ABSTRACT
Femoral malunion may result in suboptimal function and altered joint loading through various combinations of angulation/translation, shortening, and rotational malalignment (1,2). The most important consideration is the long-term effect of malalignment and altered joint mechanics, resulting in abnormal joint loading and leading to premature osteoarthritis (1-4). Malunion may result in symptoms when angular deformities exceed 5 in the coronal plane or 10 in the sagittal plane, when rotational deformities exceed 10, and when shortening exceeds 2 cm. It is critical to understand that absolute values of the angular magnitude alone cannot be considered the single most important consideration (1,2,5). Associated translation and the level of the deformity are other crucial aspects that must be considered. Those deformities with the apex near the knee have the greatest effect on the mechanical axis (1,2,5,6), whereas deformities more proximal in the diaphysis may have far less impact. Isolated rotational deformities are still prevalent even in the modern era of intramedullary (IM) fixation (7-10). Length discrepancy is still not an uncommon deformity, though certainly less frequent than when femoral fractures were managed nonoperatively.
