Osteochondritis Dissecans of the Knee

Courtesy: Prof Michael Hantes, ESSKA 1st Vice President

Lecture Topic: Osteochondritis Dissecans of the Knee

• Aim: Define the treatment algorithm for this disease.

• Overview:

  • Pediatric disease affecting the subchondral bone.

  • If it progresses, it may lead to instability and cartilage disruption, potentially causing premature osteoarthritis.

  • Can occur in elbow, knee, hip, but most commonly affects the knee.

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Location of Lesions in the Knee

• Most common site: Medial femoral condyle (75-80%), close to the notch.

• Other locations:

  • Lateral femoral condyle (15%).

  • Patella (5-10%).

  • Tibia (<1%) (very rare).

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Clinical Presentation & Diagnosis

• Symptoms:

  • Knee pain after prolonged activity.

  • Crepitus, catching, or locking (if loose body is present).

  • Swelling in some cases.

  • No pathognomonic signs for diagnosis.

• Physical Examination:

  • Limp, alignment, joint palpation, range of motion, joint effusion.

  • Wilson’s test (low sensitivity, not widely used).

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Imaging & Classification

• X-rays:

  • Can show osteochondral lesions or loose body fragments.

• MRI (Highly Recommended):

  • Most informative tool (90% sensitivity, nearly 100% specificity).

  • Helps determine size, stability, and prognosis.

• MRI-Based Hefti Classification:

  • Determines whether a lesion is stable or unstable.

  • Stable: Small signal changes, no fluid between fragment and bone.

  • Unstable: Fluid completely surrounding fragment, partially/completely detached fragment.

• Arthroscopic Classifications:

  • Guhl Classification:

    • Stage 1: Softened cartilage, intact surface.

    • Stage 2: Early separation without detachment.

    • Stage 3: Partially detached lesion.

    • Stage 4: Loose body or cartilage defect.

  • ROCK Study Group Classification:

    • Stable lesions: “Cue ball” & “Shadow”.

    • Unstable lesions: “Wrinkle in the rug,” “Locked door,” “Trapdoor,” “Crater.”

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Natural History & Prognosis

• Lesions can heal or worsen spontaneously.

• Prognostic Factors:

  • Younger age = better prognosis.

  • Smaller lesions = better healing potential.

  • Stable lesions heal better than unstable ones.

• Treatment depends on:

  • Age, lesion size, symptoms, and patient expectations.

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Non-Operative Treatment (Conservative Management)

• Recommended for young patients (?13 years old) with stable, small lesions and mild symptoms.

• Treatment approach:

  • Activity modification for 3-6 months.

  • Avoidance of high-impact sports.

  • X-ray/MRI follow-up every 3-6 months.

  • Immobilizers not recommended (healing is independent of bracing).

• Success Rate:

  • Some cases heal completely in 6 months.

  • Others progress, requiring surgical intervention.

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Surgical Treatment (When Required)

• Indicated for:

  • Unstable lesions on MRI.

  • Mechanical symptoms (clicking, locking, swelling).

  • Failure of conservative management.

• Goals:

  • Maintain joint congruity.

  • Fix unstable fragments.

  • Address the subchondral bone to promote healing.

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Surgical Techniques

1. Drilling (Stimulation of Healing):

   • Antegrade (Transarticular):

     • Simple, direct access.

     • Violates cartilage, which may not be ideal.

   • Retrograde (Through Bone, Avoids Cartilage Violation):

     • More technically demanding.

     • Requires fluoroscopy guidance.

     • Avoids growth plate damage in young patients.

2. Fixation (For Partially Detached Lesions):

   • Metal Screws:

     • Effective but require removal later.

   • Bioabsorbable Pins/Screws:

     • Preferred choice (no need for removal).

     • High success rate (80-95%).

   • Example Procedure:

     • Retrograde drilling using an ACL guide.

     • Placement of 3-4 bioabsorbable pins for fixation.

3. Other Options for Large, Detached Lesions:

   • Mosaicplasty (Osteochondral Autograft Transplantation – OATS).

   • Bone grafting (if necessary).

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Surgical Outcomes & Literature Review

• Healing Rate:

  • 90-95% success with retrograde drilling and fixation.

  • Average healing time: 3-4 months (can range from 6 weeks to 2 years).

• Clinical Study Findings:

  • 40 patients treated with bioabsorbable pins.

  • Healing observed in 90% of cases.

  • No major complications or need for secondary surgery.

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Conclusion

• Key Takeaways:

  • Early diagnosis and MRI evaluation are crucial.

  • Stable lesions can often heal with conservative management.

  • Unstable lesions require surgery, with drilling and fixation being highly successful.

  • Bioabsorbable fixation offers excellent outcomes without the need for screw removal.

• Final Message: Proper patient selection and treatment algorithm lead to optimal outcomes in osteochondritis dissecans of the knee.

Osteochondritis Dissecans of the Knee – Surgical Techniques & Management Algorithm

Considerations for Surgical Techniques

• Each technique has advantages and limitations.

• Factors to consider:

  • Cost of the procedure.

  • One-step vs. two-step procedure.

  • Patient history and literature-based outcomes.

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Alternative Surgical Options

Microfracture Technique

• Previously suggested for these types of lesions.

• Rarely used today due to poor long-term outcomes.

Fresh Osteochondral Graft

• Potential option if available in certain countries.

• Challenges:

  • Limited availability in most countries.

  • Lower success rate based on literature.

  • Risk of chondrocyte loss in long-term follow-ups.

  • High rate of reoperation in patients who undergo this method.

Mosaicplasty (Osteochondral Autograft Transfer – OATS)

• Highly effective for smaller defects (<3-4 cm²).

• Limitations:

  • Donor site morbidity can be a concern for larger defects.

Autologous Chondrocyte Implantation (ACI)

• Considered one of the best options.

• Limitations:

  • Expensive.

  • Two-stage procedure.

  • Not available in all countries.

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Newly Developed Treatment Approach

Impaction Bone Grafting with Autologous Matrix-Induced Membrane

• Developed as an alternative to overcome limitations of other techniques.

• Procedure Steps:

  1. Identify the lesion and debride the area.

  2. Microfracture the bony bed to promote healing.

  3. Harvest bone graft from the medial or lateral femoral condyle.

  4. Impact the bone graft into the defect.

  5. Place a hyaline-based membrane over the defect.

  6. Stabilize the membrane with fibrin glue.

• Key Advantages:

  • Overcomes fresh osteochondral allograft limitations.

  • Reduces concerns related to tissue availability, size matching, and cost.

  • No severe complications reported.

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Surgical Procedure Breakdown

• Pre-Operative Case Example:

  • 27-year-old patient with unstable osteochondral lesions.

  • Two osteochondral fragments removed.

• Arthroscopic Debridement:

  • Borders of the lesion are clearly defined.

  • Microfracture performed after ensuring a bleeding bone bed.

• Bone Graft Harvesting:

  • Harvested from the medial or lateral femoral condyle.

  • Defect is prepared and filled with impacted bone graft.

• Membrane Placement & Fixation:

  • Membrane cut to defect size using a template.

  • Fibrin glue applied to secure it in place.

  • Ensured that scaffold remains slightly lower than the cartilage surface.

• Final Steps:

  • Joint movements checked before finalizing the procedure.

  • Ensured the membrane stays in position as fibrin glue reaction completes.

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Clinical Outcomes & Literature Review

• Study Data:

  • 25 patients with a mean follow-up of 4 years.

  • Significant improvement in clinical scores pre-op vs. post-op.

• MRI Findings:

  • Most cases showed healed subchondral bone and cartilage restoration.

  • MOAKS MRI scoring system used for assessment:

    • Higher MOAKS scores correlated with better clinical outcomes.

    • Despite moderate MOAKS scores, patients experienced significant clinical improvements.

• Publication Reference:

  • Full details of the technique and study published in the “Chesta” journal.

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Management Algorithm for Osteochondritis Dissecans

• Treatment depends on:

  • Stage of the disease.

  • Patient age.

  • Activity level.

  • Available surgical options.

• Recommended Approach:

  • Arthroscopic drilling and internal fixation for Stage 2 and 3 lesions.

  • Bone grafting with impaction and autologous matrix-induced chondrogenesis for larger defects.

• Comparison with Other Techniques:

  • Mosaicplasty & Autologous Chondrocyte Implantation (ACI) are valid options, but cost and donor-site concerns must be considered.

  • The new impaction bone grafting technique is time- and cost-effective with promising results.

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Upcoming Events & Professional Membership Information

• Upcoming ESSKA Congress:

  • Dates: May 20-22, 2026.

  • Location: Prague, Czech Republic.

  • Looking forward to welcoming participants!

• Becoming an ESSKA Member:

  • Open to surgeons worldwide, not just in Europe.

  • One-third of members are from outside Europe.

  • Visit the ESSKA website to apply.

• European Certification Program:

  • Certifies surgeons in ACL, shoulder arthroscopy, patellofemoral instability, and other specialties.

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Closing Remarks

• Thank you to Professor Gopalan for the invitation.

• Thank you to all participants for their attention!