distribution   o!   isotope   was   not   sufficiently   characteristic   to   predict loosening or mleeUon in most of patients ,s v>.

A normal result on radionucleotides scanning suggests that loosening or infection is an unlikely cause of pain (.10).

A normal scintigram is reassuring and makes loosening or infection unlikely. In a group of patients \vho can be difficult to assess clinically, such a result is of value in their post-operative management '83).

It should be remembered, however, that increased radionuclide uptake, even after one year, is,present in approximately 85% to 90% of tibial and 60%) to 65% of femoral components in asymptomatic knees (10).

IV - Magnetic FesonaF!e€n*Tnagmg--:~

Magnetic resonance imaging is valuable in identifying the site of subtle stress fractures which occur in patients with knee prosthesis (84).

V-Arthrography :

Arthrography is of limited usefulness in the evaluation of aseptic or septic loosening (84).

3-Laboratory Investigation : I-Blood investigation :

A complete and differential blood-cell count and an assessment of the erythrocyte sedimentation rate and C-reactive protein level should help to differentiate septic from aseptic processes. (10).