Measurement of Posterior Tibial Slope in Healthy Indian Population: A CT-Based Study

Background: Recreation of near normal posterior tibial slope is required for proper knee biomechanics after unicondylar as well as total knee arthroplasties. It is also required for proper functioning of anterior cruciate ligament after high tibial osteotomies. Researchers have found differences in values of posterior tibial slopes in individuals of different ethnicities. So far there is no study measuring the posterior slopes of medial and lateral tibial plateau separately in knees of healthy Indian population via three dimensional imaging modalities like computed tomography.

Aim: The aim of our study is to find out the slopes of medial and lateral tibial plateau separately through computed tomography (CT) scans.

Materials And Methods: CT-based measurements of posterior tibial slopes were done in 62 healthy knees. There were 55 males and 7 females.

Results: Age groups were in the range of 17-45 years. Mean values of Posterior tibial slope of medial and lateral tibial plateau for combined sample were 8.60° ± 3.51° and 7.94° ± 3.91°. Mean values of medial and lateral tibial plateau for males were 8.33° ± 3.51° and 7.71° ± 4.07° respectively; while for females were 10.69° ± 2.86° and 9.77° ± 1.32°, respectively.In our study, there was a large range of slopes, extending from + 0.6° to 15.6° for medial tibial slope, from 0° to 15° for lateral tibial slope.

Conclusion: The minimum values of Medial tibial plateau slope are very low as compared to the previous study done in Asian population. Further CT based studies are required to measure values of posterior tibial slope for larger sample from Indian population. The implant design suitable and their implantation guidelines for western population may not be appropriate for Indian population.