| RHEUMATOID THUMB CLASSIFICATION | |||
| I | Boutonniere | IA | MP and IP passively correctable |
| IB | MP flexion contracture , IP correctable | ||
| IC | MP flexion and IP extension contractures | ||
| II | Combination I and III | IP hyperextension, MP flexion CMC subluxation or dislocation |
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| III | Swan | IIIA | Minimal CMC deformity, MP correctable |
| IIIB | CMC subluxation, MP correctable | ||
| IIIC | CMC dislocation, MP extension contracture | ||
| IV | Gamekeeper's | CMC adduction contracture MP abduction contracture |
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