Planning analysis of knee-adjacent deformities. I. Frontal plane deformities.

The planning analysis of leg deformities around the knee joint is based on a standardized clinical examination and on long leg standing anteroposterior (AP) radiographs, which may be complemented by spot-film radiographs and stress radiographs. The principles of true-nominal analysis in six steps are used to characterize the deformity and plan the corrective osteotomy: 1. Drawing in the anatomic points of reference. 2. Establishing the mechanical weight-bearing axis. 3. Determining the axis and orientation angles around the knee joint. 4. Determining the correction goal. 5. Deciding on the osteosynthesis technique and the osteotomy level. 6. Measuring the angle of correction. All the steps are exemplified on a valgus deformity and a varus deformity.