The relationship of anterior cruciate ligament injuries with MRI based calculation of femoral notch width, notch width index, notch shape - A randomized control study.

backgroundACL injuries are infamously known for disability in young adults and require surgical reconstruction. The need of time is to predict predisposing factors and prevent ACL injuries.The incidence of ACL injuries has been associated with various factors related to the morphology of distal femur and proximal tibia.Hence, purpose of this study was to assess the relationship of morphology of distal femur by assessing Notch Width(NW), Notch Width Index (NWI), and Notch shape calculated preoperatively on MRI in association with an ACL tear.

methodsThe following randomized control study had 60 patients enrolled with non contact injury to knee who were equally divided into 2 groups i.e. ACL injury group and control group. ACL group had patients who had MRI proven ACL tear along with clinical findings suggestive of ACL tear whereas control contained patients with intact ACL. Demographic data was collected and NW, NWI and Notch shape were determined on coronal sections of MRI sequences.

resultsPositive correlation of ACL tear was seen with NW, BCW, NWI, NWP, and NWJ. Smaller Notch Width showed higher incidence of ACL tear (p = 0.019). The mean NWI in the injured and control knee is 0.31 ± 0.01 and 0.27 ± 0.01 respectively and was statistically significant(p < 0.001). A shaped Notch (60%) was commonly seen in ACL tear group and U shaped notch (73.3%) was commonly seen in control group.We found the cut off value for the prediction of ACL tear of NWI was 0.29 with a sensitivity of 90% and specificity of 86.7%.

conclusionACL injuries in the given population have shown higher incidence with narrow femoral intercondylar notch, smaller notch width index, 'A' shaped femoral notch. If any of the above findings are present in the MRI, its important to counsel the subjects about the increased risk of ACL injuries in them and take preventive measures.