**1.12.2 International Cartilage Repair Society (ICRS) classification**

This system classifies Hyaline cartilage lesion after debridement of loose bodies, and defines a lesion as a superficial, partial thickness, or full thickness defect (Brittberg and Winalski, 2003). The ICRS classification system focuses on the lesion depth (graded 0 to 4) and the area of damage (graded from normal to severely abnormal with use of the IKDC system) (www.cartilage.org).

Figure 5 shows the ICRS system. This classifies macroscopically normal cartilage without a notable defect as ICRS 0. If the cartilage has an intact surface but fibrillation and/or slight softening is present, it is classified as ICRS 1a, and if additional superficial lacerations and fissures are found, it is classified as ICRS 1b (nearly normal). Defects that extend deeper but involve less than 50 percent of the cartilage thickness are classified as ICRS 2 (abnormal). Lesions that extend to more than 50 percent of the cartilage thickness are classified as ICRS 3 (severely abnormal). However, there are four subgroups of this grade: 3a, 3b, 3c, and 3d depending on the involvement of a calcified layer. Joint trauma may create cartilage defect that extend into the subchondral bone. These full thickness osteochondral injuries are classified as ICRS 4 (severely abnormal). Excluded from this grade are defects that are classified as osteochondritis dissecans (OCD), which have a classification system of their own (Brittberg and Winalski, 2003).


Table 1. Outerbridge grading system

classifying chondral lesions throughout the body (Noyes et al, 1977). The accuracy and reproducibility of this classification system was addressed by Cameron et al, (2003) when they determined the intraobserver reliability, interobserver reproducibility and the accuracy of the system for grading chondral lesions in knees viewed arthroscopically. They compared the results obtained by using the system with observations at arthrotomy of six cadaveric donors. The accuracy rate ranged from 22 to 100 percent, with lower grade lesions diagnosed with less accuracy than higher-grade lesions (Cameron et al, 2003). The

This system classifies Hyaline cartilage lesion after debridement of loose bodies, and defines a lesion as a superficial, partial thickness, or full thickness defect (Brittberg and Winalski, 2003). The ICRS classification system focuses on the lesion depth (graded 0 to 4) and the area of damage (graded from normal to severely abnormal with use of the IKDC system)

Figure 5 shows the ICRS system. This classifies macroscopically normal cartilage without a notable defect as ICRS 0. If the cartilage has an intact surface but fibrillation and/or slight softening is present, it is classified as ICRS 1a, and if additional superficial lacerations and fissures are found, it is classified as ICRS 1b (nearly normal). Defects that extend deeper but involve less than 50 percent of the cartilage thickness are classified as ICRS 2 (abnormal). Lesions that extend to more than 50 percent of the cartilage thickness are classified as ICRS 3 (severely abnormal). However, there are four subgroups of this grade: 3a, 3b, 3c, and 3d depending on the involvement of a calcified layer. Joint trauma may create cartilage defect that extend into the subchondral bone. These full thickness osteochondral injuries are classified as ICRS 4 (severely abnormal). Excluded from this grade are defects that are classified as osteochondritis dissecans (OCD), which have a classification system of their

**Grade Surface description Lesion diameter** 

II Fragmentation and fissuring Less than half inch

III Fragmentation and fissuring More than half inch

I Softening and swelling None

IV Exposed subchondral bone None

Outerbridge grading system is given in table.1 and figure 4.

(www.cartilage.org).

own (Brittberg and Winalski, 2003).

Table 1. Outerbridge grading system

**1.12.2 International Cartilage Repair Society (ICRS) classification** 

Fig. 4. Outerbridge system for grading chondral defects (Kocheta and Tomes, 2004)

Traumatic Chondral Lesions of the Knee Diagnosis and Treatment 189

The clinical diagnosis of a chondral injury by history and physical examination can be

The initial symptoms of this injury are often obscure, and the immediate disability may be slight. The symptoms are very suggestive of a torn meniscus because of catching, locking, and giving way of the knee (Gilley, 1981; cited by Speer et al, 1991). An accurate diagnosis of traumatic articular cartilage injury is essential as individuals with these lesions have a poor prognosis for rapid recovery. Their mean rehabilitation time is almost triple that of a routine

Conventional radiographic techniques have proved to be of limited value in the imaging of articular cartilage as such techniques only allows the indirect assessment of cartilage (Lund, 1980; cited by Recht et al, 1993). Plain radiographs, in general, significantly underestimate the extent of cartilage damage (Blackburn et al, 1994). However, plain X-ray may reveal osteochondral lesions, including osteochondritis dissecans and loose bodies (Morelli et al,

Scintigraphy and computerized tomographic evaluations are limited because of their lack of sensitivity and requirement for ionizing radiation (Blackburn et al, 1994). Computed tomography combined with arthrography improves both the visualization of cartilage and the detection of abnormalities, but this method is relatively insensitive in the delineation of small cartilage lesions (Handelberg et al, 1990). Bone scans may indicate osteochondral injuries, but is not specific and does not necessarily indicate pure chondral lesions or their

The most accurate diagnostic modality for traumatic knee articular cartilage injury is arthroscopy (DeHaven, 1980). However, even with this "Gold Standard" modality the posterior tibial and femoral lesions can be difficult to identify and may be missed (Terry, 1988; cited by Speer 1991). Although arthroscopy treatment can be performed on a chondral fracture discovered unexpectedly, it would be advantageous to know before arthroscopy whether a chondral injury is present. The surgeon then could advise the patient before surgery about treatment options and expected outcome, and decide on the type and timing

The MR imaging appearance of chondral fractures is analogous to their arthroscopic appearance (Rubin et al, 1997). Chondral separations manifest as a defect in the articular surface extending down to the subchondral plate, with vertically oriented walls and sharp demarcation from the surrounding cartilage. When a flap is present a fragment will be seen, attached on one side (Rubin et al, 1997). Lesion conspicuity can be increased by performing MR arthrography, especially if the patient is examined some time after the acute insult (Rubin, 1998). The presence of a joint effusion could alleviate the need for iatrogenic introduction of intra-articular contrast agents. The theory is that this would offer an

**2. Diagnosis of articular surface damage** 

knee meniscal injury (Speer et al, 1991).

2002).

size (Morelli, et al. 2002).

of surgery (Rubin, 1998).

**2.3 Magnetic resonance imaging** 

**2.2 Arthroscopy** 

**2.1 Conventional radiographic technique** 

difficult, and may be a source of confusion (Speer et al, 1991).

Fig. 5. ICRS classification (www.cartilage.org)
