This 2003 JBJS paper by Brittberg and Winalski presents the ICRS standardized framework for evaluating articular cartilage injuries and repair. It covers arthroscopic grading (ICRS 0–4), OCD classification (OCD I–IV), ICRS-recommended MRI protocols, repair tissue scoring, and endorsed clinical outcome instruments. The paper was written because no universally accepted system existed to describe lesion characteristics, repair tissue quality, or clinical outcomes for focal cartilage defect treatment.
Cartilage repair results were notoriously difficult to compare across studies before this paper because no agreed language existed to describe lesion depth, repair fill, or clinical outcome. The ICRS framework gave the field a common vocabulary and directly enabled meaningful comparison of ACI, microfracture, and osteochondral transfer outcomes.
When you scope a knee and find a cartilage lesion, probe every fissure carefully — a seemingly shallow lesion may extend to bone, changing the grade from ICRS 2 to ICRS 3 and fundamentally altering your treatment plan. ICRS-2 lesions (<50% depth) can be treated with debridement alone and carry a good prognosis. ICRS-3 lesions (>50% depth) require a biological restoration strategy: microfracture, osteochondral graft, or ACI.
When reviewing preoperative MRI, expect the defect to look smaller than it actually is. MRI underestimates lesion size when fragments remain in situ, and cannot distinguish ICRS 3a from 3b or 3c because the calcified cartilage and subchondral plate share similar signal. Use MRI for subchondral bone assessment and OCD stability (De Smet criteria); use arthroscopy with a graduated probe for definitive lesion sizing and grading.
This 2003 JBJS paper by Brittberg and Winalski presents the ICRS standardized framework for evaluating articular cartilage injuries and repair. It covers arthroscopic grading (ICRS 0–4), OCD classification (OCD I–IV), ICRS-recommended MRI protocols, repair tissue scoring, and endorsed clinical outcome instruments. The paper was written because no universally accepted system existed to describe lesion characteristics, repair tissue quality, or clinical outcomes for focal cartilage defect treatment.
Cartilage repair results were notoriously difficult to compare across studies before this paper because no agreed language existed to describe lesion depth, repair fill, or clinical outcome. The ICRS framework gave the field a common vocabulary and directly enabled meaningful comparison of ACI, microfracture, and osteochondral transfer outcomes.
When you scope a knee and find a cartilage lesion, probe every fissure carefully — a seemingly shallow lesion may extend to bone, changing the grade from ICRS 2 to ICRS 3 and fundamentally altering your treatment plan. ICRS-2 lesions (<50% depth) can be treated with debridement alone and carry a good prognosis. ICRS-3 lesions (>50% depth) require a biological restoration strategy: microfracture, osteochondral graft, or ACI.
When reviewing preoperative MRI, expect the defect to look smaller than it actually is. MRI underestimates lesion size when fragments remain in situ, and cannot distinguish ICRS 3a from 3b or 3c because the calcified cartilage and subchondral plate share similar signal. Use MRI for subchondral bone assessment and OCD stability (De Smet criteria); use arthroscopy with a graduated probe for definitive lesion sizing and grading.