Lecture 8 Flashcards
Lisfranc injury
- Fracture dislocation of the tarsometatarsal joint
- Commonly refers to medial aspect of the joint (1st and 2nd mets, medial and intermediate cuneiform
Primary mechanism of Lisfranc injury
- Direct: crush injury (motor vehicle accidents, industrial accidents, falls)
- Indirect (more common): rotational force and axial force through the foot while it positioned in plantarflexion
Lisfranc injuries have different degrees of severity ranging from mild sprains (partial ligament tears) and stability to joint diastasis and instability
- Purely ligamentous vs. ligamentous and bony
- 2nd met base fits into mortise created by cuneiforms
- Ligaments between the medial cuneiform and 2nd met base
- Interosseous (Lisfranc’s) and the plantar ligaments are especially important
- Dorsal ligaments are weak making dorsal dislocation common
Lisfranc injury may also be classified based on
- How much of the tarsometatarsal joint is involved
- Direction of dislocation
Lisfranc injury is most common in
- 3rd decade of life
- More common in athletes
- M > F
Lisfranc injury presentation
- May be delayed (initial impression is a minor injury is present)
- Midfoot pain and pain with weightbearing (especially with forefoot weightbearing/push-off)
- Swelling in the midfoot
- Ecchymosis can be present on the medial plantar foot
- Tenderness over midfoot, especially the tarsometatarsal joint
- Pain with forefoot abduction and eversion or just twisting the forefoot
- Pain or subluxation with passive dorsiflexion and plantarflexion at the tarsometatarsal joint (piano key test)
- Have to check dorsalis pedis
Lisfranc injury requires weightbearing x-rays that may reveal
- Misalignment of lateral margin of medial cuneiform and 1st met base
- Misalignment of the medial margin of 2nd metatarsal base and intermediate cuneiform
- Widening between 1st and 2nd metatatarsals
- Misalignment between dorsal cortex of 1st or 2nd metatarsal and medial cuneiform on lateral x-ray (step off)
- Small avulsion fragments of the bones (“fleck sign”)
- Avulsion of Lisfranc ligament
Chronic ankle instability results from
- Recurring bouts of the ankle giving way
- Develops after previous ankle sprain(s)
- Inadequate healing or rehab of the ligaments and muscles
- Each ankle sprain leads to further weakening of the ligaments, greater instability and increased chance of future ankle sprains
Previous studies associate chronic ankle instability with
- Delayed reaction time
- Ankle weakness
- Dynamic balance
Purpose of ankle instability study
- Determine what factors contribute to CAI
- Compare the potential contributors of ankle instability in those with CAI vs. normal controls
- Contributors to decreased function
Contributors to decreased function in CAI
- Peroneal RT
- Dynamic balance
- Strength
Cumberland ankle instability tool
- Questionnaire that assesses severity of instability (lower score: decreased ankle function)
CAI group participants
- Age 22.6yrs
- Height: 172 cm
- Body mass: 69.1kg
- CAIT: 19.5
Control group participants
- Age: 20.9
- Height: 172cm
- Body mass: 66.5kg
- CAIT: 28.7
CAI conclusion
- Dominant ankle (kicking leg) had the following:
- At least 1 significant ankle sprain > 3 months prior to study
- 2 or more episodes of ankle giving way in last 6 months
- CAIT score 24 or less
Exclusion criteria for both groups
- Previous lower extremity surgeries
- History of frx requiring realignment
- Acute injury previous 3 months that affected joint function (interrupted at least 1 day of activity)
Peroneal reaction time test
- Device produced 30ᵒ of inversion
- Average of 3 trials
- ~ 60-90s rest between trial
Balance test on Biodex stability system
- Ant/Post (APSI) and Med/Lat stability (MLSI)
- Stability in the sagittal and coronal plane)
- Overall stability index (OSI)
- 3 practice trials
- Average of 3-20sec test with 10sec rest
- Higher values = poorer stability
Star excursion balance test
- 8 directions tested, 45ᵒ from each other
- 4 practice trials
- Average of 3 test
- Reach distance measured for each direction (normalized to leg length)
Isokinetic strength test in eversion
- 3 different velocities: 60,180, and 300ᵒ per sec
- Eccentric and concentric contractions in eversion
- 10 min warmup and 3 submax reps
- 5 reps for each test velocity
- Peak torque normalized for body mass
- E/C ratios
Results of study
- CAI group had prolonged RT in peroneus brevis and longus
- Poor performance in overall stability index, medial/lateral stability index, anterior/posterior stability index
- Decreased reach distance in all 8 directions of the star excursion balance test
- No difference in inversion/eversion peak torques
- CAI had higher E/C ratio at 180ᵒ/sec
Moderate correlation between CAIT score and
RT of PL and PB
- Negative correlation
- Lower CAIT score longer reaction time and vice versa
Moderate correlation between CAIT score and all directions of SEBT except for AL
- Positive correlation
- Lower CAIT score lower reach distance and vice versa
Small correlation between CAIT and OSI and MLSI of BSS
- Negative correlation
Small correlation between CAIT and AL direction of SEBT
- Positive correlation
CAI study limitations
- Other factors that can alter balance might not have been excluded from the study
- Previous rehab programs not taken into account
- Inversion testing is different than real life
- Testing order was not randomized
