Proximal femoral fractures with or without instability of fragments remain a topic of vivid discussion amongst orthopedic trauma surgeons. Operative treatment of IT hip fractures was introduced in the 1950s using a variety of different implants. Implants may be either extramedullary or intramedullary in nature. The most commonly used extramedullary implant is the sliding hip screw. In this study we sought to investigate the association between the construct failure rates and the stability of the fracture among patients with IT femur fractures who underwent this SHS fixation.
While we found no significant differences in union or revision surgery rates between the two patient cohorts, the incidence of screw cut-out was significantly higher in the group presenting with unstable IT fractures. Rates of infection and/or other complications were similar between the groups regardless of potential confounding factors.
Because revision surgeries are complex and technically demanding, various fixation techniques have been developed to improve anchorage of the lag screw in the femoral head and to maintain the bone fragments in position until the fracture has healed[24–26]. Many authors have reported excellent results when treating IT femur fractures with a SHS[27, 28].
Although the use of this sliding screw device presents many advantages, including controlled impaction at the fracture site and short operation time with no need for osteotomy, unstable fractures that are comminuted at the posteromedial cortex often become displaced because of excessive sliding and extrusion of the lag screw. For example, Steinberg and colleagues reported that the failure rate increased with screw sliding > 15 mm. Common causes of failure of fixation are instability of the fracture (most important), osteoporosis[29, 30], lack of anatomic reduction, failure of the fixation device, and the location of the screw within the femoral head[9, 16, 17]. However, we believe that poor reduction and implant position result in a poor prognosis in hip fracture treatment. In the present study, implant cutout and other surgical complications were associated with a higher TAD, poor reduction, or reduction more into varus but were independent of the type of implant. Therefore, an increased focus on surgical perfection, rather than implant selection, is probably the best way to address this problem. The increased medialization in the sliding hip screw in the unstable IT fractures could not be prevented by the trochanteric stabilizing plate, and our data do not allow us to quantify the extent to which a trochanteric stabilizing plate may have helped.
Other treatment modalities for unstable IT fractures include intramedullary devices, angle blade plates, and hemiarthroplasty, although these approaches may be more technically demanding. The current literature discusses the use of other devices for unstable IT fractures, including proximal femoral nails and Gamma nails[32, 33]. However, recent high-quality evidence does not support the use of intramedullary nailing devices over procedures using SHSs for the fixation of unstable IT femur fractures[34–36]. In their Cochrane review, Parker et al showed that the incidence of operative fracture of the femoral diaphysis is significantly increased when the Gamma nail is used (RR 3.02, 95% CI 1.51 to 6.03). Pooled data for cut-out of the implant from the femoral head showed no difference between implants (RR 1.15, 95% CI 0.76 to 1.72). Data for varus deformity (expressed as angulation greater than 10 degrees, malunion or deformity) showed no statistically significant difference between the two groups. In a prospective, randomized multicenter study of 684 elderly patients were treated with the INTERTAN nail or with a sliding hip screw, Matre et al found that Regardless of the fracture and implant type, functional mobility, hip function, patient satisfaction, and quality-of-life assessments were comparable between the groups at three and twelve months. The numbers of patients with surgical complications were similar for the two groups.
Treating unstable reverse oblique with a sliding hip screw is controversial, and is not recommended by many authors[20, 37–39]. Although it is clear that SHS yields superior results for stable fractures, our findings revealed no specific confounders that might be taken into consideration. SHS remains the gold standard for such injuries. In addition, the sliding hip screw is a less expensive implant. We have continued to favor the use of the sliding hip screw for IT fractures, but we are using an additional trochanteric stabilizing plate to prevent excessive medialization of the femoral shaft.
One of the strengths of this study is that our analysis included both simple and complex fracture patterns and that the procedures were performed by several surgeons. This design increases the generalizability of our results, closely resembling a real-life setting. However, a post-hoc analysis revealed that the study was underpowered due to limited sample sizes in both groups. Therefore, the results should be interpreted as exploratory in nature.