Osteochondral Lesions of the Talus

 

Introduction

  • Common condition associated with ankle injuries
  • Terms include OCL (lesion) and OCD (defect)
  • Symptoms may be nonspecific and include:
    • pain (frequently deep seated)
    • swelling
    • stiffness
    • mechanical symptoms of locking / catching
  • Acute osteochondral injuries mostly result from ankle sprains
  • Clinical examination may only reveal diffuse swelling and painful motion

 

Characteristics

  • Trauma is the cause of most lateral OCDs but only 64% of medial
  • Medial lesions are usually deeper and more likely to become cystic
  • Lateral lesions are shallower and more likely to have an associated wafer or flake fracture
  • Location:           
    • 53% medial
    • 26% lateral
    • In the sagittal plane:
      • 80% are middle
      • 6% anterior
      • 14% posterior

 

Imaging

 

Plain radiographs

  • Standing AP & lateral +/- mortise +/- AMI (anteromedial impingement) views
  • Seen as a poorly defined radiolucent area in the affected area of the talar dome
  • Low sensitivity of plain radiographs (41%) often warrants further imaging

 

CT scan

  • 81% sensitive and 99% specific for the diagnosis of OCLs
  • Limited information on articular cartilage quality
  • Helps to assess size, location and displacement of the lesion
  • SPECT may help to identify co-existing pathology as well as showing the activity around the lesion

 

MRI

  • Considered the gold-standard imaging for ankle OCLs
  • Assessment of articular cartilage
  • Identifies lesion depth and subchondral inflammatory changes
  • 96% sensitive and 96% specific for the diagnosis of OCLs
  • Accurately predicts stability of the lesion

 

Classification

 

Brendt and Harty is based on x-rays – still most widely used for talus OCLs

 

Stage I

small focal subchondral compression

Stage II

partially detached fragment

Stage III

completely detached but undisplaced fragment

Stage IV

completely detached and displaced fragment

Stage V

osteochondral cysts just below the damaged articular surface

 

 

Hepple et al. described an MRI-based classification system:

 

Stage 1

articular cartilage damage only

Stage 2a

cartilage injury with underlying fracture and bony oedema

Stage 2b

cartilage injury with underlying fracture without bony oedema

Stage 3

detached, undisplaced fragment

Stage 4

displaced fragment

Stage 5

subchondral cyst formation

 

Treatment

  • ​Reserved for symptomatic or progressive lesions
  • Incidental findings may require follow up depending on patient’s age and level of physical activities
  • The natural history of the OCLs remains unclear due to paucity of longitudinal follow-up studies

 

Conservative treatment

 

Goals

  • Offload the injured cartilage
  • Resolve the bone oedema
  • Prevent necrosis and allow the detached fragment to heal to the underlying bone

 

Options

  • Activity modification
  • Immobilisation in the acute phase for 3-4 weeks +/- NSAIDs
  • Progressive weight bearing in a walker boot with physical therapy for 6-10 weeks
  • Intra-articular steroid injection
  • Limited evidence for PRP injections

 

Results

  • Unpredictable; may only benefit <50% of patients
  • No convincing literature to confirm duration of non-operative treatment, method of immobilisation, weight bearing status, the use of NSAIDs, and physical therapy protocol
  • True success rate of conservative treatment remains debatable
  • Some studies have reported ankle arthritis in approximately 50% patients who were managed conservatively

 

Surgical treatment

 

Options

  • Excision alone
  • Excision with curettage
  • Excision with bone marrow stimulation
  • Excision with curette and auto/allograft
  • Excision with curetted and particulated juvenile cartilage
  • Retrograde drilling
  • Excision with autologous matrix-induced chondrogenesis (AMIC)
  • Matrix-induced autologous chondrocyte implantation (MACI)
  • Osteochondral auto/allograft transplantation

 

Principles

  • Acute injuries should be managed with urgent arthroscopy
  • Larger fragments should be reduced and fixed (absorbable pins / headless screws) to their anatomical location
  • Smaller or devitalized fragments are resected, and the lesion base is prepared with bone marrow stimulation

 

Bone marrow stimulation

  • Most frequently performed intervention for primary talar OCLs
  • Good clinical results at short and mid-term follow-up
  • 85% successful outcome with combination of:
    • excision of osteochondral fragment
    • curettage of the affected area
    • bone marrow stimulation
  • Combined excision of fragments and curettage resulted in good outcome in 77% of cases
  • Excision of fragments alone in good results in 32% of cases

 

Alternative techniques

 

  • Lift, Drill, Fill and Fix (LDFF)
    • minimally invasive arthroscopic technique
    • recommended for primary lesions >1 cm2
    • two device fixation if possible to prevent rotation

 

  • Retrograde drilling 
  • requires radiographic and arthroscopic control
  • considered to be an effective option for OCLs with intact joint cartilage
  • technique:
    • using arthroscopy and fluoroscopic guidance, a guidewire is passed to the lesion without breaching the articular surface
    • cannulated drill is used to decompress
    • drill tunnel can be used for delivery of bone graft

 

  • Osteochondral autologous grafting (OAT) 
  • harvesting of cylindrical osteochondral grafts, most commonly from the non-weight-bearing surface of lateral femoral condyle, implanted into the affected lesion of the talar dome
  • technically challenging, requiring expertise and accuracy for optimum results
  • indications:
    • lesions >1.5 cm2
    • recurrent lesions or refractory to other treatment methods
    • lesions associated with subchondral cysts
  • early results are superior to debridement with microfracture

 

  • Allograft transplantation
  • indicated for lesions >3 cm2, esp at the shoulder of the talus
  • utilises fresh cadaver allograft with viable chondrocytes and normal subchondral bone (use within 2 weeks of obtaining graft) 

 

  • Autologous chondrocyte implantation (ACI) 
  • Indicated for:
    • recurrent OCLs of any size
    • primary treatment of lesions >2.5 cm2
    • with or without subchondral cysts
    • patients aged 15-55y
    • no degenerative change or mirror-image OCLs
    • no instability or joint malalignment

 

  • Matrix-induced autologous chondrocyte implantation (MACI)
  • use of a collagen membrane to carry the cells
  • eliminates the need for autograft harvesting and associated morbidity
  • encouraging early results

 

  • Matrix-augmented bone marrow stimulation (m-BMS)
  • increasingly used
  • involves debriding the chondral surface to a stable rim, preparing and filling the bone defect with autologous bone graft, then laying a matrix on top
  • matrix materials have included type I/III collagen, polyglycolic acid and hyaluronan
  • primarily indicated for larger lesions

 

  • Metallic implants
  • limited evidence
  • should only be used as a second / third-line treatment

 

Prognostic Factors

 

  • Positive prognostic factors:
  • lesions <1.5 cm2
  • contained lesions
  • anterolateral lesions

 

  • Negative prognostic factors:
  • older age (>33-40y)
  • lesions deeper than 7 mm
  • lesions > 1.5 cm2
  • cystic lesions
  • medial talar lesions
  • higher BMI
  • history of trauma
  • longer duration of symptoms
  • ankle instability – correct before or during procedure
  • limb malalignment – correct before or during procedure
  • osteophytes or degenerative change

 

 

References

  • Hepple S, Winson IG, Glew D. Osteochondral lesions of the talus: a revised classification. Foot Ankle Int. 1999;20(12):789-93.
  • Coi JI, Lee KB; Comparison of clinical outcomes between arthroscopic subchondral drilling and microfracture for osteochondral lesions of the talus; Knee Surg Sports Traumatol Arthrosc; 2016 Jul;24(7):2140-7. doi: 10.1007/s00167-015-3511-1. Epub 2015 Feb 4. 
  • van Bergen C.J., Kox L.S., Maas M., Sierevelt I.N., Kerkhoffs G.M., van Dijk C.N. Arthroscopic treatment of osteochondral defects of the talus: outcomes at eight to twenty years of follow-up. J. Bone Joint Surg. Am. 2013;95(6):519–525.
  • Reilingh ML, Murawski CD, DiGiovanni CW, Dahmen J, Ferrao PNF, Lambers KTA, et al. Fixation techniques: Proceedings of the international consensus meeting on cartilage repair of the ankle. Foot Ankle Int. 2018;39:23S–27S.
  • Migliorini F, Maffulli N, Bell A, Hildebrand F, Weber CD, Lichte P. Autologous Matrix-Induced Chondrogenesis (AMIC) for Osteochondral Defects of the Talus: A Systematic Review. Life (Basel). 2022 Oct 29;12(11):1738.
  • Maiorano E Bianchi A Hosseinzadeh MK Malerba F Martinelli N & Sansone V. HemiCAP(R) implantation after failed previous surgery for osteochondral lesions of the talus. Foot and Ankle Surgery 20212777–8.