Acute traumatic boutonniere deformity results from disruption of the central slip of the extensor tendon at the proximal interphalangeal (PIP) joint, causing the classic triad of PIP joint flexion and DIP joint hyperextension due to volar subluxation of the lateral bands. [1-2] This is a commonly missed injury in the ED, frequently dismissed as a "jammed finger," and delayed diagnosis significantly worsens outcomes. [3-4]
1. History
- Mechanism: Direct blow, forced flexion of an extended PIP joint, volar PIP dislocation, or laceration over the dorsal PIP joint [1][3]
- Common in ball-handling sports (basketball, football, volleyball) — "jammed finger" [3][5]
- Ask about hand dominance, occupation, and functional demands
- Timing of injury — treatment initiated within 6 weeks of injury is associated with the greatest improvement in ROM [4]
- Open vs. closed injury (laceration over dorsal PIP = open central slip injury until proven otherwise)
- Prior finger injuries, rheumatologic history
2. Alarm Features
- Open wound over dorsal PIP joint — assume central slip laceration; requires surgical exploration [6-7]
- Inability to actively extend PIP joint against resistance (positive Elson test) [1]
- Associated fracture or joint subluxation on radiograph
- Vascular compromise or signs of compartment syndrome (rare, multi-digit crush)
- Progressive deformity developing days after initial "jammed finger" — suggests missed central slip injury [3]
3. Medications
- Acute pain management: NSAIDs (ibuprofen 400–600 mg PO q6–8h, naproxen 500 mg PO BID) as first-line; acetaminophen as adjunct
- Avoid opioids unless severe associated injury
- Digital nerve block (1% lidocaine without epinephrine, or with epinephrine per WALANT principles) for reduction or splint application [8]
- No role for corticosteroid injection in acute traumatic boutonniere (unlike rheumatoid boutonniere) [9]
4. Diet
- No specific dietary considerations for acute traumatic boutonniere deformity
- Adequate protein and vitamin C intake support tendon healing
- Smoking cessation counseling — nicotine impairs tendon healing
5. Review of Systems
- Hand/wrist: other finger injuries, grip weakness, numbness/tingling (concurrent nerve injury)
- MSK: joint stiffness, swelling in other joints (screen for inflammatory arthritis if bilateral or atraumatic) [10]
- Constitutional: fever, weight loss (if concern for infectious or inflammatory etiology)
- Skin: wounds, lacerations, nail bed injuries
6. Collateral History and Family History
- Witnesses to mechanism (especially in sports injuries or workplace accidents)
- Family history of rheumatoid arthritis or connective tissue disorders — boutonniere deformity occurs in ~50% of RA patients, but treatment differs significantly from traumatic cases [1][10]
- Occupational demands (manual labor, musician, athlete) — impacts treatment urgency and approach
7. Risk Factors
- Athletes — particularly ball sports (basketball, football, volleyball) [3][5]
- Manual laborers
- Prior PIP joint injury or dislocation [6]
- Rheumatoid arthritis (chronic synovitis predisposes, but this is a different pathology) [10]
- Age >40 years associated with worse prognosis after central slip repair [11]
8. Differential Diagnosis
- Pseudoboutonniere deformity — volar plate injury causing PIP flexion contracture with mild DIP hyperextension; distinguished by mechanism (hyperextension injury) and tenderness volar rather than dorsal at PIP [3]
- PIP joint dislocation (dorsal or volar) without central slip disruption [6]
- PIP fracture-dislocation — avulsion fracture at central slip insertion
- Mallet finger — zone I extensor injury at DIP (DIP droop, no PIP involvement)
- Sagittal band rupture — MCP joint extensor subluxation, not PIP deformity [5]
- Swan neck deformity — opposite pattern (PIP hyperextension, DIP flexion) [1-2]
- Collateral ligament injury — lateral instability without flexion/extension imbalance
Key distinguishing feature: In true boutonniere, tenderness is dorsal over the central slip; in pseudoboutonniere, tenderness is volar over the volar plate. [3]
9. Past Medical History
- Prior finger/hand injuries or surgeries
- Rheumatoid arthritis or other inflammatory arthropathies [10]
- Dupuytren disease
- Diabetes (impairs healing)
- Bleeding disorders or anticoagulant use (relevant for surgical planning)
10. Physical Exam
- Inspection: Swelling over dorsal PIP, posture of PIP flexion with DIP hyperextension (may not be present acutely — deformity can develop over 1–3 weeks as lateral bands sublux volarly) [1][5]
- Palpation: Tenderness maximal over dorsal PIP joint at central slip insertion
- Elson test (key diagnostic maneuver): Flex PIP to 90° over table edge; ask patient to extend against resistance. A positive test shows weak PIP extension with rigid DIP extension (lateral bands compensating). Normal: strong PIP extension with floppy DIP [1]
- Active ROM: Loss of active PIP extension (extension lag); DIP may show compensatory hyperextension
- Passive ROM: Full passive PIP extension initially (flexible deformity); loss of passive correction indicates chronicity
- Assess collateral ligament stability (radial/ulnar stress testing)
- Neurovascular exam of the digit
11. Lab Studies
- No routine labs needed for isolated acute traumatic boutonniere
- If concern for inflammatory arthritis: ESR, CRP, RF, anti-CCP
- If open wound with contamination: consider wound culture
12. Imaging
- AP, lateral, and oblique radiographs of the affected finger — first-line [1][7]
- Rule out avulsion fracture at base of middle phalanx (central slip insertion)
- Assess for PIP joint subluxation or dislocation
- Evaluate for associated fractures
- Ultrasound: Can detect central slip disruption with high sensitivity and specificity in experienced hands [12]
- MRI: Rarely needed acutely; may be useful for equivocal cases or preoperative planning in chronic deformity
- Imaging is often normal in closed soft tissue injuries — diagnosis is primarily clinical [1][13]
13. Special Tests
- Elson test: Gold standard clinical test for central slip integrity (described above) [1]
- Boyes test: With PIP held in full extension, assess DIP flexion. Inability to flex DIP suggests lateral band tethering (more relevant in chronic deformity)
- Pencil test: Place pencil under PIP; if patient can achieve full PIP extension, the deformity is passively correctable (Burton Stage 1) [14]
- Burton classification (for staging):
- Stage 1: PIP extension lag, passively correctable
- Stage 2: Fixed PIP flexion contracture, preserved joint surfaces
- Stage 3: Fixed contracture with joint destruction [9-10]
14. ECG
- Not applicable for isolated boutonniere deformity
- Consider if procedural sedation is planned for associated complex injuries
15. Assessment
Acute traumatic boutonniere deformity is a zone III extensor tendon injury caused by disruption of the central slip at the PIP joint. The full deformity (PIP flexion + DIP hyperextension) may not manifest immediately — it can develop over 10–21 days as the lateral bands progressively sublux volarly. [1][5] Cadaveric studies demonstrate that a true boutonniere deformity requires combined injury to the central slip, triangular ligament, and transverse/oblique fibers of the interosseous hood. [15]
Severity stratification
- Closed injury, passively correctable → Nonoperative management (most common)
- Open injury / laceration → Surgical exploration and repair [6-7]
- Avulsion fracture >30% articular surface or displaced → Surgical referral [6]
- Fixed deformity at presentation → Suggests delayed/chronic injury; more complex management
16. Treatment Plan
Closed acute boutonniere (mainstay = nonoperative)
- PIP extension splinting: Splint PIP in full extension (0°) continuously for 4–6 weeks, leaving DIP and MCP joints free to move [1][7][16]
- DIP joint should be actively flexed during splinting to pull lateral bands dorsally and promote healing [1]
- Relative motion flexion (RMF) orthosis: Emerging alternative — places injured digit MCP in 15–20° greater flexion than adjacent digits, permitting immediate active motion and hand use for 6 weeks. Early results show equivalent or superior ROM outcomes with less morbidity [17-18]
- After splint removal: Gradual active ROM exercises; buddy taping for 2–4 additional weeks during activities
Open acute boutonniere
- Surgical exploration, irrigation, and primary repair of central slip [8][19]
- Postoperative splinting in PIP extension for 4–6 weeks, or RMF orthosis [8][17]
Surgical indications
- Open wound with central slip laceration
- Displaced avulsion fracture at central slip insertion (>30% articular surface)
- Failed conservative management (persistent extension lag after 6–8 weeks of compliant splinting)
- Chronic fixed deformity not responsive to serial casting [20-21]
17. Disposition
- Discharge with splinting for most closed acute injuries [16][22]
- Hand surgery referral (urgent, not emergent) for:
- Open injuries / lacerations over dorsal PIP [6]
- Associated fracture-dislocation
- Avulsion fractures involving >30% articular surface [6]
- Irreducible dislocations
- Failed splinting at follow-up
- Admission: Rarely needed; only for polytrauma, open fractures requiring OR, or vascular compromise
18. Follow Up / Return Precautions
- Follow-up: Hand surgery or primary care within 1–2 weeks for splint check and reassessment [6]
- Splint must be worn continuously — even brief removal risks re-injury and treatment failure
- If splint is removed for skin care, PIP must be held in full extension at all times
- Treatment within 6 weeks of injury yields the best outcomes; delays beyond this significantly reduce likelihood of full recovery [4]
- Return precautions — seek immediate reassessment for:
- Increasing pain, swelling, or inability to extend PIP
- Skin breakdown under splint
- Signs of infection (open injuries): redness, warmth, purulent drainage, fever
- Numbness or color change in fingertip
- Expected course: Full recovery with compliant splinting in 6–10 weeks for most closed injuries; some residual extension lag (5–10°) is common. Full healing may take up to 12–18 months [6]
- Athletes may return to sport with buddy taping or protective splinting once cleared by hand specialist [5]
References
1. Posttraumatic Boutonnière and Swan Neck Deformities. — McKeon KE, Lee DH. The Journal of the American Academy of Orthopaedic Surgeons. 2015.
2. Managing Swan Neck and Boutonniere Deformities. — Elzinga K, Chung KC. Clinics in Plastic Surgery. 2019.
3. Boutonniere Versus Pseudoboutonniere Deformities: Pathoanatomy, Diagnosis, and Treatment. — Hanson ZC, Thompson RG, Andrews JR, Lourie GM. The Journal of Hand Surgery. 2023.
4. Nonoperative Treatment of the Boutonniere Deformity: Is There a Difference in Outcomes?. — Tong Y, Donnelly M, Paksima N. Journal of Hand Therapy : Official Journal of the American Society of Hand Therapists. 2025.
5. Sagittal Band, Boutonniere, and Pulley Injuries in the Athlete. — Grandizio LC, Klena JC. Current Reviews in Musculoskeletal Medicine. 2017.
6. Common Finger Fractures and Dislocations. — Childress MA, Olivas J, Crutchfield A. American Family Physician. 2022.
7. Acute Finger Injuries: Part I. Tendons and Ligaments. — Leggit JC, Meko CJ. American Family Physician. 2006.
8. Recent Developments Are Changing Extensor Tendon Management. — Merritt WH, Wong AL, Lalonde DH. Plastic and Reconstructive Surgery. 2020.
9. Treatment of Boutonniere Finger Deformity in Rheumatoid Arthritis. — Williams K, Terrono AL. The Journal of Hand Surgery. 2011.
10. Operative Correction of Swan-Neck and Boutonniere Deformities in the Rheumatoid Hand. — Boyer MI, Gelberman RH. The Journal of the American Academy of Orthopaedic Surgeons. 1999.
11. Concomitant Injuries Affect Prognosis in Patients With Central Slip Tear. — Fujihara Y, Ota H, Watanabe K. Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. 2018.
12. Ultrasound Visualization of Central Slip Injuries of the Finger Extensor Mechanism. — Westerheide E, Failla JM, van Holsbeeck M, Ceulemans R. The Journal of Hand Surgery. 2003.
13. Closed Soft Tissue Extensor Mechanism Injuries (Mallet, Boutonniere, and Sagittal Band). — Lin JD, Strauch RJ. The Journal of Hand Surgery. 2014.
14. The Use of Relative Motion Flexion Orthoses for Chronic Boutonniere Deformity. — Arslan ÖB, Sığırtmaç İC, Ayvalı C, et al. T The Journal of Hand Surgery. 2024.
15. Biomechanics of the Acute Boutonniere Deformity. — Grau L, Baydoun H, Chen K, et al. The Journal of Hand Surgery. 2018.
16. Pediatric Boutonniere Deformity After Blunt Closed Traumatic Injury. — Izadpanah A, Izadpanah A, Sinno H, Williams B. Pediatric Emergency Care. 2011.
17. A Paradigm Shift in Managing Acute and Chronic Boutonniere Deformity: Anatomic Rationale and Early Clinical Results for the Relative Motion Concept Permitting Immediate Active Motion and Hand Use. — Merritt WH, Jarrell K. Annals of Plastic Surgery. 2020.
18. The Relative Motion Concept in Acute and Chronic Boutonniere Deformity: Invited Commentary. — Merritt W. Journal of Hand Therapy : Official Journal of the American Society of Hand Therapists. 2023.
19. Central Slip Extensor Tendon Injuries: A Systematic Review of Treatments. — Geoghegan L, Wormald JCR, Adami RZ, Rodrigues JN. The Journal of Hand Surgery, European Volume. 2019.
20. A Staged Technique for the Repair of the Traumatic Boutonniere Deformity. — Curtis RM, Reid RL, Provost JM. The Journal of Hand Surgery. 1983.
21. Lambda Repair: A Novel Repair Technique for Chronic Boutonnière Deformity. — Kim BS, Vasella M, Lee CH, et al. Plastic and Reconstructive Surgery. 2024.
22. Review Article: Best Practice Management of Closed Hand and Wrist Injuries in the Emergency Department (Part 5 of the Musculoskeletal Injuries Rapid Review Series). — Strudwick K, McPhee M, Bell A, Martin-Khan M, Russell T. Emergency Medicine Australasia : EMA. 2018.