Caplan fracture
A Caplan fracture is a fracture-dislocation of the proximal interphalangeal (PIP) joint of a finger, specifically involving a volar plate avulsion fracture combined with dorsal subluxation/dislocation of the middle phalanx. It typically results from a hyperextension injury.
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Searching the Web
Caplan fracture PIP joint orthopedics classification treatment
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The library doesn't have a dedicated "Caplan fracture" entry - let me check the Rockwood & Green's section on PIP joint fractures directly, as it's the most authoritative source here.
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Now let me look at the specific PIP joint fracture-dislocation volar base treatment section:
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I now have comprehensive information from Rockwood & Green's to compile the full answer. Let me also quickly check if "Caplan" is specifically named in context of a fracture elsewhere (it may refer to something different from what I initially assumed - let me check the web search results more carefully).
Looking at the web search results, none of them directly mentioned "Caplan fracture" as a named entity - the results were about PIP fracture-dislocations generally. The library search showed "Caplan" only as author names (Dellinger EP, Caplan ES). Let me clarify - a "Caplan fracture" is actually not a standard eponym for a PIP injury. It may refer to:
- Caplan's syndrome - which is a pulmonary condition in rheumatoid arthritis
- Or a less commonly used eponym
Let me verify this quickly:
Searching the Web
"Caplan fracture" eponym orthopedics hand finger
Finding Sources
The Wikipedia list of eponymous fractures does not include "Caplan fracture," and the LITFL list also does not include it. The web search for "Caplan fracture" eponym in hand/orthopedics returned zero direct results. The library search for "Caplan" in a fracture context only returned author names (Caplan ES, Caplan LR) or Caplan syndrome (a pulmonary/RA condition).
This strongly suggests "Caplan fracture" is not a standard, widely recognized eponymous fracture in the orthopedic literature. Let me check one more possibility - it may refer to a specific fracture described by a "Caplan" in a niche context:
Searching the Web
"Caplan fracture" site:radiopaedia.org OR site:orthobullets.com OR site:wheelessonline.com
The search confirms there is no recognized eponymous "Caplan fracture" in orthopedic literature. The only well-known "Caplan" in medicine refers to Caplan syndrome (rheumatoid pneumoconiosis). It's possible the user may be thinking of a different eponym - perhaps "Kaplan" or confusing it with another similar-sounding fracture name. Let me provide a comprehensive, honest answer.
"Caplan Fracture" - Does It Exist?
"Caplan fracture" is not a recognized eponymous fracture in the orthopedic or hand surgery literature. A thorough search of Rockwood & Green's Fractures in Adults (10th ed, 2025), the Wikipedia list of eponymous fractures, Radiopaedia, Orthobullets, and PubMed finds no fracture named after "Caplan."
The only well-known medical entity with the Caplan name is:
Caplan Syndrome (rheumatoid pneumoconiosis)
- Combination of seropositive rheumatoid arthritis + pneumoconiosis (originally described in coal miners)
- Characterized by pulmonary nodules on CXR/CT in an RA patient with dust exposure
- Not a fracture at all
You May Be Thinking Of...
Here are some similar-sounding named fractures that are commonly tested and discussed:
| Eponym | What it is |
|---|---|
| Kaplan | "Kaplan approach" - surgical approach to the elbow (not a fracture) |
| Chauffeur's fracture | Intra-articular radial styloid fracture from forced ulnar deviation |
| Chance fracture | Horizontal vertebral body fracture from hyperflexion (seatbelt injury) |
| Bennett's fracture | Intra-articular fracture at base of 1st metacarpal with CMC subluxation |
| Rolando fracture | Comminuted intra-articular fracture at base of 1st metacarpal |
| Volar plate avulsion fracture | Avulsion of volar plate at PIP joint base with dorsal dislocation (no specific eponym but classically described) |
PIP Joint Volar Base Fracture-Dislocation (What You May Have Meant)
If you were asking about dorsal fracture-dislocation of the PIP joint (volar plate avulsion + dorsal subluxation of the middle phalanx), this is a well-described injury - just not named "Caplan." Per Rockwood & Green's:
Mechanism: Hyperextension of the PIP joint causes volar plate avulsion ± fracture of the volar lip of the middle phalanx base. With axial loading, larger fragments and joint impaction occur (pilon fracture).
Classification (volar base fractures):
- Stable: <30% articular surface involved; stable in extension
- Tenuous: 30-50% articular surface; stable in <30° of flexion
- Unstable: >50% articular surface, or requires >30° flexion to maintain reduction
Radiographic sign: The "V-sign" on lateral X-ray - divergence of the dorsal articular surfaces indicates dorsal subluxation of the middle phalanx.
Treatment:
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Stable (<30%): Early ROM, buddy taping
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Tenuous/reducible (<30° flexion): Dorsal extension-blocking splint; start at 30° block, increase 10°/week, discontinue at 4 weeks. >90° of flexion achieved in 88% of patients
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Unstable (>50%, or >30° flexion to hold reduction): Surgery - extension block pinning (K-wire), ORIF with volar plate arthroplasty, hemi-hamate arthroplasty, or dynamic external fixation
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Rockwood and Green's Fractures in Adults, 10th ed. (2025), pp. 1969-1985
Could you clarify where you encountered the term "Caplan fracture"? It's possible it is a regional term, a typo/mishearing of another eponym (e.g., "Kaplan", "Chance", "Chauffeur's"), or a very niche reference I have not encountered. I'd rather flag this uncertainty than give you inaccurate information.
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