ankle sprain imitators leslie a. michaud, m.d. steadman hawkins clinic of the carolinas primary care...

Ankle Sprain Imitators

Leslie A. Michaud, M.D.Steadman Hawkins Clinic of the CarolinasPrimary Care Sports Medicine Fellow

Foot and ankle Statistics• 1982: NCAA develops the ISS (injury

surveillance system)• 2007 - 16 years of ISS data showed that ankle

sprains are the most common injury 14.9% of all injuries▫Compare to ACL 2.6%▫Concussion 5%

• 39.7% of high school injuries are foot and ankle

• 2004 - Olympic summer games Athens – 22% of injuries were ankle sprains

• 2002 - Olympic winter games Salt Lake City – 25% foot and ankle

• Collegiate basketball - higher rate of grade I ankle sprains in women than men

Tibia

Fibula

TalusLateral Malleolus

Medial Malleolus

Subtalar joint

Tibial Plafond

http://www.emedx.com/emedx/diagnosis_information/diagnosis_information_image_files/foot_ankle_images/ankle-xray-normal-2.jpg

Resists posterior displacement

Provides stabilization in plantarflexion

Stabilizes ankle and subtalar joint; especially during inversion

Evaluation of Foot and Ankle Injuries

• Identify and localize the injured bony and soft-tissue structures

• Determine MOI▫Clues regarding location and severity of injury▫Clues to potential concomitant injuries that

may be overlooked• More extensive evaluation in severe sprains

▫Arouse suspicion of fx or articular injury• 1% of ankle sprains are syndesmotic - more

common with eversion• Persistent symptoms 4-6 weeks despite

appropriate treatment

Imitators

•Osteochondral lesions of the talar dome

•Lateral process talar fractures

•Peroneal tendon subluxation and

dislocation

•Base of the 5th metatarsal (avulsion)

•Tarsal coalition

Osteochondral Lesions of the Talar Dome

• Injury to the cartilage and underlying bone

of the talus

•History of trauma in 98% of lateral dome

lesions

▫70% of medial dome lesions

•Trauma is often an inversion-type injury

• Initial radiographs often unremarkable

▫Seen best on mortise view

Osteochondral Lesion Presentation

•Persistent pain and swelling well after

injury

•Occasionally will have a slow onset

•+/- mechanical symptoms

▫Intraarticular process

Why do we need to catch an osteochondral lesion early?

• The fracture damages vascular supply to the

subchondral bone

• If treated early, capillaries can restore bloodflow

• If not, prolonged weight-bearing causes fibrous

tissue to accumulate which will block capillary

ingrowth

▫Leading to AVN and later DJD

Diagnosis and Treatment

•CT or MRI if radiographs negative and suspicion is high

•Conservative▫Rest and immobilization

•Surgical▫Drilling▫Debridement▫Excision of fragment▫Osteochondral graft

Lateral Talar Process Fractures

• “Snowboarder’s fracture”

• Often subtle presentation plain films

• Clinically resemble an inversion ankle sprain

• Tenderness 1 cm from the tip of the lateral malleolus at the lateral talus

Lateral Talar Process Fracture Facts

•24% of talar fractures are at the lateral

process

▫<1% of all ankle injuries are LTP fx

•15% are misdiagnosed as ankle sprains

▫Exam findings: “tenderness 1 cm inferior to

tip of lateral malleolus” mimic ATFL

• MOI: dorsiflexion + inversion + ER force

•More of an impact or crush injury

•Comminution

•More often than not have IA involvement

Evaluation and Treatment

•CT in all cases to determine intraarticular involvement and level of comminution

•Conservative▫Only for non-displaced▫SLNWB cast for 4 weeks▫Advance WB in boot for 2 additional weeks

•Operative▫Excision (fragments <1cm)▫ORIF (fragments >1cm)

Peroneal Tendon Instability

• Subluxation or dislocation

• Can be associated with chronic lateral ankle instability

▫ Functional

▫ Mechanical

▫ Previous injury

• Concern for degenerative tears of the peroneus brevis

tendon

• Persistent pain after Grade III sprains is commonly due

to incomplete rehab with too early RTP

▫ Peroneal strengthening

Superficial Peroneal Nerve

•Supplies lateral compartment muscles

•High incidence of neuropraxia

▫Grade II and III sprains

•Almost all resolve spontaneously with

time

History and Physical Exam

• Previous inversion injury

• Specific activities i.e. dancers

• Swelling and possibly ecchymosis (acute)

posterior to lateral malleolus

• Stress test

▫Resist dorsiflexion from the plantarflexed

position while the foot is in inversion

• Varus hindfoot

Treatment

• Conservative▫Acute injuries

Reduce tendon and SLWB cast for 6 weeks 50% success rate

▫Chronic PT

• Surgical▫Reattachment▫Deepen groove▫Reroute tendon▫Reconstruct retinaculum▫Bone block

Tarsal Coalition

•Congenital fusion of tarsal bones

▫Calcaneus to navicular most common

8-12 years old

▫Talus to calcaneus

12-15 years old

•Rigid flatfoot

•“Peroneal spastic flatfoot”

History and Physical Exam•Lateral ankle pain•Worse with activity•May radiate to calf•Inspect feet

▫Flat▫Hindfoot valgus▫No arch with toe raise

•Limited subtalar motion•Tight heel cords

Evaluation and Treatment•CT or MRI

▫Looking for other coalitions▫Determine size

•Conservative▫If asymptomatic – observation▫Symptomatic – orthotics or casting

•Surgical▫Resect coalition and interpose with fat

graft or EDB tendon▫Arthrodesis – not often used

Questions?

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