Different techniques of valgus angulation osteotomies have been described. All of them have two things in common; extensive pre operative planning and removal of wedges from the proximal femur. Our technique involves an oblique osteotomy just below the lesser trochanter and no wedges are taken. A greater degree of correction can be achieved with a more oblique osteotomy. A good area of contact at the osteotomy site can be maintained with an oblique osteotomy with minimal lateral displacement of the distal fragment and without significant opening up of the medial side as evident from Figures 5 and 6.
Subtrochanteric osteotomy was chosen to avoid compromising the lateral wall fragment with a proximal osteotomy especially in extracapsular fractures. A very low subtrochanteric osteotomy should be avoided as it will be through the cortical bone where union rates are less predictable and nonunion at the osteotomy site have been reported .
With an oblique osteotomy the distal fragment becomes free and can be laterally translated with ease along the osteotomy surface maintaining adequate contact with the proximal fragment. When the limb is brought to neutral, the neck shaft angle is restored to the barrel plate angle and the Pauwel angle at the fracture site is reduced due to the combination of valgus angulation of the proximal fragment and lateral displacement of the distal fragment.
Removing wedges may hinder limb length restoration and requires careful planning and templating to avoid the same. It also increases the surgical time and the blood loss.
Valgus osteotomy has a high success rate and good reproducibility among the augmentation techniques described for a femoral neck nonunion . It is especially useful in younger individuals where a replacement surgery may not be the best option. Literature on nonunion of extracapsular fractures is sparse as these fractures commonly malunite rather than going for nonunion. While union in intracapsular fractures is complicated by biological and mechanical factors, the problem with extracapsular fractures is mainly mechanical. The applicability of valgus osteotomy in both intra and extracapsular fractures is based on similar principles.
Muller  has insisted on reducing the fracture angle to less than 25 degrees to achieve consistent results though other authors have reported otherwise. We did not set any preliminary targets but aimed to bring the Pauwel’s angle to around 30 degrees with the obliquity of the osteotomy. An osteotomy not only helps by improving the biomechanics but it also improves the hemodynamics at the nonunion site. A more horizontal fracture angle was achieved in all patients and they progressed to successful union. The limb shortening was brought to less than 1 cm in all patients. 4 patients had a trendelenberg lurch which may be due to the loss of abductor lever arm.
Valgus osteotomies using blade plates have been described by several authors [6–9]. Blade plates have excellent rotational control but are technically difficult to use. The dynamic hip screw is an excellent implant in this situation. It allows application of static compression during surgery with the coupling screw and also allows controlled dynamic collapse at the fracture site maintaining the neck shaft angle. The only drawback is the suboptimal rotational stability and rotational stress which may occur during reaming. Both these problems were addressed in our series to an extent by using an anti rotation screw along with the DHS in intracapsular fractures.
Recent articles on valgus osteotomies at the intertrochanteric level with DHS fixation has been described by Hartford et al., 2005  and Schoenfeld et al., 2006 . Both techniques in the own words of the authors required extensive pre operative sketching and templating to achieve the desired result. While Schoenfeld et al. removed a partial thickness wedge to minimise limb length discrepancy Hartford et al. used a full thickness laterally based wedge.
Schoenfeld et al. also noted that the partial thickness wedge osteotomy may decrease the surface area of contact and may increase the chances of implant failure. Though the post operative Pauwel’s angle was much lesser in their series, the final clinical, radiological and functional results were much similar to the current series. While Shoenfeld achieved a good limb length restoration with his technique, the mean post operative mean limb length discrepancy in the series by Hartford et al. was 1 cm probably because of the full thickness wedge technique they had used. Surgical time and blood loss were significantly lesser in our series compared to techniques described by these two authors.
To conclude, valgus osteotomy with DHS fixation is a useful technique for varus proximal femur nonunion in younger patients. Improving the biomechanics at the nonunion site coupled with a stable fixation yields good consistent results regarding union. The sliding osteotomy technique is simple, saves surgical time, minimises blood loss and helps in limb length restoration. No elaborate planning and wedge removal are required to achieve the desired results.