Associated Injuries with Hip Fractures
Because these fractures are caused by high-energy trauma, they frequently are accompanied by associated injuries that can affect the patient’s overall outcome. Pape et al.,85 in a series of 28 patients with a mean follow-up of 11 years, found favorable outcomes in type II, III, and IV fractures according to Ratliff’s criteria.98 Poor functional outcomes were attributed to head trauma, amputation, or peripheral neurologic damage.85 In a series of 14 patients with hip fractures, all of which were caused by vehicular accidents or falls from heights, 12 patients had associated injuries including head and facial injury, other fractures, as well as visceral injury.78 In a series of fractures from high-energy trauma, Bagatur and Zorer5 similarly found associated injuries in 4 of their 17 patients. Infants with hip fractures and without a plausible cause for fracture should be evaluated for nonaccidental trauma by a careful history and an examination of the skin, other extremities, trunk, and head. Further skeletal radiographic imaging is often indicated, and an evaluation by a child protective team is required to diagnose life-threatening head and visceral injuries that can be easily missed in this group.
Signs and Symptoms of Hip Fractures
The diagnosis of hip fracture in a child is based on the history of high-energy trauma and the typical signs and symptoms of the shortened, externally rotated, and painful lower extremity. Clinical examination is usually obvious, and a patient with a complete fracture is unable to ambulate because of severe pain in the hip and has a shortened, externally rotated extremity. With an incomplete or stress fracture of the femoral neck, the patient may be able to bear weight with a limp and may demonstrate hip or knee pain only with extremes of range of motion, especially internal rotation. An infant with a hip fracture holds the extremity flexed, abducted, and externally rotated. Infants and newborns with limited ossification of the proximal femur can be challenging patients to diagnose with hip fractures as the differential diagnosis can include infection and congenital dislocation of the hip. In the absence of infection symptoms, pseudoparalysis, shortening, and a strong suspicion are the keys to a fracture diagnosis in this age group.
Imaging and Other Diagnostic Studies for Hip Fractures
A good-quality anteroposterior (AP) pelvic radiograph will provide a comparison view of the opposite hip if a displaced fracture is suspected. For the pelvic radiograph, the leg should be held in extension and in as much internal rotation as possible without causing extreme pain to the patient. A cross-table lateral radiograph should be considered to avoid further displacement and unnecessary discomfort to the patient from an attempt at a frog-leg lateral view. Any break or offset of the bony trabeculae near Ward triangle is an evidence of a nondisplaced or impacted fracture. Nondisplaced fracture or stress fractures may be difficult to detect on radiographs. Special studies may be required to reveal an occult fracture as case examples of further displacement of nondisplaced fracture have been reported.40 Adjunctive studies for stress fracture diagnosis may include a magnetic resonance imaging (MRI), computed tomography (CT) scan, or a technetium bone scan which can demonstrate increased uptake at the fracture site. The typical MRI appearance of a fracture is a linear black line (low signal) on all sequences surrounded by a high-signal band of bone marrow edema and hemorrhage. The low signal represents trabeculae impaction (Fig. 26-2). MRI may detect an occult hip fracture within the first 24 hours after injury.59 In addition, pathologic fractures may require special imaging to aid diagnosis or to fully appreciate bone quality which would impact implant placement. MRI is also a useful test in planning treatment for a pathologic fracture; this test will delineate soft tissues in and around the fracture, which can provide insight into diagnosis and delineate high-yield areas for biopsy.
In infants, an ultrasound can be used to detect epiphyseal separation. In addition, an ultrasound can determine if the patient’s epiphysis is located and the presence of an effusion which may be aspirated to confirm diagnosis of sepsis. A bloody aspirate establishes the diagnosis of fracture, whereas a serous or purulent aspirate suggests synovitis or infection, respectively. If performed in the operating room, an aspiration and confirmatory arthrogram of the hip can also be useful, especially if closed reductions and cast immobilization is chosen for the newborn with physiolysis.
In a patient with posttraumatic hip pain without evidence of a fracture, other diagnoses must be considered, including Perthes disease, synovitis, spontaneous hemarthrosis, and infection. A complete blood count, erythrocyte sedimentation rate, C-reactive protein, and temperature are helpful to evaluate for infection. MRI scan is a useful test to diagnose aseptic ON as a result of Perthes disease or more remote causes of necrosis. In children under 5 years of age, developmental coxa vara can be confused with an old hip fracture.18
Classification of Hip Fractures
Pediatric hip fractures generally are classified by the method of Delbet (Fig. 26-3).26 This classification system continues to be useful because it is not only descriptive but also has prognostic significance.74 In general, more significant rates of ON and growth arrest are noted in fractures in the proximal end of the femoral neck (type I and type II injuries); whereas lower rates of ON are noted in type III and type IV injuries. Conversely, the latter two groups tend to have higher rates of significant varus malunion if not treated appropriately. Subtrochanteric fractures have been included by some in the discussion of proximal femoral fractures but they are not included in the Delbet classification and are discussed elsewhere.
Transphyseal fractures occur through the proximal femoral physis, with (type IA) or without (type IB) dislocation of the femoral head from the acetabulum (Fig. 26-4). Such fractures are rare, constituting 8% of femoral neck fractures in children.58 Approximately half of type I fractures are associated with a dislocation of the capital femoral epiphysis. True transphyseal fractures tend to occur in young children after high-energy trauma19,34 and are different from unstable slipped capital femoral epiphysis (SCFE) of the preadolescent, which usually follows a prodromal period of activity-related hip or knee pain. Unstable SCFE differs from traumatic separation as it occurs following minor trauma, which is superimposed on a weakened physis from a combination of multiple factors including obesity and subtle endocrinopathy.
Iatrogenic fracture of the physis in children and adolescents may occur during reduction of a hip dislocation (Fig. 26-5).15,55 It is possible that these patients had unrecognized physeal injury at the time of dislocation or, alternatively, the epiphysis may be displaced with vigorous reduction methods.
Transphyseal fractures without femoral head dislocation have a better prognosis than those with dislocation. Similarly, in children under 2 or 3 years of age, a better prognosis exists than in older children. ON in younger children is unlikely, although coxa vara, coxa breva, and premature physeal closure can cause subsequent leg length discrepancy.18,21 In cases of femoral head dislocation in a type I fracture, the outcome is dismal because of ON and premature physeal closure in virtually 100% of patients.19,34
Transcervical fractures are the most common fracture type (45% to 50% of all femoral neck fractures),58 which occur between the physis and are above the intertrochanteric line, and by definition are considered as intracapsular femoral neck fractures. Nondisplaced transcervical fractures have a better prognosis and a lower rate of ON than displaced fractures, regardless of treatment.19,80,98 Necrosis can still occur in minimally displaced fractures, and this may be because of the fact that it is difficult to document how much displacement occurs at the time of trauma. Moon and Mehlman74 performed a meta-analysis of available literature and documented a 28% incidence of ON in type II fractures. The occurrence of ON is thought by these and other investigators to be directly related to fracture displacement, which may lead to disruption or kinking of the blood supply to the femoral head. In addition, the meta-analysis demonstrated higher rates of ON in children older than 10 years at the time of their injury.80 Because the pediatric hip capsule is tough and less likely to tear, some have hypothesized that a possible etiology of vascular impairment in minimally displaced fractures is a result of intra-articular hemarthrosis leading to vessel compression from tamponade.19,58
Cervicotrochanteric fractures are, by definition, located at or slightly above the anterior intertrochanteric line and are the second most common type of hip fracture in children, representing about 34% of fractures.58 It is conceivable that a certain portion of these fractures may be intra- and extracapsular as a result of anatomic differences in capsule insertion. Nondisplaced type III fractures also have a much lower complication rate than displaced fractures. Displaced type III fractures are similar to type II fractures in regard to the type of complications that can occur. For instance, the incidence of ON is 18% and is slightly less than in type II fractures80; the risk of ON is directly related to the degree of displacement at the time of injury.14 Premature physeal closure occurs in 25% of patients, and coxa vara can also occur in approximately 14% of patients.58
Intertrochanteric fractures account for only 12% of fractures of the head and neck of the femur in children.58 This fracture is completely extracapsular and has the lowest complication rate of all four types. Nonunion in this fracture is rare, and Moon and Mehlman74 documented a rate of ON of only 5%, which is much lower than in intracapsular fractures. Coxa vara and premature physeal closure have occasionally been reported.19,58,68,97,98
Unusual Fracture Patterns
Rarely, proximal femoral physiolysis occurs during a difficult delivery and can be confused on radiographs with congenital dislocation of the hip. Type I fracture in a neonate deserves special attention. This injury is exceedingly rare and, because the femoral head is not visible on plain radiographs the diagnosis can be difficult and the index of suspicion must be high. The differential diagnosis includes septic arthritis and hip dislocation. Plain radiographs may show a high-riding proximal femoral metaphysis on the involved side, thus mimicking a congenital hip dislocation. Ultrasonography is useful in diagnosis of neonatal physiolysis; with this test, the cartilaginous head remains in the acetabulum but its dissociation from the femoral shaft can be appreciated. The diagnosis can be missed if there is no history of trauma or if there is an ipsilateral fracture of the femoral shaft.2 In the absence of a known history of significant trauma in a young child, nonaccidental trauma should be ruled out.115
Stress fractures are caused by repetitive injury and result in hip or knee pain and a limp. Pain associated with long-distance running, marching, or a recent increase in physical activity is suggestive of stress fracture. Close scrutiny of high-quality radiographs may identify sclerosis, cortical thickening, or new bone formation. Undisplaced fractures may appear as faint radiolucencies. If radiographs are inconclusive, adjunctive tests such as MRI, CT, or bone scintigraphy may be helpful.
An unstable SCFE can be mistaken for a traumatic type I fracture; however, SCFE is caused by an underlying abnormality of the physis and occurs after trivial trauma, usually in preadolescents, whereas type I fractures usually occur in young children. Often in a SCFE there may be signs of remodeling or callous of the femoral metaphysis.
Fracture after minor trauma suggests weakened bone possibly from systemic disease, tumors, cysts, and infections. If the physical and radiographic evidences of trauma is significant but the history is not consistent, nonaccidental trauma must always be considered.3,115 In the multiply traumatized patient, it is easy to miss hip fractures that are overshadowed by more dramatic or painful injuries. Radiographs of the proximal femur and pelvis are obtained and examined carefully in patients with femoral shaft fractures because ipsilateral fracture or dislocation of the hip is not unusual.2
PATHOANATOMY AND APPLIED ANATOMY RELATING TO HIP FRACTURES
Ossification of the femur begins in the seventh fetal week.34 In early childhood, only a single proximal femoral chondroepiphysis exists. During the first year of life, the medial portion of this physis grows faster than the lateral, creating an elongated femoral neck by 1 year of age. The capital femoral epiphysis begins to ossify at approximately 4 months in girls and 5 to 6 months in boys. The ossification center of the trochanteric apophysis appears at 4 years in boys and girls.58 The proximal femoral physis is responsible for the metaphyseal growth in the femoral neck, whereas the trochanteric apophysis contributes to the appositional growth of the greater trochanter and less to the metaphyseal growth of the femur.25 Fusion of the proximal femoral and trochanteric physis occurs at about the age of 14 in girls and 16 in boys.52 The confluence of the greater trochanteric physis with the capital femoral physis along the superior femoral neck and the unique vascular supply to the capital femoral epiphysis makes the immature hip vulnerable to growth derangement and subsequent deformity after a fracture (Fig. 26-6).
Because of the frequency and sequelae of ON of the hip in children, the blood supply has been studied extensively.24,50,57,89 Postmortem injection and microangiographic studies have provided clues to the vascular changes with age. These observations are as follows.
• At birth, interosseous continuation of branches of the medial and lateral circumflex arteries (metaphyseal vessels) traversing the femoral neck predominately supply the femoral head. These arteries gradually diminish in size as the cartilaginous physis develops and forms a barrier thus preventing transphyseal continuity of these vessels into the femoral head. Thus metaphyseal blood supply to the femoral head is virtually nonexistent by age 4.
• When the metaphyseal vessels diminish, the intracapsular lateral epiphyseal vessels predominate and the femoral head is primarily supplied by these vessels, which extend superiorly on the exterior of the neck, bypassing the physeal barrier and then continuing into the epiphysis.
• Ogden83 noted that the lateral epiphyseal vessels consist of two branches: The posterosuperior and posteroinferior branches of the medial circumflex artery. At the level of the intertrochanteric groove, the medial circumflex artery branches into a retinacular arterial system (the posterosuperior and posteroinferior arteries). These arteries penetrate the capsule and traverse proximally (covered by the retinacular folds) along the neck of the femur to supply the femoral head peripherally and proximally to the physis. The posteroinferior and posterosuperior arteries persist throughout life and supply the femoral head. At about 3 to 4 years of age, the lateral posterosuperior vessels appear to predominate and supply the entire anterior lateral portion of the capital femoral epiphysis.
• The vessels of the ligamentum teres are of virtually no importance. They contribute little blood supply to the femoral head until age 8, and then only about 20% as an adult.
The above information has clinical importance. For instance, the multiple small vessels of the young coalesce with age to a limited number of larger vessels. As a result, damage to a single vessel can have serious consequences; for example, occlusion of the posterosuperior branch of the medial circumflex artery can cause ON of the anterior lateral portion of the femoral head.18
It is also important for surgeons to recognize where capsulotomy should be performed to decrease iatrogenic injury to existing blood supply. It is suspected that anterior capsulotomy does not damage the blood supply to the femoral head as long as the intertrochanteric notch and the superior lateral ascending cervical vessels are avoided.
Soft Tissue Anatomy
The hip joint is enclosed by a thick fibrous capsule that is considered less likely to tear than in adult hip fractures. Bleeding within an intact capsule may lead to a tense hemarthrosis after intracapsular fracture which can theoretically tamponade the ascending cervical vessels and may have implications in the development of ON. The hip joint is surrounded on all sides by a protective cuff of musculature; as such, open hip fracture is rare. In the absence of associated hip dislocation, neurovascular injuries are rare.
The sciatic nerve emerges from the sciatic notch beneath the piriformis and courses superficial to the external rotators and the quadratus medial to the greater trochanter. The lateral femoral cutaneous nerve lies in the interval between the tensor and sartorius muscles and supplies sensation to the lateral thigh. This nerve must be identified and preserved during an anterolateral approach to the hip. The femoral neurovascular bundle is separated from the anterior hip joint by the iliopsoas. Thus, any retractor placed on the anterior acetabular rim should be carefully placed deep to the iliopsoas to protect the femoral bundle. Inferior and medial to the hip capsule, coursing from the deep femoral artery toward the posterior hip joint, is the medial femoral circumflex artery. Placement of a distal Hohmann retractor too deeply can tear this artery, and control of the bleeding may be difficult.
TREATMENT OPTIONS FOR HIP FRACTURES
Rationale for Management
Much of the early, classic literature on hip fractures in children documented high rates of coxa vara, delayed union, and nonunion in patients treated without internal fixation.68,98 Canale and Bourland18 noted that fractures treated by spica casting alone had a greater incidence of coxa vara. They attributed a lower rate of coxa vara and nonunion in some of their patients to the use of internal fixation for all transcervical fractures.19 More recent literature supports the concept that attempted conservative treatment can result in unacceptably high rates of coxa vara.6 These high rates of complications may be because of an underappreciation of the uniqueness of this injury and its requisite necessity for operative treatment in most patients, which is in contrast to other pediatric injuries.6 Subsequent authors have documented lower rates of ON, coxa vara, and nonunion in patients who were aggressively treated with anatomic reduction (open or closed) and internal fixation (with or without supplemental casting) within 24 hours of injury.5,22,37,82,87,105 A recent paper of 36 patients followed until healing concluded that patients treated with open reduction had a smaller complication rate and recommended open reduction and internal fixation (ORIF) over closed reduction and internal fixation (CRIF) whenever possible.7 Therefore, contemporary management is directed at early, anatomic reduction of these fractures with stable internal fixation and selective use of supplemental external stabilization (casting), with the goal of minimizing devastating late complications.22,98,111
Nonoperative Treatment of Hip Fractures
Indications/Contraindications (Table 26-1)
TABLE 26-1 Hip Fractures
Nonoperative treatment in children less than 1 year may be either a Pavlik harness or abduction brace. In older children treated non-op a spica cast past the knee may be considered. There are no outcome studies on spica or brace treatment but a spica cast should only be considered in younger children up to 5 years with nondisplaced fractures. Non-operative and spica cast treatment alone is not optimal in older children as the potential for nonunion is to great not to perform internal fixation. A supplemental spica cast is recommended for children that are not near skeletal maturity secondary to the fact that internal fixation will often stop distal to the epiphyseal physis.
Operative Treatment of Hip Fractures
Indications/Contraindications for Surgical Versus Nonsurgical Treatment
Internal fixation is indicated in children with displaced femoral neck fractures. Internal fixation is also recommended for most acute nondisplaced fractures except in children where size limits the effect of internal fixation (0 to 5 years). Completely nondisplaced fractures may have percutaneous screw placement with or without capsulotomy. If there is any residual displacement after an attempted closed reduction, an open reduction should be performed. The threshold for open reduction should be any displacement to decrease the incidence of ON and nonunion.
The Watson-Jones Approach (Anterior Lateral Approach)
Preoperative Planning (Table 26-2).
TABLE 26-2 Watson-Jones Approach
Surgical Approach. If open reduction is necessary, the Watson-Jones approach is a useful and direct approach to the femoral neck. A lateral incision is made over the proximal femur, slightly anterior to the greater trochanter (Fig. 26-7A). The fascia lata is incised longitudinally (Fig. 26-7B). The innervation of the tensor muscle by the superior gluteal nerve is 2 to 5 cm above the greater trochanter, and care should be taken not to damage this structure. The tensor muscle is reflected anteriorly. The interval between the gluteus medius and the tensor muscles will be used (Fig. 26-7C). The plane is developed between the muscles and the underlying hip capsule (Fig. 26-7D). If necessary, the anterior-most fibers of the gluteus medius tendon can be detached from the trochanter for wider exposure. After clearing the anterior hip capsule, longitudinal capsulotomy is made along the anterosuperior femoral neck. A transverse incision can be added superiorly for wider exposure (Fig. 26-7E). Once the hip fracture is reduced, guidewires for cannulated screws can be passed perpendicular to the fracture along the femoral neck from the base of the greater trochanter.
The Smith-Peterson Approach (Anterior Approach)
Preoperative Planning (Table 26-3)
TABLE 26-3 Smith-Petersen Approach
Surgical Approach. A longitudinal incision distal and lateral to the anterior-superior iliac spine or bikini approach can be used through the Smith-Petersen interval (Fig. 26-8). Care should be taken to identify and protect the lateral femoral cutaneous nerve. The fascia over the tensor fascia muscle is opened longitudinally. Blunt dissection is then done to expose the medial aspect of the muscle as far proximal as the iliac crest. The rectus muscle is seen and the lateral fascia of the rectus is incised and the rectus can then be retracted in a medial direction. The fascia on the floor of the rectus is incised longitudinally and the lateral iliopsoas is elevated off the hip capsule in a medial direction to expose the hip capsule. The sartorius and rectus muscles can be detached for greater exposure of the hip capsule if required. Medial and inferior retractors should be carefully placed around the femoral neck once the capsule is incised to avoid damage to the femoral neurovascular bundle and medial femoral circumflex artery, respectively. Care must be taken not to violate the intertrochanteric notch and the lateral ascending vessels. Because the lateral aspect of the greater trochanter is not exposed, wires must be passed percutaneously once the hip fracture is reduced.
Lateral Approach for Decompression. In many cases, an adequate closed reduction can be obtained thus avoiding the need to open the hip joint for reduction purposes. However, the surgeon may decide to perform a capsulotomy to decompress the hip joint. The authors prefer to do this from a lateral approach. With this method, a 4-cm incision is made distal and lateral to the greater trochanter. From this incision, the fascia lata is incised and guide pins for cannulated screws are placed and screws are inserted in the standard manner. The anterior fibers of the gluteus medius are elevated allowing incision of the anterior capsule with a Cobb elevator, knife, or osteotome.
Surgical Dislocation of the Hip
Preoperative Planning (Table 26-4)
TABLE 26-4 Surgical Dislocation of the Hip
Positioning. Patients are positioned in the lateral position on a radiolucent table. The opposite leg should be well padded so there is no pressure on the peroneal nerve. An axillary roll is needed and both upper extremities should be carefully positioned to avoid any pressure or tension on the upper extremity and brachial plexus. The complete left hip and leg is draped free as high as the iliac crest.
Surgical Approach. The technique was originally described by Ganz et al.39 A lateral incision is performed centered on the anterior third of the greater trochanter. The proximal extent of the incision is at least at the midpoint between the greater trochanter and the iliac crest. The tensor fascia is incised in the anterior third of the greater trochanter and along the anterior border of the gluteus maximus muscle. This is known as the Gibson modification79 which protects the neurovascular bundle of the gluteus maximus. This exposes the upper vastus lateralis, gluteus medius, and greater trochanter. The leg is positioned with the hip in slight extension and internal rotation to better visualize the anatomic landmarks for this portion of the approach. The piriformis tendon is visualized deep to the posterior/distal aspect of gluteus medius. Once exposed the tendon can be slightly retracted distal to expose the inferior margin of the gluteus minimus fascia. The inferior fascia of the minimus is opened to allow the muscle to be retracted in an anterior-superior direction off the hip capsule. It is easier to visualize this interval prior to the trochanteric osteotomy. A greater trochanteric osteotomy is performed from anterior to the tip of the greater trochanter to the posterior border of the vastus lateralis ridge. The width of the osteotomy is approximately 10 to 15 mm in children. A muscular flap including the gluteus minimus, gluteus medius, osteotomized greater trochanter, vastus lateralis, and vastus intermedius is elevated sharply off the hip capsule in an anterior/superior direction. Flexion and external rotation of the operative hip will facilitate the muscle dissection. The dissection is all anterior to the piriformis tendon the majority of which should be still attached to the trochanter (not the osteotomized fragment). Keeping the piriformis tendon intact with dissection anterior to the tendon protects the retinacular branch of the medial circumflex artery. The capsule should be visualized as anterior as the medial region of the indirect tendon.
The hip capsule is then opened in a “z”-shaped fashion. The longitudinal limb is along the axis of the femoral neck in line with the iliofemoral ligament. The distal aspect is proximal but in line with the intertrochanteric ridge. The posterior limb of the capsule is opened in the capsular recess of the acetabulum as far posterior as the piriformis tendon. Therefore, the lateral and posterior capsular flap is created that protects the retinaculum as it pierces the hip capsule. Once the capsule is opened the anatomy and fracture can be visualized. If hip dislocation is indicated the leg is flexed and externally rotated and placed in a sterile leg bag. The hip is subluxated with a bone hook and curved large scissors are used to transect the ligamentum teres.
The location of the hip fracture will dictate the next step after the capsulotomy. If dislocation is warranted temporary fixation of the fracture with a threaded Kirschner wire (K-wire) is recommended for safe dislocation. Without temporary fixation damage may occur to the retinaculum that is easily visualized in the lateral and posterolateral region of the femoral neck.
After fracture fixation the hip capsule is loosely approximated. The greater trochanter is reduced and fixation with 2 to 3 screws (3.5 mm) is performed. Weight-bearing restrictions are dependent on the fracture type.
Current Treatment Options
Type I. Fracture treatment is based on the age of the child, presence of femoral head dislocation, and fracture stability after reduction. In toddlers under 2 years of age with nondisplaced or minimally displaced fractures, simple spica cast immobilization is likely to be successful. Because the fracture tends to displace into varus and external rotation, the limb should be casted in mild abduction and neutral rotation to prevent displacement. Close follow-up in the early postinjury period is critical. Displaced fractures in toddlers should be reduced closed by gentle traction, abduction, and internal rotation. If the fracture “locks on” and is stable, casting without fixation is indicated. If casting without fixation is done, repeat radiographs should be taken within days to look for displacement because the likelihood of successful repeat reduction decreases rapidly with time and healing in a young child.
If the fracture is not stable, it should be fixed with small-diameter (2-mm) smooth pins that cross the femoral neck and into the epiphysis. Use of smooth pins will theoretically decrease risk of physis injury in younger patients with a transphyseal fracture. An arthrogram after reduction and stabilization of the fracture may be indicated to insure alignment is anatomic. An arthrogram prior to reduction and pinning may obscure bony detail and hinder assessment during reduction.
Children older than 2 years should have operative fixation, even if the fracture is nondisplaced; because the complications of late displacement may be great, fixation should cross the physis into the capital femoral epiphysis. Smooth pins can be used in young children, but cannulated screws are better for older, larger children and adolescents. In this older group (>10 years) the effect of eventual limb length discrepancy is small and is a reasonable tradeoff for the superior fixation and stabilization needed to avoid complications in larger and older children.
Closed reduction of type IB fracture-dislocations may be attempted, but immediate open reduction is necessary if a single attempt at closed reduction is unsuccessful. Internal fixation is mandatory. The surgical approach should be from the side to which the head is dislocated, generally posterolateral. Parents must be advised in advance about the risk of ON.
Postoperative spica cast immobilization is mandatory in all but the oldest and most reliable adolescents who have large-threaded screws crossing the physis. Fixation may be removed shortly after fracture healing to enable further growth in patients.
Type II and Type III. Intracapsular femoral neck fractures mandate anatomic reduction and, in most cases, internal fixation. In rare cases, children under 5 years of age with nondisplaced and completely stable type II and cervicotrochanteric fractures can be managed with spica casting and close follow-up to detect varus displacement in the cast.29,58,68 However, in almost all cases, internal fixation is recommended by most investigators for nondisplaced transcervical fractures40,58 because the risk of late displacement in such fractures far outweighs the risk of percutaneous screw fixation, especially in young children.16
Displaced neck fractures should be treated with anatomic reduction and stable internal fixation to minimize the risk of late complications. Coxa vara and nonunion were frequent in several large series of displaced transcervical fractures treated with immobilization but without internal fixation.6,19,68 However, when an anatomic closed or ORIF was used, the rates of these complications were much lower.19,37,82,111
Gentle closed reduction of displaced fractures is accomplished with the use of longitudinal traction, abduction, and internal rotation. Open reduction frequently is necessary for displaced fractures and should be done through a Watson-Jones surgical approach.
Internal fixation with cannulated screws is done through a small lateral incision with planned entry above the level of the lesser trochanter. Two to three screws should be placed; if possible, the most inferior screw will skirt along the calcar with the remaining screws spaced as widely as possible.15 Usually, the small size of the child’s femoral neck will accommodate only two screws. Care should be taken to minimize unnecessary drill holes in the subtrochanteric region because they increase the risk of subtrochanteric fracture.
In type II fractures, physeal penetration may be necessary for purchase58,82; the sequelae of premature physeal closure and trochanteric overgrowth are much less than those of nonunion, pin breakage, and ON. Treatment of the fracture is the first priority, and any subsequent growth disturbance and leg length discrepancy are secondary. Consideration may be given to simultaneous capsulotomy or aspiration of the joint to eliminate pressure from a hemarthrosis at the time of surgery.
Displaced cervicotrochanteric fractures have been shown to have a complication rate similar to that for type II fractures and should be treated similarly. If possible, screws should be inserted short of the physis in type III fractures. Fixation generally does not need to cross the physis in type III fractures. Alternatively, a pediatric hip compression screw or a pediatric locking hip plate62,102 can be used for more secure fixation of distal cervicotrochanteric fractures in a child over 5 years of age particularly if there is a smaller region for screw purchase lateral and distal to the fracture. Spica casting is routine in most type II and III fractures, except in older children where the screws can cross the physis.37
Type IV. Good results can be obtained after closed treatment of most intertrochanteric fractures in younger children, regardless of displacement. Traction and spica cast immobilization are effective.15 Instability or failure to maintain adequate reduction and polytrauma are indications for internal fixation. Older children (>10 years) or those with significant displacement can be treated with ORIF (Fig. 26-9). A pediatric hip screw or pediatric hip locking plate provides the most rigid internal fixation for this purpose. Smaller hip screw devices have made ORIF an option in children younger than 10 years. This may avoid the period of spica cast treatment and a more anatomic alignment.
AUTHOR’S PREFERRED TREATMENT FOR HIP FRACTURES
Nondisplaced or minimally displaced stable fractures in toddlers up to age 2 should be treated in a spica cast without internal fixation. The limb should be casted in a position of abduction and neutral rotation to prevent displacement into varus. If the fracture requires reduction or moves significantly during reduction or casting maneuvers, then internal fixation is mandatory. Two-millimeter smooth K-wires are inserted percutaneously to cross the physis. We recommend two or three wires. Wires should be cut off and bent below the skin for retrieval under a brief general anesthetic when the fractures healed. We do not recommend leaving the wires outside the skin. Frequent radiographs are necessary to check for migration of the pins into the joint space. A spica cast is always applied in this age group and should remain in place for at least 6 weeks.37 Even if type I fractures in children older than 2 years are anatomically reduced, these patients should always have stabilization with internal fixation. While K-wires are appropriate for small children, 4- to 7.3-mm cannulated screws crossing the physis can be considered in older, larger children after closed reduction. Fluoroscopically placing a guide pin across the femoral head and neck allows one to locate the proper site for a small incision overlying the lateral femur in line with the femoral neck. Two guide pins are placed into the epiphysis, and the wires are overdrilled to the level of the physis (but not across to avoid growth arrest as much as possible). The hard metaphysis and lateral femoral cortex are tapped (in contrast to elderly patients with osteoporosis) to the level of the physis and stainless steel screws are placed.
If gentle closed reduction cannot be achieved, an open approach is preferred for type IA fractures. For type IB fractures, the choice of approach is dictated by the position of the femoral epiphysis. If it is anterior or inferior, a Watson-Jones approach should be used. On the other hand, most type IB fractures are displaced posteriorly, in which case a posterior approach should be selected. A surgical dislocation approach may also be used to give complete visualization of the hip and retinacular vessels. Under direct vision, the fracture is reduced and guidewires are passed from the lateral aspect of the proximal femur up the neck perpendicular to the fracture; predrilling and tapping are necessary before the insertion of screws. All children are immobilized in a spica cast.
Older children and adolescents will usually require similar reduction methods on a fracture table, and the fracture is stabilized after closed or, if needed, open reduction. Larger 6.5- or 7.3-mm screws are needed and are placed after predrilling and tapping over the guide pins. Through a lateral incision, the screws are placed, and an anterior capsulotomy is performed. Such stout fixation usually obviates the need for spica casting in an adolescent but, if future patient compliance or fracture stability is in doubt, a spica cast is used. The lateral position is utilized for the surgical dislocation approach. The fracture can be reduced without the need for a traction table in the surgical dislocation approach.
Types II and III
In all cases, we attempt a closed reduction. It is critical that the fracture be reduced anatomically to decrease the potential of nonunion and AVN. If unsuccessful, a reduction can be performed through a Watson-Jones approach because it provides direct exposure of the femoral neck for gentle fracture reduction. If there is experience with the surgical dislocation approach this will give the surgeon visualization for fracture reduction and fixation. Both approaches allow the fracture to be anatomically reduced under direct vision. Once the fracture is visualized and anatomically reduced, guidewires are then placed up the femoral neck perpendicular to the fracture. If possible, penetration of the physis should be avoided.21,36 However, in most unstable type II fractures, penetration of the physis may be necessary to achieve stability and avoid the complications associated with late displacement.15,82 Good fixation of type III fractures generally is possible without penetration of the physis. With the surgical dislocation approach, the reduction can usually be performed without dislocation of the femoral head. If femoral head dislocation is required the fracture and femoral head should be provisionally reduced and fixed prior to subluxation and transecting the ligamentum teres to prevent traction on the retinaculum with the dislocation. Once dislocated a guidewire can be placed retrograde through the fovea.
Type II and III fractures should be stabilized with 4- to 4.5-mm cannulated screws in small children up to age 8. After the age of 8, fixation with 6.5-mm cannulated screws is appropriate. Two or three appropriately sized screws should be used, depending on the size of the child’s femoral neck. As in type I fractures, we recommend placing at least two guide pins, and predrilling and tapping of the femoral neck is necessary to avoid displacement of the fracture while advancing the screws. Finally, we believe that if the physis is not crossed with implants, supplementary spica casting is needed to prevent malunion or nonunion.
Undisplaced type IV fractures in children younger than 3 to 4 years are treated without internal fixation with immobilization in a spica cast for 12 weeks. Great care is needed to cast the limb in a position that best aligns the bone (Fig. 26-10A, B). Frequent radiographic examination is necessary to assess for late displacement, particularly into varus. In some cases, it may be difficult to assess reduction in a spica cast so that alternative testing such as a limited CT scan may be useful to compare to intraoperative positioning (Fig. 26-10 C, D). Displaced type IV fractures in all children more than 3 years should be treated with internal fixation with a pediatric or juvenile compression hip screw or pediatric locking hip plate placed into femoral neck short of the physis. It is important to place an antirotation wire before drilling and tapping the neck for the dynamic hip screw. Closed reduction often is possible with a combination of traction and internal rotation of the limb. If open reduction is necessary, a lateral approach with anterior extension to close reduce the fracture is preferred.