Femoral neck fractures in children and adolescents

A neck fracture in persons under 18 years of age is even more seldom. For every 100 to 300 neck fractures in adults one accounts for one infantile neck fracture (Ratcliff, 1962; Zolczer et al, 1972; Bohler, 1981; Fornaro et al, 1982; Niethardt, 1982; Ruter and Krenczer, 1982; Schlickewei and Paul, 1993; Canale and Tolo, 1995). These fractures are caused by a great force and therefore often occur during a major trauma or polytrauma. The serious complications may lead to a life long incapacity. This danger can be reduced by immediate surgery done under the conditions that specialized and technical care is available (special implant, image intensifier). If these prerequisites are not met, the injured child should be immediately transferred to an institution specializing in childcare provided the child can be transported.

At the age of one year the ossific nucleus of the femoral head starts to develop. At age four the ossific nucleus of the trochanter appears. In this way two physes develop that are continuous and surrounded by cartilage. The two physes separate at the age of 12 years. The trabecular structure appears only after end of puberty (Fig. 216) (Manninger and Fekete, 1982).

These two important morphologic features distinguish the pathology of infantile injuries from that of similar fractures in adults.

(1) Up to the moment of formation of cancellous bone, the infantile bone of neck and head is very compact. Consequently, a fracture cannot be impacted during reduction. A good contact and stable position can only be reached with a precise reduction. For the same reason no nail and no blade-plate such as a 90 or 130° plate should be used, as they cannot be inserted without serious tissue damage and diastasis of the fracture.

In 1950 one of us (J. M.) assisted his chief during an open internal fixation of a neck fracture suffered by an 18-year-old boy. He observed that during nailing the fracture gap widened by 0.5 to 1 cm. Im-paction led to a closure of the gap, but after resumption of hammering the gap reappeared. Radiographs showed that the nail tip had entered the head by only 1 cm. Removal of the nail to permit predrilling before reinsertion of the nail was unsuccessful in spite of the use of a very strong screwlike extractor. It was therefore decided to leave the nail in place. Follow-up radiographs taken after 16 years showed a complete bony consolidation (see Fig. 111). In spite of the successful outcome we do not recommend this technique. Nevertheless, this case documents the extraordinary compactness of adolescents' bone and the excellent purchase of an implant in bone.

Contrary to the nail, screws can be easily inserted after drilling and tapping and their holding power is reliable. Placement of a Kirschner wire or spiral drill bit preceding the screw insertion will prevent any rotatory displacement.

(2) The second major difference with bones of adults is the blood supply to the femoral head in children clearly shown by investigations of Trueta (1957), Ogden (1974) and Chung (1976). The bony nucleus of the epiphysis of children up to the age of 7 years receives only its blood supply from the lateral epiphyseal vessels that run along the femoral neck. In 8-year old children the vessels of the round ligament of the femur also contribute. Vessels of the metaphysis do not contribute as they do not cross the physis in girls up to the age of 14 years and in boys up to the age of 17 years. According to the studies of Trueta (1957) the vessels of the femoral head function like end-arteries. Anastomoses between the three areas of blood supply are only formed at the end of puberty (Chung, 1976) (Fig. 217).

Femoral Head Ossific Nucleus

Fig. 216. Schema of the development of the ossific nuclei in the proximal femur (Manninger and Fekete, 1982).

years

Fig. 216. Schema of the development of the ossific nuclei in the proximal femur (Manninger and Fekete, 1982).

Fig. 217. Arteries of the femoral head in children (Trueta, 1957).

The corrosion specimen documents very well the absence of vessels crossing the physis. Vessels of the round ligament run separately

Physis Femoral Children

For this reason the risk of avascular necrosis after neck fractures in children and adolescents is especially elevated: no possibility of a compensatory blood supply. The absence of a metaphyseal drainage heightens the importance of the hemarthrosis responsible for an intracapsular pressure increase: the compression of the superficially running vessels, in particular the thin-walled veins, greatly limits the drainage of the congested blood from the head. Should an immediate surgery in children and adolescents with neck fractures not be possible, a pressure-decreasing joint aspiration is mandatory. Our experience has shown that a hemarthrosis empties spontaneously through the drill channel during immediate internal fixation. Therefore an arthrotomy or an evacuation of the blood is not needed during surgery.

In infantile neck fractures there is one positive factor as M. Müller emphasized during the AO-courses: the regeneration potential of children's bones is markedly superior to that of adults' bone. A timely intervention (internal fixation, osteotomy, pedicled bone graft) (see Fig. 218) may lead to healing and a normal function in instances of a partial necrosis (see Fig. 226).

Five main types of infantile neck fractures must be distinguished depending on their radiologic aspect:

— Transepiphyseal fractures with or without dislocation (usually corresponds to the Salter-Harris types I and II up to the age of 10 years);

— Transcervical fracture;

— Cervico-trochanteric fracture;

— Pathologic fracture.

According to Ratliff (1962) the transepiphyseal fracture is characterized by a small metaphyseal fragment attached to the epiphysis (epiphyseal injury type II of the Salter-Harris classification). It may also happen that a small fragment of the epiphysis has broken off.

If a fracture-dislocation is present, an immediate open reduction is obligatory. If the reduction of small fragments proves impossible, they should be removed. The precise anatomic reduction, the exact contact between the fracture surfaces (adaptation), and the reliable internal fixation are indispensable for the regeneration of the broken epiphysis, even if it is has been completely separated (Fig. 218, see also Fig. 80).

The transepiphyseal fractures occur usually after a major trauma and their prognosis is the worst. Fortunately, they are very rare. They should not be confused with epiphysiolyses caused by hormonal or constitutional factors that are prevalent during puberty. Characteristic for an acute epi-physiolysis is the fact that it can be carefully and easily reduced and can heal well when stabilized with Kirschner wires; they are normally not accompanied by circulatory disturbances (Fig. 219).

The risk of circulatory disturbances is also elevated for transcervical fractures (Fig. 220).

The base of neck fracture that occurs most frequently runs extraarticular. For this reason its prognosis is usually favorable (Fig. 221).

Recently, the cervico-trochanteric fracture has been described; it runs cranially from the head-neck junction to the base of the neck or often distal to the lesser trochanter (Fig. 222).

For practical purposes a difference must be made between the above enumerated fractures and the pathologic fractures irrespective of the fact that they occur at the same levels than the other fractures (see Sect. 9.5).

The guiding principle in the treatment of these fractures is the immediate reduction, if at possible within 1-2 hours after admission. If a closed reduction is not met with success, an immediate open reduction and internal fixation is mandatory.

After successful closed reduction of a transepi-physeal fracture its fixation through the physis should be as atraumatic as possible. Consequently, we introduce two to three parallel titanium Kirschner wires that find a reliable hold in the compact bone. Cancellous bone screws should not be employed as they cause an unnecessary loss of cancellous bone. They cause injury to the physis that may cause a precocious bony bridging leading to growth disturbances.

For transcervical and base of neck fractures in pre-school children a fixation with three parallel inserted 2.5 mm or 3 mm titanium wires with delicate threads on their tips is sufficient; use of 2.8 mm or 3.5 mm cancellous bone screw may also be envisaged. For children over 6 years of age we recommend implantation of two and, at the age of puberty, three parallel 4.5 mm cancellous bone screws. (The use of 8 mm cannulated screws would render aiming more reliable but they are too thick in relation to the femoral head). The physis should never be perforated with drill bits or screws. The tip of the screw should never be closer to the physis than 2 mm.

In essence, the internal fixation during childhood and puberty for most fractures consists of a screw fixation between greater trochanter and neck metaphysis. To achieve this, cancel-lous bone screws with a short threaded section should be used. A longer threaded section that crosses the fracture gap will lead to a separation of the fragments interfering with fracture healing and possibly to screw breakage or non-union!

If the closed reduction is unsuccessful after one or two careful attempts, one should stop. A repeated manipulation puts the blood supply at risk. The hip joint should be immediately opened through an anterior or anterolateral approach. The reduction is then carried out under visual control.

During this intervention we have observed repeatedly such a high bone density that the tip of the Kirschner wire was deflected by the oblique proximal fracture surface. The wire should be inserted into the femoral head only after use of a spiral drill bit.

If an emergency operation of neck fractures in children or adolescents is impossible for any reason (polytrauma, poor general condition), a reduction must be done immediately and the leg positioned in traction on a Braun splint. Aspiration of the hemarthrosis should not be forgotten. After open reduction the blood from the femoral head can seep into the soft tissues through the fracture and beside the implant. If thereafter a persisting hemarthrosis is suspected, a sonography should be done early on and the blood evacuated by aspiration.

Open Reduction Internal FunctionTransepiphyseal

Fig. 218. Transepiphyseal fracture-dislocation of the femoral neck (Stock et al, 199!; Stock and Hierner, 1994; Hankiss et al, 1995).

This 11-year-old girl sitting in the back seat of a car suffered an injury to the left hip, a commotion and multiple contusions when their car was hit from the left side; a, b. Left posterocranial transepiphyseal fracture-dislocation. The radiographs show well avulsed meta-and epiphyseal fragments; c, d. The joint was exposed during the emergency surgery, the totally isolated epiphysis was removed, rinsed and replaced. Stabilization with Kirschner wires for valgus tilt, translational displacement by half a bone width as seen in the a.-p. projection and antecurvature as seen in the lateral projection; e. Four months later consultation in our institution on account of delayed fracture healing. A tendency for subluxation was also diagnosed; f. At this time the femoral head could still be reduced by abduction (the reduced density of the femoral head is very well visible). We recommended continuation of physiotherapy and wait and see; g. After three months the symptoms increased. A deformation is starting as seen by the shrinkage and cranial subluxation. Even in abduction an internal rotation was not possible anymore. We opted for a varus osteotomy and fixation with a blade-plate and additional screw fixation; h. In spite of a satisfying congruence, the subluxation recurred after one month; i. A Chiari osteotomy was therefore performed apparently achieving a reduction of subluxation. Nevertheless, the symptoms persisted; the apparent cause being a progressing avascular necrosis. To assess the blood supply to the head a MRI was done (see Fig. 80) that showed an almost total necrosis; when compared to the unaffected hip. Only the neck and the posterocranial part of the head exhibited an acceptable blood supply. The three dimensional CT reconstruction showed a preserved head contour justifying a revascularization. As a pelvic osteotomy had been done previously we opted in favor of a free pedicled bone graft with the branches of the deep iliac circumflex artery and vein harvested from the opposite iliac crest. (This was the first free transplantation with microsurgical sutures performed in our institute by Professor W. Stock, Munich). After five major surgical interventions the girl had no more pain 21 months after the accident. The range of motion of the hip was identical to the opposite side, the limb shortened by 3 cm. She uses a walking aide and a 2 cm heel lift. She is able to bear weight partially and goes swimming; j. Radiographs show that the shrinkage of the head does not progress anymore and the joint has widened and is almost congruent, an evidence of regeneration. This is the most remarkable change when comparing the films to those taken before revascularization. Obviously future corrective interventions may become necessary to equalize the leg length discrepancy

Epiphysiolysis Hip

Fig. 219. Non-traumatic epiphysiolysis.

This 8-year-old girl took ballet lessons. For weeks she complained about increasing left hip pain to a point of being unable to walk; a. Radiograph shows an epiphysolysis with a varus displacement amounting to 50% of the width of the physis and antecurvature. She was treated by traction; b. Thereafter, a very careful reduction was done under anesthesia lasting 30 minutes increasing the traction to 40 kg. The reduction was found to be good. The blood supply to the head was checked with an intraosseous venography; it showed a good drainage through the circumflex vein without any noticeable stagnation; c, d. Stabilization with Kirschner wires and a small fragment cancellous bone screw; e. Four years later, the girl was symptom-free and the shape of femoral head and neck was identical to the opposite side

Fig. 219. Non-traumatic epiphysiolysis.

This 8-year-old girl took ballet lessons. For weeks she complained about increasing left hip pain to a point of being unable to walk; a. Radiograph shows an epiphysolysis with a varus displacement amounting to 50% of the width of the physis and antecurvature. She was treated by traction; b. Thereafter, a very careful reduction was done under anesthesia lasting 30 minutes increasing the traction to 40 kg. The reduction was found to be good. The blood supply to the head was checked with an intraosseous venography; it showed a good drainage through the circumflex vein without any noticeable stagnation; c, d. Stabilization with Kirschner wires and a small fragment cancellous bone screw; e. Four years later, the girl was symptom-free and the shape of femoral head and neck was identical to the opposite side

Femoral Neck Fracture Child

Fig. 220. Infantile, transcervical neck fracture.

This 11-year-old boy was run over by a car at the day of admission and admitted to a hospital elsewhere; a, b. Right transcervical neck fracture; c, d. Seven hours later an internal fixation was done with cancellous bone screws having a short threaded section. Slight valgus position and over rotation. The screw tips do not cross the physis (the lateral picture deceives); e. Five years later the fracture has consolidated in a slight valgus position. To compensate for the leg length discrepancy of 1 cm a lift has been described and the boy is symptom-free

Fig. 220. Infantile, transcervical neck fracture.

This 11-year-old boy was run over by a car at the day of admission and admitted to a hospital elsewhere; a, b. Right transcervical neck fracture; c, d. Seven hours later an internal fixation was done with cancellous bone screws having a short threaded section. Slight valgus position and over rotation. The screw tips do not cross the physis (the lateral picture deceives); e. Five years later the fracture has consolidated in a slight valgus position. To compensate for the leg length discrepancy of 1 cm a lift has been described and the boy is symptom-free m

Varus Left Femoral Neck Internal Leg Fixation Internal Fixation

Fig. 221. Infantile, base of neck fracture.

This 5-year-old girl fell in a staircase and hit her left hip; a, b. Base of neck fracture; c, d. Within six hours closed reduction and fixation with cancellous bone screws, achieving a perfect position; e, f. Eleven years later the girl is symptom-free, the fracture has healed and the leg is not shortened

Fracture Trochanter Maior

Fig. 222. Cervico-trochanteric fracture.

The 2 1/2-year-old boy was run over by a car. The initial treatment was done elsewhere and the boy transferred in a temporary cast to our institution; a. b. Right cervico-trochanteric fracture. During the stabilization of his general condition a traction was applied; c. d. On day 3 the fracture was reduced open and fixed with a cancellous screw and a Kirschner wire to achieve a tension band effect of the avulsed greater trochanter; e. Two years after the accident a minimal valgus position persists, position of head and neck is normal, the contours preserved

Fig. 222. Cervico-trochanteric fracture.

The 2 1/2-year-old boy was run over by a car. The initial treatment was done elsewhere and the boy transferred in a temporary cast to our institution; a. b. Right cervico-trochanteric fracture. During the stabilization of his general condition a traction was applied; c. d. On day 3 the fracture was reduced open and fixed with a cancellous screw and a Kirschner wire to achieve a tension band effect of the avulsed greater trochanter; e. Two years after the accident a minimal valgus position persists, position of head and neck is normal, the contours preserved

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  • iain muir
    Why is a separation from the head of the femur from the neck popular in children?
    12 months ago
  • stefan salonen
    Why is it common in teens for trauma to seperate the head of the femur from the neck?
    20 days ago
  • Cherubino
    Why is femur separation more common in adolescents?
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