ISOTOPE BONE SCANS IN PATIENTS WITH PAINFUL KNEE REPLACEMENTS - DO THEY ALTER MANAGEMENT

A retrospective review of the scintigraphic appearances, clinical find ings and outcome in 12 patients presenting with painful knee replaceme nts was made. Three patients required revision surgery; symptoms in th e remaining nine patients settled without operative management. Three examinations failed to identify prostheses proven to be infected by as piration and four were falsely positive for infection without supporti ve clinical evidence. Four examinations demonstrated loosening and in one patient the bone scan was normal but the prostheses was loose at r evision surgery. There were no specific features to predict which pros theses required surgical revision and the ability to diagnose or exclu de infection was limited. It is concluded that the results of three ph ase Tc-99(m) bone scans in symptomatic knee prostheses are of little a ssistance in guiding clinical management and that a period of conserva tive management should be considered prior to operative intervention.