Updated: 2/18/2020

Osteochondral Lesions of the Talus

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https://upload.orthobullets.com/topic/7034/images/osteochondral lesion.jpg
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https://upload.orthobullets.com/topic/7034/images/retrograde_drilling.jpg
https://upload.orthobullets.com/topic/7034/images/talus_blood_supply.jpg
Introduction
  • Overview
    • focal injuries to the talar dome with variable involvement of the subchondral bone and cartilage resulting in osteochondral lesion of the talus (OLT) 
    • may be caused by traumatic event or result of repetitive microtrauma
  • Epidemiology
    • incidence
      • 69% of ankle fractures
      • 70% of ankle sprains
      • 10% are bilateral
      • medial talar dome lesions more common
    • location
      • medial talar dome
        • usually no history of trauma
        • more posterior
        • larger and deeper than lateral lesions
      • lateral talar dome 
        • usually have a traumatic history 
        • more superficial and smaller
        • more central or anterior
        • lower incidence of spontaneous healing
        • more often displaced and symptomatic
  • Pathophysiology
    • mechanism of injury
      • ankle inversion and dorsiflexion during axial load creates shearing of lateral talar dome and lateral OLT 
      • ankle inversion, external rotation, and plantarflexion during axial load creates shearing of medial talar dome and medial OLT
    • pathophysiology
      • possible repeitive microtrauma creates ischemic environment and loss of integrity of subchondral bone
      • leads to softening and disruption of overlying cartilage
  • Associated conditions
    • lateral ankle ligamentous insufficiency
    • cavus hindfoot alignment
  • Prognosis
    • lesions may progress to involve entire ankle joint 
Anatomy
  • Osteology
    • talus geometrically complex structure
    • resembles a frustrum
    • anterior portion broader than posterior
    • no muscular attachments
  • Cartilage
    • covers 70% of talus
    • among the thickest in the body (implications for osteochondral autografting)
    • maintains tensile strength longer than femoral head with aging process
  • Blood supply 
    • relies on extra-osseous blood supply
    • deltoid artery supplies majority of talar body and dome 
  • Biomechanics
    • ankle is a highly congruent mortise joint, oriented 15 degrees externally from midsagittal line of ankle
    • talus articulates with the medial malleolus medially, tibial plafond superiorly, posterior malleolus posteriorly, and fibula laterally
Classification
 
Berndt and Harty Radiographic Classification  
Stage 1  • Small area of subchondral compression
Stage 2  • Partial fragment detachment. 
Stage 3  • Complete fragment detachment but not displaced. 
Stage 4  • Displaced fragment. 
 
Ferkel and Sgaglione CT Staging System
Stage 1  • Cystic lesion within dome of talus with an intact roof on all view
Stage 2a  • Cystic lesion communication to talar dome surface
Stage 2b  • Open articular surface lesion with the overlying nondisplaced fragment.
Stage 3  •  Nondisplaced lesion with lucency
Stage 4  • Displaced fragment
 
Hepple  MRI Staging System
Stage 1  • Articular cartilage edema
Stage 2a  • Cartilage injury with underlying fracture and surrounding bony edema
Stage 2b  • Stage 2a without surrounding bone edema
Stage 3  • Detached but nondisplaced fragment
Stage 4  • Displaced fragment
Stage 5  • Subchondral cyst formation
 
Presentation
  • History
    • inversion ankle sprain
  • Symptoms
    • pain centered over ankle joint line
    • joint effusion
    • mechanical symptoms such as catching or locking
  • Physical exam
    • inspection
      • joint effusion
      • palpation rarely reproduces pain
      • cavus hindfoot alignment
    • motion
      • often limited secondary to pain or effusion
    • provocative tests
      • evaluate for ligamentous laxity or insufficiency
Imaging
  • Radiographs  
    • recommended views
      • standard weightbearing ankle series
    • findings
      • often normal
      • subtle lucency or bone fragmentation
  • Bone scan
    • indications
      • suspicion for OLT in setting of equivocal radiographs
    • sensitivity and specificity
      • 94% sensitive and 96% specific for OLT
  • CT
    • findings
      • helpful in evaluating subchondral bone and cysts
      • less reliable in purely cartilaginous lesions of nondisplaced OLTs
      • provides fine detail of lesions for pre-operative planning
  • MRI
    • indications
      • persistent pain following injury, ankle sprains that do not heal with time 
    • findings
      • variable edema patterns, may overestimate degree of injury
      • unstable lesions show fluid deep to subchondral bone
    • sensitivity and specificity
      • predicts stability of lesion with 92% sensitivity
Treatment
  • Nonoperative
    • immobilization and non-weight bearing
      • indications
        • acute injury
        • nondisplaced fragment with incomplete fracture
  • Operative
    • arthroscopy with removal of the loose fragment, debridement and marrow stimulation  
      • indications
        • chronic lesions 
        • size < 1 cm
        • displaced smaller fragment with minimal bone on the osteochondral fragment (poor healing potential)
    • retrograde drilling and/or bone grafting  
      • indications
        • size > 1 cm with intact cartilage cap
    • osteochondral grafting (osteochondral autograft transplantation, autologous chondrocyte implantation, bulk allograft) 
      • indications
        • size > 1 cm and displaced lesions, shoulder lesions
        • salvage for failed marrow stimulation or drilling
      • contraindications
        • diffuse ankle arthritis
        • bipolar kissing lesions
        • advanced osteonecrosis of the talar done
Techniques
  •  Immobilization and non-weight bearing 
    • period of immobilization in cast or boot for 6 weeks, followed by progressive weight bearing with physical therapy emphasizing peroneal strengthening, range of motion, and proprioceptive training
    • outcomes
      • 45% good-excellent outcomes
  • Arthroscopy with marrow stimulation (microfracture or antegrade drilling)
    • approach
      • standard arthroscopic approach to ankle  
    • instrumentation
      • debridement of unstable cartilage flaps to create stable and contained defect using curettes or shaver
      • loose bodies and cartilage removed using shaver or grasper
    • bony work
      • microfracture awl placed perpendicular to surface and tapped into subchondral bone 2-4 mm deep 
        • holes spaced 2-3 mm from each other 
        • inflow stopped to allow fat or blood to emanate from holes, indicating adequate penetration 
      • Kirschner wire can be passed using anterior portals, or transmalleolar for central or posterior lesions
        • commercial targeting guides available
        • talus dorsiflexed and plantar flex to necessitate only 1 transosseous passing of wire
    • complications
      • articular cartilage delamination and graft failure
    • outcomes
      • 85% pain improvement
      • 65-90% improvement in patient reported outcomes
      • fibrocartilage formation at site of lesion in 60% of patients on second-look arthroscopy, no correlation noted with patient outcomes
  • Arthroscopy with retrograde drilling and bone grafting
    • approach
      • standard arthroscopic approach to ankle
    • instrumentation
      • evaluate cartilaginous surface for softening, dimpling with probe seen
      • confirm integrity of cartilaginous cap
    • bony work
      • Kirschner wire drilled from sinus tarsi into defect
        • commercial targeting guides available
        • fluoroscopy often helpful to confirm location
      • if bone grafting indicated, cannulated drill placed over K wire
        • curette out cystic material
        • graft harvested and placed
    • complications
      • violation of intact cartilage cap
  • Osteochondral autograft and allograft transplant
    • approach
      • dictated by location of OLT and concomitant procedures required (i.e. Brostrum)
      • medial malleolar osteotomy for medial and posterior lesions
        • longitudinal incision centered over medial malleolus
        • anterior arthrotomy to expose joint line
        • flexor retinaculum released posteriorly; PTT retracted posteriorly
        • osteotomy guided based of 2 parallelly placed K-wires, with goal to enter plafond at lateral extent of OLT
        • prior to osteotomy, 2 drill holes placed to aid in reduction following procedure
        • sagittal saw and osteotome used to complete osteotomy, care taken not to cause thermal necrosis to bone or damage cartilage
      • lateral malleolar osteotomy or ATFL/CFL release for lateral lesions
        • longitudinal incision centered over lateral malleolus
        • oblique osteotomy planned, with predrilling of small fragment screws holes to aid in reduction following procedure
        • alternatively, if lateral ligament reconstruction is planned, extensor retinaculum may be released 
        • peroneal tendons retracted posteriorly and ATFL and CFL released, ankle inverted and plantarflexed to expose talar dome
      • bone work
        • OLT debrided and measured using sizing guide
        • appropriately sized autograft may be harvested from knee and placed into OLT, impacted gently into defect
        • OATs harvested from the knee have a cartilage thickness less than the native talus
          • this will cause immediate post-operative xrays to show a prominent graft despite the cartilage surface being flush
      • complications
        • osteotomy site delayed- or non-union
          • do not release deltoid ligament as may jeopardize deltoid artery blood supply
        • ankle impingement if graft plug left proud
        • autograft harvest site morbidity
  • Autologous chondrocyte implantation
    • approach
      • two-stage procedure consisting of
        • arthroscopic harvest of chondrocytes (from ankle or alternatively from knee) are sent for cultured growth
        • open approach via osteotomy for implantation
    • instrumentation
      • debridement of lesion to create stable cartilage rim, subchondral bone exposed
      • bone graft may be placed if underlying cyst and bone loss
      • periosteum from tibia taken and fitted to defect
      • this is sutured into place this small caliber suture, omitting one area to leave access to underlying defect
      • water-tight seal confirmed, cultured chondrocytes placed under flap and suture placed, fibrin glue placed over defect
    • outcomes
      • newer technique of matrix-based chondrocyte implantation (MACI) shown equivalent outcomes to ACI and may obviate need for osteotomy
Complications
  • Graft failure
    • complication of all grafting procedures
  • Persistent pain
    • small percentage of patients do not achieve pain relief regardless of treatment
 

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(OBQ13.46) A 43-year-old male sustained a left ankle injury 3 years ago. Radiographs at the time were negative and his pain improved over the next two months. However, for the last six months, he has developed persistent ankle pain with intermittent swelling. He has been treating his symptoms with physical therapy and anti-inflammatory medications with little effect. Physical examination elicits pain with ankle dorsiflexion and plantarflexion, although subtalar motion is normal. Figures A and B are radiographs of the left ankle. Figure C shows the corresponding MRI. What would be the next most appropriate step for treatment? Review Topic | Tested Concept

QID: 4681
FIGURES:
1

Total contact cast immobilization and nonweight-bearing for 6 weeks

12%

(340/2877)

2

Ankle arthrodesis

1%

(21/2877)

3

Open autologous chondrocyte implantation

11%

(327/2877)

4

Arthroscopic marrow stimulation

69%

(1980/2877)

5

Ankle corticosteroid injection

7%

(191/2877)

L 4 C

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(OBQ12.74) A 21-year-old male reports right ankle pain after sustaining an inversion ankle injury 2 years ago. He complains of mechanical symptoms with ankle movement that continue to be symptomatic with everyday activities. During his workup, an MRI shows a 1x1 cm lateral talar osteochondral defect (OCD). When compared to medial talar OCDs, which of the following statements is true regarding lateral talar OCDs? Review Topic | Tested Concept

QID: 4434
1

Increased incidence of traumatic etiology

67%

(3539/5308)

2

Lesions are usually deeper

4%

(201/5308)

3

Better chance of spontaneous resolution

10%

(546/5308)

4

Usually more posterior

11%

(569/5308)

5

Are more common

8%

(413/5308)

L 3 B

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(OBQ06.213) A 30-year-old professional ballet dancer presents with persistant ankle pain after an ankle sprain 6 months ago. Physical therapy and NSAID's have not alleviated the symptoms. Physical exam reveals some joint swelling but no ligamentous instability. Radiographs are unremarkable. What is the next appropriate step in the management of this patient? Review Topic | Tested Concept

QID: 224
1

Continue physical therapy

1%

(42/3096)

2

Avoidance of dancing with CAM walker boot for 2 weeks

7%

(208/3096)

3

MRI of the ankle

90%

(2796/3096)

4

Ankle steroid injection

1%

(20/3096)

5

Diagnostic ankle arthroscopy

1%

(22/3096)

L 1 D

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