Courtesy: Francesca Vannini, Rizzoli Orthopaedic Institute, Bologna, Italy

1. Background

   Osteochondral lesions of the talus are increasingly encountered in clinical practice due to:

   • Rising participation in sports

   • A younger, highly active population

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   Treatment Goals

   Management aims to:

   • Relieve pain

   • Restore cartilage (ideally hyaline-like)

   • Prevent progression to ankle osteoarthritis

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   Classification (Van Dijk–Based)

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   Acute Lesions

   Lesion Size	Management
   < 1 cm²	Debridement
   > 1 cm² with viable fragment	Fragment fixation

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   Chronic Lesions

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   Type 0

   Features

   • Intact cartilage

   • Pathology confined to subchondral bone

   Treatment Options

   • Retrograde drilling

   • Bone marrow aspirate concentrate (BMAC)

   • Subchondroplasty

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   Type 1

   Features

   • Cartilage damage present

   • Lesion < 1.5 cm²

   Treatment

   • Microfracture

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   Type 2

   Features

   • Lesion > 1.5 cm²

   • Depth > 5 mm

   Treatment

   • Cartilage repair or replacement

   • Bone graft or bone substitute

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   Type 3

   Features

   • Very large lesion

   • Extensive joint surface involvement

   Treatment

   • Osteochondral allograft transplantation

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   Pathophysiology (Van Dijk Theory)

   A small defect in the subchondral bone plate leads to:

   • Joint loading forces fluid into bone

   • Increased intraosseous pressure

   • Subchondral cyst formation

   • Bone marrow edema

   • Pain

   Key Insight:
   Cartilage may remain intact — treatment can be directed at the subchondral bone

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   Subchondral Bone Treatment Options

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   Retrograde Drilling

   Indication

   • Intact cartilage with subchondral cyst

   Purpose

   • Stimulates bone healing

   • Preserves overlying cartilage

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   Bone Marrow Aspirate Concentrate (BMAC)

   Technique

   • Bone marrow aspirated (usually posterior iliac crest)

   • Concentrated and injected under imaging guidance

   Benefits

   • Provides mesenchymal stem cells

   • Enhances bone healing

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   Subchondroplasty

   Method

   • Injection of calcium phosphate bone substitute

   Advantages

   • Provides structural support

   • Acts as a biological scaffold

   Indications

   • Bone marrow edema

   • Subchondral cysts

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   Cartilage Repair Techniques

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   Autologous Chondrocyte Implantation (ACI)

   Procedure

   1. Cartilage biopsy

   2. Cell culture

   3. Implantation under periosteal flap

   Advantages

   • Suitable for large lesions

   • Produces hyaline-like cartilage

   Disadvantages

   • Two-stage procedure

   • Expensive

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   Matrix-Induced Autologous Chondrocyte Implantation (MACI)

   Concept

   • Chondrocytes embedded in a collagen scaffold

   • Implanted arthroscopically

   Advantages

   • Less invasive than ACI

   • Improved cell distribution and support

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   Bone Marrow–Derived Cell Transplantation

   Steps

   • Harvest bone marrow

   • Concentrate cells

   • Load onto scaffold

   • Arthroscopic implantation

   • Cover with platelet-rich gel

   Advantages

   • Single-stage procedure

   • Cost-effective

   • Good clinical outcomes

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   Important Associated Factors

   Successful treatment requires addressing:

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   Ligament Stability

   • Instability must be corrected
      Failure leads to poor outcomes

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   Alignment

   • Malalignment adversely affects results

   Corrective Procedures

   • Fibular lengthening

   • Supramalleolar osteotomy

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   Arthritis

   • Presence and severity influence prognosis

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   Rehabilitation Protocol

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   Phase 1 (0–8 Weeks)

   • Non-weight bearing for 6 weeks

   • Begin:

     • Pool exercises

     • Cycling

   • Gradual partial weight bearing after 8 weeks

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   Phase 2 (16 Weeks Onwards)

   Assessment

   • Gait

   • Proprioception

   Progression

   • If normal — light running

   • If pain/swelling — continue physiotherapy

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   Return to Sports

   • Directional training: ~6 months

   • Full sports activity: ~8 months

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   Osteochondral Allograft (Large Lesions)

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   Indications

   • Massive talar dome defects

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   Advantages

   • Restores both:

     • Bone

     • Cartilage

   • No donor site morbidity

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   Disadvantages

   • High cost

   • Difficulty in graft matching

   • Risk of immune reaction

   • Prolonged rehabilitation

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   Types

   Partial Allograft

   • For localized talar dome lesions

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   Bipolar Allograft

   • Replaces both:

     • Tibial surface

     • Talar surface

   Indication

   • Severe ankle arthritis

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   Complications

   • Graft malposition

   • Failure due to early weight bearing

   • Recurrence of arthritis

   • Immunologic reaction

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   Postoperative Consideration

   • Often requires prolonged non-weight bearing (~6 months)

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   Key Takeaways

   • OLT incidence is increasing in young active patients

   • Treatment depends on:

     • Lesion size

     • Cartilage status

     • Depth

   • Subchondral bone is a key pain generator

   • Always correct:

     • Instability

     • Malalignment

   • Large lesions may require osteochondral allograft

   • Rehabilitation is prolonged and crucial for outcomes