April 11, 2024

Cartilage is a flexible connective tissue that is made up of chondrocytes and matrix components.

Histology of cartilage

Functions of cartilages

  1. To give support
  2. Withstand tension, torsion, and bending
Composition of cartilages
Composition of cartilages

Three types:

  • Hyaline cartilage
  • Elastic cartilage
  • Fibrous (Fibrocartilage)

Etiology of injury

  • Traumatic
  • Degenerative

See also: Osteochondritis dessicans

  • Localized cartilage lesion due to the unexplained localized poor blood supply
  • Most commonly: Lateral part of the medial femoral condyle


(Based on severity)

Outerbridge Classification

Classification of cartilage injury
Outerbridge staging
0Normal cartilage
1Softening and swelling
2Fragmentation and fissure in < 0.5 inch in diameter
3Fragmentation and fissure in > 0.5 inch in diameter
4Exposed subchondral bone

International Cartilage Repair Society

Normal Grade 0
Almost Normal Grade 1aSuperficial layer/ softening
Grade 1b1a and/or superficial cracks/fissures
AbnormalGrade 2Extends < 50%
Grade 3aExtends > 50%
Grade 3bExtends down to calcified layer
Severe Grade 3cExtends up to the surface of the subchondral bone (no penetration)
Grade 3dIncluding bulging of cartilages around the lesion
Very severeGrade 4aPenetration of subchondral bone but not across the entire diameter of the defect
Grade 4bPenetration across the full diameter of the defect
ICRS Classification

Bauer and Jackson’s classification


Treatment Options

Consider the following things before treatment:-

  • Size
  • Location
  • Depth
  • Associated Instability
  • Malalignment
  • Age
  • The activity level of patient
  • Partial-thickness/ Full thickness

Conservative treatment

Aims of conservative treatment are

  • Decreasing load on joint
  • Alter activities
  • Strength of the muscle across joint
  • Orthoses or braces are also beneficial
  • Analgesics and anti-inflammatory medication

Operative Treatment

If non-operative treatment fails

  • The choice depends upon the size of the lesion
  • Activity demands of patient

Partial thickness

Arthroscopic debridement: Minimal symptoms and small lesion (< 2 cm)=> Decrease inflammation/ mechanical irritation to joint

Full thickness

Four basic techniques:

  1. Stimulation of intrinsic healing potential: debridement with drilling, abrasion arthroplasty, and microfracture
  2. Alteration of load: Eg. Proximal tibial osteotomy
  3. Transfer of autologous tissue: Eg. Osteochondral autograft transplanted into a damaged area
  4. Transfer of allograft tissue
Lesion sizeOperative treatment
< 1cm Observation
Abrasion chondroplasty
Osteochondral autograft transfer
1 cm -2cmAbrasion chondroplasty
Osteochondral autograft transfer
2 cm- 3.5 cmFresh Osteochondral graft
Autologous chondrocyte implantation
3.5 cm – 10 cm or MultipleFresh Osteochondral graft
Autologous chondrocyte implantation
Summary of treatment as per size

See also: Autologous Chondrocytes Implantation

See also: The stem cell in orthopedics