Study of relationship of posterior tibial slope in anterior cruciate ligament injury.

Objective: To determine the relationship between Posterior Tibial slope in terms of medial and lateral in Anterior cruciate ligament deficient patients.

Methods: Magnetic resonance images (MRI) of the knee of 100 ACL injured patients and 100 ACL intact patients were studied. Their medial and lateral posterior tibial slopes were measured using MRI. Of 200 subjects, 100 (Male- 63, Female- 37) were controls, other 100 (Male - 68, Female-32) were ACL injured cases. Using DIACOM viewer software,the slopes of both medial and lateral slopes were measured. Range of Variation, mean value and standard deviation of medial tibial plateau slope (MTS), lateral tibia plateau slope (LTS) of controls and ACL injured patients were measured. The data collected were entered into Microsoft excel worksheet and analysed using statistical package for social sciences, Version 15.0 (SPSS Inc. Chicago, IL, USA). Distribution of data was confirmed using Shapiro's Wilk Test and appropriate parametric statistics were applied. For all analysis p value < 0.05 was set to be significant.

Results: In control (ACL uninjured) population mean MTS was 5.95° with SD 3.09°, mean LTS was 6.08° with SD 3.48°. In ACL injured population mean MTS 6.41° with SD 2.66°, mean LTS was 8.12° with SD 3.65°. So ACL injured population had MTS steeper than control population with no statistical significance (p value < 0.27) and LTS was steeper than control population with statistical significance (p value < 0.001),where as there were comparable results between male and females.

Conclusion: Our current results indicate that lateral PTS is a risk factor for patients with primary ACL tears as compared with ligament-intact controls. Therefore,PTS should be considered as independent modifiable risk factors in ACL injury.