## 7 Discussion
Although our number of patients is small, no implant failures have occurred in our study. Dynamic fixation secures robust stability between the fragments. In addition, it is implemented by improving load transmission (over valgus correction), making the implementation of the DHS with other devices unnecessary. 2. Immediate full weight bearing is allowed from the first postoperative day. In previous procedures, full weight bearing is often limited to weeks, along with the limitations this entails, especially for the elderly population. 3. Grafting of the nonunion site is never required. Bone grafting is necessary in most procedures to promote bone union, which adds comorbidity for the patient. A bone union rate of up to 100% using extramedullary devices that involve bone grafting has been reported [15]. The same 100% bone union rate was obtained in our series. Even expensive, non-risk-free therapies, such as teriparatide or recombinant human bone morphogenetic protein (BMP), have also been used to aid fixation, with promising results [22,23]. Dynamic compression offers an excellent biomechanical environment that promotes quick and significant callus formation, making them unnecessary. Our technique is friendlier to perform than the current surgical procedures described to date using extramedullary devices. Achieving the desired intraoperative close bone contact to achieve intraoperative compression using non-dynamic fixation is challenging. In our technique, close bone contact does not necessarily need to be achieved intraoperatively. Even if no bone contact is achieved intraoperatively (due to nonunion patterns like bone defects, comminution, or technical aspects), strong areas of bone contact will appear when walking due to the dynamic construct created. As described above, this results from the shaft's medialization conducted through the DHS (Figure 7). Only a tiny area of bone contact between fragments is necessary to develop a large bone callus (Figures 8 and 9). Dynamic fixation reinforces a progressive and strong (due to this highly stressed area) contact between the ends of the bone fragments. In other cases, a wide bone contact area was achieved intraoperatively (Figure 10). median offset was 50.4 mm (range 42-59) before surgery and 19.6 mm (range 17-24) after surgery. This is especially relevant for young patients; therefore, this technique is not desired as the first option for this population. Despite this, the main objective when operating on a subtrochanteric nonunion is to achieve bone union, and we believe it provides more benefits than drawbacks, as was the case with our youngest patient, who underwent surgery up to three times prior. The use of a dynamic hip screw for trochanteric nonunion was first reported in 2011 [24] and recently reproduced with promising results [25; 26]. The trochanteric area is quite different from the subtrochanteric area. The physiological bone distribution forces are different; it is a less stressed and well-vascularized zone compared to the subtrochanteric area. Additionally, dynamic compression fixation is more straightforward to perform with a DHS. Over-valgus corrections of the hip have also been reported in recent papers. [PERSON] et al. [27] performed a valgus osteotomy, overcorrecting the valgus of the hip and fixing it with a molded 95\({}^{\circ}\) dynamic condylar screw. This technique does not allow for dynamic fixation; only static compression between fragments at the fracture site is achieved intraoperatively, and iliac autograft was needed in eight cases. Our technique is quite different and less demanding. Our valgus correction is gross, and the bone union is promoted through dynamic fixation using DHS. In contrast, the fibrous tissues at the nonunion site are unnecessary to remove, avoiding extra surgical procedures that can worsen the vascular deficit in this area, and no bone grafting is needed. They report that the preoperative mean HHS was 40, which improved to 85 postoperatively, with most patients reporting good or excellent results.