Why they matter
The proximal interphalangeal joint becomes stiff quickly. Treatment must balance stability with early motion.
Volar plate injury
Hyperextension may injure the volar plate with or without an avulsion fracture.
Assess:
- concentric reduction
- size of articular fragment
- stability through motion
- tendency to dorsal subluxation
Stable injuries are treated with early protected movement and neighbour strapping or an extension-blocking splint as appropriate.
Fracture-dislocation
If a joint remains stable after reduction, controlled early movement is preferred. A large volar lip fracture may permit recurrent dorsal subluxation and require operative stabilisation.
Options include:
- extension-block pinning
- percutaneous or open fragment fixation
- dynamic external fixation
- reconstructive procedures for selected comminuted injuries
Pilon fracture
Axial loading can produce comminution of the middle-phalanx base. The goal is to maintain length and joint alignment while allowing motion; exact reconstruction may not be possible in severe comminution.
Central slip injury
A missed central slip injury can progress to boutonnière deformity. Examine active PIP extension and use appropriate provocative testing when suspected.
Principle
For most PIP injuries, a stable joint that moves early gives a better functional result than a perfectly aligned joint immobilised for too long.
Why the PIP joint is unforgiving
The PIP joint is prone to stiffness, swelling and instability after even apparently minor injury. The treatment goal is a concentrically reduced joint stable enough for early motion.
Anatomy
Stability is provided by:
- collateral ligaments
- volar plate
- central slip/extensor mechanism
- congruent joint surfaces
Different injury patterns reflect failure of different structures.
Dorsal dislocation and volar-plate injury
Hyperextension can injure the volar plate and produce dorsal dislocation.
After reduction assess:
- concentric joint position
- fracture fragment
- stability through motion
- collateral injury
Small stable avulsion injuries are usually managed with protected early movement rather than prolonged immobilisation.
Fracture-dislocations
Dorsal fracture-dislocation usually involves the volar base of the middle phalanx. Stability depends on the proportion of articular surface involved and whether the joint remains reduced through motion.
Management options include:
- extension-block splinting
- K-wire techniques
- dynamic external fixation
- ORIF
- hemi-hamate reconstruction in selected chronic or comminuted cases
The procedure should restore concentric motion while minimising additional soft-tissue injury.
Central-slip injury
A volar PIP dislocation or direct injury can damage the central slip. Missed injury may progress to boutonnière deformity.
Examine active PIP extension and use targeted testing when suspected.
Collateral ligament injuries
Most stable collateral injuries are treated functionally with buddy support and early motion. Persistent instability or substantial associated fracture may require more.
Stiffness prevention
Prolonged immobilisation is a major cause of poor outcome. Once stability permits, early controlled movement is critical.
FRCS synthesis
Do not describe PIP management by fracture fragment size alone. The decisive issue is whether the joint is concentrically reduced and stable through a functional arc.