The chapter concludes with the post-operative management techniques and rehabilitation protocols followed after the osteotomy is performed.
Need for Distal Femoral Osteotomy
Femoral osteotomy is a highly convenient treatment for limb deformities in patients. Angular deformities can occur in the distal femur either in the developmental stages or through mal-alignment acquired later on. These are found in patients suffering from fracture malunion, osteoarthritis, metabolic disorders, adolescent-onset Blount disease or idiopathic processes (Seah et al. 2011). The axial alignment of lower limbs is affected by limb deformities, and is of immense concern when mechanical forces occurring during ambulation influence the articular cartilage. The varus and valgus alignment of the knee, when investigated through biomedical studies, have been shown to increase the medial and lateral load, thereby resulting in the progression of osteoarthritis.
Studies have shown that degenerative valgus deformities of the knee are less frequent than varus deformities (Wheeless 2012). In order to treat these deformities, the angle between the femur’s anatomical axis and the tibia’s mechanical axis has to be corrected up to 0-2° of valgus. This procedure will result in the unloading of the lateral tibio-femoral joint compartment, thus preventing the deformity from reoccurring. For the treatment of genu varum, high tibial osteotomy has been used successfully (Wheeless 2012). On the other hand, it is found to be less effective in case of genu valgum as it results in the formation of an oblique joint line. The tilting results in the generation of shear force across the knee, apart from lateral tibial subluxation, wherein the distal femur seems to fall off the plateau of the medial tibia. In such an instance, distal femoral osteotomy is apparently a better treatment option. Shoji and Insall (cited in Paddu et al. 2009), who studied 49 patients through a 31 month follow up, showed that only 26 of the 49 patients who had had proximal medial tibial closing wedge osteotomy had total relief from pain. Only seven of the patients had partial relief while sixteen had no relief at all. As already described, this treatment has been ineffective because when a major deformity in the valgus is corrected, the joint line slopes in the frontal plane superaolaterally. If the angle between the tibial mechanical axis and the anatomic femoral axis is more than 12-15° of the valgus, or if there is a deviation of the joint plane by more than 10° from the horizontal, distal femoral osteotomy is indicated. This specification was given by Bouillet and Van Gaver (cited in Paddu et al. 2009). A number of other studies have also suggested that osteotomy in the distal femur should be performed rather than in the proximal tibia if the angle between the tibia and femur is more than 12°. Another study by Maquet (cited in Paddu et al. 2009) has provided evidence that distal femoral osteotomy is a better treatment option for valgus deformity in patients as it helps in restoring the lower extremity’s mechanical axis, thereby reducing the Q angle and biomechanically altering the patellofemoral joint. Phillips and Krackow (1999) have suggested that this feature is an additional benefit as valgus malalignment is usually associated with patellofemoral disorders. In presence of restricted motion of the knee or inflammatory arthrititides, distal femoral osteotomy is contraindicated (Wheeless 2012; Distal Femoral Osteotomy 27450 2012). Preoperative Planning Before performing an