Computer-aided methods for assessing lower limb deformities in orthopaedic surgery planning.

Accurate, simple, and quick measurement of anatomical deformities at preoperative stage is clinically important for decision making in surgery planning. The deformities include excessive torsional, angular, and curvature deformation. This paper presents computer-aided methods for automatically measuring anatomical deformities of long bones of the lower limb. A three-dimensional bone model reconstructed from CT scan data of the patient is used as input. Anatomical landmarks on femur and tibia bone models are automatically identified using geometric algorithms. Medial axes of femur and tibia bones, and anatomical landmarks are used to generate functional and reference axes. These methods have been implemented in a software program and tested on a set of CT scan data. Overall, the performance of the computerized methodology was better or similar to the manual method and its results were reproducible.