Neurologic and vascular structures at risk during anterior-posterior locking of retrograde femoral nails

A Single Proximal Interlocking Bolt May Be Sufficient for Retrograde Nailing of Extra-articular Femur Fractures

OBJECTIVE

To evaluate whether a single proximal interlocking bolt was sufficient during the treatment of extra-articular femur fractures with retrograde medullary nailing.

DESIGN

Retrospective comparative study.

SETTING

Academic Level 1 trauma center.

PATIENTS

The study included 136 patients with extra-articular femur fractures treated with retrograde medullary nailing who met inclusion and follow-up criteria.

INTERVENTION

The intervention included surgical treatment for a femur fracture with retrograde medullary nailing, with comparisons made between those treated with a single proximal interlocking (1 IL) bolt and those treated with 2 proximal interlocking bolts (2 IL).

MAIN OUTCOME MEASUREMENT

The main outcome measurements were as follows: (1) rate of nonunion and (2) rate of catastrophic implant failure.

RESULTS

There was no difference in the rate of nonunion requiring surgical intervention between the 2 groups. There were no catastrophic failures in either group.

CONCLUSIONS

A single proximal interlocking bolt may be sufficient when using retrograde nailing for the treatment of extra-articular femur fractures.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The relationship of the Phantom® Lapidus Intramedullary Nail System to neurologic and tendinous structures in the foot: An anatomic study

BACKGROUND

The purpose of our cadaveric study was to determine the proximity of nail insertion and interlocking mechanisms in the Phantom® Lapidus Intramedullary Nail System to neurologic and tendinous structures in the foot.

METHODS

We used 10 fresh-frozen human lower-extremity specimen cadavers. For each specimen, the Nail System was inserted as described in the published technique guide. We then performed dissection on the tibialis anterior tendon, extensor hallucis longus tendon, and medial dorsal cutaneous branch of the superficial peroneal nerve and we measured and averaged the distances from each of these structures from the nail.

RESULTS

The tibialis anterior tendon was in closest proximity to the insertion of the proximal medial interlock K-wire with an average distance of 0.4mm from the tendon. The extensor hallucis longus tendon was in closest proximity to nail insertion with an average distance of 1.2mm. The medial dorsal cutaneous branch of the superficial peroneal nerve was in closest proximity to the distal interlock K-wire with an average distance of 7.5mm.

CONCLUSIONS

The tibialis anterior tendon, extensor hallucis longus tendon, and the medial dorsal cutaneous branch of the superficial peroneal nerve are at risk with the insertion of the nail system. Blunt dissection should be performed using this system with a path to bone before instrumentation to reduce the risk of nerve and tendon injury in the foot.

Use of novel and inexpensive radiolucent soft tissue protector for insertion of proximal locking screws in femoral retrograde intramedullary nailing

We use a straightforward technique for insertion of proximal interlocking screw fixation during retrograde intramedullary nailing of the femur utilizing a common 3 cc syringe as a radiolucent soft tissue protector. Following insertion of the implant and distal interlock insertion, the distal Luer-Lok tip of a 3 cc syringe is cut off to create a hollow tube. Once the correct location of the proximal locking holes is confirmed fluoroscopically, the syringe is inserted through the incision into the soft tissue over the long drill sleeve and trochar. The inner drill guide and trochar is then removed, leaving only the syringe. Through this syringe, the proximal interlocking hole is drilled and measured, and the screw is inserted. The syringe establishes a safe pathway for passage of instrumentation, mitigating damage to the surrounding soft tissues, and allowing for unobstructed fluoroscopic visualization throughout insertion of the locking screws. This technique is safe, inexpensive and reproducible; utilizing common equipment available in most operative settings.

Management of a Broken PRECICE Femoral Nail at an Ununited Distraction Osteogenesis Site: A Case Report

CASE

A 20-year-old man with a history of right lower extremity fibular hemimelia previously treated with PRECICE femoral nail lengthening presented with a broken magnetic nail and a displaced fracture through an ununited distraction osteogenesis site. Using a combination of techniques, we removed the broken implant while maintaining the achieved limb length and preserving the native biology without bone grafting.

CONCLUSION

The unique challenges associated with the removal of a broken PRECICE femoral nail are described, with a technique for implant removal that preserves the achieved length, the innate biology of the distraction osteogenesis site, and promoting union without bone grafting.

Incarcerated Cortical Fragments in Intramedullary Nailing

In fractures with varying degrees of comminution, it is possible for cortical bone fragments to become entrapped within the intramedullary canal. There have been prior case reports on complications associated with incarcerated fragments; however, there has been no proposed solution. The current case shows how 2 cortical fragments in the distal segment of a comminuted femur fracture impeded passage of the intramedullary reamer and induced deformity at the fracture site during the reaming. The authors describe a simple method of retrieval without having to formally open the fracture site. Recognizing the presence of an incarcerated fragment and appropriately managing it intraoperatively allows for fracture fixation to occur uneventfully. [Orthopedics. 2016; 39(3):e582-e586.].

Is There an Optimal Proximal Locking Screw Length in Retrograde Intramedullary Femoral Nailing? Can We Stop Measuring for These Screws?

Insertion of locking screws through the proximal thigh while locking retrograde femoral nails is arguably more difficult and traumatic to local tissues than locking at other intramedullary nail sites. The purpose of this study was to evaluate whether a "standard" screw length for proximal interlocking of retrograde nails is possible, therefore assessing whether the act of measuring for these screws can be omitted. This article retrospective evaluates screw position and estimated proximal locking screw length in patients undergoing retrograde nailing using a large radiographically measured computed tomography cohort, with validation through a smaller clinical cohort. According to these data, it seems reasonable to skip depth gauge measurement during anteroposterior interlocking of retrograde femoral nails and insert a standard length screw based on location relative to the lesser trochanter. This should decrease the amount of local trauma to the patient at the locking screw site while increasing operating room efficiency by avoiding what can often become a difficult step during the procedure.

Relationship between distal screws and femoral arteries in closed hip nailing on computed tomography angiography

BACKGROUND

Iatrogenic vascular injury as a result of closed hip nailing is not common, but is a regularly reported complication after hip fracture surgeries.

METHODS

To prevent vascular injury in closed hip nailing by identifying the range of distances and angles between deep and superficial femoral arteries (DFAs and SFAs) and distal screws.

PATIENTS AND METHODS

Forty subjects who underwent computed tomography angiographies were included in this study. Imaginary lines marking the distal screws (proximal femoral nail antirotation-II [PFNA-II], 180 and 300 mm; inter-trochanteric/sub-trochanteric nails [ITST], 200 and 300 mm) were drawn on the scout film. On arterial phase images, angles between distal screw lines and those marking DFAs or SFAs, as well as the distance between each artery and far cortex, were measured using the cross-reference capabilities of the picture archiving and communication system.

RESULTS

The short nails (PFNA-II 200 mm and ITST 180 mm) were closest to the DFAs, indicating that these nails are most likely to cause injury (PFNA-II 200 mm: 11.2 ± 13.7° anterior and 9.87 ± 5.83 mm; ITST 180 mm: 22.56 ± 15.92° posterior and 9.24 ± 4.74 mm). The short nails were relatively distant from the SFAs, which were located posteriorly to the long nails (PFNA-II 300 mm and ITST 300 mm).

CONCLUSIONS

These data indicate that insertion of distal screws into intramedullary nails increases the risk of injury to vascular structures. Surgeons must take care in drilling or inserting screws to ensure the prevention of vascular injury.

The safe zone for external fixator pins in the femur

OBJECTIVE

To define the anatomic "safe zone" for placement of external fixator half pins into the anterior and lateral femur.

METHODS

In 20 fresh-frozen hemipelvis specimens, the femoral nerve and all branches crossing the femur were dissected out to their final muscular locations. The location where the nerves crossed the anterior femur was measured from the anterior superior iliac spine and inferior margin of the lesser trochanter. The knee joint was then opened, and the distance from the superior reflection of the suprapatellar pouch to the last branch of the femoral nerve crossing the anterior femur was measured, defining the safe zone for anterior pin placement.

RESULTS

The last branch of the femoral nerve crossed at an average distance from the anterior superior iliac spine of 174 ± 43 mm (range, 95-248 mm) and from the lesser trochanter at a distance of 58 ± 36 mm (range, 0-136 mm). The average distance from the proximal pole of the patella to the superior reflection of the suprapatellar pouch was 46.3 ± 13.1 mm (range, 20-74 mm). Using the linear distance between the last crossing femoral nerve branch and the superior reflection of the pouch, the average safe zone measured 199 ± 39.8 mm (range, 124-268 mm). The safe zone correlated with thigh length (r = 0.48, P = 0.03). All nerve branches terminated at their muscular origins without crossing lateral to a line from the anterior greater trochanter to the anterior aspect of the lateral femoral condyle.

CONCLUSIONS

The safe zone for anterior external fixator half pin placement into the femur is on average 20 cm in length and can be as narrow as 12 cm. Anterior pins should begin 7.5 cm above the superior pole of the patella to avoid inadvertent knee joint penetration. Because the entire lateral femur is safely available for half pin placement, including distally, we recommend the use of alternative frame constructs with either anterolateral or lateral pins given the limitations and risks of anterior pin placement.

The dangers of damage control orthopedics: a case report of vascular injury after femoral fracture external fixation

BACKGROUND

Placement of external fixation frames is an expedient and minimally invasive method of achieving bone and joint stability in the setting of severe trauma. Although anatomic safe zones are established for placement of external fixation pins, neurovascular structures may be at risk in the setting of severe trauma.

CASE REPORT

We present a case of a 21-year-old female involved in a high speed motorcycle accident who sustained a Type IIIB open segmental femur fracture with significant thigh soft tissue injury. Damage control orthopedic principals were applied and a spanning external fixator placed for provisional femoral stabilization. Intraoperative vascular examination noted absent distal pulses, however an intraoperative angiogram showed arterial flow distal to the trifurcation. Immediately postoperatively the dorsalis pedis pulse was detected using Doppler ultrasound but was then non-detectable over the preceding 12-hours. Femoral artery CT angiogram revealed iatrogenic superficial femoral artery occlusion due to kinking of the artery around an external fixator pin. Although the pin causing occlusion was placed under direct visualization, the degree of soft tissue injury altered the appearance of the local anatomy. The pin was subsequently revised allowing the artery to travel in its anatomic position, restoring perfusion.

CONCLUSION

This case highlights the dangers associated with damage control orthopedics, especially when severe trauma alters normal local anatomy. Careful assessment of external fixator pin placement is crucial to avoiding iatrogenic injury. We recommend a thorough vascular examination pre-operatively and prior to leaving the operating room, which allows any abnormalities to be further evaluated while the patient remains in a controlled environment. When an unrecognized iatrogenic injury occurs, serial postoperative neurovascular examinations allow early recognition and corrective actions.

Biomechanical strain analysis of the proximal femur following retrograde intramedullary nailing

BACKGROUND: The purpose of this study was to examine the influence of proximal retrograde intramedullary nail position on proximal femoral strain, since stress risers occurring at the end of an implant can increase fracture risk. METHODS: Proximal femoral strains during axial and torsional loading were measured in composite Sawbone femurs after placement of retrograde intramedullary nails that ended at three different locations (2 cm proximal, 4 cm distal, and at the level of the lesser trochanter). RESULTS: No statistically significant difference was found between the axial or torsional strain observed in the intact femur and that seen after placement of a retrograde femoral nail ending at any of the three positions. Gages proximal to the nail tip demonstrated higher strains than the strains for the intact femur when compared with gages distal to the nail tip. CONCLUSION: The ending location of a retrograde nail in the proximal femur does not appear to significantly alter strain in the proximal femur under the axial and torsional loading methods used in the study.

Intramedullary nailing of femoral shaft fractures: current concepts

Intramedullary nailing is the preferred method for treating fractures of the femoral shaft. The piriformis fossa and greater trochanter are viable starting points for antegrade nailing. Alternatively, retrograde nailing may be performed. Each option has relative advantages, disadvantages, and indications. Patient positioning can affect the relative ease of intramedullary nailing and the incidence of malalignment. The timing of femoral intramedullary nailing as well as the use of reaming must be tailored to each patient to avoid systemic complications. Associated comorbidities, the body habitus, and associated injuries should be considered when determining the starting point, optimal patient positioning for nailing, whether to use reduction aids as well as which to use, and any modifications of standard technique. Intramedullary nailing of diaphyseal femur fractures provides a stable fixation construct that can be applied using indirect reduction techniques. This method yields high union rates and low complication rates when vigilance is maintained during preoperative planning, the surgical procedure, and the postoperative period.

An alternative direction for proximal locking in retrograde femoral nails

Lateral-to-medial proximal interlocking screw insertion for retrograde femoral nails avoids potential neurovascular injury while maintaining stable interlocking mechanics.

The effect of locked distal screws in retrograde nailing of osteoporotic distal femur fractures: a laboratory study using cadaver femurs

OBJECTIVES

To examine the effects of locked distal screws in retrograde nails used in unstable osteopenic distal femur fractures.

DESIGN

Biomechanical testing of paired human cadaveric femurs.

INTERVENTION

Seven matched pairs of embalmed, moderately osteopenic cadaver femurs were instrumented with 12-mm intramedullary nails in a statically locked, retrograde fashion. One femur of each pair had locked distal screws and the other femur had unlocked distal screws. A 2.5-cm gap of bone was cut nine centimeters from the distal condyles to simulate an unstable fracture. The locked distal screw nails were compared to unlocked distal screw nails for collapse of the fracture gap, medial-lateral and anterior-posterior translation of the nail within the fracture site, and fracture angulation. The femurs were axially loaded, cycled, and then loaded to failure.

MAIN OUTCOME MEASURES

Motion at the fracture site with axial cyclic loading and site of failure when loaded to failure.

RESULTS

After cycling, both locked distal screw and unlocked distal screw nails demonstrated several millimeters medial and anterior translation within the fracture site and approximately 1 mm collapse of the fracture gap. Although no statistically significant differences were found, the locked distal screw nails had less anterior and medial translation, angulation, and collapse of the fracture gap after cycling. Loads to failure were similar for both locked distal screw and unlocked distal screw nails. It was noted that proximal femur failure occurred at the level of the proximal screw hole in the nail at the subtrochanteric level in 7 (4 locked distal screws and 3 unlocked distal screw groups) of the 14 samples. Four other samples failed through the intertrochanteric region (2 locked distal screw and 2 unlocked distal screw groups) and the remainder within the distal fragment by fracture of the femur along the medial cortex.

CONCLUSIONS

Although most differences in fixation stability were not significant, the locked distal screw nails exhibited less fracture collapse and anterior and medial translation of the nail at the fracture site than the unlocked distal screw nails. The degree of varus angulation after cyclic loading was also less for the locked distal screw nails. The length of the nail chosen should avoid having proximal locking screws distal to the lesser trochanter, thus averting proximal femur stress risers and fractures.

Retrograde intramedullary nailing in distal femoral fractures--results in a series of 46 consecutive operations

We present a series of 44 consecutive patients with 46 distal femoral fractures, who were treated with a retrograde intramedullary nail (Distal Femoral Nail (DFN)). Operational data, per- and post-operative complications and the outcome were studied retrospectively after a mean follow-up of 9 months. The final union rate was 95%, with a mean union time of 17.5 (8-68) weeks. Restoration of the limb axial alignment and length was inadequate in two cases, whereas three losses of reduction and one non-union were observed. Two cases of distal locking screw breakage were also observed. Moreover, one patient suffered from an iatrogenic lesion of the branch of the deep femoral artery. No deep, but three superficial infections were observed. In conclusion, our results suggest that DFN is a reliable alternative in distal femoral fracture treatment with a low complication rate.

Optimal entry point for retrograde femoral nailing

OBJECTIVE

The purpose of this study is to identify the optimum entry point for retrograde femoral nailing, defined as that point which will provide adequate fracture alignment while minimizing soft-tissue and articular cartilage injury.

DESIGN

Cadaveric study.

SETTING

Biomechanics laboratory.

MAIN OUTCOME MEASURE

Anatomic relationships and fracture reduction. METHODS Eleven cadaveric femori with attached knee joints underwent retrograde femoral nailing with a Synthes femoral nail (Synthes, Paoli, PA, U.S.A.). After placement of the nail, the specimens underwent an osteotomy 3 inches proximal to the articular surface. Multiple entry points were tested to determine fracture alignment and extent of articular cartilage injury. Medial-lateral and anterior-posterior displacements, in addition to any soft-tissue or articular surface trauma, were recorded for these various points of entry.

RESULTS

An entry point of 1.2 cm anterior to the femoral origin of the posterior cruciate ligament resulted in the least anterior-posterior displacement of the femoral shaft following fracture. In the coronal plane, an entry point at the midpoint of the intercondylar sulcus was identified as minimizing the displacement following fracture. This ideal position allows for proper seating of the nail within the intercondylar sulcus, resulting in minimal damage to the articular cartilage and posterior cruciate ligament and minimal disruption of the patella femoral joint.

CONCLUSION

Retrograde femoral nailing should be used cautiously in select patients, when conventional antegrade nailing cannot be used, due to the unavoidable injury to the knee articular surface associated with this technique. The optimum entry point of 1.2 cm anterior to the femoral posterior cruciate ligament origin and centered in the intercondylar sulcus provides the optimal balance of fracture reduction and knee joint sparing. It may be difficult to target this site with a percutaneous technique and may require direct visualization of the intercondylar sulcus for ideal nail placement.

Vascular compromise after insertion of a retrograde femoral nail: case report and review of the literature

The authors describe entrapment of the popliteal artery within fragments of an open supracondylar femur fracture after reduction and stabilization with a retrograde femoral nail. At the time of fracture fixation, the loss of pedal pulses was noted, and an exploration of the popliteal vessels was performed. The popliteal artery was easily identified and dissected free after extension of the patient's lateral thigh wound. Following thrombectomy, blood flow to the distal extremity was restored and no postoperative vascular sequelae were encountered.

Potential of increased risk of neurovascular injury using proximal interlocking screws of retrograde femoral nails in patients with acetabular fractures

OBJECTIVES

Neurologic and vascular structures are at risk of iatrogenic injury from proximal interlocking screw insertion after retrograde nailing. This risk may increase in the presence of acetabular fractures because of the displacement of soft tissues resulting from hematoma. The purpose of this study was to establish and compare the relative safe zones (RSZs) for interlocking screw insertion in adults with and without concomitant acetabular fractures.

MATERIALS AND METHODS

Thirty pelvic computed tomography scans of patients with acute unilateral acetabular fracture and magnetic resonance imaging scans of five healthy legs were used to evaluate the course of the femoral sheath, neurovascular complex, and the sciatic nerve as they course through the proximal thigh in sixty-five limbs.

RESULTS

The anatomy of the neurovascular structures on the fractured side was statistically different from that of the normal side. On the normal side, the RSZ at the lesser trochanteric level was identified from +7 degrees medial to +20 degrees lateral to the sagittal axis (27-degree angle zone) for anteroposterior screw placement. These values for the fractured side, respectively, changed to +1 degrees and +14 degrees (13-degree angle zone), a 52 percent decrease. The RSZ for lateral-medial screw placement was 28 degrees anterior to 39 degrees posterior to the coronal axis (67-degree angle zone) for the normal side, which changed, respectively, to 32 degrees and 41 degrees (73-degree angle zone) for the fractured side. At the level of the lesser trochanter, rotation in the femoral shaft was mimicked only in part (approximately 50 percent) by the neurovascular structures.

CONCLUSION

Lateral-medial screw insertion is safer than anteroposterior insertion. Anteroposterior screw insertion becomes even more critical if the acetabulum is fractured. Femoral external rotation after rod insertion, but before screw insertion, will enlarge the safe zones.

Arterial injury during retrograde femoral nailing: a case report of injury to a branch of the profunda femoris artery

The management of femoral shaft fractures by retrograde intramedullary nailing is becoming more widespread. There have been no reported intraoperative neurovascular injuries to the surrounding anatomy using the retrograde femoral nailing technique. We report a case of injury to a branch of the profunda femoris artery during placement of the anteroposterior proximal locking screw.

Retrograde nailing of the femoral shaft

Retrograde intramedullary nailing of fractures of the femoral shaft with use of a distal intercondylar intra-articular entry portal is a relatively new surgical technique. This method of nailing represents a modification of the previously described procedure in which an extra-articular entry portal in the medial femoral condyle was used. The earlier procedure was plagued by technical difficulties, which limited its use; these problems were mainly related to the fact that the entry portal was not in line with the intramedullary canal, as well as to the fact that purpose-specific implants and instrumentation were not available. Modification of this technique, by using the intercondylar entry portal and a nail designed for retrograde insertion, has proved very effective in clinical studies. There have been theoretical concerns regarding postoperative knee function and intraoperative injury to important anatomic structures, such as branches of the femoral nerve; however, laboratory and clinical findings have dispelled many of these concerns and have provided firm support for continued use of the technique. Nonetheless, further study is required to delineate the long-term outcome of knee joint function. Current indications for use of this technique include multisystem injuries, multiple fractures (including ipsilateral lower-limb combination injuries), ipsilateral vascular injuries, periprosthetic fractures, and morbid obesity.