Anterograde Intramedullary Nailing Of the Femur Shaft Fracture

■    A femoral shaft fracture is any fracture of the femoral diaphysis from 5 cm below the lesser trochanter to within 6 to 8 cm of the distal femoral articular surface. 

■    Some fracture lines extend proximal or distal to the shaft and are therefore not considered shaft fractures. 

■    This description is mostly semantic, as the more important aspect of definition is understanding the “personality” of the fracture. 

■    Fractures  whose  essential element  is  diaphyseal  with “extensions” into the outer regions are different than fractures whose essential element is subtrochanteric or supracondylar with extension into the diaphysis. 

■    In some circumstances there may be enough involvement of proximal or distal aspects that treatment must change. 

■    For the purposes of this chapter, we will focus on fractures that are amenable to antegrade nailing.10 

■    The  Abbreviated  Injury  Scale  (AIS)  score for  an  isolated femoral shaft fracture is three, thus making the Injury Severity Score for an isolated femoral shaft fracture a nine. 

■    Open fractures are usually graded according to the GustiloAnderson classification, but one must keep in mind that this classification  system was  designed for  the  tibia,  a  subcutaneous bone. Thus,  if absorbed energy is considered, theoretically, significantly more energy would be required to fracture a femur and disrupt the soft tissue envelope around a femur than  around  a  tibia.  Nonetheless,  this system is widely employed in the femur for descriptive purposes. 

■    The fracture classification system previously used most commonly was the Winquist classification, but it has been modified and standardized with the AO/OTA classification, which is the recommended system.16,27

 

■    The femur is the longest bone in the body. It is subject to very high stresses in the proximal region because of the need to transition the forces of body weight via a lever arm (femoral neck) into  more axial  forces distally.  As  such,  the subtrochanteric area is subject to very high stresses.14 

■    The femur has an anterior bow and is not a circular bone. 

■    Anteriorly and laterally there are flattened surfaces, and posteriorly there is a taper that is confluent with the linea aspera. 

■    The linea aspera is a very thick fascial structure and frequently remains in continuity but separates from the femur. 

■    Entrapment of the linea aspera between the fracture ends may impede closed fracture reduction, especially with simple fracture patterns. The bone ends may need to be “unwound” to effect a reduction. 

■    Both anterior and lateral bowing is important to recognize, especially if abnormal (eg, metabolic bone disease). 

■    The anterior bow has an average radius of  curvature of about 120 cm. 

■    If there is excessive bowing, good preoperative planning is needed. 

■    Surgical options for such abnormal bowing include plate fixation or a controlled osteotomy to allow nail placement.16 

■    The endosteal diameter is important to recognize, especially with young or sclerotic bone. 

■    Normal aging and osteoporosis results in a biomechanical adaptation  of  enlarged inner diameter. Thus,  elderly individuals  may  have  a  larger-diameter femoral  shaft  with  a thinner cortex.  As  in  other cylindrical  tubes, the bending rigidity of the femur is roughly proportional to the radius to the fourth power. 

■    The vascular supply to the femur is from a nutrient artery off  the second perforating branch of  the profunda  femoris, entering posteriorly along the linea aspera. 

■    Normally,  periosteal branches supply the outer one quarter to one third of the cortex as the direction of blood flow is centripetally outward from the medulla to the cortex. 

■    Once  fracture  occurs,  a  reversal of  blood  flow  occurs from the periosteal vessel, radially inward. 

■    The linea aspera protects many perforating periosteal vessels, except in severe fractures, and may help explain the high healing rate of femoral shaft fractures (about 95%). 

■    There are three thigh compartments: anterior, posterior, and medial. 

■    Thigh  compartment syndrome may occur and generally involves the anterior compartment.  Frequently, release of the anterior compartment will relieve pressure. 

■    The  proximity  of  the gluteal  compartment places it  at risk as well. It should also be considered with compartment syndromes.

■    Femoral  shaft  fractures  are  high-energy  injuries  in  the young; in the elderly simple falls from ground level are sufficient to fracture the femur. 

■    Fracture patterns give clues to the mechanism. 

■    For example, a simple transverse fracture with a butterfly fragment is due to a bending force (eg, T-bone vehicle crash). 

■    Spiral fracture patterns are usually due to torsional forces. 

■    Indirect high-energy mechanisms, such as a fall from a height or motor vehicle crashes, will usually incur a significant initial deformity during the fracture process. 

■    The active and passive recoil of the muscle soft tissue envelope will decrease the initial displacement. Thus, the extent of soft tissue injury can be difficult to appreciate. 

■    Open  fractures in  this  setting are  usually  “inside-out” injuries. 

■    Direct mechanism fractures are from ballistic injuries, crush injuries, or other weapons (eg, chainsaw, axe). 

■    With these injuries, there may be less initial displacement of the fracture and soft tissues, but the amount of soft tissue injury can still be extensive. 569 570       

■    In ballistic injuries, the shock and cavitation can result in extensive tissue necrosis. 

■    In both  mechanisms, it is important to  recognize that the zone of tissue injury may extend well beyond the fracture site.

■    In the early 20th century, the natural history of femur fractures was poor. 

■    The mortality of wartime femur fracture before and during World War I was approximately 80%.  Serendipitous use of a wheeled splint for transport off the battlefield resulted in a precipitous drop in the mortality rate (the Thomas splint was thus developed). 

■    Because surgical techniques were primitive in those times, fears about  infection  and  surgical  complications  resulted in most fractures being treated in traction. 

■    The outcome was frequently a shortened, rotated, varus malunion of the femur. 

■    Additional  problems such as decubiti, venous thromboembolism, and pulmonary infections with prolonged bed rest resulted in high morbidity and mortality by today’s standards. 

■    Kuntschner is considered the father of intramedullary nailing. 

■    Kuntschner’s original technique was an open nailing, exposing the fracture site, and in the Western nations,  poor surgical  technique resulted in  high  rates of  infection  and nonunion. 

■    As a result, this method of fracture care was abandoned until late into the 1970s.16 

■    Kuntschner’s method was resurrected in the United States by early traumatologists, like S.  Hansen  and M.   Chapman,  who used Kuntschner’s newer technique of “closed” femoral nailing. 

■    The success rate of femoral nailing using closed technique resulted in low morbidity and began a change in practice to what we perform today. 

■    Early studies outlined the benefits of early reamed femoral nailing. 

■    As  survival  of  more  traumatized patients increased,  a subset of patients who may benefit from “subacute” nailing developed. 

■    Later studies identified patients at risk (eg, pulmonary injury, incomplete resuscitation, and brain injury) who benefited from stabilization of life-threatening injuries before fixation. 

■    This  reflects the paradigm  shift from  early total  care (ETC)  to damage control orthopedics (DCO).3,19,22 

■    While some have advocated plating in such cases, there have been no studies demonstrating the superiority of one method over the other in terms of patient survival.4 

■    Relevant  history includes age,  sex,  mechanism of  injury, associated injuries, loss of  consciousness, weakness, paralysis, or loss of sensation. 

■    Metabolic  conditions and any musculoskeletal conditions should be elucidated if possible. 

■  Patients should be evaluated according to the advanced trauma life support (ATLS)  guidelines. 

■    Particular attention should be given to  hypotension, since femoral shaft fractures can be associated with up to 3 to 4 L of  blood  loss.  While  not  solely responsible for  hypotension, femur shaft fractures can be a contributory source. 

■    The limb should be aligned and placed in a traction device, such as a Sager splint or a Thomas splint. 

■    These devices should be removed and replaced with skeletal or limb traction because of the risk of skin problems in the perineal or ischial and ankle areas. 

■    It  is  essential to  inspect  the  affected  limb  for  any  open wounds, swelling, and ecchymosis (see Exam  Table for Pelvis and Lower Extremity Trauma,  page 1). 

■    The extent of the open wound does not always correlate with the degree of soft tissue or fascial stripping due to the fracture. 

■    Vascular  evaluation should include manual palpation of the popliteal, posterior tibial, and dorsalis pedis pulses. 

■    It is important to understand that a pulse is a pressure wave and can still be present in the absence of flow. 

■    Alternatively,  the  absence  of  pulse  does  not  always mean absence of flow. 

■    Use of Doppler and examination of the contralateral limb are needed. 

■    Hypotension with peripheral vasoconstriction may accompany such injuries. 

■    The limb should be aligned before vascular examination. 

■    Asymmetric or absent pulses warrant a measurement of the ankle-brachial index (ABI). 

■    An ABI less than 0.9 is abnormal. 

■    Arteriography should be considered to rule out vascular injury. 

■    Neurologic  evaluation includes motor and sensory function of the femoral and sciatic nerve. 

■    The femoral nerve may be difficult to examine secondary to pain associated with the fracture. 

■    Sciatic nerve function can be evaluated for both peroneal and tibial branches. 

■    The peroneal branch is tested with ankle and toe dorsiflexion and sensation on the top of the foot. 

■    Tibial branch function is tested with ankle and toe plantarflexion as well as sensation to the sole of the foot. 

■    The tenet of imaging a joint above and a joint below should be followed. 

■    Good   anteroposterior (AP)  and  lateral  views of  the  hip, femur, and knee are required. 

■    Such films can be obtained in the operating room but are essential in planning,  since the presence of  a femoral neck fracture or a fracture about the knee will greatly change the operative tactic. 

■    Attempts should be made to get an internal-rotation AP view of  the femoral neck.  However,  with current trauma algorithms, the commonality of the pelvic CT  scan allows imaging of  the femoral neck.  The  scan should be viewed before deciding on the surgical tactic. 

■    If radiographs are normal but the clinical examination suggests injury (eg, unable to bear weight, pain out of proportion to injury), coronal MRI imaging may elucidate an occult fracture. 

■    CT   scanning  in  these situations  may  not  be  sensitive enough to find such fractures. 

■    Occult  femoral fractures may be hard to identify with preoperative radiographs. 

■    Use of CT  scans of the abdomen that go to the level of the femoral  neck  have  been found  to  be  sensitive enough  to Chapter 10   571 identify such occult  femoral neck fractures and should be done for most cases.23 

 

■    Other  injuries may  occur  concomitantly  with  femur fractures, including pelvic fractures, acetabular fractures, femoral neck fractures, and ligamentous injuries to the knee. 

■    If an effusion is present in the knee, the index of suspicion for a knee injury should be elevated. 

■    Distal femur fracture may also occur but may not be radiographically evident, especially in osteoporotic bone. 

■    In the absence of a reasonable mechanism, other causes for fracture such as metabolic bone disease or metastatic (or primary) fracture should be ruled out. 

■    Nonoperative  management has typically been reserved for patients who are unfit for surgery, patients who are quadriplegic  or  paraplegic,  patients in  whom  the  benefits do  not outweigh the risks, or other precluding factors (eg, active infection). 

■    Truly nondisplaced fractures in a compliant and able patient may also be treated nonoperatively. 

■    Infants and young children may also be treated nonoperatively because of their ability to remodel. 

■    Nonoperative management consists of bed rest and skeletal traction  (either through  the distal  femur or  proximal  tibia) with 20 to 30 lb of weight. 

■    Attention should be given to mechanical and pharmacologic venous thromboembolism prophylaxis if this treatment is considered. 

■    Isolated femur fractures are not urgent. Appropriate evaluation and medical clearance should be performed. It is in the best interests of the patient and system to stabilize the patient expeditiously,  but  when appropriate resources are available (eg, knowledgeable staff, anesthesia). It is not necessary to stabilize such fractures during off shifts unless indicated for other reasons (eg, open fracture, polytrauma). 

■    Patients with  isolated  femur  fractures should  have  some method of  traction,  pain  control,  and deep vein thrombosis prophylaxis while awaiting surgical intervention. 

■  Currently, statically locked femoral nailing with limited reaming is the standard of care. 

■    The studies by Brumback et al determined that statically locked nails do not affect healing and avoid the problems of malrotation and shortening. Unreamed nails were proposed to limit effects of canal fill and the theoretical concern of infection. Neither concern was proven, and in fact small unreamed nails had the same problems as in the tibia: higher rates of nonunion. Currently, the “ream to fit”  technique is used.5–9,26 

■    In the multiply injured patient (Injury Severity Score of more than 18), with pulmonary compromise or head injury, fracture fixation  should be delayed until suitably cleared for surgical intervention, and damage control methods with use of a temporary external fixator should be considered.2,4,17,21 

■    Recently,  the  reamer-irrigator-aspirator has  been used to minimize the pressure-induced embolization from the marrow. As studies are ongoing, this method may reduce the risks in the multiply injured patients. 

■    Open  fractures can be safely nailed if a thorough débridement and irrigation is performed. 

■    Absorbable antibiotic beads (calcium sulfate, not calcium phosphate, mixed with vancomycin or tobramycin) can be used at the time of definitive closure to provide local antibiotic delivery.20 

■    In severely contaminated fractures, a staged approach using temporary antibiotic beads (using polymethylmethacrylate mixed with vancomycin or tobramycin) and temporary external fixation,  followed by nailing within 2 weeks (with or without use of absorbable beads), can be employed. 

■    Conversion  of  external fixation  to  intramedullary nails can safely be performed within 2 to 4 weeks, as long as there is no indication of pin tract problems. 

■    In such cases, the risk of infection is increased but acceptable in lieu of prolonged bed rest. 

■   Because  of deforming forces in proximal fractures, the proximal segment tends to flex and externally rotate. 

■    Care  should be taken to ensure that the posterior cortex of the proximal fragment is not inadvertently reamed away. 

■    In  distal fractures, the distal segment tends to  flex  at  the knee (recurvatum of fracture). 

■    With distal fractures, care should be taken to avoid varus or valgus reduction. This can occur because the opening of  the medullary canal distally does not have intimate contact with the nail and does not “self-align.” 

■    Transverse fractures may contain a segment of  intact linea aspera that peels off the posterior aspect and may get entrapped in the fracture. 

■    It can result in shortening that may be difficult  to overcome without either “unwinding” the fracture or opening the fracture site. 

■    In skeletally mature children, intramedullary nailing offers the same benefits as in adults. 

■    Attention should be paid to adolescents with very valgus neck  angles,  as some have hypothesized that  this can  increase the risk of  avascular necrosis of  the femoral  head. However, with modern implants, a trochanteric starting point may alleviate such concerns. 

■    Skeletally immature children may still be considered for some form of intramedullary treatment after considering remaining growth,  type of  fracture, and benefits over other methods of treatment.1,11 Preoperative Planning 

■    All  films should be reviewed, with particular attention paid to the presence of an ipsilateral femoral shaft and neck fracture. 

■    The overall condition of the patient and any associated injuries should be contemplated before embarking on a surgical tactic. 

■    In the presence of pelvic or acetabular fracture, pregnancy, or obesity, one should consider a more elegant tactic, such as retrograde nailing, as opposed to antegrade nailing. 

■    If suitable, antegrade nailing in the supine position can be safely performed with proper positioning and knowledge. 

■    Several options have to be considered during preoperative planning. They include: 

■    Table: fracture table or radiolucent 

■    Position: supine or lateral 

■    Entry point: piriformis or trochanteric 

■    Type of nail: cephalomedullary or standard 

■    Use of traction: skeletal, boot, or manual 572       

■    Strong consideration should be given to  checking fine cut CT  scans to search for femoral neck fractures when possible. As part of the operative plan, the femoral neck should also be checked radiographically after fixation and prior to leaving the operating suite. Positioning 

■    Fracture table 

■    Standard fracture tables (eg, those used commonly for hip fractures) can be used for antegrade femoral nailing but are best used for supine position nailing. 

■    A large and well-padded perineal post should be used. 

■    Traction   should   be  used  sparingly  and   only   when needed. 

■    The legs should be scissored to facilitate imaging and allow for appropriate countertraction. Placing the opposite leg in lithotomy position can allow rotation of the pelvis when traction is applied. 

■    The  ability to  image all  aspects of  the femur should be verified before preparing and draping (FIG  1A). 

■    Radiolucent tables 

■    Newer  tables allow  free image  intensifier access to  the lower extremity. 

■    Some of  the tables (Jackson  table,  OSI,  California)  also provide traction assemblies. These types of tables are suitable for multiple limb operations (FIG  1B). 

■    Our preferred method uses a radiolucent Jackson table with traction apparatus and lateral positioning (FIG  1C). 

■    Supine position 

■    The supine position may be easier for surgeons to visualize anatomic relationships. 

■  It is more difficult to use supine positioning in obese patients. 

■    It may be the preferred position in patients with spinal cord injuries or severe chest injuries. 

■    It can be used with and without traction. 

■    If the supine (floppy) positioning on a radiolucent table is chosen, it helps to position the patient at the edge of the bed with a small bolster under the pelvis. 

■    Preparing and draping should include the posterior aspect of the gluteal area, since crossing the leg over will facilitate access to the piriformis. 

■    Even  with  the newer trochanteric entry technique and implants,  the  ability  to  manipulate  the  leg  in  adduction may be useful during the procedure (FIG  1D). 

■    Lateral position 

■    The  lateral position  facilitates  gaining  an  entry point, especially with a piriformis starting point in obese patients. 

■    It can be used with and without traction. 

■    When using the lateral position,  the pelvis is rolled forward about 15 degrees to allow lateral imaging of the proximal femur. 

■    Care   should   be  taken  during  positioning  for   proper padding and spinal precautions if occult spinal injury may be present.                                       D FIG 1 • A.  Supine positioning on  a fracture table with legs  scissored. Slight  obliquity using a bump under the sacrum helps with hip  visualization. B. Supine position without traction on flat-top table. The ipsilateral hip  should be  close  to the edge, and a bump under the sacrum will help with visualization. Standard lateral views  of the hip  for  entry points can  be  used, but so can  frog-leg laterals. C.  Lateral position with traction. Skeletal traction in the proximal tibia or distal femur can  be  used. The perineal post is pictured here in the perineum, which is best for  proximal fractures. In fact,  little traction is usually needed and the post is frequently positioned under the apex of the fracture and used to overcome gravitational sagging. If traction will be  needed, we  have found that placing a blanket on  the “down” leg  and securing the contralateral thigh with a sling  of tape coursing in a proximal and oblique fashion will resist moderate amounts of traction. D.  Preparation and draping of the leg  using a flat-top table without traction should include posterior sections of the buttocks. The leg  can  be crossed over  to gain easier access  to the piriformis starting point. Chapter 10   573 

■    Traction 

■    If traction is used, it frees an assistant and the length and rotation can be “set.” 

■    If manual traction is used, the length and rotation need to be checked before final interlocking. 

■    Skeletal traction can be via the proximal  tibia or distal femur. 

■    The surgeon should be careful if there is any ligamentous instability of the knee, as suggested by a knee effusion or other sign of injury. 

■    In such cases, distal femoral traction can be used, and it can be prepared and draped into the operative field. 

■    Use of distal femoral traction can complicate distal interlocking because of the proximity of the traction apparatus with the interlocking site. 

■    Boot traction is a very common alternative. 

■    Unlike  tibial  or  femoral  skeletal traction,  where the knee is  slightly  bent,  boot  traction  uses a  straight leg (FIG  1A). 

■    Care  should be taken to avoid nerve traction injury (eg, avoid prolonged and excessive traction). 

■    Small  perineal posts and  long  durations  of  traction have been shown to increase the risk of pudendal nerve injury. 

■    If   traction   is  used,   it   should   be  first  applied  to determine the  “reducibility”  of  the  fracture.  Then  it should be reduced during prepping and applied as needed. 

■    Large  and well padded perineal posts should be used whenever possible.6,15 SOFT TISSUE DISSECTION 

■            Whether  using a  cephalomedullary  nail   or   piriformis fossa  nail,  the surgical approach is similar. 

■            The surgeon palpates the greater trochanter. 

■            For trochanteric entry, the skin incision is based about 4 to 10 cm above the trochanter in line  with the femur. 

■       The tensor fascia  is incised and the gluteus maximus is gently separated. 

■       The tendinous insertion of  the gluteus medius is frequently more distal, and this  tendon can  be  gently spread to identify a bursal area just below the medius and above the minimus. 

■            For piriformis entry, the incision is made about a handbreadth along the line  between the trochanter and the posterior superior iliac spine. 

■       Once   the gluteus maximus is gently separated, the access  to the piriformis is posterior to the medius. 

■       The piriformis fossa  can  be easily palpated as a “dimpled ledge” behind the  trochanter. This  anatomic feature is  used during the  percutaneous approach for  proprioceptive feedback during pin  placement.

 

■            After  soft   tissue  dissection, the  tip   of   the  greater trochanter is palpated. The  piriformis fossa  is palpated medially. 

■            The ideal starting point for a piriformis fossa  nail is in the fossa    along   the   medial  upslope  of    the  greater trochanter, since  this  is most in line  with the shaft. 

■       This point may  vary  between patients and should be confirmed with intraoperative fluoroscopy. 

■       The surgeon can have an assistant adduct the extremity to aid  in exposing this  spot (TECH FIG 1A). 

■            Once  the starting point is identified by  palpation and confirmed with fluoroscopy, the  cortex is  penetrated with either an  awl  or a threaded Kirschner wire. 

■       Every effort should be  given to establishing an  accu- rate starting point (ie,  one that is in  line  with the femoral shaft). TECH FIG 1 • A.  AP image of the correct position  of   a   guide  pin   for   piriformis  entry. B.  Lateral image of  piriformis starting point. The pin need only start in the piriformis; it will frequently course anterior, and care  should be taken not to penetrate  the anterior cortex. The  rigid  reamer need only  open the top of A                                                              B                                                                                the bone for  access  to medullary canal. 574       

■       If this is not possible, as long as the entry site is collinear with the shaft, the pin can be directed anteriorly. 

■       In these cases,  care  should be  taken not to perforate the anterior cortex (TECH FIG 1B). 

■            In supine nailing, especially with obese patients, this  can be  very  difficult. Adduction of  the limb  may  not always be possible because of body habitus and setup and especially with proximal fractures.

■ In these cases,  preparing under the buttock and accessing from a more posterior approach may  allow access to the fossa. 

■            The lateral positioning allows the easiest access,  with very few  problems. In fact,  nailing can  be  performed percutaneously (described below) with little problem when using the lateral position. 

 

■            The  percutaneous method of  nailing29  uses  cutaneous landmarks to identify the ideal entry site, which is usually about one full  handbreadth (8  cm)  from the posterior corner of  the trochanter towards the posterior superior iliac spine (TECH FIG 2A). 

■            The incision is a stab wound. 

■            A guide pin  is advanced to the trochanteric bursa (TECH FIG 2B). 

■            The   pin   is  “rolled”  off   the  posterior  slope  of   the trochanter  and  then  advanced distally and  anteriorly (TECH FIG 2C,D). 

■            A very  distinct resistance is felt, as  if  on  a  pedestal or ledge of bone. The tip of the pin provides proprioceptive feedback when this  occurs,  and it can  be  felt  that there are   structures anterior and medially, which constitute the “walls” of the fossa.                                       D TECH FIG  2  •  A.   The  cutaneous site  for  percutaneous nailing, situated about midway and slightly posterior to midpoint between  tip  of  trochanter and posterior superior iliac  spine. B.  Photograph showing pin  driven into piriformis via percutaneous wound. C.  The  pin  usually finds  the trochanteric bursa. It is then “rolled” off  the back  and advanced anterior and distal until a distinct resistance is felt. It should rest  on  the “ledge” of bone known as the piriformis fossa.  D.  The pin  has  a resistance to anterior and distal advancement but can  move medial and posterior. (continued) Chapter 10   575 E                                                                                                   F G                                                                                                    H TECH FIG 2 • (continued) E. The rigid  reamer advances over  the pin to enter the proximal  femur. Use of irrigation will help prevent soft  tissue catching. F. Insertion of the nail  over  the guidewire. With  use  of  a bent guidewire and “ream-to-fit” technique, the likelihood of an  incarcerated reamer is very low,  and exchange of the guidewire with a chest tube is not needed (unless a ball-tip guidewire is used). G. Intraoperative photo of final  wounds. H. Entry  site  wounds are  usually about 1.5 cm. 

■            At this  point image verification is performed. 

■       If the pin  is not coaxial with the femur, what is most important is that the tip  of the pin  is centered. 

■       The pin  is advanced to engage the cortex, and then a 9to 12-mm rigid  reamer is used to open the proximal femoral cortex (TECH FIG 2E). 

■       This  reamer need only  be  advanced enough  to open the cortex and provide access  to medullary contents. Care  should be  taken not to ream too deeply and perforate the cortex of  the proximal femur anteriorly (see  Tech Fig 1). 

■            Once this step is accomplished, the remainder of the proce- dure can be done with standard methods, and instruments are  passed via the keyhole skin incision (TECH FIG 2F–H). 

■            After soft  tissue dissection (as described previously), the surgeon palpates the tip  of  the greater trochanter and its anteroposterior dimensions. 

■            Because of the inherent anatomy of the proximal femur, the ideal starting spot for  a trochanteric entry nail  is at the tip  of  the greater trochanter (mediolateral) and the junction of  the  anterior one third and posterior two thirds of the greater trochanter. 

■       This spot may vary from person to person, but the cor- rect   starting point is  one that is  in  line   with the femoral shaft. 

■       Once  the correct starting spot is identified, the outer cortex is penetrated with either an  awl  or  a pointed guidewire (TECH FIG 3A). 

■            In  this   method,  because the  abductor  mechanism is being split,  soft  tissue protection is important. 

■            After the  starting point is  identified, a  guidewire  is placed into the proximal femur and passed down the canal. 

■       Forceful and  jerking  motions  can   be   avoided  by firmly twisting the guidewire through the cancellous bone. 

■       A gentle J bend at the distal 1 cm of the wire  allows the wire   to be   “bounced” off   cortices and to  be “steered” in metaphyseal areas (TECH FIG 3B). 

■       The proprioceptive feedback of  a wire  passing along the  medullary canal is  similar   to the  sensation of pushing a stick on  a sidewalk. 576       A B E C D                                                                                                    F TECH FIG 3 • A.  The entry point for  the trochanter is usually on  the anterior one-third junction. B.  Bent  straight guidewire. This helps to “steer” the wire  in metaphyseal bone and will prevent reamer heads from disengaging (relevant only in modular designs). C.  The “wand.” It is available on some sets,  or can be performed with some extraction rods.  It is placed over  the guidewire into the proximal segment, down to the level  of the lesser  trochanter. It can  manipulate the proximal fragment to aim  it into the distal segment, after which the guidewire is advanced into the distal fragment. This is much more desirable than struggling with manual methods. D. F bar. This can be placed around the thigh to effect the desired translation. In out-of-plane deformities, the bar  can find  the “ideal” orientation and effect a  reduction. E.  The  joystick  method. Small  terminally threaded wires  can  be  drilled into the cortex of each segment and used to manipulate the fragments into reduction. Small  external fixator pins  can  also  be  used and have been previously described. F. Intraoperative image of guidewire passed across  fracture. 

■            If the fracture is not reduced sufficiently to easily  pass the wire  across, there are  several techniques available to facilitate reduction and wire  passing. 

■       Some  nail  systems provide a  cannulated rod  that is placed over  the wire  and passed into the proximal femur. This  rigid   wire   holder functions as  a  wand to  manipulate the  proximal fragment as  the  wire approaches the fracture so that it can easily be passed across  (TECH FIG 3C). 

■       An F or H bar, a crutch, or both can  also  be  useful to manipulate the proximal and distal fragments (TECH FIG 3D). Chapter 10   577 

■            Sometimes the fracture cannot be perfectly reduced, but enough provisional alignment can  be  established to pass the guidewire. 

■       If the fracture is unstable and difficult to reduce after numerous attempts, a small incision can be made along the lateral thigh over  the fracture and the fracture can be digitally reduced and provisionally aligned. 

■       In some cases, the incision can be lengthened to allow placement of “lobster claw”-type clamps. 

■            Other methods include the use  of  unicortical “joystick” half-pins from an  external fixator set  (usually a  5-mm half-pin). Alternatively, 3-mm  threaded guide pins  can also  be  used (TECH FIG 3E). 

■            The  guidewire  position in  the  distal segment is  con- firmed with intraoperative fluoroscopy. 

■       The  guidewire should be  passed down to the distal femur physeal scar  and should be  center-center on both the AP and lateral views. 

 

■            Once  the guidewire has  been placed, the length of  the nail  is measured either with a measuring device (usually supplied by the intramedullary nail  system) or by using a guidewire of the same length. 

■       Placing the second wire  at the entry site  and measur- ing  what is not overlapping with the inserted wire provides nail  length. 

■       Before measuring, the surgeon confirms the proximal position of the ruler on  the greater trochanter. 

■      The  surgeon should make sure  that there is no  soft tissue between the ruler and the top of  the greater trochanter, as this  can  artificially increase the length of the nail  chosen. 

■       Average nail  lengths range from 38 to 42 cm. 

■            Using  the radiographs of the femur, the surgeon can  estimate the beginning reamer size. 

■       With  “tight” canals, reaming should begin with lower sizes, and sequential reaming can  begin starting with the lowest size available (usually 8 or 9 mm). 

■       When starting to ream, the surgeon should pay  par- ticular attention  to keep the reamer medial in  the proximal femur to prevent reaming out the posterior or lateral cortex. 

■       If the reamer does not pass easily, the surgeon should check  its position with fluoroscopy since  the reamer may  be  hitting cortical bone (usually anteriorly). 

■            Reaming can  be  increased by  1.0-mm increments until distinct “chatter” is encountered, after which it  should increase in 0.5-mm increments. 

■            Once  endosteal “chatter” is encountered, reaming should continue for  another 1.0 to 2.0 mm,  and a nail  diameter of   1.0   to 1.5   mm   smaller than  the  largest diameter reamed should be  used. 

■       With  modern nail  designs, most male patients can  be treated with 11 to 13-mm nails  and most females with 10to 12-mm nails. 

■            Care  should be  taken when there is a  tendency for  a deforming force to allow for  “eccentric” reaming (eg, proximal fractures). 

■       In these cases,  without attention,  eccentric reaming can   remove cortical bone  and  create  defects that result in deformity or a nail  outside the bone. 

■            If a ball-tipped wire  is used, the surgeon should confirm that it can be pulled through the nail or exchanged for a smooth-tip wire. 

■            After the nail  has  been inserted, its position is checked distally, at the fracture site,  and proximally near its insertion site. 

■       The  surgeon ensures that the nail  is not too proud above the greater trochanter and fossa. 

■            If the fracture site  is distracted, traction should be  reduced or adjusted to effect a satisfactory reduction. 

■            Length and  rotation  need  to  be   reconfirmed before interlocking. Several methods can  be  used.12,13,24,25 

■       Cortical characteristics 

■       The femur diameter is not symmetric. Variances in cortical thickness can be used to estimate rotation. 

■       Fracture  lines   can   be   used to  estimate  correct rotation. 

■       Radiographic methods 

■       One  method checks  the true hip  lateral with the distal femoral lateral  in  the intact contralateral femur. The measured difference is mirrored in the fractured side. 

■       In cases  of comminution or bilateral fractures, an- other method can  be used to determine or set  the rotation. A true lateral of  the distal femur is obtained, and the intensifier is then moved orthogonal  to this  position, and the proximal femur is visualized to obtain a  profile of  the lesser trochanter. The  images are   saved for  reference, and mirrored on  the fractured side,  or  contralateral  side  if bilateral. 

■            Surprisingly, rotational  deformities appear  to  be  well tolerated, with an  average of  28%  of  patients having a deformity of more than 15 degrees. 

■       Internal rotation  is  tolerated  better  than  external rotation. 

■      In  all  cases,   a  clinical   examination  of   rotation  of both legs with the pelvis supine and the hip flexed to 90 degrees can  be  used to estimate symmetry. 

■            Unless  the patient is in extremis, all nails  should be  statically locked. 

■       The order of interlocking should be  considered. 

■       In axially stable cases, the distal segment should be interlocked, and compression applied by back-slapping the nail. 

■       In unstable cases,  traction and alignment should be maintained until interlocking is complete. Usually distal  interlocking precedes proximal interlocking.5,28 578       

■            There are  guides with each system that allow placement of proximal screws.  In general, at least one screw  should be  placed. 

■            Unless   the  fracture is  stable,  the  static  screw   hole should be  used, and the hole closest to the fracture is preferred. 

■            Distal  screw  placement is usually done with a freehand technique. This can be one of the most challenging parts of the case  for  some surgeons and the easiest for  others. 

■            In general, setup and image positioning can greatly facil- itate this  part of the procedure. 

■            Using  the concentric circle concept, the image intensifier or the leg  is rotated to obtain a perfect circle. 

■       If the image is oval  or  shaped like  an  eye,  the image intensifier is not perpendicular to the axis of the nail, or in other words, parallel or co-axial with the axis of the screw  hole. 

■       The  goal is to align the axis of  the image intensifier with that of  the screw  hole. Getting perfect circles is the first  critical  step. 

■       In TECHNIQUES FIGURE 4A, the image intensifier is not aligned in the coronal plane (varus  or valgus to the femoral nail). 

■       In TECHNIQUES FIGURE 4B,  the image intensifier is not aligned in the axial–transverse plane (rotationally to the nail). 

■       In TECHNIQUES FIGURE 4C,  both screw  holes in the  nail   line   up,   giving the  “perfect  circle” wherein the image intensifier is co-linear to the axis of the screw  hole in the nail. 

■            Next, a drill or scalpel is used to determine the cutaneous location for an incision, which should go through the fascia and to bone. 

■       A drill  is centered over   the hole and held securely (TECH FIG 4D). 

■       At this  point there are  two options: the drill  can  be gently tapped to engage the near cortex, or it can  be drilled. 

■       The  axis  of  the drill  bit  should be  aligned with the center of  the image intensifier (which is parallel to that of  the hole). Thus,  if  the drill  tip  is centered over  the hole and aligned with the center of the intensifier, it  should be  co-axial with the axis  of  the hole. A                                                            B                                                                             C TECH FIG 4  • A.  The  perfect circle  method for  freehand interlocking. If the image appears as  two circles  overlapped, the shape of an  8 will appear. The central area is elliptical and indicates that the image intensifier axis is not collinear with the axis of  the screw  holes. The  appropriate corrective direction is parallel to the short axis of the central ellipse (or  perpendicular to the long axis).  In this  case,  the correction would be  in the coronal plane (proximal-to-distal). B. In this situation, the rotation of the image does not match. It will need to be corrected along the path of the C. C.  The image of a perfect circle.  (continued) Chapter 10   579 12 mm ~3 nail diameters 36-40 mm ~5.5 nail diameters 65 mm D                                                                      E                                                                                F TECH FIG 4 • (continued) D.  The drill point should be in the middle of the circle. Then  the axis of the drill can  be made collinear with that of  the image intensifier. E.  The drill  can  pass  anterior or  posterior to the nail  and “feel” pretty good. Care  should be taken to make sure the drill point does not drift during this motion. Proprioceptive feedback will frequently indicate when the drill passes through the nail  and the contralateral cortex. If the drill “kicks” in one direction (anterior or posterior) it may  have missed the nail.  If it is not aligned in the coronal plane, it may hit the nail.  It is important to verify all implant positions before leaving the operating room. F. A method of measuring using the nail as a “yardstick.” If the diameter of the nail is known, then the diameter of the bone at the level of the interlocking hole can be estimated by seeing how many multiples of the nail will fit in that segment. With  some practice the accuracy of this technique is impressive: we  estimate our  accuracy to exceed 90%  using this technique. 

■       Once  the drill is into the bone and advanced, fluoroscopic  verification should be  obtained, after  which the drill is advanced to the far  cortex. 

■       If the drill bit  “kicks” or jerks  into a different direction or cannot be advanced, it is likely that it either glanced off the nail (missed the hole anteriorly or posteriorly) or is hitting the nail (proximally or distally) (TECH FIG 4E). 

■            Measurement 

■       The drill can  be  removed and measured with a depth gauge or in many systems read directly from the drill guide. 

■       An alternate method, which we  have used with surprising accuracy, is to use  the known diameter of the nail  as a legend. 

■       Comparing the width of  the femoral canal at the level of the screw  hole with that of the nail and estimating the number of  nail  widths in  that segment allows for  an  estimate of the screw  length. 

■       With   a  little practice, this  method is fairly  reli- able, especially considering that many companies provide screws   only  in  5-mm   increments (TECH FIG 4F). 

PEARLS AND PITFALLS

 Preoperative                                       

■  Correct position and traction are  chosen based on  patient size and assistant availability. Intraoperative                                    

■  After nail  insertion the surgeon should always check  limb  rotation, limb  length, and the femoral neck  (iatrogenic fracture).