Statistical analysis of knee ligament lengths

Absolute locations of the main knee ligamentous structures' insertion sites on the femur, the tibia and the patella have been obtained for 30 knees originating from 18 fresh human cadavers. For each knee, the length of ten selected structures was deduced. These length data form the input of the statistical analysis presented in the paper. The correlations between the ligament lengths are presented. A comparison of the lengths from the left and right (laterality) knees of the same specimen is also done and shows no significant difference. The sex difference is also studied and does not seem to be a determinant parameter for the sample investigated. Prediction equations are proposed to estimate the ligament lengths for the knee in extension with respect to the three external parameters: height, weight and femoral condyle width. The menisco-femoral length, the patellar tendon length and the patellar length are not related to the external parameters and predictions are based on mean values. For the other six ligament lengths, the square multiple correlation coefficient with the external parameters ranges between 0.22 and 0.43. The condylar width is the most often used external parameter in these equations while the weight parameter is never present.