Description
Background: Posterior elongation of the physiological terminal sulcus (TS) due to lateral femoral condyle impaction fracture (LFC-IF) after an ACL tear has not been well described. While deepening of TS by LFC-IF was well described, its elongation has only been investigated in a few studies. Posterior TS elongation could potentially decrease the weight-bearing area of the tibiofemoral joint, decrease the tension on lateral meniscus and cause flattening of the LFC which would influence rotational knee motion and cause anisometry of the lateral and anterolateral stabilizers. Therefore, the study hypothesis was that the LFC-IF elongates the physiological TS posteriorly.
Methods: 100 patients MRIs (75 males, 25 females, mean age 32.2 years, SD=8.2) were included with a 1:1 ratio between the full-thickness ACL tear group and the control group. Two independent authors evaluated the sagittal T1-weighted pre-selected MRI scans. The principal measurement of interest was the distance from the intersection of the Blumensaat line with subchondral bone to the posterior border of the TS/LFC–IF.
Results: The median distance from the Blumensaat line to the posterior border of the TS/LFC-IF was significantly higher in the ACL tear group: 14.34 mm, IQR=11.64-16.40 mm vs. control group: 12.80 mm, IQR=9.04-14.97 mm, p=0.038. Intra- and inter-rater reliabilities were>0.90.
Conclusion: The proof-of-concept for significant posterior elongation of the TS due to a LFC-IF was confirmed, justifying further research on its clinical importance. Specifically, there is a need for further studies focused on assessing if it may be a factor associated with a higher risk of failure or not returning to play at the preinjury level after an ACL reconstruction.
