Boutonniere Deformity 

Boutonniere Deformity – Introduction

• Also known as buttonhole deformity
• •Deformity of the finger involving flexion of the proximal interphalangeal (PIP) joint and hyperextension of the distal interphalangeal (DIP) joint ( Fig. 84.1 )Fig 84.1Extensor tenotomy for supple boutonniere deformity. The deformity is characteristic of the chronic boutonniere deformity.(Adapted from Green DP, Hotchkiss RN, Pederson WC, Wolfe SW, eds. Green’s Operative Hand Surgery . 5th ed. Philadelphia: Churchill Livingstone; 2005, Fig. 6.22A.)
• •Caused by disruption or attenuation of the central slip and triangular ligament of the extensor expansion on the dorsal finger ( Fig. 84.2 )Fig 84.2Pathomechanics of the boutonniere deformity. Attenuation of the central slip results in unopposed flexion at the proximal interphalangeal joint.(Adapted from Strauch RJ. Extensor tendon injury. In: Wolfe SW, Hotchkiss RN, Pederson WC, et al, eds. Green’s Operative Hand Surgery . 7th ed. Philadelphia: Elsevier; 2017, Fig. 5.20A.)
• •Traumatic, infectious, or inflammatory etiology
• •The balance of the finger extensor mechanism is altered, which over time leads to fixed volar subluxation of the lateral bands and focus of extension force exclusively on the distal joint. This causes loss of active PIP joint extension and hyperextension of the DIP joint, respectively.
• •If left untreated, fixed flexion occurs at the PIP joint secondary to volar plate and oblique retinacular ligament contracture.

History

• •Closed injury
• •Forced flexion of an actively extended PIP joint (“jammed” finger)
• •Crush injury
• •Volar dislocation of the PIP joint
• •Open injury
• •Laceration over the PIP joint
• •Open wound at the level of the PIP joint with tendon necrosis
• •Burns
• •Infection
• •Subcutaneous infection
• •Intra-articular infection of the PIP joint
• •Inflammatory
• •Rheumatoid and other inflammatory arthritides
• •Gout

Physical Examination

• •Acute
  • •The examiner must have a high index of suspicion because the deformity may evolve over the course of 1 week after the initial injury
  • •PIP joint effusion
  • •Localized tenderness over the dorsal aspect of the PIP joint at the insertion of the central tendon
  • •Elson test ( Fig. 84.3 )Fig 84.3Elson test. (A) With a disrupted central slip, attempted active extension of the proximal interphalangeal joint against resistance allows proximal movement of the origin of the lateral bands holding the distal joint in extension. (B) With an intact central slip, attempted active extension of the proximal interphalangeal joint against resistance affects the middle phalanx but leaves the distal joint flail.
  • •A positive test result is demonstrated when the patient bends the PIP joint 90 degrees over the edge of a table and, with resisted middle phalanx extension, the DIP joint goes into rigid extension (all the forces are distributed to the terminal tendon through the intact lateral bands)
  • •A negative test result is demonstrated when the DIP joint remains floppy with this maneuver
• •Boyes test
  • •Assess ability to actively flex DIP with the PIP held in extension
  • •Fix the PIP joint and ask patient to flex the DIP joint
  • •Intact extensor mechanism should demonstrate full DIP flexion motion
  • •Patients with contracted lateral bands will have decreased active flexion
  • •May not be positive in an acute setting
• •Chronic
  • •Assess the PIP and DIP joints for flexibility and evidence of arthritis
• •True boutonniere deformity should not be confused with a pseudo deformity
  • •Pseudo deformity: flexion contracture of PIP joint in which the triangular ligament is competent, thus allowing for the DIP to retain mobility
  • •Flexion contracture caused by scarring of the volar plate
  • •Distinguish by using the Elson and Boyes test as described previously

Imaging

• •Radiographs of acute and chronic injuries are imperative in determining the mode of treatment. Look for bony fragments and subtle DIP extensions.
• •Standard views of the affected digit should include anteroposterior, lateral, and oblique views.

Differential Diagnosis

• •Pseudo-boutonniere deformity
  • •Flexion contracture of the PIP joint but without restriction if DIP joint mobility
  • •Extensor mechanism is unaffected
  • •Caused by PIP joint hyperextension injury that results in fibrosis of the volar ligamentous complex
  • •Treated with aggressive motion as opposed to true boutonniere, which requires a period of immobilization
  • •Radiographs often demonstrate avulsion fractures of the PIP volar plate and calcification about the volar mechanism of the proximal phalanx.

Treatment

• •Depends on the chronicity of the injury and the flexibility of the digit
• •Acute injuries (0 to 2 weeks)
  • •Lacerations require exploration and anatomic reapproximation of the central slip
  • •Closed injuries not involving a fracture require 6 weeks of immobilization of the PIP joint in extension, leaving the DIP joint free ( Fig. 84.5 )Fig 84.5(A) Schematic representation of a boutonniere deformity. (B) A Bunnell splint is applied to maintain extension at the proximal interphalangeal (PIP) joint. The strap over the PIP joint is progressively tightened until the PIP joint is fully extended. The patient is encouraged to actively and passively flex the distal interphalangeal joint. The splint is worn until the patient can maintain active extension of the PIP joint.(From Piper SL, Lattanza L: Extensor tendon injuries. In Trumble TE, Rayan GM, Budoff JE, et al. Principles of Hand Surgery and Therapy . 3rd ed. Philadelphia: Elsevier; 2017.)
  • •Flexion of the DIP joint draws the extensor mechanism distally and facilitates dorsal translation of the lateral bands
  • •Closed injuries involving a fracture or dislocation require reduction followed by an assessment of joint stability
  • •If the reduction is adequate and the joint is stable, immobilize the PIP joint with the DIP joint free for 6 weeks
  • •If the reduction cannot be obtained or the joint is unstable, open reduction and internal fixation are required
• •Subacute injuries (2 to 8 weeks)
  • •Treat supple PIP joints like acute closed injuries without fractures, except leave the splint on for 8 weeks
  • •Stiff PIP joints require treatment to regain full mobility
  • •Dynamic or progressive static splints can be used
  • •If full motion is restored, leave the splint on for an additional 8 weeks
  • •If motion cannot be restored, treat the injury like a chronic stiff boutonniere deformity (see the following)
• •Chronic injuries (>8 weeks)
  • •Probably will not be amenable to splint therapy
  • •The status of the PIP and DIP joints determines the treatment protocol in these long-standing injuries
  • •Flexible PIP joints require operative rebalancing of the extensor mechanism through anatomic repair, reconstruction using local tissue, or tendon grafting
  • •Treatment of stiff PIP joints requires staged treatment
  • •The first priority is to reestablish joint motion through splinting or surgery
  • •Once full motion is established, an extensor tendon reconstruction is typically required
  • •Arthritic PIP joints require arthroplasty or fusion depending on whether the extensor mechanism is intact or disrupted, respectively

When to Refer

• •Open injuries
• •Fractures or irreducible dislocations requiring open reduction and internal fixation
• •Residual deformity after failure of splinting program
• •Flexion contracture unresponsive to conservative treatment

Troubleshooting

• •Early diagnosis is essential for successful treatment.
• •The examiner must have a high index of suspicion of central slip injury during the acute phase because a boutonniere deformity may be delayed.
• •In a stiff deformity, full extension must be obtained either through splinting or surgical release before definitive treatment can be performed.
• •It is important to differentiate between boutonniere and pseudo-boutonniere deformities because surgery for either condition when the other is actually the problem will have poor results.
• •The most common complication encountered in treating acute closed deformities is incomplete correction.
• •Full flexion of the PIP and DIP joints with an extension lag of 20 degrees or less produces a finger with few functional limitations.

Patient Instructions

• •The splint for acute injury must be worn full time for a minimum of 6 weeks.
• •An additional 6 weeks of night splinting follows for protection.
• •Concomitant active and passive flexion of the DIP joint must be done during splint wear.

Considerations in Special Populations

• •Rheumatoid arthritis patients can be treated with a similar algorithm.
• •It is important to address the wrist pathology before surgical treatment of boutonniere deformity in these patients.
• •Severe rheumatoid boutonniere deformities often require joint fusion.

Acknowledgment

The author thanks Drs. Jack Ingari and Daniel T. Fletcher, Jr. for their contributions to the previous edition of this chapter.

Suggested Readings

1. Baratz ME, Schmidt CC, Hughes TB: Extensor tendon injuries . In Green DP, Hotchkiss RN, Pederson WC, Wolfe SW (eds): Green’s Operative Hand Surgery ., 5th ed 2005. Churchill Livingstone , Philadelphia pp. 199-205.
2. Coons MS, Green SG: Boutonniere deformity . Hand Clin 1995; 11: pp. 387-402.
3. Elson RA: Rupture of the central slip of the extensor hood of the finger, a test for early diagnosis . J Bone Joint Surg Br 1986; 68B: pp. 229-231.
4. Massengill JB: The boutonniere deformity . Hand Clin 1992; 8: pp. 787-801.
5. McKeon KE, Lee DH: Posttraumatic boutonnière and swan neck deformities . J Am Acad Orthop Surg 2015; 23 (10): pp. 623-632.
6. Souter WA: The problem of boutonniere deformity . Clin Orthop Relat Res 1974; 104: pp. 116-133.