Radiological signs of loosening of the femoral stem in cementless total hip arthroplasty.

The radiological evaluation of cementless stem hip arthroplasty has received scant attention in medical publications. A retrospective analysis of 34 patients who underwent RM iso-elastic hip arthroplasty indicated the existence of a reproducible series of radiological features visible on plain radiography, which correlated both with clinical failure and with arthrographic evidence of loosening in 10 cases. In addition, there was correlation with scintinographic results and findings at revision surgery. The radiological signs were as follows: radio-opaque lines within radiolucent zones, the 'pedestal' sign, stem shift, localised cortical hypertrophy, and proximal bony overgrowth.