Relationship of LCL finding after post-op ACLR with anterior tibial translation, femorotibial rotation, knee scores, and functional performance: a retrospective cohort study

Background This study aimed to examine the relationships between anterior tibial translation (ATT) distance, femorotibial rotation (FTR) angle, coronal lateral collateral ligament (LCL) sign, and functional lower extremity results obtained from single leg hop tests (SLHT), which are indirect magnetic resonance imaging (MRI) findings used to assess knee instability following anterior cruciate ligament (ACL) tear detection and ACL reconstruction (ACLR). Methods This study included a total of 28 patients, 12 females (43%) and 16 males (57%), aged 18-40 years with ACL tear. Pre-operative (pre-op) ATT distance, FTR angle and LCL sign were measured by MRI, and Lysholm Knee Scoring Scale (LKSS), International Knee Documentation Committee Score (IKDC) and Tegner Activity Score (TAS) were measured and recorded by patient self-assessment. At six months post-operatively (post-op), the SLHT test was conducted alongside the same measurements. Differences between pre-op and post-op results, as well as correlations between post-op test outcomes, were analyzed based on the presence of the LCL sign. Results After ACLR, there was no significant difference in ATT distance (p = 0.061) or FTR angle (p = 0.470) compared to the pre-op period. The presence of the post-op LCL sign did not lead to significant differences in ATT distance, FTR angle, LKSS, TAS, or any SLHT results (p > 0.05). However, the presence of LCL sign was associated with a significant increase in the IKDC scale (p = 0.047, ES=-0.78). In analyzing the correlations between ATT, FTR results, their changes, knee scores, SLHT results on the operative side, and limb symmetry index (LSI) ratios, significant correlations were found in various parameters for the entire group and the group without the LCL sign. In contrast, no significant correlations were found between any parameters in the group with the LCL sign (p > 0.05). Conclusions ACLR did not result in a significant change in indirect MRI findings (ATT distance, FTR angle, and LCL sign) at the 6-month post-op mark. Additionally, the LCL sign was not a distinguishing factor in knee scores or lower extremity functional performance at six months post-op. In order to understand the potential effects of the LCL finding, longer follow-up and studies evaluating various sub-parameters such as age, gender, different surgical techniques are needed.