After TKA femoral preparation, retrograde IMN did not significantly impact the flexion gap when a femoral component was in place. Without a femoral component in place, the extension gap was unchanged after IMN placement. Although the flexion gap was statistically greater after IMN placement when measured without a femoral component, the clinical relevance is questionable given this difference was, on average, only 1.5 mm greater and a femoral component was not present. Similarly, the differences in AP translation observed without a femoral component were attenuated once the component was in place, which may have been further attenuated if a tibial component was able to be placed. These findings suggest limited clinical impact of retrograde IMN of the knee in the context of modern TKA femoral preparation.
Rainey et al. (Tue,) studied this question.