Open Reduction and Internal Fixation of Femoral Neck Fractures

Lawrence X. Webb, MD, MBA

John C.P. Floyd, MD

Dr. Webb or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of the Musculoskeletal Transplant Foundation; serves as a paid consultant to or is an employee of Biocomposites; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research-related funding (such as paid travel) from Kinetic Concepts, Doctors Group, Smith & Nephew, Stryker, and Synthes; and serves as a board member, owner, officer, or committee member of the Orthopaedic Trauma Association Southeastern Fracture Consortium Foundation. Dr. Floyd or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew; serves as a paid consultant to or is an employee of Synthes; serves as an unpaid consultant to Bongiovi Medical and Health Technology; and has stock or stock options held in Bongiovi Medical and Health Technology.

INTRODUCTION

Femoral neck fractures most frequently occur through low-energy mechanisms (typically falls) in older individuals. Osteoporosis, which is more common in women, is thought to be a major contributor to the high incidence of this fracture in the elderly. This fact and the greater longevity of women account for the 4 to 1 ratio of women to men in the occurrence of femoral neck fractures.¹

Less commonly, femoral neck fractures occur in younger individuals through a high-energy mechanism. In this setting, accompanying injuries must be suspected, and early management using Advanced Trauma Life Support (ATLS) protocols is appropriate.²

Femoral neck fractures may be intracapsular or extracapsular. Extracapsular fractures (basicervical) behave biologically and mechanically like intertrochanteric fractures and usually can be managed with reduction and internal fixation using a fixed-angle device such as a sliding hip screw. This chapter focuses on the management of the intracapsular femoral neck fracture.

FIGURE 1 Illustration shows the Garden classification of femoral neck fractures. Garden I: incomplete (most often valgus-impacted). Garden II: complete, nondisplaced. Garden III: complete, incompletely displaced. Garden IV: complete, completely displaced.

It is important to carefully assess the morphology of the fracture. To this end, the classification systems of Garden (Figure 1) and Pauwels (Figure 2) are relevant.³^,⁴ The alphanumeric AO/Orthopaedic Trauma Association classification system also is used. This system is quite detailed and is used primarily in the research and publication settings.⁵

PATIENT SELECTION

Femoral neck fractures generally are managed surgically because morbidity and mortality are significantly higher with nonsurgical management.⁶ Surgical management with anatomic reduction (if the fracture is displaced) and secure fixation or arthroplasty is the best solution for pain control and patient mobilization. Nonsurgical management usually is reserved for patients who are medically extremely frail and in whom surgical intervention is contraindicated. Immobilization sets the stage for deep vein thrombosis, pulmonary emboli, and pneumonia. Pain associated with an unstable fracture presents the
need for ongoing narcotic pain medication. Hip immobilization and prolonged patient recumbency make skin breakdown and hip flexion contractures more likely. In otherwise nonsurgical candidates with a nondisplaced or incomplete fracture, a local anesthetic and percutaneous screw fixation may be appropriate.⁷ In nonsurgical candidates with displaced fractures, satisfactory relief of acute pain can be challenging. Consultation with a pain control service for regional anesthesia provided by way of an indwelling periarticular catheter may be useful, at least in the acute phase in select patients.⁸^,⁹

FIGURE 2 Illustration depicts the Pauwels classification of femoral neck fractures. Type I: The angle subtended by the horizontal and the line of the fracture on an AP radiograph is less than 30°. Type II: The angle subtended by the horizontal and the line of the fracture on an AP radiograph is between 30° and 50°. Type III: The angle subtended by the horizontal and the line of the fracture is greater than or equal to 50°.

PREOPERATIVE IMAGING

The patient with a femoral neck fracture has pain in the affected hip area and tenderness with motion and axial loading. With a displaced fracture, the lower extremity is shortened and externally rotated. A radiograph obtained while gentle traction is maintained gives a better depiction of the fracture anatomy. This is especially important when the fracture is displaced. When an open reduction and internal fixation is planned and neck comminution or segmentation is present, a CT scan with three-dimensional reconstruction views is helpful. The fracture usually is seen clearly on radiographs. The exceptions are nondisplaced and incomplete fractures. When plain radiographs fail to reveal these fractures in patients with a consistent history and physical findings, MRI is indicated.¹⁰

PROCEDURE

Instruments/Equipment/Implants

The equipment needed to successfully perform open reduction and internal fixation of femoral neck fractures includes the following: two Gelpi retractors; a C-arm; small, medium, and large pointed Weber tenaculum clamps; two Freer elevators; a dental pick; trocar-tipped terminally threaded Schantz pins (2.5 mm for the femoral head fragment and 5.0 mm for the distal trochanteric/femoral shaft fragment); and 2.0-mm Kirschner wires (K-wires). Required implants include 6.5-to 7.3-mm cannulated screws or, for Pauwels type III fractures, a 130° blade plate or its equivalent (eg, a spiral blade and side plate) and a bone graft if a need for grafting is anticipated. A minifragment set with 1.5-and 2.0-mm plates also should be in the room and available.

Surgical Technique

Internal fixation is appropriate for young patients (physiologic age <65 years) with an intracapsular femoral neck fracture. For patients with nondisplaced or minimally displaced fractures that are amenable to closed reduction, this is commonly accomplished on a fracture table. For patients with nondisplaced fractures (Garden types I and II) without the need for a reduction, this is commonly accomplished on a radiolucent table or a fracture table. Fixation can be provided by placement of parallel cannulated screws (Figures 3, 4, 5) or a sliding hip screw device, depending on the fracture pattern, bone quality, and surgeon preference. For patients with displaced fractures (Garden types III and IV), fixation is preceded by an open reduction that can be accomplished by a modified anterior (Smith Petersen) approach (Figure 6) or an anterolateral (Watson-Jones) approach¹¹^,¹² (Figure 7).

VIDEO 72.1 The Modified Smith Petersen Approach for Open Reduction and Internal Fixation of Femoral Neck Fractures. Lawrence X. Webb, MD; John C.P. Floyd, MD (5 min)

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Video 72.1

FIGURE 3 Photograph shows the parallel drill guide for 7.3-mm cannulated screws.

FIGURE 4 Illustrations show correct screw placement for femoral neck fracture fixation using three screws, which usually is sufficient. The pattern of screw placement is important. A, The first screw is directed tangential to and contiguous with the calcar at the level of the fracture on the AP view. Starting screws below the level of the lesser trochanter (dashed line) should be avoided to minimize the likelihood of an iatrogenic subtrochanteric fracture. B, On the lateral view, the first screw is seen bisecting the head and neck. C, The spread between the screws should be maximized, as shown on the cross-sectional view of the neck.

The modified Smith Petersen approach (Figure 6) can be used for the reduction and provisional fixation of the fractured femoral neck. In this approach, the patient is positioned supine on a radiolucent table with a folded sheet placed beneath the upper buttock on the affected side. This facilitates preparation and draping as well as obtaining a lateral C-arm view of the femoral neck and enables slight hip extension should it be needed in reduction. Following appropriate preparation and draping, the projected line between the anterior superior iliac spine and the lateral edge of the patella is incised caudally for approximately 15 cm, starting from 1 cm distal to the anterior superior iliac spine. The incision is deepened in the interval between the tensor fasciae latae muscle and the sartorius muscle, with care taken to avoid injury to the lateral femoral cutaneous nerve. The rectus femoris muscle lies at the base of the interval. The rectus femoris should be traced proximally to its tendon, which can be tagged with suture and tenotomized from its origin, leaving enough tendon attached to the anterior inferior iliac spine to afford an easy repair at closure. Once the muscle and its reflected head are elevated and retracted, the underlying hip capsule lies exposed and should be
opened in an inverted T fashion. It may be helpful to guide the ideal placement of the incision in the capsule by pulling gentle traction through the femur and approximating the reduction. The capsular leaves are tagged with suture, and suitable Hohmann retractors are introduced to enable direct visualization of the fracture.

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