OCD

DefinitionTalus OCD MRI Coronal

 

Fracture talus through articular cartilage into subchondral bone

- 2° force transmitted from distal tibia

 

Osteochondritis dissecans v osteochondral fracture

 

Epidemiology

 

6% ankle sprains

Average age = 25 

M > F

 

Location

 

1.  Anterolateral 50% 

 

Talus OCD Anterolateral FragmentTalus OCD Anterolateral 2

 

2.  Posteromedial 50% 

 

Talus OCD MedialAnkle OCD Medial

 

Aetiology

 

30% associated with other injuries

- medial and lateral malleolar fractures

- ankle sprains

 

A.  Traumatic / anterolateral

 

2° to inversion injuries

- will usually heal

 

B.  Atraumatic / posteromedial

 

2/3 caused by trauma

- 1/3 no history trauma 

- are chronic and won't heal 

 

Non-traumatic causes

- ? AVN 

- 20% bilateral (can be asymptomatic)

- some patients have multiple joints with OCD

- can have family history of talus OCD

 

Pathology

 

Start as acute intra-articular fracture

 

Bony fragment may

- revascularise & unite

- undergo AVN & not unite

 

Overlying cartilage may degenerate

 

Cyst may develop under fragment

 

Berndt & Harty Xray Classification

 

Stage 1 

- subchondral compression fracture

 

Stage 2 

- partially attached osteochondral fragment / flap

 

Stage 3 

- fragment detached in-situ / not displaced

 

Talus OCD Medial Type 3

 

Stage 4 

- detached displaced fragment

 

Talus OCD Medial Type IV

 

MRI 

 

Determine stability of fragment

- stable lesion has intact overlying cartilage

- unstable lesion has fluid at fragment-crater interface

 

Stage 1

- stable

- no detachment, no synovial fluid

 

Stage 2

- partially detached, some synovial fluid

 

Talus OCD Type 2

 

Stage 3

- completely detached, not displaced

 

Talus OCD Anterolateral MRI0001Talus OCD Anterolateral MRI0002

 

Talus OCDTalus OCD

 

Stage 4

- displaced

 

History

 

Lateral ankle sprain from inversion injury

 

Chronic symptoms after ankle sprain settled

- activity-related pain, stiffness & swelling

- crepitus, instability & locking (true locking rare)

 

Symptoms of lateral ligament instability

 

Examination

 

Tenderness around ankle joint

 

Pain with dorsiflexion / eversion

 

Decreased ROM, especially dorsiflexion

 

Effusion

 

Test for ligament instability

 

DDx

 

Chronic ligament instability

Lateral gutter ST impingement

Calcaneal fracture

Lateral process fracture

Tarsal coalition

Sinus tarsi syndrome

  

Management

 

Non Operative

 

Higher success with acute injury

- POP & NWB 6/52

- progressive to weight bearing over 3 - 4 months

 

Tol et al Foot Ankle Int 2000

- meta-analysis

- 14 studies with 201 patients

- 45% success rate

 

Operative

 

1.  Percutaneous Drilling

 

Indication

- Type 1, 2

 

Ankle OCD ArthroscopyAnkle OCD Percutaneous Drilling 1Ankle OCD Percutaneous Drilling 2

 

2.  ORIF

 

Indications

- acute

- large type 2 , 3

- in situ but unstable and not healing

 

Approach

 

A.   Lateral lesion

- approached through anterolateral approach

- ± Fibular osteotomy if large 

 

B.  Medial lesion

- approached through anteromedial approach

- ± medial malleolar osteotomy

 

Medial Malleolar Osteotomy

 

Technique

- partially displace

- debride base

- insert bone graft as paste

- fix with bioabsorbably headless compression screws

 

3.  Excision / curettage / abrasion / microfracture

 

Indications

- small lesion

- fragment detached with chondral lesion

 

Results

 

Tol Meta-analysis

- 88% success stage 3 and higher

- less if no curettage or dilling

- can do so arthroscopically

 

Ankle Scope OCD Grade 4Ankle Scope OCD Abrasion

 

Talus Chondral LesionTalus OCD Bleeding

 

4.  Allograft

 

Indications

- large lesions

- > 1cm diameter and > 5mm thick

 

Post operative

- PTB brace 1 year

 

Results

 

Gross Foot Ankle Int 2001

- 3/9 resorbed

 

4.  Osteochondral autograft / mosaicoplasty

 

Indications

- stage 4 lesion

 

Donor Site

- taken from knee NWB surface

- allograft

 

Technique

- fresh frozen talus

- 6.5 mm chisel used to take 10 mm plug

- medial malleolar osteotomy

- 6.5 mm drill into OCD site with drill guide, over drill 4 mm

- dilator

- insert plug, countersink 1 - 2 mm

 

Medial Malleolar Osteotomy

 

Talus MosaicplastyTalus Mosaicplasty 1Talus Mosaicplasty 2

 

Results

 

Management Algorithm

 

Stage 1

 

Restricted activity / watch to see if heals

 

Stage 2 

 

Symptomatic 

- SL POP for 6/52 

- Successful in 90%

 

Failure

1.  ORIF

2.  Removal of necrotic fragment & drill base 

 

Stage 3 

 

Surgery probably indicated as very unstable

- ORIF

 

Stage 4 

 

Surgery

- acute ORIF if possible (i.e fragment is replaceable)

- chronic may have to discard fragment 

- manage chondral defect / abrasion