Introduction
The preferred treatment for fractures of the femo- ral shaft has become the antegrade insertion of a femoral nail. Multiple authors have demonstrated high union rates, restoration of limb function and low complication rates utilizing this technique [5].
One of the few drawbacks to this procedure is that most surgeons perform the surgery with trac- tion being applied via a fracture table. Although this set-up provides mechanical traction that aids in realignment, there are a number of complica- tions that have been reported with the use of a fracture table. These include pudendal nerve palsy [2], transient impotence and compartment syn- drome of the opposite leg [3]. Some surgeons at- tempt to minimize these complications by per- forming this procedure with traction being ap- plied with the patient in the lateral position; how- ever, this position is difficult to set up and poten- tially compromising to patients with multiple in- juries. In addition to these potential complica- tions, a skeletal traction pin is required and there is significant amount of time spent positioning a patient on a fracture table.
These drawbacks have led some to perform this procedure without the use of a fracture table. In appropriate circumstances this can facilitate start- ing point creation, save time and eliminate the potential for complications related to the tech- nique [4, 6].
Technique Patient Preparation
The reduction of a femoral shaft fracture is ea- siest if surgery is performed soon after the frac- ture has occurred. Delays can lead to muscle spasm, which makes length restoration difficult.
Ideally, surgery is performed on the day of injury after ªadvanced trauma life supportº protocols have ruled out concomitant injury. If delays of
24 h or more are anticipated prior to surgery, it is helpful to place a skeletal traction pin with one- fifth of the patient's body weight attached. This will prevent muscle shortening and will facilitate subsequent reduction. Muscle-relaxing anesthesia is administered as well as prophylactic antibiotics.
Prior to positioning, it is of great value to deter- mine nail length from the intact femur. This is done with fluoroscopic examination of the oppo- site knee and hip with varying length rods held adjacent to the leg. The nail length that most closely extends from the piriformis fossa to the distal physeal scar is chosen. Alternatively an electrocautery cord can be fluoroscopically visual- ized and used to measure the length of the medul- lary canal. The opposite leg is also examined to assess the patient's normal limb rotation so that this may be reproduced during surgery. This re- quires that the C-arm be aligned with a reproduc- ible rotational femoral marker and the foot's rota- tional position noted in relation to this axis. The best marker in the proximal femur is the lesser trochanter. In an anteroposterior projection, the femur can be internally rotated until the lesser trochanter is eclipsed by the femoral shaft and no longer visible. This same radiographic marker can be used to check rotation in the fractured limb after nail interlocking to assure restoration of physiologic rotational position.
The use of a completely radiolucent operating table is strongly recommended as multiple oblique fluoroscopic projections will be required.
Metal side-rails will interfere with some of these projections. Femoral nailing without a fracture ta- ble can be performed in a lateral position. This is particularly useful for subtrochanteric fractures because flexion of the fractured leg removes the deforming influence of the iliopsoas. In all re- maining patients positioning with the ipsilateral buttock elevated 20 cm from the table surface with sheets is preferred because of simplicity and physiologic advantages (Fig. 4.5.1). Prior to skin preparation a fluoroscopic check is performed to ensure that coronal and sagittal imaging of the
Antegrade Femoral Nailing
Without the Aid of a Fracture Table
R.A. Probe
entire femur is possible. In this position the limb is draped free with split-sheets applied in a fash- ion that leaves a large area of skin proximal to the greater trochanter exposed (Fig. 4.5.2).
Surgery
Controversy exists over the ideal starting point, with some surgeons preferring a trochanteric start position rather than one in the piriformis fossa. If a nail without a trochanteric bend is chosen, it is generally preferable to utilize the piriform fossa because this point is in line with the medullary canal. Deviation from this position will generate large hoop stress during nail insertion or lead to malunion. To gain access into the piriformis fossa, the hip is flexed, adducted and internally rotated.
A 2-cm longitudinal skin incision is placed proxi-
mal to the trochanter in a spot that represents the virtual extension of the axis of the proximal fe- mur. This should be confirmed fluoroscopically in both planes with a guide wire placed collinear with the femoral axis. This is typically one hand- breadth proximal to the trochanteric tip. If adhe- sive drapes are used, they should be removed around the margin of the incision to ensure that they are not caught within the rotating reamers.
The fascia of the gluteus maximus is incised and a finger is used to create a path through this mus- cle, exposing the underlying gluteus medius and trochanter. With the hip flexed it is possible to gain entrance into the piriformis fossa posterior to the gluteus medius with digital palpation. Stay- ing posterior to the muscles minimizes insertion damage and postoperative abductor weakness.
Once a path has been created, a 3.2-mm guide- wire is drilled into the piriformis fossa and its po- sition verified with biplanar image intensification.
The wire is drilled down to the level of the lesser trochanter (Fig. 4.5.3) and then the hole is ex- panded with a 12-mm cannulated drill. It is criti- cal that this channel be created exactly in line with the axis of the proximal segment. There is a tendency for inserting muscles to pull this seg- ment into varus and flexion. This must be avoided or malunion will result, particularly in subtrochanteric fractures. Following channel crea- tion a ball-tipped guide wire is introduced into the proximal medullary canal.
Passage of the guide wire across the fracture is occasionally challenging without the use of a frac- ture table and represents the greatest argument against this technique. The initial strategy is to match the axis of the proximal segment by bring- ing the distal segment to it. With assistants pull- ing on the leg, the surrounding musculature will often align the segments allowing for passage of the wire (Fig. 4.5.4). Sustained pulls are generally most effective in overcoming muscle shortening because of their viscoelastic properties. If several attempts fail, a number of alternative measures may prove helpful. One of these is to ream the proximal segment to 11 mm and then insert an intramedullary reduction tool (Fig. 4.5.5). This tool will allow for control of the proximal frag- ment and allow the surgeon to align this with the distal segment and subsequently pass the wire through the cannulated tool. Occasionally, fracture angulation or translation will prevent entrance into the distal segment. This can usually be cor- rected with application of strategically placed op- posing forces through the skin. If a segment is posteriorly translated or the fracture angulated posteriorly, then sterile bumps placed posterior to
Fig. 4.5.1.Leg positioned to allow for adduction and access to the piriformis fossa
Fig. 4.5.2.The leg is draped to allow access proximal to the trochanter and free manipulation
the deformity can provide a corrective force. This alignment can be augmented with a counter-force being applied to the anterior fragment manually.
If these measures are not successful more invasive measures such as the placement of a percutaneous Schantz pin or bone hook for manipulation can also be helpful. If the principal impediment to re- duction appears to be muscle contracture, appli- cation of a femoral distractor [1] may prove use- ful. The complexity of doing this is placing the anchoring pins in locations that are outside of the eventual nail tract. Distally this is not difficult as there is ample bone posterior to the nail tract to place a 5-mm pin from lateral to medial. Proxi- mally, the pin can either be placed in the femur or the acetabulum. If the acetabulum is chosen, the supra-acetabular bone is ideal and has the ad- vantage of not interfering with nail placement. In the femur, the best location is just above the cal- car in an anterior to posterior direction. As great
precision is required of this pin, it is recom- mended to place this under fluoroscopic control and to place the pin through sleeves so that the risk of neurovascular injury is minimized. On rare occasions, all of the adjunctive techniques for obtaining fracture reduction fail and opening of the fracture site may be required. With experi- ence, this should occur in less than 10% of cases.
If limited open reduction is required, it is per- formed with minimal stripping of bone so that the fracture biology is not disturbed. If fracture opening is required, this incision should be closed after guide wire passage. This will allow the os-
Fig. 4.5.3.Two-plane confir- mation of guide wire place- ment
Fig. 4.5.4. Manual traction being applied, which allows for guide wire passage
Fig. 4.5.5.This cannulated tool allows for proximal fragment manipulation
teogenic reaming debris to remain localized at the fracture site and promote healing.
Once the guide wire is passed, the remainder of the procedure is similar to standard nailing.
Reaming is performed in 0.5-mm increments until cortical chatter is heard. During the reaming pro- cess it is helpful to maintain the leg with some degree of longitudinal traction and in a reduced position. This will prevent eccentric reaming of the distal fragment. A nail diameter 1 mm less than the reamed diameter is chosen. With the driving rod and screw guides assembled, the ac- curacy of the proximal screw guides is checked prior to nail insertion. The nail is inserted over the guide wire with progress being verified with fluoroscopy. Once the distal end of the nail has reached the position determined by preoperative planning, it is locked with traditional ªfree-handº technique. The image intensifier is rotated into a position that allows for the holes in the nail to be seen as perfect circles (Fig. 4.5.6). Through percu- taneous incisions the pilot hole is drilled and the screw placed. With the distal rod now locked in its predetermined position, final length adjust- ments are made. If the fracture pattern allows for cortical contact, the fracture gap is useful to esti-
mate length. Occasionally, the driving rod will re- quire ªback-slappingº to gain cortical contact in length stable fractures. If no cortical references are available, length should be estimated based on nail length from the preoperative plan. Final ad- justments are made so that the proximal end of the nail rests precisely where it was planned on the normal limb. This can be done by driving the nail forward or backward assured that the distal segment will be moved because of interlocking.
Once length has been restored, proximal locking is performed through the available guides. With a single locking screw both proximal and distal, ro- tation is checked to be certain that it is compar- able to the opposite side. This is done by check- ing foot rotation against the hip rotation markers that were assessed preoperatively. Should signifi- cant discrepancy exist, either interlocking screw is removed and corrections are made. In the ma- jority of cases a single proximal and distal locking screw is all that is required. If a fracture ap- proaches either end of the femur or healing diffi- culties are anticipated, consideration should be given to the addition of the second interlocking screw.
Wounds are irrigated and routinely closed. At the completion of the procedure it is imperative to examine the knee for concomitant ligament in- jury. It is also necessary to review quality radio- graphs of the femoral neck to rule out an asso- ciated femoral neck fracture.
Discussion
Femoral nailing without a fracture table has many potential advantages when compared to tradi- tional nailing. Time savings have been shown dur- ing positioning, surgery and for total anesthesia [4, 6]. From a surgical standpoint, access to the piriformis fossa is easier, injury to the gluteus medius may be avoided and correct rotation may be easily assessed. Importantly, it also removes the potential for complications directly related to the fracture table. The incidence of pudendal palsy has been reported between 10% and 15%
[1, 6]. Fortunately those cases reported in the literature have been transient but nonetheless, disconcerting to patients. Additional advantages include the ability to perform other procedures simultaneously as well as providing a means of femoral nailing in those patients with unstable pelvic and spine trauma who would be potentially compromised with the use of a fracture table.
Despite these advantages there are limitations to this technique. Patients presenting for surgery
Fig. 4.5.6.Surgical instrument is used to identify the posi- tioning of the skin incision for distal locking
after 24 h often have excessive shortening, which is difficult to overcome. Because of soft tissue ten- sion, shortening of comminuted fractures is prob- lematic and transverse, isthmic fractures in mus- cular individuals can also be very difficult to re- duce without the aid of the sustained traction provided by the fracture table. Perhaps the most significant negative is the need for additional knowledgeable scrubbed personnel to assist with fracture reduction. In many cases three individ- uals are required: one for traction, one for frac- ture alignment and a third for manipulation of the guide wire. Even though these factors can make this procedure challenging, in certain cir- cumstances it is clearly of benefit in the manage- ment of the trauma patient.
References
1. Baumgaertel F, Dahlen C, Stiletto R, Gotzen L (1994) Technique of using the AO-femoral distractor for femo- ral intramedullary nailing. J Orthop Trauma 8(4):315±
2. Brumback RJ, Ellison TS, Molligan H, Molligan DJ, Ma-321 haffey S, Schmidhauser C (1992) Pudendal nerve palsy complicating intramedullary nailing of the femur. J Bone Joint Surg Am 74(10):1450±1455
3. Meldrum R, Lipscomb P (2002) Compartment syndrome of the leg after less than 4 hours of elevation on a frac- ture table. South Med J 95(2):269±271
4. Reynders P, Broos P (1998) Unreamed intramedullary nailing of acute femoral shaft fractures using a traction device without fracture table. Acta Orthop Belg 64(2):
175±179
5. Winquist RA, Hansen ST Jr, Clawson DK (1984) Closed intramedullary nailing of femoral fractures. A report of five hundred and twenty cases. J Bone Joint Surg Am 66(4):529±539
6. Wolinsky PR, McCarty EC, Shyr Y, Johnson KD (1998) Length of operative procedures: reamed femoral intra- medullary nailing performed with and without a frac- ture table. J Orthop Trauma 12(7):485±495
