Introduction

Cartilage lesions could be either traumatic or nontramatic. Common for all lesions are that they are irregular and need to be cleaned for a secure repair possibility, irrespective of which type of repair is to be used (Fig. 3-1):

• In the literature, the deep to bare-bone lesions seem troublesome. Lesions that extend through >50% of the cartilage thickness are classified as ICRS 3^1,2 (Figs. 3-3 and 3-4).

FIGURE 3-1 An irregular defect to be debrided. The defect has been treated before with bone marrow stimulation.

FIGURE 3-2 The ICRS cartilage defect classification.

FIGURE 3-3 ICRS Grade 2.

FIGURE 3-4 ICRS Grade 3 a-d.

There are four subgroups of this grade:

• Deep defects that extend through >50% of the cartilage depth but not to the calcified layer are classified as ICRS 3a.^1,2

• Deep defects that extend through >50% of the cartilage down to the calcified layer are classified as ICRS 3b.^1,2

• Defects that extend down to but not through the subchondral bone plate are classified as ICRS 3c.

• Finally, blisters are classified as ICRS 3d.^1,2

All of the lesions in category ICRS 3 are simply defined as defects that extend through >50% of the cartilage thickness, through the cartilage but not through subchondral bone plate.

While debridement of unstable edges (as is suggested for ICRS-2 lesions) is suitable for ICRS-3 lesions, further treatment is recommended for these more extensive lesions.

Joint trauma may create cartilage defects that extend into the subchondral bone. These full-thickness osteochondral injuries are classified as ICRS 4^1,2 (Fig. 3-5). ICRS-4 lesions can be treated in the same manner as described for ICRS-3 lesions, but a lesion with extensive cavitations into the bone may require bone-grafting.

FIGURE 3-5 ICRS Grade 4.