You are in: eMedicine Specialties > Orthopedic Surgery > HIP Subtrochanteric Hip FracturesArticle Last Updated: Jan 16, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Mark A Lee, MD, Assistant Professor, Department of Orthopedic Surgery, University of California at Davis School of Medicine Mark A Lee is a member of the following medical societies: AO Foundation and Orthopaedic Trauma Association Coauthor(s): Janos P Ertl, MD, Clinical Assistant Professor, Department of Orthopedic Surgery, University of California at Davis; Director of Amputee Clinic, Chief of Orthopedic Trauma, Kaiser Hospital Editors: Steven I Rabin, MD, Clinical Associate Professor, Loyola University Medical Center; Chair, Department of Orthopedic Surgery, Dreyer Medical Clinic; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; B Sonny Bal, MD, Associate Professor, Department of Orthopedic Surgery, University of Missouri School of Medicine; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; William L Jaffe, MD, Clinical Professor of Orthopedic Surgery, New York University School of Medicine; Vice Chairman, Department of Orthopedic Surgery, Hospital for Joint Diseases Author and Editor Disclosure Synonyms and related keywords: broken hip, hip pain, subtrochanteric femur fractures INTRODUCTIONSection 2 of 12
  History of the ProcedureDuring the last 50 years, the treatment of subtrochanteric femur fractures has evolved with improved understanding of both fracture biology and biomechanics. Previously, nonsurgical treatment of these fractures was associated not only with significant shortening and malrotation but also with the morbidity and mortality of prolonged immobilization. Early techniques of surgical repair demonstrated unacceptably high rates of complications; however, the benefits of restoring the anatomy and encouraging early mobilization are recognized and have led to significant research and improvement in implants. Currently, the subtrochanteric fracture remains technically challenging, even to experienced fracture surgeons.1, 2 ProblemThe difficult nature of treating this fracture stems in part from the fact that this injury pattern is anatomically distinct from other proximal femoral peritrochanteric fractures and also from the difficult features of femoral shaft fractures. As a result, it must be treated with specially designed implants that can withstand significant muscular forces for prolonged periods of healing. Not surprisingly, this fracture has significantly higher rates of malunion and nonunion than other femoral fractures. Still, with an improved understanding of this fracture and the specific treatment options, successful results can be attained.1, 2 FrequencySubtrochanteric fractures account for approximately 10-30% of all hip fractures, and they affect persons of all ages. Most frequently, these fractures are seen in 2 patient populations, namely older osteopenic patients after a low-energy fall and younger patients involved in high-energy trauma. EtiologyIn elderly patients, minor slips or falls that lead to direct lateral hip trauma are the most frequent mechanism of injury.3 This age group is also susceptible to metastatic disease that can lead to pathologic fractures. In younger patients, the mechanism of injury is almost always high-energy trauma, either from direct lateral trauma (eg, motor vehicle accident [MVA]) or from axial loading (eg, a fall from height). Gunshot wounds cause approximately 10% of high-energy subtrochanteric femur fractures. PathophysiologyThe subtrochanteric region of the femur, arbitrarily designated as the region between the lesser trochanter and a point 5 cm distal, consists predominantly of cortical bone. Healing in this region is predominantly through a primary cortical healing. Thus, the fracture is quite slow to consolidate.4 In addition, this region is exposed to high stresses during activities of daily living. Axial loading forces through the hip joint create a large moment arm, with significant lateral tensile stresses and medial compressive loads. In addition to the bending forces, muscle forces at the hip also create torsional effects that lead to significant rotational shear forces. During normal activities of daily living, up to 6 times the body weight is transmitted across the subtrochanteric region of the femur.5 Classification A universally accepted fracture classification does not exist for subtrochanteric femur fractures. The Arbeitsgemeinschaft für osteosynthesefragen–Association for the Study of Internal Fixation (AO-ASIF) has developed a complicated 3-part classification system with 10 subtypes that is most useful in research settings (see Image 4). In 1978, Seinsheimer presented an important classification with 8 subgroups that identified fractures with loss of medical cortical stability (see Image 3).6 The Russell-Taylor classification system is helpful because it assists in determining the proper mode of treatment (see Image 5). Type 1 fractures do not involve the piriformis fossa. They are subdivided into type A, for fractures below the lesser trochanter, and type B, for fractures involving the lesser trochanter. Type 2 fractures involve the piriformis fossa. Type 2A fractures have a stable medial buttress. Type 2B has no stability of the medial femoral cortex. Type 1 fractures can be treated with first- or second-generation intramedullary devices while type 2 fractures typically require open reduction and internal fixation (ORIF) with screw plate devices or fixed-angle implants. ClinicalPhysical findings at the time of injury often include a shortened extremity on the fractured side. Significant swelling is frequently present, with tenderness to palpation in the proximal thigh region. The leg may lie in internal or external rotation. The patient cannot flex the hip or abduct the leg. Hemorrhage into the injured thigh may be substantial, and the patient should be monitored for systemic shock and compartment syndrome. In high-energy fractures, a complete system examination must be performed. Associated injuries to the cranium, thorax, and abdomen (Waddell triad) must be recognized.7 Pelvic, spine, and long bone injuries are also common, especially on the ipsilateral side, and these should be identified early to optimize treatment and outcomes. INDICATIONSSection 3 of 12
The goals of treatment are important to recognize and include anatomic alignment, early mobilization, and effective rehabilitation. With the improvements in surgical techniques and implants, most of these goals can be achieved with surgical treatment. Current indications for surgical treatment include displaced and nondisplaced fractures in adults, fractures in patients with multiple traumatic injuries, open fractures, severe ipsilateral extremity injuries, and pathologic fractures. RELEVANT ANATOMYSection 4 of 12
The subtrochanteric region of the femur consists primarily of cortical bone. The femoral head and neck are anteverted approximately 13º with respect to the plane of the femoral shaft. The piriformis fossa lies at the base of the neck and is oriented in line with the femoral shaft. The lesser trochanter is posteromedial, and it is the point of insertion for the psoas and iliacus tendons. The femoral shaft has both an anterior and a lateral bow. The major muscles that surround the hip create significant forces that contribute to fracture deformity. The gluteus medius and minimus tendons attach to the greater trochanter and abduct the proximal fragment. The psoas and iliacus attach to the lesser trochanter and flex the proximal fragment. The adductors pull the distal fragment medially. All of these muscles are well vascularized, and this can lead to significant hemorrhage at the time of injury or during surgical approaches. In order to approach the proximal lateral femur, the vastus lateralis must be split or elevated off the intermuscular septum close to the large perforating branches of the profunda femoris artery. Division of these vessels can lead to copious bleeding, making surgical exposure difficult. CONTRAINDICATIONSSection 5 of 12
In selected patients with grossly contaminated fractures and in patients who are medically unstable for surgical intervention, treatment with skeletal traction can be considered. In skeletally immature patients, traction followed by cast bracing is an accepted treatment option. WORKUPSection 6 of 12
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TREATMENTSection 7 of 12
Medical therapyDuring the past 25 years, treatment of subtrochanteric fractures in adults has become almost exclusively surgical. A number of nonsurgical treatment protocols are of historic interest. In the late 1960s, cast bracing was used but was soon abandoned because of poor results with fractures in the subtrochanteric region. Treatment with traction was also advocated, followed by fracture bracing with a hip spica cast. However, with increasing evidence of the morbidity of prolonged bed rest in elderly people or in patients with multiple traumatic injuries, nonoperative treatment methods are seldom used. Surgical therapySurgical treatment can be divided into 3 main techniques: external fixation, open reduction with plates and screws, and intramedullary fixation. External fixation is rarely used but is indicated in severe open fractures. For most patients, external fixation is temporary, and conversion to internal fixation can be made if and when the soft tissues have healed sufficiently. External fixation becomes complicated when significant fracture comminution extends proximally, which may require more proximal stabilization to the iliac crest.8, 10, 11, 12 13 In 1984, Tencer compared the biomechanical attributes of 7 different plate and intramedullary fixation devices for subtrochanteric femur fractures.14 Femur-implant constructs using intramedullary devices had up to 5% torsional stiffness as compared to intact cadaveric femora tested identically, while plate-fixed fractures were nearly 50% as stiff. In combined bending and compression to failure, a test to simulate forces due to body weight, the intramedullary locked rods were found to support 300-400% of body weight, while the plate systems failed at loads 100-200% of body weight.15 When plate fixation is chosen for fixation of subtrochanteric fractures, the traditional option is the AO-ASIF blade plate. This implant was first used 3 decades ago, with variable success rates. High union rates were reported when the procedure was appropriately planned, and medial dissection was avoided. However, high rates of complications were also reported with this technique. As a result of the complications and the technical difficulties inherent in the blade plate technique,16 the sliding hip screw (dynamic hip screw [DHS]) and the dynamic condylar screw (DCS) evolved as treatment options.17, 18, 19 These devices were believed to allow fracture impaction, and they had the biomechanical advantages of the blade plate but with a less complicated insertion technique. Several early reports suggested good rates of fracture union and low complication rates with both devices. Intramedullary nails are emerging as the treatment of choice for subtrochanteric femur fractures.20, 21 The most widely used nails are either centromedullary (contained within the medullary canal) or cephalomedullary (including those that affix to the femoral neck and head). Essentially all subtrochanteric fractures below the level of the lesser trochanter can be nailed with a centromedullary locking nail. For fractures with extension above the lesser trochanter (Russell-Taylor type 2), a fixed-angle device such as a blade-plate or DCS can be used, but these seem to provide less predictable results. Most type 2A and 2B fractures can be successfully treated with cephalomedullary nails, such as the Richards reconstruction nail or the gamma nail.22 Preoperative detailsPreoperative templating is advisable. Treatment of these fractures is technically demanding, and the surgeon needs flexibility in the choice of implant and approach. When proximal comminution requires the use of a fixed angle device, detailed templating is required to ensure that an implant with the proper blade or compression screw length, as well as plate length, is chosen. When an intramedullary device is chosen, templating for length, as well as canal diameter, is necessary for proper planning. In addition, because significant comminution could make limb length determination difficult, it can be helpful to obtain radiographs of the unaffected femur with a ruler to ascertain the normal femur length. Intraoperative detailsThe proximal fracture fragment is invariably flexed and externally rotated. If a reconstruction type nail is chosen, it is particularly difficult to locate the piriformis fossa in the proximal fragment. Occasionally, a small incision with insertion of a bone hook, fracture clamp, or Schanz pin can be helpful to orient the proximal fragment. During intramedullary nailing, the intramedullary fracture reduction tool is frequently helpful to reduce the proximal fragment for guidewire passage. Care must be taken to maintain the reduction during reaming to avoid eccentric reaming and fracture malposition after nail insertion. If a trochanteric nail, such as the Gamma nail, is chosen, the entry point for the device is easier to localize, even with small incisions. Still, malrotation of the fracture fragments can make this task difficult. In addition, proximal fragment comminution makes reduction and positioning of the head and neck fragment challenging. During plating, comminution at the proximal lateral femur can make lateral start site localization very difficult. It is frequently helpful to position a guidewire anteriorly on the femoral neck, approximating the axis of the femoral neck, to assist in proper orientation of the starting chisel in the proximal femoral fragment. Fractures with large fragments and limited comminution can typically be reduced with traditional techniques, including lag screw fixation of fragments followed by plate neutralization. However, in the presence of severe comminution, indirect reduction and minimally invasive bridge plating techniques may preserve the soft tissues and contribute to successful union. Acute bone grafting is occasionally suggested but is most likely appropriate in the setting of comminution, including the medial cortical buttress along the proximal calcar region of the proximal femur in closed fractures. In the setting of pathologic fractures, prophylactic stabilization of the entire femur may be indicated to prevent problems with multiple metastases in the same bone and facilitate possible treatment with radiotherapy. If an intramedullary device is chosen, care must be taken to ensure that adequate material for biopsy is obtained, usually with the intramedullary reamings. If necessary, open fracture reduction may be facilitated to obtain adequate material for pathologic analysis. Postoperative detailsFollowing intramedullary nailing, if the bone quality and cortical contact is adequate, 50% partial weightbearing can be allowed immediately. With less stability, patients can perform touchdown weightbearing. Following ORIF and plate fixation, minimal protected weightbearing can begin immediately but is advanced slowly beginning approximately 4 weeks after surgery, with full weightbearing anticipated at 8-12 weeks. Elderly patients may have difficulty with compliance with weightbearing restrictions. Such patients are slow to progress and generally avoid aggressive weightbearing on the injured extremity. As a result, most elderly patients can be safely permitted to progress to full postoperative weightbearing status. Follow-upClose follow-up is required following fixation of subtrochanteric fractures. The wound is checked for proper healing 7-14 days postoperatively. The patient should have monthly clinical evaluations and radiographs to monitor healing. Quadriceps rehabilitation should begin within 2 weeks postoperatively. Most patients have significant disability for a minimum of 4-6 months. The authors suggest that impact activities may be possible at 6 months, but patients should wait a full year before returning to full contact sports. If a nonunion becomes evident, autogenous bone grafting is usually indicated, usually before 1 year has passed since the index procedure, to avoid hardware failure. COMPLICATIONSSection 8 of 12
Common complications include nonunion, malunion, failure of fixation, and wound infection.23 Nonunion is usually accompanied by significant pain after 4-6 months with the inability to bear full weight. If not obvious on plain radiography, tomography may help delineate nonunions; occasionally, bone scanning can be helpful. In the presence of stable fixation, autogenous bone grafting can lead to successful fracture unions. In patients treated with intramedullary nails, exchange nailing with over-reaming is also appropriate with or without static locking of the new nail device. Malunion is usually evident as a limp from shortening or rotational deformity with limitation of hip rotation. Frequently, gross rotational deformity can be detected prior to awakening a patient from an intramedullary nailing procedure and can be corrected at that time. Late detection of malrotation may require a derotational osteotomy of the affected bone. Shortening is often secondary to varus at the neck shaft junction and can be addressed with a valgus osteotomy. Failure of a screw plate device can be salvaged with a repeat plating and bone graft procedure or with second-generation nailing. Deep sepsis may be manifested by fracture nonunion. Workup for infection includes standard hematologic analysis including WBC, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). In addition, aspiration can occasionally be diagnostic. Finally, WBC scanning can also provide information about deep infection. OUTCOME AND PROGNOSISSection 9 of 12
Relatively few data exist regarding the outcome of patients with subtrochanteric femur fractures. In young patients, these injuries are common among patients with multiple traumatic injuries; thus, outcomes are likely to be poorer than those in patients with isolated femur fractures. Associated fractures and soft tissue injuries to the knee can complicate rehabilitation efforts. In older patients, subtrochanteric fractures can be grouped with other proximal femur fractures with relatively high morbidity and mortality. FUTURE AND CONTROVERSIESSection 10 of 12
The use of indirect reduction techniques may prove beneficial in those fractures stabilized with plate fixation techniques. In 1989, Kinast et al demonstrated a lower delayed union/nonunion rate and more rapid consolidation with blade plate fixation and indirect reduction versus blade plate fixation via direct visualization.24 As minimally invasive plating techniques evolve and improve, applications in high-energy proximal femoral fractures may become feasible and allow for a more biologically favorable approach with less soft tissue dissection and disruption of native blood supply. There is no literature regarding total hip arthroplasty (THA) for subtrochanteric fractures in elderly patients, and any conclusions must be extrapolated from data regarding THA for femoral neck fractures or intertrochanteric fractures. This body of literature suggests possible functional advantages, such as more rapid mobilization and shorter lengths of stay in select groups (eg, pathologic fractures, fractures in patients with renal disease, patients with pre-existing arthritis). Thus, the authors consider THA in this fracture type quite controversial.25 MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Subtrochanteric Hip Fractures excerpt Article Last Updated: Jan 16, 2008 | ||||||||||||||||||||||||||||||||||||||||
