P Chiron, N Reina
(Toulouse)
The smaller the head fragment, the more likely it is located at the bottom and in front of the femoral head, which then determines the most suitable approach. • A CT scan is essential after reduction and before resumption of weight-bearing to verify the size and congruence of the fragments and whether there are foreign bodies and/or a fracture of the posterior wall.
• Classifications should include the size of the fragment and whether or not there is an associated fracture of the acetabulum or femoral neck (historical ‘Pipkin’, modernised ‘Chiron’).
• In an emergency, the dislocation should be rectified, without completing the fracture (sciatic nerve palsy should be diagnosed before reduction).
A hip prosthesis may be indicated (age or associated cervical fracture). • Delayed orthopaedic treatment is sufficient if congruence is good. A displaced fragment can be resected (foreign bodies and ¼ head), reduced and osteosynthesised (⅓ and ½ head), and a posterior wall fracture reduced and osteosynthesised. Small fragments can be resected under arthroscopy. The approach is medial (Luddloff, Ferguson, Chiron) to remove or osteosynthesise ⅓ or ¼ fragments; posterior for ½ head or a fractured posterior wall.
• The results remain quite good in case of resection or an adequately reduced fragment. Long-term osteoarthritis is common (32%) but well tolerated with a low rate of prosthetisation. Avascular necrosis remains a possible complication (8.2%). Sciatic nerve palsy (4% of fracture dislocations) is more common for dislocations associated with posterior wall fractures.