Is arthroscopic knee surgery feasible in an otherwise healthy 11‑year‑old with a focal cartilage defect?

Arthroscopic Knee Surgery for Cartilage Defects in an 11-Year-Old

Yes, arthroscopic knee surgery is feasible and appropriate for an 11-year-old with a focal cartilage defect, particularly for sports-related cartilage injuries, meniscal tears, or unstable osteochondritis dissecans lesions that have failed conservative management. 1

Guideline Support for Pediatric Knee Arthroscopy

The American Academy of Pediatrics explicitly recommends referral to pediatric orthopedic surgeons for children and adolescents with sports injuries including cartilage injuries, establishing that surgical intervention is within the standard of care for this age group 1. An 11-year-old falls squarely within the "child" category (2-12 years) where these guidelines apply 1.

Specific Indications Based on Cartilage Defect Type

For Osteochondritis Dissecans (OCD)

• Symptomatic skeletally immature patients with salvageable unstable or displaced OCD lesions should be offered surgical intervention as consensus opinion from the American Academy of Orthopaedic Surgeons 1
• Arthroscopic drilling is an option for symptomatic patients with stable lesions who have failed ≥3 months of conservative treatment 1
• MRI is recommended to characterize the OCD lesion and assess for concomitant pathology (meniscal tears, ACL injury) 1

For Focal Cartilage Defects

• Children and adolescents have greater regenerative capacity for articular cartilage compared to adults, making them particularly good candidates for cartilage repair procedures 2
• Arthroscopic techniques traditionally performed in adults can be safely performed in children with appropriate modifications for joint size 2
• No differences in complication rates have been reported in pediatric patients compared to adults 2

Treatment Algorithm by Defect Characteristics

Small Defects (<2 cm²)

• Microfracture is the first-line arthroscopic treatment for contained, full-thickness defects 3, 4
• Technique involves debridement of friable cartilage, creating perpendicular edges of healthy cartilage, and making 3-4mm deep holes spaced 3-4mm apart in subchondral bone 3
• Results show 93% fill rate with good-quality cartilage at second-look arthroscopy 3

Medium Defects (2-6 cm²)

• Microfracture remains appropriate for acetabular lesions 5
• Mosaicplasty (osteochondral autograft) is indicated for patients <45 years with focal full-thickness lesions <3 cm² 1, 3

Large Defects (>2.5 cm²)

• Autologous chondrocyte implantation (ACI) has particularly good biological potential in children and adolescents, especially for large-diameter defects 2
• Osteochondral allograft transplantation is appropriate for patients ≤50 years with substantial subchondral bone loss 3

Critical Considerations for Pediatric Patients

Skeletal Maturity Assessment

• The distinction between skeletally immature and mature patients fundamentally changes treatment algorithms 1
• Skeletally immature patients with symptomatic lesions warrant more aggressive surgical consideration due to growth potential 1

Concomitant Pathology

• 42% of patients with focal cartilage defects have concomitant meniscal injury and 26% have ACL injury 6
• Arthroscopy allows simultaneous treatment of multiple pathologies 1
• MRI should be obtained when concomitant pathology is suspected 1

Common Pitfalls to Avoid

Diagnostic Accuracy

• Arthroscopy significantly overestimates cartilage defect size compared to open evaluation (mean 5.69 cm² arthroscopic vs 4.54 cm² open), particularly for smaller defects and less experienced surgeons 7
• However, arthroscopic grading using ICRS classification is reliable with 80.9% consensus with open grading 7

Conservative Management Failures

• For OCD lesions, document at least 3 months of failed conservative treatment before proceeding to arthroscopic drilling 1
• Conservative treatment serves primarily as a temporizing measure and does not address underlying cartilage defects 5

Subchondral Bone Considerations

• Particular attention must be given to subchondral bone, which is frequently affected in children and adolescents 2
• Intact subchondral bone is required for microfracture success 4

Contraindications to Consider

• Bipolar lesions (kissing lesions) are contraindications to joint-preserving surgery 3
• Inflammatory arthritis excludes patients from cartilage repair procedures 3
• Significant osteoarthritis (though rare at age 11) would alter the treatment approach 3