2 What is a midfoot fracture? Fracture of the midfoot involving the:Tarsometatarsal joint (Lisfranc Fracture)CuneiformsTarsal navicular boneCuboid bone
3 What is a Lisfranc Fracture? Between the tarsal and metatarsal bonesThe 1st & 2nd metatarsal articulates with the medial cuneiforms and are the keystones of the footSupplies stability between the midfoot & forefoot during gait
4 Lisfranc FractureFrontal view of the foot shows fracture/ dislocation in the tarsometatarsal joint (Lisfranc's joint) with dislocations of the 1st through 5th metatarsals
5 Various fractures of the tarsal navicular bone include: Cortical avulsionsMost commonResults from twisting forces on the mid footFracture of the tuberosityMay involve the post. tibial tendonBony fracturesStress fractures
6 Tarsal Navicular Fracture Frequently have posttraumatic arthritis & discomfort in all phases of gaitRequires immobilization in a non-weight bearing short leg cast
7 Cuboid FractureKnown as nutcracker fractures because the cuboid is cracked like a nut b/w the 5th metatarsal & the calcaneous as the forefoot is forced into abduction.
8 Cuneiform Fracture Uncommon Usually occur w/ high-energy injuries Open reduction & internal fixation is recommended
9 Mechanism of Injury 3 common causes Twisting of the forefoot Often occur during vehicle accidents when the foot is abductedAxial loading of a fixed footOccurs when falling on an extremely dorsiflexed foot or axial loading from body weight, stepping off a curbCrushingTo the dorsum of the footUsually in industrial accidentsClinician should be aware of compartment syndrome & injury to the dorsal pedis artery
10 Treatment Goals Alignment- Restoring the alignment with the cuneiforms -Important for normal weight bearing-Load distribution of the foot-To maintain the medial arch of the footRestoring the length & alignment of:cuneiformscuboidnavicular
11 Treatment Goals Stability Stable fixation of the navicular & cuboid Allows effective transfer of weight from the hind footHelps with eversion & inversion of the subtalar jt.A stable reconstruction of the Lisfranc jointImportant in maintaining the medial arch of the foot & a pn free and secure gait
12 Range of Motion Motion Normal Functional Ankle Plantar Flexion 45° 20 °Ankle Dorsiflexion20-25 °10 °Foot Inversion35 °Foot Eversion25 °
13 Muscle Strength Invertors Evertors Dorsiflexors Plantar Flexors Tibialis AnteriorTibialis PosteriorEvertorsPeroneus LongusPeroneus BrevisDorsiflexorsToe extensorsPlantar FlexorsGastrocnemiusSoleusPeroneous Longus weaknesscan result from severe dislocationsof the Lisfranc Fracture becausethis muscle inserts on the 1stmetatarsal & 1st cuneiform
14 Time of Bone Healing Tarsometatarsal or Lisfranc Fracture 8-10 weeksTarsal Navicular6-10 weeksCuboid & Cuneiform Fracture
16 Treatment Methods Tarsometatarsal or Lisfranc Fx: Cast: Biomechanics: stress-sharing deviceMode of Bone Healing: Secondary, with callus formationIndications: May be treated w/ a short leg cast for 6 wks. May bear weight when pn free.
17 Treatment Methods Open Reduction & Internal Fixation Biomechanics: stress-shielding device w/ screw fixationMode of healing: Primary, w/ rigid fixationIndications: Pt placed in a weight bearing cast for 6 wks. Unprotected weigh bearing is not recommended until screws are removed at least wks after surgery.
18 Treatment Methods Closed Reduction & Percutaneous Pinning Biomechanics: Stress-sharing device w/ pin fixationMode of bone healing: Secondary, w/ callus formationIndications: Kirschner-wire fixation. Placed in a non-weight bearing short leg cast after fixation. Wires removed at 6 wks, followed by protective weight bearing.
19 Treatment Methods Tarsal Navicular Fx Cast Biomechanics: stress-sharing deviceMode of bone healing: Secondary, w/ callus formationIndications: May be placed in a short leg cast.Cortical avulsion fx: short leg walking cast, 4-6 wks.Tuberosity fx: Short leg walking cast, 4-6 wks.
20 Treatment Methods Open Reduction & Internal Fixation Biomechanics: Stress-shielding device w/ rigid fixationMode of bone healing: Primary, w/out callus formationIndications: To avoid severe deformity & arthritis, must be treated w/ reduction & rigid fixation
21 Treatment Methods Cuboid & Cuneiform Fx Cast Biomechanics: Stress-sharing deviceMode of bone healing: Secondary w/ minimum callus formationIndications:Cuboids: closed in a weight bearing castCuneiforms: short leg cast, immobilized because of ligamentous damage
22 Treatment Methods Open Reduction Internal Fixation Biomechanics: stress-shielding deviceMode of bone healing: primary, w/ rigid fixationIndications:open reduction & internal fixation for any amount of displacement, followed by a 6 wk. period of non-weight bearing.
23 Special Considerations of the Fx AgeJoint stiffness particularly w/ navicular fx’sActive Pts. Also are probe to jt. Stiffness w/ a navicular fxArticular InvolvementPosttraumatic arthritis & fusionLimited pronation & supinationLocation or possibleOpen FracturesDamage to the dorsal pedis arteryOpen fx must undergo irrigation, debridement, & intrevenous antibioticsAlways a possibility of compartment syndromeTendon & Ligament InjuriesExtensor tendons should be inspected for possible damage
24 Gait Stance Phase Heel Strike Foot-Flat Mid-Stance Push-Off 60% of gait cycleHeel Strike↑ pn from inversion to eversionFoot-FlatPainful b/c of injured bones of the medial archMid-StancePainful as foot is moving from neutral to eversionPush-OffPt may limit plantar flexionCycle is shortenedSwing Phase40% of gait cycleNot affected by any of these fxs b/c foot is not in contact w/ ground