What are the treatment options for a full thickness cartilage defect?

Treatment Options for Full Thickness Cartilage Defects

The treatment of full thickness cartilage defects should be based on lesion size, location, and patient factors, with microfracture recommended for smaller defects (<2 cm²) and osteochondral allograft transplantation for medium-sized defects (2-6 cm²). 1

Treatment Algorithm Based on Lesion Size

For Femoral Head Lesions:

• <2 cm² defects:

  • First-line: Microfracture 1
  • Second-line: Mosaicplasty or osteochondral allograft transplant (single plug) 1

• 2-6 cm² defects:

  • First-line: Osteochondral allograft 1
  • Second-line: Osteochondral transplantation 1
  • For lesions not identified preoperatively: Microfracture 1

• 6-8 cm² defects:

  • Total hip arthroplasty 1

• >8 cm² defects:

  • Total hip arthroplasty 1

For Acetabular Lesions:

• <2 cm² defects: Microfracture 1
• 2-6 cm² defects: Microfracture 1
• >6 cm² defects:
  • Microfracture 1
  • For delaminated chondral flap with viable cartilage: Suture repair 1
  • Consider conversion to total hip arthroplasty for extensive damage 1

Detailed Treatment Options

1. Microfracture

• Mechanism: Creates small holes in subchondral bone to release marrow cells and growth factors that form fibrocartilage to fill the defect 1
• Technique:
  • Debride friable cartilage parts with a shaver
  • Create a well-contained lesion with perpendicular edges of healthy cartilage
  • Use an awl to make 3-4 mm deep holes spaced 3-4 mm apart 1
• Outcomes:
  • Studies show 93% fill rate with good-quality cartilage macroscopically at second-look arthroscopy 1
  • Patients treated with microfracture for smaller lesions (<3 cm²) showed substantially higher Nonarthritic Hip Scores compared to those treated with chondroplasty alone 1
• Limitations:
  • Creates fibrocartilage rather than hyaline cartilage
  • May have limited durability 2
  • Risk of intralesional bone formation and elevation of the subchondral bone plate 2

2. Mosaicplasty (Autologous Osteochondral Transplantation)

• Mechanism: Uses autologous osteochondral cylindrical grafts to fill chondral defects 1
• Indications: Patient age <45 years, no signs of osteoarthritis, focal full-thickness lesion <3 cm² 1
• Technique:
  • Measure and prepare the defect area
  • Create drill holes penetrating subchondral bone
  • Harvest osteochondral graft from lateral trochlea and implant into prepared holes 1
• Advantages:
  • One-step procedure (unlike ACI which requires two procedures)
  • Provides hyaline cartilage with superior mechanical properties
  • Allows immediate or near-immediate weight bearing 1
• Limitations:
  • Harvest site morbidity
  • Potential degeneration of surrounding cartilage
  • Risk of necrosis of transplanted cylinders
  • Lack of integration with surrounding cartilage 2

3. Osteochondral Allograft Transplantation (OAT)

• Mechanism: Uses cadaveric donor tissue to replace damaged cartilage and bone 1
• Indications: Patient age ≤50 years, no evidence of osteoarthritis, defect >2.5 cm² or substantial subchondral bone loss 1
• Technique:
  • Debride friable edges to obtain healthy, stable cartilage
  • Drill lesion to accept allograft
  • Insert size-matched allograft in press-fit manner 1
• Advantages:
  • Eliminates donor site morbidity
  • Immediately provides functioning joint surface
  • Suitable for larger lesions
  • Provides hyaline cartilage replacement 1
• Limitations:
  • Risk of disease transmission
  • Limited donor tissue availability
  • Complex graft handling and procurement
  • Reduced graft viability after 28 days of storage 1

4. Autologous Chondrocyte Implantation (ACI)

• Mechanism: Cultured autologous chondrocytes are implanted under a periosteal or synthetic patch 1, 3
• Results: Studies show good-to-excellent results in 14 of 16 patients with femoral condylar transplants after two years 3
• Limitations:
  • Two-stage procedure
  • Longer rehabilitation period
  • Risk of hypertrophic regenerative cartilage
  • Potential delamination and insufficient cartilage regeneration 2

Patient Selection Criteria

For joint-preserving management, patients should meet the following criteria:

• Age ranging from skeletal maturity to 50 years
• Minimal (Tonnis grade ≤1) or no sign of osteoarthritis on radiography
• No inflammatory arthritis
• One or more full-thickness defects, but no bipolar lesions
• Well-contained lesion
• Ability to perform rigorous postoperative physical therapy regimen 1

Common Pitfalls and Considerations

• Classification is crucial: Use established systems like Outerbridge, Beck, or ALAD to properly assess defect severity 1, 4
• Long-term monitoring: Essential as chondromalacia may progress to osteoarthritis if not properly managed 4
• Rehabilitation: Critical component of successful outcomes regardless of surgical technique 5
• Stem cell therapy: Not currently recommended by the American College of Rheumatology/Arthritis Foundation due to heterogeneity and lack of standardization 4
• Limited evidence: Most studies are small case series or case reports with no long-term data or control groups, making comparison of treatment modalities difficult 1