Radiography and scintigraphy in the assessment of early gonarthrosis.

The radiographic and scintigraphic appearances in early gonarthrosis were compared in 62 knees. Early femorotibial osteoarthrosis was found to be confined to one compartment (medial or lateral) of the joint. However, concomitant patellofemoral osteoarthrosis was common. 99Tcm-MDP scintigraphy was consistently positive when the joint space (femorotibial and patello-femoral) was reduced by 75 per cent or more. Joint space narrowing by as much as 50 per cent could be observed in a scintigraphically normal knee. The inconsistency between the radiologic and scintigraphic findings in the earliest stages of gonarthrosis points to the importance of appropriate radiographic technique.