Hjelle (2002) — Articular cartilage defects in 1,000 knee arthroscopies

Articular Cartilage Defects in 1,000 Knee Arthroscopies

Hjelle, Brittberg·Arthroscopy·2002·937 citations·Sports Medicine

This prospective study looked at 1,000 consecutive knee arthroscopies to measure how often articular cartilage defects occur. Each lesion was graded with the ICRS system, which classifies by measurable depth and area. The goal was to estimate how many patients would actually be candidates for cartilage repair surgery.

Study Snapshot

Design

Prospective cohort

Setting: Single hospital, Bergen, Norway

Objective

Whether articular cartilage defects are common in symptomatic knees and how many patients qualify for repair surgery

Outcome(s)

Prevalence and ICRS characteristics of chondral/osteochondral defects at arthroscopy

Subjects

1,000 consecutive knee arthroscopies

623Male
377Female

Inclusion

Consecutive symptomatic knee arthroscopies
Performed Jan 1997 to Nov 1999

Exclusion

Preplanned cartilage repair procedures excluded

Statistics

Descriptive statisticsMean and SD

Key Findings

Cartilage lesions of any type showed up in 61% of symptomatic knees, confirming these defects are common, not rare. But most were not the kind repair surgery targets.
Of the 606 lesions found, most were degenerative: osteoarthritis 44% and chondromalacia patellae 23%, with only 28% being focal chondral lesions. This matters because cartilage repair is generally not offered for OA or diffuse chondromalacia.
Focal chondral or osteochondral defects (the potentially repairable kind) were found in 19% of arthroscopies, and 80% of these were single lesions.
The medial femoral condyle was the dominant location at 58%, far ahead of patella (11%), lateral tibia (11%), lateral femoral condyle (9%), trochlea (6%), and medial tibia (5%).
By ICRS depth, most main focal defects were grade III (55%) — full-thickness but not into bone. Grade I was 14%, grade II 26%, and grade IV only 5%.
Focal defects rarely came alone: concomitant meniscal injury in 42% and ACL injury in 26%, with both present in 12%. Plan to address these at the same setting.
Applying strict repair criteria (single grade III/IV defect ≥1 cm² in a young patient) narrowed candidates to just 5.3% under 40, 6.1% under 45, and 7.1% under 50 of all arthroscopies.

Board PearlCartilage lesions appear in 61% of symptomatic knee arthroscopies, but only about 5-7% meet strict criteria for cartilage repair surgery.

Clinical Relevance

Cartilage lesions are common, but true repair candidates are not. This paper draws that line clearly: 61% of symptomatic knees have some lesion, yet only about 5% to 7% fit the classic profile for cartilage repair (a single grade III/IV focal defect at least 1 cm² in a young patient without OA).

When you find a focal defect, characterize it the way the ICRS system does: location, area in cm², and depth grade. Those are the parameters that actually drive whether debridement, microfracture, ACI, or mosaicplasty is on the table. Also expect company. Meniscal tears (42%) and ACL injuries (26%) frequently coexist, so a cartilage defect should trigger a full look at the meniscus and ligaments.

Remember the anatomy for boards: the medial femoral condyle is the most common site, and most focal defects are grade III full-thickness lesions.

Core

Articular Cartilage Defects in 1,000 Knee Arthroscopies

Articular Cartilage Defects in 1,000 Knee Arthroscopies

Study Snapshot

Key Findings

Clinical Relevance

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Articular Cartilage Defects in 1,000 Knee Arthroscopies

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