Open Reduction and Internal Fixation of the Hip
Patricia A. Gray, Mayra Saborio Amiran and Edward Pratt
Hip fractures are the bony injuries that require surgical intervention in the United States most frequently. The annual expense for the treatment of these patients has been estimated as high as $7.3 billion. Because the incidence of osteoporosis in our steadily aging population is increasing, the number of hip fractures is expected to increase from 275,000 per year in the late 1980s to more than 500,000 by the year 2040.1
Surgical Indications and Considerations
Numerous classification systems have been devised to describe hip fractures. However, in the context of surgical exposure, soft tissue injury, and rehabilitation potential, they can be simplified into five main categories:
1 Nondisplaced or minimally displaced femoral neck fractures
2 Displaced femoral neck fractures
3 Stable intertrochanteric fractures
All categories of these fractures can demonstrate good outcomes with surgical intervention and early mobilization.2 This is true regardless of age, gender, or comorbidities. The rare exception is an incomplete or impacted femoral neck fracture in a nonambulatory or extremely ill individual. The expected postoperative stability of the hip is directly proportional to the severity of the injury, the quality or density of the bone to be repaired, and the technical expertise of the surgeon.
The patient’s overall preinjury physical and mental condition is also a predictor of postoperative success. Patients with major cardiopulmonary afflictions, obesity, poor upper body strength, osteoporosis, or dementia in its various forms have increased risk for complications in the treatment of hip fractures. Overall mortality rates of 20% after 1 year, 50% at 3 years, 60% at 6 years, and 77% after 10 years have been reported.3 This is not surprising, because most hip fractures occur in the older adult population.
The traditional goal of rehabilitation has been to restore patients to the level of function that they had before the injury. In many cases this may not be realistic. Only 20% to 35% of patients regain their preinjury level of independence. Some 15% to 40% require institutionalized care for more than 1 year after surgery. Many—50% to 83%—require devices to assist with ambulation.4
Rehabilitation goals must be individualized, with the therapist taking into account all comorbidities, fracture severity, and motivational level of the patient.
Displaced or minimally displaced femoral neck fractures represent the least severe injuries in the spectrum of hip fractures. They are stable and can bear the full weight of the patient immediately after surgery. Moreover, they require no limitations on range of motion (ROM) or exertion in the immediate postoperative period. The preferred surgical procedure is a fluoroscopically aided placement of cannulated 6.5-mm screws through a limited or percutaneous lateral approach. This approach violates the skin, subcutaneous fat, deep fascia of the fascia lata, and fascia and muscle fibers of the vastus lateralis. Typically blood distends the joint capsule, creating some limitation in hip ROM and pain. No major nerves or vessels are at risk in this approach.
The patient is brought to the operating room, and anesthesia is induced. The patient is positioned supine on a fracture table capable of distracting and manipulating the affected limb. After satisfactory position of the fracture fragments is verified with an image intensifier, surgery is begun.
A 2-cm incision is made along the lateral femur in line with the fractured femoral neck. A guide pin is then placed percutaneously through the lateral musculature at or about the level of the lesser trochanter. The pin is introduced up the femoral neck and across the fracture into the subchondral bone of the femoral head. After two to four guide pins have been placed, the outer cortex is drilled with a cannulated drill and cannulated screws are introduced over the guide pins (Fig. 21-1). The soft tissues are repaired, and a dressing is applied. Femoral neck fractures that occur more toward the base of the femoral neck require fixation that is able to resist the bending movement between the femoral neck and shaft. These are treated much like intertrochanteric fractures, and the operative procedure is described in that section.
Displaced Femoral Neck Fractures
Femoral neck fractures in which the femoral head has been separated widely from the neck do not heal if reduced and fixed by screws or pins. In these fractures the vascular supply to the femoral head (specifically the medial and lateral femoral circumflex arteries) are often severed. In younger patients it is still desirable to attempt fixation despite the high rate of nonunion and osteonecrosis. When open reduction is attempted, the anterolateral exposure of Watson-Jones is preferred because it preserves the blood supply to the femoral head, which enters through the posteroinferior femoral neck.5 This approach is discussed in the section on total hip replacement (THR). Older adult patients are often best treated by bipolar, endoprosthetic, or THR procedures using a posterolateral approach.
The posterolateral approach involves violation of the skin; subcutaneous tissue; fascia lata; gluteus maximus; and short external rotators of the hip, including the piriformis, obturator internus, gemelli, and quadratus femoris. The capsule is incised posteriorly and often released anteriorly. Traction is applied on the gluteus maximus, gluteus medius, and gluteus minimus throughout the procedure. Nerves and vessels at risk include the sciatic nerve, the superior gluteal nerve, the inferior gluteal nerve, and their accompanying vessels. Although the psoas is left alone, it is often inflamed and can scar down and across the anterior hip capsule if adequate postoperative mobilization is not encouraged. Generally incisions are healed by 2 weeks, deep soft tissue healing is well advanced by 6 weeks, and full bony healing is expected at 12 weeks.
The patient is anesthetized and placed in the lateral decubitus position with the injured hip up (see Fig. 15-4); the torso is stabilized, and the hip and affected leg are draped to move freely. The initial incision is centered over the greater trochanter and taken distally 3 inches along the femoral shaft, then proximally and medially 4 inches along the course of the fibers of the gluteus maximus. The deep fascia is incised over the greater trochanter and carried distally along the same line as the skin incision, exposing the origin of the vastus lateralis without violating it. The surgeon digitally palpates the interval between the gluteus maximus and tensor fascia lata proximally, then extends the deep incision in this interval. A large, self-retaining retractor is then positioned to hold the deep fascia apart. The greater trochanteric bursa is incised to expose the short external rotators. The interval between the piriformis, gluteus medius, and gluteus minimus is identified, and the glutei are retracted anteriorly. Carefully the short external rotators are taken off the posterior femoral neck along the posterior hip capsule as a single cuff of tissue for later repair. Alternatively the capsule can be released separately with a T incision. Generally the surgeon must release the piriformis, gemelli, obturator internus, and half of the quadratus to expose the femoral neck to the level of the lesser trochanter. The hip is then flexed and internally rotated to bring the fracture into view. A saw is used to cut the femoral neck smoothly at the proper level, and the femoral head is retrieved from the acetabulum. The acetabulum is examined, and bone fragments are removed along with the ligamentum teres. After exposure is completed, the prosthesis is installed. It is often inserted in 15° to 20° more anteversion than was present with the biologic hip to minimize the risk of dislocation. This occasionally limits external rotation (ER) after surgery but usually not enough to create a functional impairment.
Closure is somewhat more controversial. The author prefers to repair the capsule and short external rotators with a large No. 2 nonabsorbable suture extending through drill holes in the greater trochanter and intertrochanteric line. This limits the formation of heterotopic bone, decreases the incidence of postoperative dislocation, and improves proprioception during rehabilitation. The deep fascia is then repaired, followed by the subcutaneous tissue and skin.
The initial postoperative rehabilitation is predicated on early mobilization to prevent morbidities associated with recumbency, such as deep venous thrombosis, atelectasis, pneumonia, decubiti, and loss of muscle strength and joint mobility. Full weight bearing is encouraged. After arthrotomy each patient must be educated and drilled regarding potentially dangerous hip positions that can lead to dislocation. The risk inherent in the posterolateral approach is greatest with hip flexion greater than 90° and internal rotation (IR), adduction, or both across the midline.
Patients with prosthetic hips should be instructed to follow their hip precautions religiously for the first 6 weeks after surgery, at which time the soft tissue has regained most of its tensile strength. Even then they are at greater risk of dislocation than they were before surgery.
Intertrochanteric Hip Fractures
Intertrochanteric hip fractures tend to be the most technically challenging. The intertrochanteric region joins the femoral shaft and neck at an angle of about 130°. 
The angular movement created by weight bearing is greatest here, and often weight bearing in the initial postoperative period is not feasible. Morbidity tends to be higher after these fractures, owing to significant comminution of bone and the resultant inadequate stabilization provided by the internal fixation.
These patients often must remain at touch down weight bearing (TDWB) or non–weight bearing until fracture healing is demonstrated. The most important prognosticator in this subset of patients is the evaluation of fracture stability (i.e., the tendency of the fracture to collapse or angulate under physiologic loads after surgery). Fractures with an intact posteromedial cortex and those at the base of the femoral neck are stable. These fractures tolerate limited weight bearing in the initial postoperative period without shifting. Surgeons best treat patients with these fractures by placing a sliding compression hip screw device in an anatomically aligned fracture.
The best surgical approach for the unstable fracture is controversial. Suggested approaches include hip screw devices with or without medial displacement, third-generation intermedullary reconstruction nail fixation, and calcar replacement endoprostheses. The surgical exposure for placement of a calcar replacement prosthesis is as described under the use of endoprostheses for displaced femoral neck fractures. The exposure and morbidity involved in the placement of an intermedullary nail are discussed in the section on subtrochanteric fractures. The exposure for placement of a dynamic compression hip screw is the same regardless of whether a stable or unstable fracture is being addressed. Typically a long lateral approach is used. This approach violates the skin, subcutaneous tissue, fascia lata, vastus lateralis fascia, and muscle belly. Generally in unstable fractures the lesser trochanter and inserting psoas tendon are left free, limiting hip flexion strength in the initial postoperative period.
Controversy exists as to whether it is better to align unstable fractures anatomically with a highly angled 145° to 150° compression plate and allow them to collapse into stability under physiologic loads or to perform a “medical displacement” osteotomy to obtain good posteromedial cortical abutment and stability during surgery (Fig. 21-2).
Both methods can lead to stability or instability; therefore each case must be discussed with the surgeon to ascertain the degree of stability obtained and the permitted amount of weight bearing. In addition, both methods shorten the distance between the insertion of the hip abductors in the greater trochanter and the center of rotation of the hip, creating a mechanical disadvantage for the abductors. This can lead to Trendelenburg gait, which must be overcome during the postoperative rehabilitation period.
The patient is placed supine on a fracture table with the afflicted limb in the traction boot. Care is taken to place the correct rotation on the distal limb to prevent malalignment. Reduction is carried out under an image intensifier until satisfactory reduction is achieved. Occasionally a satisfactory preoperative reduction is not possible because of posterior sag of the bony fragments, and further reduction must be done manually. After the limb has been prepared and draped, a lateral incision is made from the level of the greater trochanter distally approximately 7 inches, depending on the length of plate to be used. The incision is developed in the same line through skin, subcutaneous fat, and fascia lata. At this point the fascia of the vastus lateralis is followed posteriorly to its origin in the linea aspera. By incising it here the surgeon limits the amount of muscle denervated by the exposure and protects the main muscle mass from damage. The surgeon accesses the lateral cortex of the femoral shaft and places a retractor to maintain anterior retraction of the vastus lateralis, exposing the lateral femoral shaft. After exposure is completed, placement of the fixation device is begun (Fig. 21-3). Closure involves interrupted repair of the fascia of the vastus lateralis, fascia lata, subcutaneous tissue, and skin. The dynamic-compression screw device was not designed to hold the head and neck segment firmly (Fig. 21-4). Rather it allows the ambient muscle forces across the hip joint to pull the fracture fragments together until encountering good bony resistance. In many comminuted osteoporotic fractures, the ability of the screw device to contract is exceeded before good cortical abutment is obtained between the fracture fragments.
In such cases weight bearing must be curtailed until bony healing ensues, or the screw will “cut out” and all stabilization will be lost. Again, the skin is healed by 2 weeks, the deep fascia and soft tissues are healed by 6 weeks, and good bony healing is expected by 12 weeks. In older adult osteoporotic patients with severely comminuted fractures, bony healing can sometimes be delayed for as long as 4 to 6 months. In patients with obviously unstable fractures, weight bearing should be delayed until good bony healing is demonstrated on radiographs. The resultant collapse can often leave a limb significantly shorter. Leg length should be checked after healing and a lift provided if appropriate.
Subtrochanteric Hip Fractures
The use of advanced intermedullary nailing techniques has revolutionized the treatment of subtrochanteric fractures. Traditionally, these fractures have been difficult to fix because of the extreme angular force centered in this region, as well as the muscular deforming forces and minimal bony interface between the two fragments available for healing (Fig. 21-5).
Moreover, the bone in this region is more cortical in character, with a poorer blood supply and less osteogenic activity than in the intertrochanteric region. The use of a sliding compression screw device has yielded a higher implant failure and nonunion rate than in other regions. The femur can be stabilized with a static locked intermedullary nail without exposing the fracture or disturbing its periosteal blood supply. The two preferred methods of fixation for patients with these fractures are a routine lateral approach for the placement of an extended compression screw device and the placement of a static locked intermedullary nail. The exposure for the lateral compression plate is discussed in the section on intertrochanteric fractures and deviates only in that the exposure must be taken more distally, causing more damage to the fascia lata and the vastus lateralis.
Although this design stabilizes the fracture, weight bearing usually must be delayed, soft tissue exposure is extensive, and healing is often delayed because of destruction of periosteal blood supply around the fracture.
The more limited exposure for a static locked or reconstruction nail runs more proximally through the abductors, with a second stab incision for the interlocking screws at the level of the greater or lesser trochanter and a third stab incision laterally along the supracondylar femur. The newer reconstruction nails run the more proximal interlocking screws from the lateral femoral cortex (at the level of the lesser trochanter), and across and through the prefabricated holes in the nail in the intermedullary canal. The nails then run up the femoral neck, ending in the hard bone of the subarticular femoral head. The distal interlocking screws pass lateral to medial through the lateral cortex of the femur the nail, and finally the medial femoral cortex. This design effectively neutralizes deforming forces across the subtrochanteric femur, allowing full weight bearing from the outset (Fig. 21-6).
The patient is placed supine on a fracture table with both legs inserted into traction boots. Traction is applied over a perineal post. The legs are positioned with the involved leg adducted across the midline and slightly flexed at the hip. The uninvolved leg is abducted and extended at the hip, lying adjacent to the operative leg (Fig. 21-7). An incision is started 1 inch proximal to the greater trochanter (Fig. 21-8). It is developed proximally and slightly medially 3 inches. The surgeon then extends the incision through the skin and subcutaneous tissue to the fascia of the gluteus medius, which is divided for about 2 inches in line with the skin incision and the fibers of the gluteus medius. Using a small guide pin and fluoroscopy, the surgeon makes a small entry point at the base of the superior posterior femoral area, the piriformis fossa. The guide pin is passed down the femoral shaft approximately 6 inches, and a cannulated reamer is placed over the guide pin to enlarge the entry hole and begin the reaming process. A larger ball-tip guide that is run down across the fracture and down the intermedullary canal to the intercondylar notch replaces the initial guide pin. After this the canal is reamed with flexible reamers in progressively larger sizes until obtaining a good cortical fit. After overreaming a millimeter or two, the surgeon carefully inserts the nail across the fracture under fluoroscopic guidance and then inserts the interlocking screws. The screws at the proximal end of the nail are aimed with the use of a special jig that attaches to the proximal end of the nail (Fig. 21-9). They are inserted percutaneously through the deep fascia and vastus lateralis. The distal screws are usually placed freehand, again percutaneously, using the image to visualize the holes in the nail passing through the iliotibial band and vastus lateralis. Closure consists of repairing the deep fascia, subcutaneous tissue, and skin.
