Table 2 Protocol for MR evaluation

Full visualization of the screw integrity

0 = no

1 = yes

Tissue in the screw canals (> 90% of the canals)

0 = fluid

1 = mix

2 = solid bone

Edema in the bone adjacent to the screw canals

0 = no

1 = yes

Other MRI signal in the bone adjacent to the screw canals (e.g. fat signal)

0 = no

1 = yes

Intraosseous cysts adjacent to the screw canals

0 = no

1 = yes

Metal particle artefacts in relation to the screw canals

0 = no

1 = yes

Edema adjacent to the screw insertion site

0 = no

1 = yes

Ectopic bone formation

0 = no

1 = yes