History
The athlete typically sustains an axial loading blow to the finger that is combined with hyperextension.
Dorsal trauma produces a volar dislocation force with a concurrent central slip injury.
Radial- or ulnar-directed forces could produce a collateral ligament injury/lateral dislocation.
Inquire about potential dislocations that were reduced on the field. Careful attention to the mechanism of injury may help pinpoint the diagnosis.
Physical Examination
Consider obtaining radiographs before physical examination of the affected finger to evaluate for potentially unstable fractures/dislocations.
Document the integrity of the neurovascular status of the affected finger as well as that of the entire hand.
Observe and palpate the affected finger, with attention to focal areas of tenderness and edema.
Assess tendon function and ROM of the affected finger, with particular attention to active extension. Loss of active extension indicates a central slip injury.
Assess the joint stability of the affected finger.
If pain of the affected finger precludes a definitive diagnosis, consider using metacarpal block anesthesia to examine the digit's tendon function and stability. [10]
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Anatomy of the proximal interphalangeal joint. The central slip passes directly over the joint and inserts on the base of the middle phalanx. The lateral bands pass around the joint, combine with the retinacular ligaments, and unite to form the extensor tendon that attaches on the distal phalanx. Lateral motion is minimized by the collateral ligaments, and extension is limited to 0º by the thick volar plate.
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Volar plate disruption with a stable, nondisplaced avulsion fracture of the middle phalanx.
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Dorsal dislocation of the proximal interphalangeal joint.
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Typical boutonniere deformity.
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Extension block splint with the proximal interphalangeal joint at 30°.
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Proximal interphalangeal joint that has been splinted in extension for the treatment of a central slip injury.
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Dynamic spring extension splint for the treatment of a boutonniere finger deformity.
