Subtrochanteric Femoral Fractures: Is a Nail or Plate Better?

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Chapter 61 Subtrochanteric Femoral Fractures: Is a Nail or Plate Better?

Subtrochanteric fractures remain a problematic fracture for treatment because of the local biomechanics, deforming forces of the attached musculature, and fracture configuration. The combination of high-stress concentration in an area of dense, cortical, hypovascular bone results in a propensity for nonunion. The soft-tissue stripping from the fracture can be further exacerbated with surgical dissection, resulting in a greater risk for delayed union and nonunion.

The deforming forces of the muscular attachments on the fragments combined with the effect of weight bearing result in the typical deformity of varus, apex anterior angulation, shortening, and external rotation of the proximal fragment. When inadequately corrected, a significant malreduction can increase the stress on the implant, leading to further deformity and implant failure. If the implant selected has poor fixation, or if weight-bearing limits are not adhered to, delayed displacement, malunion, or nonunion are the usual results.

Several classification systems are currently in use, including the Russell–Taylor classification,¹ the Seinsheimer classification,² and the AO/OTA classification. Each has its own method of stratification and nomenclature; however, they have not been shown to be useful in predicting treatment and outcome.^3,⁴

The treatment principles are similar to other nonarticular long bone fractures of the lower extremity. These include preoperative optimization, including smoking cessation, preoperative planning, surgical positioning, operative reduction and fixation emphasizing soft-tissue preservation, and postoperative rehabilitation protocols.

OPTIONS

The question of whether subtrochanteric femur fractures are best treated with an intramedullary nail device or an extramedullary plate device has been long debated and studied.^5,⁶ Devices currently in use include cephalomedullary nails, with either a piriformis or trochanteric start, and fixed-angle plating implants including blade plates, sliding hip screws, and locking plates. The purpose of this review is to guide surgeons in selecting the appropriate implant for this potentially troublesome fracture based on the best available evidence.

EVIDENCE

No Level I studies were available comparing treatment options for subtrochanteric fractures. The available Level II studies focused on pertrochanteric fractures, but few stratified for a subtrochanteric fracture group and even fewer specifically analyzed data for this fracture. Most of the studies were underpowered to show significant differences. Both biomechanical and clinical studies are available. However, extrapolating biomechanical results to the clinical situation must be done with caution because the most stable implant in the laboratory may not necessarily be optimal in a biological sense.

The available Level III and IV case series describing the treatment results with individual implants noted impressive success rates up to 100% and complication rates as low as 0%.⁷^–¹¹ Although these studies may give some indication as to the success and pitfalls of various implants, they provide little help in guiding treatment considerations of one implant versus another.

Specific patient or fracture characteristics may limit the treatment options available. In patients with previous surgery or hardware distally in the femur, such as a total knee prosthesis,¹² with previous deformity, or in pediatric fractures with open proximal growth plates, a fixed-angle plate device may be preferred. In patients with a significant lateral soft-tissue injury, or with extensive comminution or a segmental injury extending down the femoral shaft, a cephalomedullary nail is less traumatic to the soft-tissue envelope. In the case of a pathologic fracture, a cephalomedullary nail treats the fracture and provides prophylactic support or fixation for distal lesions.¹³ It would be difficult to produce randomized trials for each potential scenario comparing treatment strategy, and the level of evidence in this regard is therefore limited to Level V (expert opinion).

Biomechanics

The ideal fracture fixation device would be able to withstand the physiologic loads of postoperative rehabilitation. Typically, to stand in single-leg stance would axially load the femur with 750 N; however, walking or other activities of daily living would generate three to seven times that load.

Tencer and colleagues ¹⁴ compared seven devices in a cadaveric subtrochanteric fracture model tested in axial loading and found that the plate devices (compression hip screw and AO angled blade plate) failed between 1100 and 1500 N compared with a locked nail at 3000 N.

In a cadaveric study by Haynes and coworkers,¹⁵ the short Gamma nail (GN) was tested against the dynamic hip screw (DHS) in an osteotomized proximal femur simulating a subtrochanteric fracture with intertrochanteric extension. The authors found that in the harder bone model, the GN had a failure load of 5761 N versus the DHS with a failure load of 4660 N in axial loading. In the soft bone model, the failure loads were 5725 N for the GN and 3225 N for the DHS. The modes of failure were fractures of the femoral shaft around the distal locking screws for the GN, and lateral plate and screw pullout with the DHS.

It can be concluded from these and other similar studies that intramedullary devices are able to withstand greater axial loads than plate devices in unstable subtrochanteric fractures with medial comminution. The effect of nonaxial muscular forces on the fragments and construct stiffness may be a factor in the development of a delayed union or nonunion; however, the differences between implants in this regard have not been adequately reported in the literature.

Clinical Trials

Few studies include the comparison of an intramedullary device versus a plate device for subtrochanteric fractures in a randomized controlled trial. Ekstrom and coworkers ¹⁶ conducted a pertrochanteric fracture fixation trial on 203 patients that included analysis of the subtrochanteric fracture data, 18 treated with the proximal femoral nail (PFN), and 13 treated with the Medoff sliding plate (MSP) (Level III). They found significant advantages in operating room time, blood loss, and earlier ability to walk 15 m at 6 weeks for those treated with the PFN. The MSP held the advantage for shorter fluoroscopy time. They also studied other functional parameters including intraoperative complications, walking ability at 4 and 12 months, hospital stay, transfusions, infection, and mortality, and they found no significant differences.

Goldhagen and colleagues ¹⁷ randomized 75 patients with pertrochanteric fractures to compare the GN and the compression hip screw (CHS), which included analysis of 12 subtrochanteric fractures. The GN was used in seven patients, and the CHS was used in five. The authors found a trend for shorter operative time with the GN (82 vs. 99 minutes); however, they were unable to show statistical significance. Other outcomes studied including fluoroscopy time, blood loss, transfusions, length of hospital stay, functional outcomes, and mortality showed no difference (Level II).

In another study by Miedel and coauthors,¹⁸ 217 patients with pertrochanteric fractures were randomized to treatment with the standard Gamma nail (SGN) or a MSP. Their analysis included stratification of some of the subtrochanteric fracture data: 16 patients treated with the SGN, and 12 treated with the MSP. They report a greater postoperative fixation complication rate with the MSP with loss of reduction in two patients. In their pooled data analysis of all the fractures, they report better operative reduction, less blood loss, and lower mortality for those treated with the SGN. Other outcomes examined including intraoperative fractures, operative time, transfusions, infections, length of hospital stay, and functional outcomes showed no significant differences.

Parker and Handoll ¹⁹ report in the Cochrane review on cephalomedullary versus extramedullary implants for the treatment of extra-articular pertrochanteric fractures that there were better intraoperative results and less fracture fixation complications in the subtrochanteric subgroup treated with a cephalomedullary device (Level I).

Of the available randomized trials that pooled subtrochanteric and intertrochanteric data, most of the outcomes studied showed no difference, except for a significant incidence of femoral shaft fracture with the use of a short intramedullary device, and a subsequent greater reoperation rate ^20,²¹ (Level II).

RECOMMENDATIONS

Nails

The complication of femoral shaft fracture with short intramedullary devices has prompted further implant design and study. Kraemer and coworkers ²² used a cadaveric model to compare the Russell–Taylor reconstruction nail, the short intramedullary hip screw (IMHS), and the long IMHS in an unstable subtrochanteric fracture. In axial loading, the reconstruction nail and short IMHS were stiffer than the long IMHS in nondestructive cyclic loading. The reconstruction nail had the highest ultimate load to failure compared with either IMHS nails and failed by femoral head screw cutout, whereas the short IMHS failed by femoral shaft fracture.

In a cadaveric study by Wheeler and colleagues,²³ unstable subtrochanteric fractures were simulated and fixed with three different cephalomedullary nails, the Richards Russell–Taylor reconstruction nail, the Synthes spiral blade nail, and the Zimmer ZMS nail. The Richards and Zimmer constructs were significantly stiffer and had a higher failure load than the Synthes construct in axial loading. The Richards constructs typically failed by fracture of the distal femur at the interlocking screw holes. The Zimmer constructs failed by bending of the proximal end of the nail. The Synthes constructs failed by bending of the spiral blade and fracture of the femoral neck.

Starr and coauthors ²⁴ report on a series of pertrochanteric fractures treated with a piriformis start or trochanteric start cephalomedullary nail. They found no difference in intraoperative or postoperative parameters studied (Level I). Thus, if a nail is to be used, a long cephalomedullary nail with either a piriformis or trochanteric start and appropriate proximal and distal locking should be selected.

Plates

There remains a wide variety of plates used for subtrochanteric fractures, including blade plates, 95- and 135-degree sliding hip screw constructs, biaxial sliding constructs, and locking plates. Many of these implants have not been tested in a comparative study either biomechanically or in a randomized clinical trial.

Tencer and colleagues ¹⁴ report a study of seven types of fixation in a stable and unstable subtrochanteric fracture model. In the stable fracture model, the 150-degree hip screw and 95-degree blade plate demonstrated similar stiffness in torsion, which was significantly greater than the intramedullary implants tested (none in current use). In axial loading, both plate systems were as rigid as the nails. In the unstable fracture model, both plate systems remained stiffer than the nails in rotation, but resistance to axial loading was poor.

In a clinical trial, Madsen and researchers ²¹ report on randomized pertrochanteric fractures that the DHS with trochanteric side plate (TSP) had less postoperative redisplacement and lag screw cutout compared with the CHS. They also report a longer hospital stay with the DHS with TSP compared with the CHS (Level I). Another study by Lunsjo and coworkers²⁵ reports that the MSP had less fixation failure than the DHS, dynamic condylar screw, and DHS with TSP (Level I).

With the advent of new plate designs, as well as improvements in indirect reduction and biologic plating techniques, it remains unclear which plate construct is best suited for subtrochanteric fractures, although a fixed angle device with adequate proximal fixation is recommended.

Nails versus Plates

With the change in practice to using long intramedullary devices, femoral shaft fracture complications are rare; however, the apparent shorter operating room time reported with short intramedullary nails compared with plates ^16,¹⁷ may no longer be significant because of the extra time required to lock long nails distally. The disadvantage of greater intraoperative blood loss with plating is not seen clinically after surgery with the same transfusion rates as nailing.^16,¹⁸

A potential advantage of earlier return to function in unstable fractures with intramedullary nailing exists, as supported by increased resistance to axial loading seen in biomechanical studies (14, 15) and clinically by Ekstrom and coworkers,¹⁶ who reported better ability to walk 15 m at 6 weeks after surgery in those treated with an intramedullary nail. This difference is no longer seen at 4 and 12 months (Level III). This factor may be particularly important in patients who are unable to comply with postoperative weight-bearing restrictions.

Varus malreduction and inaccurate screw placement in the femoral head have been correlated with an increased risk for failure and further deformity.¹⁶ Given the lack of clear evidence of the superiority of one implant over another, it is likely more important that the surgeon chooses the implant with which they are most facile, and able to get the most accurate reduction and appropriate implant position, whereas maximally preserving the local biology and soft-tissue envelope.

With the new armamentarium of current implants and soft-tissue–preserving techniques, further study is needed to determine what differences exist between nails and plates, and in which fracture types they are best applied. Table 61-1 provides a summary of recommendations.

TABLE 61-1 Summary of Recommendations