Indications for using cannulated screw fixation with open or closed reduction are impacted or minimally displaced femoral neck fractures in any patient or displaced femoral neck fractures in the younger patient (<60–65 years old; Figure 71.1). The sliding hip screw is another construct providing stable fixation useful in fixation of the femoral neck fracture in a younger patient. It may be necessary to perform an open reduction if a satisfactory reduction of the fracture cannot be achieved by closed means. Surgical treatment of the displaced femoral neck fracture in the younger patient is considered a
surgical emergency due to the increased risk of osteonecrosis and nonunion with these injuries that are believed to be increased with surgical delay.

Contraindications for cannulated screw fixation of a femoral neck fracture include any active infection in the affected hip or in those patients who are not stable enough to tolerate a surgical procedure for medical reasons.

Cannulated screw fixation is accomplished using three large (7.3-mm or 6.5-mm) cannulated screws that are placed over guidewires once adequate reduction is accomplished. If three independent cannulated screws are used, they are typically placed in an inverted triangle position across the fracture site to engage the femoral head. The most inferior screw is placed along the inferior cortex of the femoral neck to support the calcar; the other two screws are placed in the anterosuperior and posterosuperior positions. The starting point for the inferior screw is at or above the level of the lesser trochanter to prevent a stress riser in the subtrochanteric region, which can increase the risk of subtrochanteric fractures. Maximal spread of the screws within the femoral neck provides the most stable construct. If placed percutaneously, there is minimal soft-tissue disruption. However, open reduction is commonly performed in the younger patient with displaced femoral neck fractures in order to anatomically reduce the fragments and lessen the insult on the vascular supply to the femoral head. Weight-bearing restrictions after this treatment varies considerably, with bone quality, surgeon preference, and patient age each playing a role. Toe-touch or touch-down weight bearing on the surgical extremity is usually preferred to protect the reduction until fracture healing is confirmed clinically and radiographically. However, many elderly patients are unable to tolerate this due to loss of strength and balance. Therefore, they may weight bear as tolerated with an assistive device in order to preserve and promote as much mobility as possible.

Sliding hip screw fixation is preferred by some surgeons for fixation of midcervical and basicervical femoral neck fractures. It may offer biomechanical advantages while requiring more exposure. This technique is described in the intertrochanteric section to follow. When used in the femoral neck, a separate cannulated screw may be placed more proximally for rotational control.

Complications include osteonecrosis of the femoral head, nonunion or malunion, and screw penetration into the hip joint. These would present with acutely increased and persistent pain in the hip or groin region, which can limit rehabilitation. The abductors are rarely violated during this procedure; thus, postoperative Trendelenberg gait is not frequently seen. The occurrence of dislocation is generally very low; therefore, postoperative hip precautions are typically not necessary. As with all proximal femur fractures, there is a high risk of deep venous thrombosis (DVT) and/or pulmonary embolus (PE); thus, mechanical and chemical (when appropriate) prophylactic measures are essential to avoid this complication.

Indications for hemiarthroplasty include displaced femoral neck fractures in low-functioning, elderly patients (Figure 71.2). Those elderly patients who are higher functioning or those with preexisting hip osteoarthritis are candidates for the more costly total hip arthroplasty. The osteoporotic bone precludes reliable fixation, while the expected increased activity level may induce wear on the acetabular cartilage and pain.

Contraindications include any active infection within the hip or those who are not medically stable to undergo the operation.

Hemiarthroplasty involves removal of the femoral neck and head, and replacement with a prosthetic device. A bipolar hemiarthroplasty also contains an outer bearing over the prosthetic head that serves to theoretically decrease wear on the native articular surface of the acetabulum, while a unipolar hemiarthroplasty does not contain this outer bearing. A total hip arthroplasty replaces the femoral neck and head with a prosthetic component while replacing the acetabular surface with a prosthetic cup as well.

Anterolateral, direct anterior, and posterior surgical approaches are commonly used for hemiarthroplasty and total hip arthroplasty. Anterolateral approaches either utilize the intermuscular plane between the tensor fasciae latae and the gluteus medius, thereby sparing the abductors (Watson-Jones approach), or can split the gluteus medius anteriorly and detach a portion of the abductors from the greater trochanter. The direct anterior approach (Smith-Peterson, and its variants) utilizes an internervous plane between the sartorius (femoral nerve) and the tensor fascia lata (superior gluteal nerve), often detaching a portion of the reflected head of the rectus femoris. In both the anterolateral and direct anterior approaches, an anterior capsulotomy is performed to gain access to the hip joint. The posterior approach splits the gluteus maximus muscle and detaches the short external rotators prior to a posterior capsulotomy, leaving the abductors unviolated aside from intraoperative retraction. In each case, the proximal fracture fragment, including the femoral head, is removed and the neck is prepared with a cut perpendicular to the longitudinal orientation of the neck. The femoral canal is prepared with a series of broaches in order to accept the final implant. Femoral stems can either be cemented or uncemented depending on surgeon preference and the quality of the bone. In a total hip arthroplasty, the acetabular cup is then prepared with a series of reamers to medialize and position the replacement cup with appropriate anteversion and inclination. Once the components are implanted and reduced, care is taken to repair the capsulotomy. The abductors are then repaired in the case
of the anterolateral approach and the short external rotators are repaired in the case of the posterior approach. The subcutaneous tissues and skin are closed according to surgeon preference. Patients can weight bear as tolerated following hemiarthroplasty or total hip arthroplasty, though they often must maintain hip precautions during the initial postoperative period to decrease the risk of dislocation. For a posterior surgical approach to the hip and posterior capsulotomy, the hip is most unstable in flexion, adduction, and internal rotation. Thus, typical posterior hip precautions include no hip flexion past 70°, no adduction past the midline of the body, and no internal rotation of the hip past neutral. Typically, the patient is placed in a wedge-shaped abduction pillow postoperatively to prevent adduction while in bed. Also, low chairs and toilets are avoided to prevent excessive hip flexion. For anterior approaches to the hip with anterior capsulotomies, most instability occurs with abduction and external rotation. Patients are cautioned against such positioning, though specific devices are not as commonly needed to prevent these unwanted positions.