DISPLACED FEMORAL-NECK FRACTURES AT THE BONE-SCREW INTERFACE AFTER IN-SITU FIXATION OF SLIPPED CAPITAL FEMORAL EPIPHYSIS

Two patients had displaced femoral neck fractures at the bone-screw in terface after in situ fixation of slipped capital femoral epiphysis. B oth fractures required closed reduction and internal fixation. Inadver tent derotation of the femur occurred in both patients and allowed fix ation of the fracture through the intramedullary canal of the femoral neck without anterior penetration of the pins into the joint; a nonuni on occurred in this patient. The other patient developed chondrolysis and avascular necrosis. Because the femoral neck is vulnerable to stre ss fractures in young adults, there is some question whether pins plac ed anteriorly through the femoral neck cortex should be removed.