Michael L. Salamon M.D.

Sports Conference

October 21, 2004

Ankle Sprains

•      Common

•      23,000 inversion ankle sprains/ day in U.S.

•      Incidence: 7 per 1000 person years

•      Mechanism: inversion of plantarflexed foot

•      Up to 40% of all athletic injuries

•      45% basketball injuries involve the ankle

•      17-20% soccer injuries are ankle inversion sprains

Anatomy

•      ATFL:

–    1° restraint to inversion of ankle through its arc

–    Collateral ligament in plantarflexion

•      CFL:

–    1°  restraint to inversion when ankle in DF (always torn with ATFL)

•      PTFL:

–    rarely torn and not addressed surgically

Acute Ankle Instability

•      Treatment of Acute Sprains

•      Nonoperative functional rehabilitation for all sprains

–   “RICE”

–   Early ROM

–   After acute injury:

•   Strengthening (evertors)

•   Proprioception

Acute Ankle Instability

•      Kannus et al., JBJS, 1991

–   Critical review of 12 prospective, randomized studies

–   Rx of choice:  early functional rehab over….

•    surgery + cast

•   cast immobilization alone      

However…

Not all “ankle sprains” are ankle sprains

Case #1

•      19 year old male fell after getting “huge air” on his Snowboard

•      Immediate pain with weight bearing

•      No history of previous ankle injuries

•      Seen at local ugent care center

–    Negative radiographs

–    Swelling/echymosis around lateral ankle

Told he had a “sprain” and given air cast splint

Lateral Process of Talus Fracture (Snowboarder’s Fx)

•      Dorsiflexion/inversion

•      Frequently misdiagnosed as ankle sprain

•      May involve up to 1/3 posterior facet

•      Broden’s views and CT help with diagnosis

Lateral Process of Talus-Fracture

•      Non displaced fractures

–   NWB cast for 4-6 weeks

•      >1cm fragments or 2mm displacement

–   Treat surgically (ORIF)

–   Can involve up to 1/3  of posterior facet

•      Excision of small comminuted fragments

•      Significant malunion may lead to loss of subtalar and arthrosis

Case #2

•      22 year old female Univ. of Iowa athletic training student falls down stairs at party two nights ago

•      Told by ER M.D. that she “sprained her ankle”

•      ER xrays negative

•      Pain/swelling along lateral hindfoot

•      Difficulty with weight bearing

Fractures of the Anterior Process of the Calcaneus

“sprain-fracture”

•      2 Types:  Avulsion and Compression

•      Avulsion more common

–    Adduction, plantarflexion, and tension on bifurcate ligament

•      Compression Fracture

–    Abduction of forefoot with compression of C-C joint

•      Oblique radiograph of foot, CT help with diagnosis

Fractures of the Anterior Process of the Calcaneus

•      Most treated successfully with cast immobilization

•      Fixation of large displaced fragments

•      Excision of fragments if nonunion

Case #3

•      25 year old  presents with “sprained ankle” 6 weeks ago while playing basketball

•      Still has pain, swelling, occasional mechanical symptoms

•      Pain localized to anterolateral ankle

•      Initial radiographs in ER read: “negative,  no fracture”

MRI

OCD:  Arthroscopy

OCD Lesions of the Talus

•      Etiology: probably traumatic but may have a vascular component

•      Incidence: .09%-6.5% of acute ankle sprains

•      High prevalence with chronic ankle instability

Osteochondral Lesions of the Talus

•      Location:

–    Posteromedial

•    Most common

•    deeper cup shaped lesion

•    Less symptomatic, better healing potential

–    Anterolateral

•    Less common

•    Shallow, wafer shaped lesions

•    Usually more symptomatic

•    More frequently displaced

OCD Lesions of the Talus

•      Treatment:

–   Ankle arthroscopy for evaluation and treatment

–   Debridement and microfracture/drilling usually has good results

–   Larger lesions (>1 cm) may require further treatment

–   Malalignment and ankle instability may need to be addressed

OCD Talus : Summary

•      OLT are common cause of disability post ankle sprain

•      Evolving strategies in management of larger lesions in younger patients

•      Role of osteochondral resurfacing and ACI continues to evolve

Differential Diagnosis in

“Ankle Spains ”

•      OCD Talus

•      Anterior process calcaneus

•      Lateral process talus

•      Proximal 5th MT fx

–    P.B. Avulsion or Jones

•      Syndesmosis injury

–    “High ankle sprain”

•      Subtalar injury

•      Tendon injury

–    Peroneal (tear/dislocation)

–    Achilles

•      Extensor retinaculum injury/disruption

•      Malleolar fracture

•      Non-displaced talar neck fracture

Differential Diagnosis

younger patients

•      Physeal (growth plate) injury

–   Salter-Harris I

•      Tarsal Coalition

–   (recurrent ankle sprains)

“Ankle Sprain”

In Summary

In Summary

•      Remember: have a high index of suspicion

•      Focused, complete physical exam of the foot and ankle

•      Think about the anatomy

•      Appropriate use of imaging modalities

•      Beware of the “ankle sprain” that does not improve after reasonable amount of time