Number of Screws Instrumented (N) | Screw Violation | Gertzbein Robbins Grade |
---|---|---|
Case 1 | ||
N = 4 | 4/4 screws without violation | 4/4 screws Grade A |
Case 2 | ||
N = 4 | 3/4 screws without violation | 3/4 screws Grade A |
1/4 screw with lateral cortical violation | 1/4 screw Grade B |