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.

The Debridement Procedure in Defects Grade 3 and 4

After adequate exposure is obtained, the defect must be thoroughly debrided of all unhealthy cartilage surrounding the lesion. This includes all fissures and undermined cartilage, in addition to any fibrocartilage present in the base of the defect (Fig. 3-6).

FIGURE 3-6 A cartilage lesion with loose flaps and central part down to bone on a medial femoral condyle. How much to excise as part of the debridement is outlined.

The zone of damaged cartilage surrounding the chondral defect needs to be fully excised, and if you perform open surgery use a fresh scalpel blade, cutting vertically through the cartilage down to the level of, but not into, the subchondral bone (Fig. 3-7). A ring curette or a raspatorium can be used to remove the damaged cartilage or any fibrocartilage in the base of the defect.

FIGURE 3-7 The defect in Figure 3-6 has been debrided.

When arthroscopic debridement is done, a raspatorium or ring curette is used.

Vertical walls are formed with the raspatorium. A full radius shaver can be used after vertical walls have been formed. The shaver is used from the central part of the defect and conducted with sweeping movements, cleaning the defect toward the periphery (Figs. 3-8, A-B and 3-9, A-B).

FIGURE 3-8 A, A ring curette or a raspatorium can be used to remove the damaged cartilage or any fibrocartilage in the base of the defect. B, Walls should be made as vertical as possible.

FIGURE 3-9 A, A shaver can be used after vertical walls have been formed. B, The shaver is used from the central part of the defect and conducted with sweeping movements, cleaning the defect toward the periphery.

Internal osteophytes in the subchondral bone can be the result of penetration of the subchondral bone either from injury or from prior surgical procedures, such as drilling, abrasion, or microfracture. These bony prominences, if small, can be addressed by gently tapping them back into the subchondral bone plate with a smooth, noncorrugated bone tamp.

Thermal debridement is also possible.³ Electrocautery, laser, and radiofrequency energy devices can be used. However, earlier it was shown that these devices cause greater chondrocyte death compared to mechanical debridement and shaver use.⁴ Recent publications show that the new radiofrequency devices now reach similar results regarding cell death as mechanical debridement:⁵

Instruments for Debridement

FIGURE 3-10 A typical debridement and cartilage repair instrument set.

From top, scalpel, Wiberg raspatorium, curved curette, ring curette, arthroscopic meniscal rasp, cartilage harvester, and angled wall debrider.

Pearls and Pitfalls

Radical excision is crucial. All flaps and fissures must be excised. The most common error is not to be radical enough (Fig. 3-11).

FIGURE 3-11 A radically debrided defect with a clean bare bone surface.

Start with a raspatorium or ring curette. A shaver can be used from a central position first when the defect has been debrided to vertical walls.

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 the subchondral bone plate. Debridement of unstable edges (as is suggested for ICRS-2 lesions) is suitable also for ICRS-3 lesions, but further treatment is recommended for these more extensive lesions.