Fractures of the femoral shaft in children are the second most common diaphyseal fracture seen in children, after those of the forearm . They are the most common musculoskeletal injury in children requiring hospitalization . These injuries have an annual incidence of between 16.5 and 28 per 100 000 children per year [3▪]. The cause of these injuries varies with age; in preschool children the most common mechanism is a fall from a height of less than 1 m. In children aged 4–12 years accidental injury during sport is the predominant cause. In older children and the adolescent road traffic accidents are the predominant cause [3▪]. The method of management of these injuries varies with age and weight of the child, although local cultural and socioeconomic factors also play a major role [3▪,4]. Controversies still persist over the safety of locked anterograde intramedullary nailing and the use of elastic nails in length unstable diaphyseal fractures.
FRACTURES OF THE PROXIMAL FEMUR
Fractures to the proximal femur are rare and represent fewer than 1% of all paediatric fractures. They are usually high-energy injuries and may present as part of the injury pattern of the polytraumatized patient. Children commonly sustain these injuries as a result of a fall from height or as a pedestrian in a motor vehicle accident.
These injuries are traditionally classified using the Delbet's system, popularized by Colonna , which typifies these injuries (see Table 1).
There is an increasing trend towards stable internal fixation for these injuries, with implants of a suitable size for the child in question. Nonunion and malunion are prevented by the use of modern angular stable implants.
Each fracture pattern carries a chance of risk of avascular necrosis (AVN) and subsequent posttraumatic arthritis. This risk increases with the proximity of the fracture (see Table 1) and with the age of the child. Moon demonstrated this risk increases 1.14 times with each year of age ; several case series suggest the risk is greatest in children older than 10 .
Initial displacement of the fracture and subsequent delay to reduction are also contributory to AVN development. Results for fractures reduced and fixed emergently are significantly better than those delayed beyond this time frame. Flynn et al.  demonstrated an 8% AVN rate in his series all fixed within 24 h; this jumps to 60% in Dhar's series, in which the median delay to surgery was 8 days [9▪].
Some recent studies have shown open rather than closed reduction, followed by internal fixation, results in a lower incidence of AVN [10,11▪,12]. This relates both to the quality of the reduction achieved prior to fixation, and to the fact that open reduction necessitates decompression of the tamponading haematoma in the hip joint. The conclusion drawn from these comparable, albeit small, case series is that anatomical reduction reduces the risk of development of AVN.
FRACTURES OF THE FEMORAL SHAFT
The following discussion is organized and divided using age as the primary denominator.
Infants 0–18 months old
Fractures in this early age group must arouse suspicion in the treating clinician and the possibility of nonaccidental injury (NAI) excluded. The child is nonambulatory for much of the first year of life; hence the application of an external force is a more likely aetiology in this group. Eighty percent of all abusive fractures occur in this age group, yielding an incidence of four in every 100 000 children under 18 months of age . The incidence of these fractures caused by NAI is seen to decrease with age, in keeping with the onset of ambulation and growth of the child. The presence of synchronous fractures (especially to the ribs), evidence of previous abusive injury (physical or radiological) and a history/presentation which raises suspicion are also strong indicators of NAI [14,15]. Paediatricians should be aware that, although NAI is common, a regular traumatic cause is more common.
Options include traction or hip spica casting, or a combination of both. We recommend gallows traction for small children (i.e. <12 kg), which involves inline skin traction with the hip flexed at 90°. The application of traction mandates hospital admission and allows thorough investigation of the circumstances of the injury in a controlled environment. Use of this technique in larger children is to be avoided as it has been associated with compartment syndrome, volkmanns contracture and peroneal nerve palsy.
Immediate hip spica casting is an acceptable form of treatment with proven results . Femoral fractures in this age group very rarely suffer from the shortening seen in older children treated with this method. Its application requires the availability of a paediatric anaesthetist. Given the emergent presentation of many of these injuries, this service is not always immediately available. In resource limited environments spica casting is applied after a brief period in traction (1 week or so) and can often be achieved without anaesthesia . Up to 15 mm of shortening and 30° of angulation are considered acceptable, given the considerable remodelling potential at this age . Rotational deformity, although rare, does not remodel.
Fractures of the femur during birth are rare and often discovered latently. The newborn can be immobilized in a Pavlik harness for up to 3 weeks. Rapid callus formation is typically observed with little in the way of long-term sequelae. Risk factors for these injuries include breech deliveries, twin pregnancies and osteoporosis of birth related to prematurity or maternal neurological conditions which reduce intrauterine movements (i.e. spina bifida) .
TREATMENT OF CHILDREN AGED 18 MONTHS TO 4 YEARS
In this ambulant age group the most common cause is a simple fall. Hence these are often isolated, low energy injuries. Nonaccidental injury becomes much less common, representing one in 205 fractures in this age group compared with one in nine below the age of 18 months .
Traction or hip spica is the mainstay of treatment. We prefer balanced Hamilton–Russell skin traction applied with 1 pound of weight per year of age, as it has the benefit of controlling both external rotation and shortening.
Hip spica casting may be used either immediately or subsequent to initial traction. Immediate application is said to reduce treatment costs, but has been associated with subsequent malunion [18–20], especially in length unstable fractures. These fractures benefit from a brief period of balanced traction before definitive management with spica casting. Shortening of more than 15 mm, if appreciated in the early follow-up period, is an indication for resumption or initiation of traction methods. Angulation of up to 15° of varus/valgus and 25° in the sagittal plane can be tolerated .
CHILDREN AGED 4–12 YEARS
In these older children operative intervention is increasingly indicated.
This may still be used, usually as a temporizing measure prior to operative intervention. Comparative studies between skin and skeletal traction have shown little benefit of one modality over another, especially in the young children . Skeletal traction should be avoided, especially in the proximal tibia, due to the risk of growth arrest.
Hip spica management in the over-4s is not appropriate. Wright et al.'s  randomized controlled trial (a rarity in paediatric orthopaedics) demonstrated that external fixation was better, although not without its own complications.
This is now the technique of choice for stabilizing femoral fractures in children of this age group. Superior results to spica casting have been demonstrated in terms of length of hospital stay, time to mobilization and patient satisfaction .
Elastic nails act both as a reduction device and secondarily as an implant. They may be applied to most femoral fractures including length unstable injuries if appropriate precautions are undertaken.
LIMITATIONS OF ELASTIC NAILING
Poor outcomes in terms of loss of alignment and delayed union have been described in larger children, that is, over 49 kg, and in those fractures which have gross comminution . There is also a reported increased risk of shortening and malunion in length unstable fractures compared with stable configurations treated with this technique [26,27].
For fractures that tend towards axial instability, the use of an end cap should be considered. This device is placed over the protruding nail end and its screw thread grips in the cortex. It is intended to prevent extrusion of the nail and controls shortening of the fracture. Ex-vivo biomechanical studies have shown this technique to be effective and a clinical case series has shown these devices to be safe and of benefit [28▪].
Distal third femoral fractures may also be addressed with this technique, using an antegrade insertional technique. This requires two proximal start points, the first 1 cm proximal and just anterior to the second. Two nails are again used, the first C shaped and the second S shaped. This allows two apical curves to rest at the same level via two lateral entry points, but does represent a greater technical challenge .
Postoperatively immediate mobilization occurs with protected weight bearing for the first 2–3 weeks. No brace or cast is routinely used unless special circumstances require this. Metalwork removal is generally performed at 6 months postoperatively.
External fixators have been used to manage comminuted fractures with associated severe soft tissue injuries since the 1970 s. Historically this technique has been associated with delayed union, refracture, malalignment and pin site infection [30–32]. Fractures treated by external fixation heal slowly, such that devices have to remain in situ for up to 12 weeks to reduce refracture rates to an acceptable level . Late dynamization seems to be of little benefit to stimulate healing; hence the recommendation is to use less rigid frame constructs from the outset to allow early callus formation .
For adult open fractures the trend is away from external fixation in favour of primary intramedullary nailing with synchronous extensive soft tissue debridement and grafting. Randomized comparative studies in the paediatric population comparing external fixation with intramedullary nailing are awaited, but cohort studies do exist . This small retrospective study compared a combination of elastic and rigid nailing with external fixators and found that the ex fix group were 2.7 times more likely to have a complication (refracture, delayed or malunion and limb length discrepancy). Despite the shift in practice, the external fixator retains a place in the management of the polytraumatized child due to its speed and simplicity of application.
Rarely required in this age group except for very proximal fractures beyond the scope of elastic nails.
OLDER CHILDREN AND ADOLESCENTS
In this group operative management is nearly always indicated.
This is technically feasible; however, the work of Moroz et al.  showed the incidence of radiographic malunion increases five-fold if performed in children weighing more than 49 kg. It should be pointed out that this statement arises from a study which did not include fracture type as a variable; hence there are accounts of elastic nailing used in the older child (weighing up to 85 kg) in selected cases of ‘length stable’ fractures. Comparative studies have shown no difference in outcome in these cases compared with locked rigid intramedullary nailing . If elastic nailing is undertaken, augmentation with femoral brace or a brief period of bed rest should be considered. Some authors have advocated augmentation of the construct with a temporary external fixator to provide added axial stability. End caps increase the strength of the construct six-fold [28▪].
Plate fixation provides another treatment option for femoral fractures in the older child and adolescent. This has been performed historically with good results reported . This approach conventionally requires a substantial approach and soft tissue dissection; a substantial scar must also be expected, which can be a problem in some children.
The introduction of locked plates has broadened the indications for plating and offers a ready alternative treatment option to the external fixator in the treatment of closed, grossly comminuted fractures . The locked plate has been likened to an ‘internal external fixator’ and hence may be used to bridge across comminuted fractures or stabilize those at the metaphyseal/diaphyseal junction, wherein the space available to achieve distal fixation is limited. The locked plate may also have a role to stabilize fractures within pathological bone, for example osteopenia or osteogenesis imperfecta.
Disadvantages include difficulty in obtaining adequate reduction prior to plating, especially if minimally invasive plating is attempted. The locked plate is also not designed for load sharing. Hence, if it is repetitively loaded prior to bone healing there is a chance of implant failure.
LOCKED ANTEGRADE INTRAMEDULLARY NAILING
This is the gold standard treatment for femoral fractures in the adult population. Its use in children has been restricted due to concerns over avascular necrosis of the femoral head and growth arrest in the proximal femur secondary to operative technique. In the series that do exist, there can be little doubt as to the efficacy of intramedullary nailing in treating diaphyseal fractures of the paediatric femur . The indications for this technique are increasing due to the trend towards heavier patients in the paediatric population.
The main concern arises from the entry point of the nail, which historically was the piriform fossa. Until skeletal maturity the blood supply of the femoral head depends almost entirely on the lateral ascending cervical artery, arising from the ascending branch of the medial femoral circumflex artery. This passes in close proximity to the piriformis fossa and hence is at risk from nail insertion using this at the start point.
To avoid this devastating, untreatable complication some authors have advocated a trochanteric entry point (TEP) [39,40]; this has been associated with growth arrest of the proximal femur resulting in valgus deformity of the hip and narrowing of the femoral neck and metaphysis [41,42]. This would suggest that the medial wall of the trochanter must be preserved to avoid damage to the proximal femoral vasculature. To this end a lateral trochanteric entry point (LEP) has been described to allow insertion of modified humeral nails [43▪], novel flexible interlocking intermedullary nails [44,45▪] and specifically designed adolescent nails [46▪▪].
The true incidence of AVN after this procedure is unknown but a recent review of published case series describes the data from 19 retrospective studies, containing cases using all three techniques [45▪]. The coalition of these cases revealed a 2% AVN rate in the piriformis fossa entry point group (N = 239), a 1.4% AVN rate in the TEP case (N = 139) and no cases of AVN in the LEP group (N = 80). Six further case reports of AVN subsequent to intramedullary nailing are described in the literature, all using the piriformis fossa entry point technique. Although this data is all from nonrandomized, retrospective studies in nonmatched populations, the logical suggestion is, however, that a lateral entry point is safer for this technique.
FRACTURES OF THE DISTAL FEMUR
Growth plate fractures of the distal femur are rare injuries and carry a high rate of complication. Primary among these is growth arrest, the rate of which has been stated as between 40 and 52% . This increases with the grade of the fracture, degree of displacement and presence of proximal fragment comminution . The Salter–Harris classification is used.
SALTER–HARRIS I INJURIES
Undisplaced injuries may be placed in a cast, nonweight bearing for 4 weeks. Displaced injuries deemed unstable enough to warrant internal fixation should undergo closed manipulation followed by anterograde crossed K wiring. These wires are left proud of the skin and should cross the physis to ensure solid fixation. Entry points should be parallel and proximal to the joint capsule to the knee. The leg is cast as above and wires are removed with the cast at 4 weeks.
SALTER–HARRIS II INJURIES
These are often seen resulting from sporting injuries. Some authors advocate fixing all SH II fractures regardless of initial displacement . If managed conservatively, regular radiographs are required. Operative intervention depends on the size of the metaphyseal fragment. If large enough, the fracture may be held with one or two screws placed perpendicular to the fragment's surface into the metaphysis. Orientation of this screw is vital to achieving solid fixation and operative planning may be aided by computed tomography (CT) scanning or oblique radiographs. Crossed wires may be used if the fragment is too small for screw fixation.
SALTER–HARRIS III AND IV INJURIES
These injuries are transphyseal intraarticular fractures and should be operatively stabilized. CT is useful for operative planning. Open reduction and internal fixation are required. Malreduced fractures will lead to rapid onset posttraumatic arthritis.
Methods of management vary depending on anatomical location of fracture, age of patient and associated injuries. Units treating paediatric fractures need access to specialist surgeons and equipment to treat the full range of femoral fractures and improve outcomes. Further randomized controlled trials are needed to determine optimal treatment modalities for some fractures of the femoral shaft.
Conflicts of interest
There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING
Papers of particular interest, published within the annual period of review, have been highlighted as:
- ▪ of special interest
- ▪▪ of outstanding interest
Additional references related to this topic can also be found in the Current World Literature section in this issue (p. 151).
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This article nicely describes the lateral entry point to the proximal femur.
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Review A article summarizing all the current evidence for this topic.
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