Principles and Evidence: The Optimal Treatment of Pertrochanteric Hip Fractures

Commentary This randomized clinical trial highlights several important principles in the management of pertrochanteric and subtrochanteric proximal femoral fractures in the elderly. The authors compared intramedullary and extramedullary fixation for these fractures with respect to pain, function, complications, and radiographic parameters for up to one year. As was the case in previous studies1, the authors were unable to identify a significant difference in functional outcome, although a recent large trial did show a trend toward better recovery of mobility with intramedullary fixation2. In the present study, the authors found that patients treated with nailing had slightly less pain with mobility early on but not after hospital discharge. However, there were differences in the radiographic parameters and some technical issues and complications that bear closer scrutiny. Lack of Sliding Increases the Risk of Implant Failure The authors reported several cases of cutout of both the nail and the sliding hip screw. In figures included with the article, it appears that this happened without the medial bone fragment having been able to move along the sliding implant axis. It bears reminding that both intramedullary and extramedullary devices can be used in sliding mode to maintain contact across the fracture surface and thereby promote bone healing. When a rigid or locked implant is used, resorption at the fracture site results in stress concentration across small fracture gaps and the likelihood of implant failure is high. With pertrochanteric fractures, this usually involves implant cutout as bone collapses around a nonsliding or locked implant3. If the bone cannot slide along the intended path of the sliding mechanism of the nail or plate, the construct becomes analogous to a locked implant and fixation cutout is more likely, especially in poor-quality bone. Avoidance of a varus position, attention to the tip-apex distance, and proper alignment on the lateral radiographic view should enable sliding in most cases of either intramedullary or extramedullary fixation. By design, sliding implants will result in some degree of shortening. The surgeon must consider how much shortening is likely to occur, how important this might be to patient function, and what alternatives there are to minimize fracture collapse. In very poor-quality bone and with a comminuted fracture, it may be impossible to prevent excessive collapse. In fact, the sliding mechanism may reach its limit, thus becoming a rigid implant, and cutout can still occur as the poor-quality bone continues to collapse around it. When excessive collapse is expected in otherwise highly functional/high-demand individuals, the surgeon might consider hip replacement arthroplasty to restore proper hip biomechanics. A Lateral Cortex Is Required Haidukewych has drawn attention to the fact that a sliding hip screw without a trochanteric side plate should never be used when there is no intact lateral cortex4. The intact lateral cortex above the level of insertion of the sliding hip screws is lost with type-A3 fractures and more proximal subtrochanteric fractures. As was true in previous reports1, the authors of this study included a variety of fracture patterns including type A3 (reverse obliquity) and a variety of subtrochanteric fractures. Ideally, these patterns would be studied separately from A1 and A2 fractures. Although the authors tried to stratify the subanalyses by fracture type, the small number of type-A3 (n = 139) and subtrochanteric (n = 20) fractures makes it difficult to draw firm conclusions, as statistical power is limited. However, the authors re-emphasized the fact that a sliding hip screw must not be used without a trochanteric side plate in these cases because there is no lateral cortex to stop sliding of the implant and therefore severe medialization of the shaft will inevitably occur. An intramedullary device may decrease medialization in these cases by acting as a metal buttress analogous to the trochanteric side plate but in a more medial location. Indeed, Table E-2 shows that medialization was significantly less with the nail for all fractures, presumably because the intramedullary metal stops the medial bone fragment from sliding before the lateral cortex or the metal side plate of the sliding hip screw does. Thus, in the absence of an intact osseous lateral cortex, one must create a barrier to excessive sliding with either an intramedullary (nail) or extramedullary (trochanteric side plate) metal device to avoid extreme shaft medialization. Varus and Other Technical Problems Nailing with a trochanteric start point can result in varus deformity with consequent shortening and increased risk of fixation failure. Table E-2 shows more varus deformity and more shortening with the nail. While the authors were unable to relate this to function or pain, another study showed femoral neck shortening and loss of offset in femoral neck fractures to be associated with a worse functional outcome in a group that included elderly patients5. Given that shortening and medialization (loss of offset) appear to be related to function, and because shortening was seen more commonly in the nail group and medialization was more prevalent in the sliding-hip-screw group, it may not be surprising that there was no functional difference between the two groups. Previous authors have described strategies to avoid varus deformity and shortening after nailing with a trochanteric start point4,6. For some comminuted pertrochanteric fractures and for most subtrochanteric fractures, my personal preference is to use a straight nail with a piriformis start point, which makes anatomic reduction easier in both planes. A variety of percutaneous reduction aids can be utilized. Regardless of the implant chosen, the important point is to have the fracture reduced during the entire process from guidewire insertion through reaming, nail insertion, and locking. Summary In summary, there is some prior evidence to suggest that even in elderly patients loss of femoral offset and length is associated with functional compromise. Treatment of proximal femoral fractures with either an intramedullary or an extramedullary sliding device results in some fracture collapse depending on the quality of bone. The intramedullary location of the nail may result in less medialization of the shaft by preventing excessive sliding, but it is more difficult to avoid varus deformity and associated shortening. The literature supports the use of either intramedullary or extramedullary devices for proximal femoral fractures. However, further study is required to determine optimal management strategies for specific fracture patterns, different sorts of bone quality, and different levels of patient demand. Surgeons should not limit themselves to one surgical strategy; instead, a thoughtful analysis of a given fracture pattern by the treating surgeon and expert execution capability of both intramedullary and extramedullary fixation are required to achieve optimal results for a given patient.

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