718 - Palmar dislocation of the inferior radioulnar joint: A case report and literature review.

Case Diagnosis: Palmar dislocation of the inferior radioulnar joint is poorly reported in the literature due to the rarity of this lesion, which goes unnoticed in half of the cases.

Case Description: This is a 46-year-old female patient who consulted for wrist trauma with possible wrist flexion and extension and painful pronosupination block. Radiography had shown a palmar dislocation of the inferior radioulnar joint and a fracture of the ulnar styloid. The patient had a reduction followed by cast immobilisation for six weeks.

At the last follow-up, there was good wrist mobility with a slight decrease in clamping force.

Discussions: Distal radioulnar joint dislocation is an often-late diagnosed injury, going unnoticed in 50% of cases. Clinical examination will find retained mobility in flexion and extension with a marked decrease in pronation amplitude in the case of palmar dislocation, or even a blockage. The frontal radiograph shows a distal radioulnar superposition and the side will show a displacement of the distal ulna. In contentious situations, comparative x-rays or a CT scan can confirm the diagnosis. The first step in treatment is reduction under general anaesthesia followed by cast immobilisation. Irreducibility indicates a late diagnosis or interposition of the triangular carpal ligament requiring surgical treatment with dislocation and fixation by radioulnar pinning.

Conclusions: Early diagnosis based on clinical and radiological findings improves the prognosis of orthopaedic treatment, surgery being reserved for failures of the orthopaedic treatment and for irreducible forms.