Updated: 11/9/2022

Sagittal Band Rupture

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  • summary
    • Sagittal Band Ruptures lead to dislocation of the extensor tendons and may be caused by trauma or by a chronic inflammatory process such as rheumatoid arthritis.
    • Diagnosis is made clinically with the inability to initiate MCP extension but the ability to hold MCP in extension once passively extended.
    • Treatment of acute traumatic injuries is generally splinting where chronic injuries often require surgical reconstruction.
  • Epidemiology
    • Demographics
      • more common in pugilists
        • index and middle finger in professionals
        • ring and little finger in amateurs
    • Anatomic location
      • the middle finger is most commonly involved
        • index 14%
        • middle 48%
        • ring 7%
        • little 31%
      • the radial SB is more commonly involved
        • radial:ulnar = 9:1
  • Etiology
    • Mechanism
      • traumatic
        • forceful resisted flexion or extension
        • laceration of extensor hood
        • direct blow to MCP joint
      • atraumatic
        • inflammatory (e.g. rheumatoid arthritis)
        • spontaneously during routine activities
    • Associated conditions
      • MCP joint collateral ligament injuries
  • Anatomy
    • Extensor mechanism comprises
      • tendons
        • EDC/EIP/EDM
        • lumbricals
        • interossei
      • retinacular system
        • sagittal bands
          • the sagittal bands are part of a closed cylindrical tube (or girdle) that surrounds the metacarpal head and MCP along with the palmar plate
          • origin
            • volar plate and intermetacarpal ligament at the metacarpal neck
          • insertion
            • extensor mechanism (curving around radial and ulnar side of MCP joint)
        • retinacular ligaments
        • triangular ligament
    • Sagittal band
      • function
        • the SB is the primary stabilizer of the extensor tendon at the MCP joint
          • juncturae tendinum are the secondary stabilizers
        • resists ulnar deviation of the tendon, especially during MCP flexion
        • prevents tendon bowstringing during MCP joint hyperextension
      • biomechanics
        • ulnar sagittal band
          • partial or complete sectioning does not lead to extensor tendon dislocation
        • radial sagittal band
          • distal sectioning does not produce extensor tendon instability
          • complete sectioning leads to extensor dislocation
          • sectioning of 50% of the proximal SB leads to extensor tendon subluxation
        • extensor tendon
          • instability after sectioning is greater with wrist flexion
          • instability after sectioning is greater in the central digits (than border digits)
            • the least stable tendon is the middle finger
            • the most stable tendon is the little finger
              • junctura tendinum stabilize the small finger
  • Classification
      • Rayan and Murray Classification 
      • Type I
      • Sagittal band injury without extensor tendon instability
      • Type II
      • Sagittal band injury with tendon subluxation
      • Type III
      • Sagittal band injury with tendon dislocation
  • Presentation
    • Symptoms
      • pain
        • MCP soreness
      • swelling
        • focal MCP swelling or tenderness
      • snapping senstion with extension
    • Physical exam
      • tendon snapping
      • ulnar deviation of the digits at the MCP joint (rheumatoid arthritis)
      • inability to initiate extension
        • can hold MCP in extension once placed there
        • unable to extend finger from flexed MCP position (causes tendon to subluxate)
      • pseudo-triggering - key to recognize to avoid unnecessary trigger release surgery
        • this is the snapping that takes place from subluxation and relocation
      • extensor tendon dislocation into intermetacarpal gully
        • most unstable during MCP flexion with wrist flexed
        • least unstable during MCP flexion with wrist extended
      • provocative test
        • pain when extending MCP joint against resistance (with both IP joints extended)
  • Imaging
    • Radiographs
      • required views
        • hand PA, lateral, oblique
      • optional view
        • Brewerton view
          • AP with dorsal surface of fingers touching the cassette and MCP joints flexed 45deg
        • stress view
          • to rule out collateral ligament avulsion/injury
      • findings
        • exclude mechanical/bony pathology limiting extension, or predisposing to sagittal band rupture
        • may show dropped fingers and ulnar deviation in rheumatoid arthritis
    • Ultrasound (dynamic)
      • indications
        • when swelling obscures the physical exam
      • findings
        • subluxation of EDC tendon relative to metacarpal head on MCP flexion
    • MRI
      • indications
        • to establish diagnosis of SB disruption (radial or ulnar SB)
        • may show underlying etiology e.g. synovitis in rheumatoid arthritis
      • views
        • axial images at the level of the long MCP
        • with MCP joint flexed for maximum EDC tendon displacement
      • findings
        • poor definition, focal discontinuity and focal thickening in acute injury
        • subluxation of extensor tendon in radial direction due ulnar SB defect
        • dislocation of extensor tendon into ulnar intermetacarpal gully radial SB defect
  • Differentials
    • Digital collateral ligament injury
    • EDC tendon rupture
    • Trigger finger
    • Junctura tendinum disruption
    • Congenital sagittal band deficiency
    • MCP joint arthritis
  • Treatment
    • Nonoperative
      • extension splint or yoke splint for 4-6 weeks
        • indications
          • acute injuries (within 6 weeks)
    • Operative
      • direct repair (Kettlekamp)
        • indications
          • chronic injuries (more than 6 weeks) where primary repair is possible
          • professional athlete
      • extensor centralization procedure (realignment)
        • indications
          • chronic injuries (more than 6 weeks) where primary repair is NOT possible
          • professional athlete
  • Techniques
    • Extensor Centralization Procedures (Realignment)
      • anesthsia
        • local
      • approach
        • dorsal incision
      • reconstruction (various techniques described)
        • trapdoor flap
          • ulnar based partial thickness capsular flap created
          • tendon placed deep to flap
          • flap resutured to capsule
        • Kilgore tendon slip
          • distally based slip of EDC tendon on radial side
          • looped around radial collateral ligament
          • sutured to itself after tensioning to centralize tendon
        • Carroll tendon slip
          • distally based slip of EDC tendon on ulnar side
          • routed deep to affected tendon and around radial collateral ligament
          • sutured to itself after tensioning to centralize tendon
        • McCoy tendon slip
          • proximally based slip of EDC tendon
          • looped around lumbrical insertion
          • sutured to itself after tensioning to centralize tendon
        • Watson EDC tendon transfer
          • distally based slip of EDC tendon slip
          • looped under deep transverse metacarpal ligament
          • weaved to remaining EDC tendon after tensioning to centralize tendon
        • Wheeldon junctural reinforcement
          • for a middle finger radial SB rupture, the juncturae tendinum (JT) of the ring finger is divided close to the ring finger,
          • bring JT over the extensor tendon
          • attach JT to the torn SB
        • fascial strips or free tendon graft
      • rehabilitation
        • 0-4 weeks
          • resting splint MPs an IPs at 0 degrees
        • 2 weeks
          • motion splint, MPs at 0 degrees, IPs free, most of day
        • 4-8 weeks
          • AROM >8 weeks - progressive strengthening
  • Complications
    • MCP flexion contracture
      • usually from non-operative treatment or delayed presentation
      • secondarily intrinsic tightness develops
Flashcards (60)
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Questions (5)
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(OBQ18.180) Which of the following findings would be present in a patient with a sagittal band injury?

QID: 213076

Locking of the digit in a flexed position



Laxity of the PIP joint to valgus stress when the PIP is flexed 30° and the MCP is flexed 90°



Rigidity of the DIP joint when the PIP is flexed 90° over edge of a table and the patient is asked to extend the digit



Inability to actively flex the DIP joint



Inability to actively extend the MCP joint but able to maintain MCP extension after passive extension



L 2 A

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(OBQ12.262) A 28-year-old NFL running back complains of continued hand pain three days following an injury sustained while being tackled. He was splinted on the field. He has tenderness over the long finger metacarpal head, with subluxation of the extensor tendon into the intermetacarpal area during active metacarpophalangeal joint flexion. A representative MRI is shown in Figure A. What is the next best step in management of this patient?

QID: 4622

Observation alone



Continued splinting in flexion



Continued splinting in extension



Open repair of the disrupted junctura tendinae



Open repair of the disrupted sagittal band



L 3 C

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(OBQ06.92) A 20-year-old man has pain, swelling, and popping over his index metacarpophalangeal joint after striking a wall 3 days ago. Radiographs are normal, but physical exam reveals a palpable defect over the dorsum of the joint with clenching of the fist, and this defect is resolved with extension of the metacarpophalangeal joint. What is the next most appropriate step in treatment?

QID: 203

Trigger finger steroid injection



Extension splinting of the metacarpophalangeal joint



Metacarpophalangeal synovectomy



Extensor hood reconstruction



Metacarpophalangeal joint arthrodesis



L 3 D

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Evidence (8)
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