Intertrochanteric Femoral Fracture
IT femoral fractures are extracapsular proximal femoral fractures located in the region between the greater and lesser trochanters. IT fractures represent approximately 50% of hip fractures in the elderly. Like FN fractures, they occur with a bimodal distribution, with most caused by low-energy falls in the elderly.
The IT region represents the anatomic transition from the FN to the femoral shaft. It is made of dense cancellous bone, and it is highly vascularized by the medial and lateral femoral circumflex arteries, which provide an improved healing environment (in comparison to intracapsular FN fractures). The region includes the calcar femorale, which is a vertical wall of dense posteromedial bone that aids in force transfer from the FN to the femoral shaft. Multiple muscle groups attach to the peritrochanteric region of the femur, which create fracture deforming forces that are critical in the understanding of fracture reduction. These muscle forces and attachments are further discussed in the ST portion of this review.
Multiple IT fracture classification systems have been developed; however, there is none that is consistently used. The Evans classification divides IT fractures into type I, in which the primary fracture line extends proximally and laterally from the lesser trochanter, and type II, in which the fracture line extends distally and laterally. The AO/OTA classification is a comprehensive system that defines IT fractures based on the number and orientation of fracture lines. Most practicing surgeons define IT fractures based on stability. Stable IT fractures maintain an intact posteromedial cortex, and unstable fractures involve comminution of the posteromedial cortex. Examples of unstable fracture patterns include fractures with a large posteromedial fragment, ST extension, and reverse obliquity fractures where the fracture line extends laterally and distally from the medial cortex.
Nonoperative management of IT femoral fractures is not indicated in the vast majority of individuals because of the high rate of associated morbidity and mortality. Nonoperative management results in prolonged immobilization and is associated with pneumonia, urinary tract infections, decubitus wounds, and deep venous thromboses. Most IT fractures are treated operatively and should be completed within 48 hr of the injury unless additional medical optimization will significantly decrease the surgical risk. Most IT fractures are managed with a sliding hip compression screw or a cephalomedullary nail (CMN); hip arthroplasty rarely is indicated in most centers. Fracture pattern dictates implant selection.
For stable IT fractures, SHS can be used. This involves a lateral plate with a fixed barrel through which a large compression screw enters the femoral head. The fracture is allowed to collapse in line with the angle of the barrel to provide dynamic interfragmentary compression and promote fracture healing.
CMN can be effectively used in most IT fracture patterns and are the most effective in treating unstable fractures. The implant involves an intramedullary rod with a compression screw that inserts into the femoral head (Figure 5). It allows for dynamic compression of the fracture, but it also provides a biomechanical advantage as the nail acts as an intramedullary buttress preventing excessive shaft medialization in addition to decreasing the lever arm of the construct. In the treatment of unstable IT fractures, the use of a CMN improved early mobility and decreased limb shortening when compared to the sliding hip screw. Hip arthroplasty can provide positive functional results with early postoperative weightbearing for IT fractures with severe comminution, preexisting symptomatic osteoarthritis, or severely osteoporotic bone that would not hold internal fixation. Optimal treatment of IT fractures requires intimate knowledge of IT anatomy, fracture patterns, and implant design.
For stable IT fractures, choice of implant has generally shown no significant difference in functional outcomes between SHS and intramedullary nailing, despite some theoretical advantages. SHS have the benefit of being more cost effective but have a higher rate of femoral neck shortening and medialization of the shaft, which contribute to abductor dysfunction. Several studies suggest that this biomechanical advantage confers an improvement in early mobility,[43,46] but controls for preinjury function are needed to support this evidence.
The length of the IMN used has shown no difference in functional outcomes or periprosthetic fracture rate,[48,49] although costs and operative times are lower for short nails. When periprosthetic fracture does occur, it happens at the midshaft in short nails and can often be fixed by exchanging for a long nail, whereas periprosthetic fracture in long nails tends to be a distal femoral fracture that can present greater treatment dilemmas. Distal locking results in decreased rates of periprosthetic fracture in both long and short nails.
Although biomechanically advantageous in terms of cutout when compared with screw and sideplate implants, helical blade intramedullary constructs confer no improvement in functional outcome or complications over single screw CMN fixation of the femoral head in IT fractures in some studies.[51,52] At least one study, however, shows an increased rate of medial blade penetration through the femoral head. Furthermore, studies have shown better healing and functional recovery when using intramedullary constructs with dual screw head fixation.
Studies show promising data regarding cement augmentation of IMN fixation in IT and ST fractures, and an augmented nail system has recently been approved in the US market for osteoporotic fractures. Cement augmentation has shown increased load to failure and stiffness over nonaugmented nails in cyclic testing, and a recent prospective RCT showed more stability and less varus angulation with cement versus a metal device alone.
Curr Orthop Pract. 2019;30(4):385-394. © 2019 Lippincott Williams & Wilkins