Complex metacarpophalangeal joint dislocation of the litter finger: A sesamoid bone seen within joint. What does it mean?

Dislocation of the metacarpophalangeal joint is a rare injury. The index finger is most frequently involved, followed by the thumb; the little finger is very seldom affected. The Complex dislocation of the little finger metacarpophalangeal joint is extremely rare. A few cases only had been described. Herein, we report a case of 40 years old presented, after a road accident, a dorsal metacarpophalangeal joint dislocation of the litter finger confirmed on radiographs with a clear view of the sesamoid bone within joint prompting the patient to undergo open reduction with no attempts of closed reduction initially. We elected, to treat our case, for the volar approach which allowed successful relocation of the head of the metacarpal in its anatomical position. The view of sesamoid bone within the joint is pathognomonic of volar plate entrapment. Recognition of this fact should alert the treating physician to the inevitability of open reduction for anatomical repositioning of the joint and avoid repeated attempts at closed reduction which may arise the risk of degenerative arthritis and reduced final range of motion.