# Outerbridge — Outerbridge classification of articular cartilage lesions

> Grades one articular-cartilage lesion by direct visual and tactile morphology from softening through exposed subchondral bone. MRI use is an adaptation and must retain its modality and operational thresholds.

**Situação:** vigente · **Órgão:** Musculoesquelético · **Órgão emissor:** Outerbridge · **Versão:** 1961 original arthroscopic system; MRI adaptations must be labeled · **Ano:** 1961

## Procedência e vigência
- Família: léxico
- Tipo de lógica: flat
- Modalidade: Arthroscopy, MRI
- Fonte primária: Outerbridge RE. The etiology of chondromalacia patellae (1961) — https://pubmed.ncbi.nlm.nih.gov/14038135/
- Última verificação: 2026-07-24
- Última checagem: 2026-07-24

## Lógica de decisão
Retain the observation method. Apply the original diameter and bone-exposure boundaries only when supported, label MRI adaptations, and never turn this macroscopic grade into autonomous treatment or prognosis.

## Categorias

| Código | Rótulo | Critérios | Conduta | Risco | Localizador | Verificado |
| --- | --- | --- | --- | --- | --- | --- |
| 0 | Grade 0, normal intact cartilage | Conventional Grade 0: normal, intact articular cartilage at the named surface, without softening, swelling, fragmentation, fissuring, erosion or exposed subchondral bone. Grade 0 is the later conventional normal state; the original 1961 lesion grades were I-IV. | Document the inspected surface and assessment method. A Grade 0 surface requires no cartilage-lesion action from this scale, but it neither excludes another lesion elsewhere nor determines management of pain, instability, alignment, meniscal disease or another joint abnormality. | Grade 0 denotes no macroscopic lesion at the assessed surface, not a zero probability of symptoms, biochemical cartilage change or future degeneration. Outerbridge supplies no calibrated risk estimate for a normal-appearing surface. | Slattery and Kweon 2018, PMC6259817, Description and Fig. 1 define the conventional Grade 0 as normal cartilage; History explains that the original system was based on direct visualization and later expanded beyond the patella. | ✓ |
| I | Grade I, softening and swelling | Grade I: articular cartilage softening and swelling without the fragmentation or fissuring of Grade II and without subchondral-bone exposure. In the original macroscopic method, confident recognition commonly requires tactile feedback with a probe even when the surface looks intact. | Report the exact surface, extent and whether softening was directly probed. Grade I alone does not prescribe observation, chondroplasty or cartilage repair; management depends on symptoms and the lesion, patient and whole-joint context. | This is the earliest macroscopic lesion grade, but the classification does not assign a probability of pain, progression or treatment failure. MRI signal change cannot reproduce tactile softening and should be labeled as a modified-MRI assessment with limited confidence. | Slattery and Kweon 2018, PMC6259817, Description defines Grade I as softening and swelling and explains the need for tactile probe feedback; Limitations highlights difficulty and variable reliability for this grade and states that the system does not provide treatment guidance or clear prognosis. | ✓ |
| II | Grade II, partial-thickness fissuring not greater than 0.5 inch | Grade II: a partial-thickness cartilage defect with fragmentation or fissuring whose maximum surface diameter does not exceed 0.5 inch, approximately 12.7 mm, and which does not reach or expose subchondral bone. Preserve the measured diameter instead of rounding to force the threshold. | State location, maximum diameter, estimated area, depth, stability and associated joint findings. The Grade II label is descriptive and cannot by itself select debridement, marrow stimulation, grafting or rehabilitation. | Grade II is more extensive than softening alone but is not a validated patient-specific prognostic stratum. The II-III diameter boundary has limited reader reliability, so a near-threshold lesion should retain the measurement and adjacent-grade uncertainty. | Slattery and Kweon 2018, PMC6259817, Description defines the partial-thickness Grade II lesion and the 0.5-inch limit; Validation and Limitations discuss reader variability and difficulty separating Grades II and III by lesion size. | ✓ |
| III | Grade III, deep fissuring greater than 0.5 inch without bone exposure | Grade III: deep cartilage fragmentation or fissuring greater than 0.5 inch, approximately 12.7 mm, in maximum surface diameter, extending down toward subchondral bone but without unequivocal bone exposure. Bone exposure changes the grade to IV regardless of diameter. | Map the full lesion and any unstable flap, delamination or opposing lesion, then integrate symptoms, containment, subchondral bone, alignment, meniscus, age and activity in specialist planning. Grade III alone does not mandate a named procedure. | Some cohorts associate Grade III-IV lesions with worse outcomes after specific meniscal, hip or shoulder arthroscopic procedures, but those are context-dependent associations. Outerbridge provides no universal per-grade probability of progression, pain or failed treatment. | Slattery and Kweon 2018, PMC6259817, Description defines Grade III by fissuring over 0.5 inch extending down to subchondral bone; Validation summarizes procedure-specific outcome associations; Limitations rejects a clear prognostic or treatment rule. | ✓ |
| IV | Grade IV, exposed subchondral bone | Grade IV: full-thickness erosion of articular cartilage with exposed underlying subchondral bone. Exposure of bone is the defining feature and overrides the Grade II-III diameter boundary; record the size of the exposed component separately. | Report the exposed-bone area, lesion containment, location, opposing surface, reactive bone change and whole-joint mechanics. The severe morphology is clinically important, but the code alone cannot determine cartilage restoration, osteotomy, arthroplasty or conservative care. | Grade IV is the maximum macroscopic grade and procedure-specific cohorts group Grade III-IV with worse outcomes, yet the scale is not a calibrated prognosis. Symptoms and outcome depend on lesion extent, site, bone, alignment, meniscus, patient factors and selected treatment. | Slattery and Kweon 2018, PMC6259817, Description defines Grade IV by erosion exposing subchondral bone; Validation and Limitations describe limited prognostic associations, variable reliability and the absence of grade-directed treatment guidance. | ✓ |

### Citações por categoria
- **0**: Slattery C, Kweon CY. Classifications in Brief: Outerbridge Classification of Chondral Lesions (2018) — https://pmc.ncbi.nlm.nih.gov/articles/PMC6259817/ · Slattery and Kweon 2018, PMC6259817, Description and Fig. 1 define the conventional Grade 0 as normal cartilage; History explains that the original system was based on direct visualization and later expanded beyond the patella.
- **I**: Slattery C, Kweon CY. Classifications in Brief: Outerbridge Classification of Chondral Lesions (2018) — https://pmc.ncbi.nlm.nih.gov/articles/PMC6259817/ · Slattery and Kweon 2018, PMC6259817, Description defines Grade I as softening and swelling and explains the need for tactile probe feedback; Limitations highlights difficulty and variable reliability for this grade and states that the system does not provide treatment guidance or clear prognosis.
- **II**: Slattery C, Kweon CY. Classifications in Brief: Outerbridge Classification of Chondral Lesions (2018) — https://pmc.ncbi.nlm.nih.gov/articles/PMC6259817/ · Slattery and Kweon 2018, PMC6259817, Description defines the partial-thickness Grade II lesion and the 0.5-inch limit; Validation and Limitations discuss reader variability and difficulty separating Grades II and III by lesion size.
- **III**: Slattery C, Kweon CY. Classifications in Brief: Outerbridge Classification of Chondral Lesions (2018) — https://pmc.ncbi.nlm.nih.gov/articles/PMC6259817/ · Slattery and Kweon 2018, PMC6259817, Description defines Grade III by fissuring over 0.5 inch extending down to subchondral bone; Validation summarizes procedure-specific outcome associations; Limitations rejects a clear prognostic or treatment rule.
- **IV**: Slattery C, Kweon CY. Classifications in Brief: Outerbridge Classification of Chondral Lesions (2018) — https://pmc.ncbi.nlm.nih.gov/articles/PMC6259817/ · Slattery and Kweon 2018, PMC6259817, Description defines Grade IV by erosion exposing subchondral bone; Validation and Limitations describe limited prognostic associations, variable reliability and the absence of grade-directed treatment guidance.

## Histórico de versões

| Data | Evento | Detalhe | Situação |
| --- | --- | --- | --- |
| 1998-09-01 | revised | A prospective MRI-to-arthroscopy study operationalized a five-point Outerbridge assessment on specialized knee MRI; MRI use remains an adaptation of the macroscopic system. | confirmed |
| 1961-11-01 | published | Outerbridge published the original direct-visualization grading framework for chondromalacia patellae. | confirmed |


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> Conteúdo de referência reescrito. Confira a publicação primária vigente. Não é dispositivo médico nem substitui o julgamento clínico. O radiologista responsável pelo laudo permanece o autor e o responsável.

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