Three-dimensional digital reconstruction and measurement of posterior condylar angle of distal femur

Abstract

Objective To explore digital measurement of the posterior condylar angle (PCA) on three-dimensional reconstruction of CT images of the normal adult distal femur, because it may provide rea-sonable parameters for the rotational alignment in the total knee arthroplasty. Methods CT scanning of bilateral knees was conducted for 32 normal adults (18 males and 14 females) . Three-dimensional recon-struction of distal femur was performed using Mimics10.0 software on the basis of the CT data. The bony landmarks determining PCA were made on the three-dimensional images of the normal distal femur. PCA was measured across lateral and medial femoral epicondyli on the three-dimensional images. Results In the 36 male knees, the left side PCA averaged 4.33°± 0. 67° and the right side 4.45°±0.72° (mean, 4.39°±0. 69°). In the 28 female knees, the left side PCA averaged 4.45°± 0. 73° and the right side 4.68°± 0. 37°(mean, 4. 57°±0. 58°) . There was no statistically significant difference in gender or side. Conclusions It is feasible to accurately identify the bony landmarks determining PCA on the three-dimensional recon-struction of the distal femur. Digital measurement of PCA can provide reasonable parameters for rotational alignment in the total knee arthroplasty. It can also be useful in the design of femoral prosthesis. Key words: Digitalization ; Three-dimensional reconstruction; Knee joint