- ## Fibrocartilaginous thickening of the MPJ capsule plantarly that is strongly attached to base of proximal phalanx just distal to the articular surface and loosely to metatarsal head just proximal to the flare of its head
when the plantar plate tears, where does it occur?
base of proximal phalanx
what happens if the plantar plate ruptures?
- Proximal phalanx moves dorsally
- Extensor tendons cannot extend PIPJ and DIPJ
- Over time, the extensors act as a deforming force on the MPJ and cause further dorsal subluxation
- Flexors are ineffective plantarflexors of the MPJ and do not help stabilize the toe against the ground
- As the proximal phalanx moves dorsally, the interossei and lumbricales, which are the major plantar stabilizers of the MPJ, also move dorsal to the axis of motion and lose their plantarflexory power
etiology of predislocation syndrome (biomechanics)
- Lateral weight transfer (HAV/MPAV, Short first,
Elevated or unstable first, Long or plantarflexed metatarsal *second, Equinus) - Muscle weakness (Intrinsic weakness and loss of stabilization)
- Rheumatologic Disease
- Pes Cavus- Overload
- Traumatic (10%)
anatomic results of overload with predisloation syndrome
- Degeneration
- Plantar plate insufficiency
- MTPJ subluxation
- Long flexor and extensor imbalance
s/s subjective predislocation syndrome
- “bruised” feeling
- walking on a “pebble”/ “stone”
“wadded up sock” - feeling as if the toe has “moved”
- feeling the toe is swollen
- May be associated with numbness secondary to inflammation of a common plantar nerve or its digital branches from joint or bursal synovitis
- Increased pain barefoot/hardwood floors
objective s/s of predislocation syndrome
- Pain with palpation of one or more MPJ’s
- May palpate a generalized (more commonly) or focal swelling inferior to the metatarsal head
- Swelling of the base of the proximal phalanx which may be seen dorsally
- Visible elevation/deviation (Look at foot in the chair as soon as you walk into the room)
- NOT focal shaft pain
- No dorsal metatarsal shaft swelling
how do you perform the vetical stress test/lachman/drawer?
- Stabilize the metatarsal head only between finger and thumb. If you can move the base of the proximal phalanx dorsally by at least 2 mm, it is a positive test
- must compare to contralateral side
- push back b/w MPJ joint, not directly on met
staging of predislocation syndrome ***
Stage I
- Mild plantar and dorsal edema
- Extreme tenderness with palpation
- No clinical anatomic malalignment
Stage II
- Moderate edema
- Deviation of toe both clinically and radiographically
- Toe does not purchase ground in stance
Stage III
- Moderate edema about entire circumference of MPJ
- Edema extends into toe
- More pronounced deviation with possible dorsal dislocation
- Can proceed to crossover 2nd toe
diagnosis of predislocation syndrome
- Primarily a CLINICAL diagnosis
- AP X-ray in early stages may show increased joint space while later films will show lack of clear space as the base of phalanx moves over the metatarsal head
- Subluxation noted on lateral/oblique
- May also show transverse plane migration of the base of the proximal phalanx
- Can perform a vertical stress test and observe dorsal migration on the lateral
why is pronation an etiology for predislocation syndrome?
- Leads to an unstable forefoot at toeoff and causes shearing forces under the lesser MPJ’s
- Can lead to a medial and dorsal dislocation of a digit (usually the second) due to weakness of the quadratus plantae
- Causes the FDL to function medial to the axis of the MPJ and to weaken its resistance to dorsiflexion
hypermobile 1st ray –>
causes excessive weightbearing pressure beneath the 2nd and/or 3rd metatarsal heads
hammer digit syndrome –>
causes a retrograde plantarflexory force on the metahead
Stretch/strain of the PP
conservative tx predisloation syndrome
Oral NSAID’s and steroids (**pain only) Rest, ice Taping-Figure 8 Orthotics Metatarsal pad Padding/Splinting (Budin splint) Shoe modifications Increased support Complete off loading with cam boot Intra-articular phosphate steroids-rupture of capsular structures ***DO NOT DO
surgery is indicated when ..
Surgery is indicated when flexibility and reducibility of deformity are lost
The stage of “turf toe” injury to the hallux which involves a partial tear to the intersesamoidal ligament is:
two
The stage of pre-dislocation syndrome where a lesser digit first appears to not purchase the ground is:
two
All of the following are components of/insert into or close to the plantar plate EXCEPT: A. FDL tendon B. Collateral ligaments of the MPJ C. Deep transverse metatarsal ligament D. lumbrical muscle E. Plantar fascia
FDL tendon
tx based on etiology
Overload
- Lateral weight transfer
(Lapidus or First MTPJ Fusion or Osteotomy of Lesser Metatarsal)
- Intrinsic weakness and loss of stabilization
(PIPJ Fusion & MTPJ Release or Long Flexor Transfer)
- Equinus (Posterior Lengthening)
Anatomic Result of Overload - Degeneration (Resection, Replacement, Fusion) - Plantar Plate Insufficiency (Repair or MTPJ release, FDL Transfer, PIPJ Fusion)
