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    Femoral Shaft Fracture Fixation: It’s All in the Details

    The case of an 18-year-old female patient with a closed proximal diaphyseal left femur fracture illustrates how important it is to meticulously follow the principles of intramedullary nailing to achieve a successful outcome.

    Author

    Brandon J. Yuan, MD

    Introduction

    There are no guarantees in surgery, and orthopaedic trauma surgery is no exception. The surgeon must be diligent and meticulous because small details, when overlooked, can mean the difference between success and failure.

    The following case is an example of how even one of the most familiar and successful operations in orthopaedic surgery can have a suboptimal outcome if basic principles are not followed.

    Patient Presentation and Initial Surgery

    An otherwise healthy 18-year-old female was transported to a local hospital after she was involved in a high-speed motor vehicle collision. A primary survey, confirmed by radiographs, revealed a closed proximal diaphyseal left femur fracture without other injuries (Figure 1). The ipsilateral femoral neck was shown to be intact on CT scan of the pelvis.

    Figure 1. Initial radiographs show the minimally comminuted proximal diaphyseal fracture of the left femur. No other fractures or injuries were identified.

    The patient was taken to the operating room for stabilization of the left femur fracture. A traction table was utilized to reduce the fracture. An antegrade, reamed, trochanteric-start reconstruction-style nail was placed and statically locked with a single interlocking bolt proximally and distally (Figure 2). The operative note indicates that a 9-mm nail was utilized was based on preoperative templating.

    Figure 2. Radiographs show the femoral nail with interlocking bolts placed proximally and distally.

    What Went Right?

    Modern techniques of intramedullary nailing have dramatically improved the outcomes after femoral shaft fracture, with union rates approaching 98% in published reports. [1-3]

    In this case, the surgeon did several things right: Notably, utilizing a reamed nail and paying close attention to femoral rotation by matching the coritical diameters at the fracture site. [4] The reduction is nearly anatomic, with only slight varus and translation at the fracture site. The patient was also appropriately instructed to be weight-bearing as tolerated postoperatively. [5]

    The patient did well initially but noted gradual onset of increasing left thigh and knee pain. She presented to the author’s clinic 6 weeks after surgery, complaining of activity-related thigh pain and a reproducible sensation of mechanical clunking coming from her mid-thigh.

    Radiographs at that time demonstrated some callus formation at the fracture site, but with persistence of the fracture line (Figure 3). More importantly, the single distal interlocking bolt had broken and the nail had bent into varus at the fracture site.

    Figure 3. Radiographs 6 weeks after surgery show persistence of the fracture line, as well as the broken distal interlocking bolt and bent nail the fracture site.

    What Went Wrong?

    Why did the interlocking bolt and nail fail so quickly? The reduction was good, the surgeon utilized the correct type of nail, and the nail was statically locked. However, the surgeon failed to follow one of the most important principles of intramedullary nailing: Ensure that the nail is the appropriate diameter. In this case, the nail is too small.

    Prior to the development of interlocking nails, endosteal fixation through the isthmus was the only method by which an intramedullary rod imparted stability to a long bone fracture. Interlocking nails were an improvement, as they allowed the surgeon to impart much more rotational and axial stability with an intrameduallary implant. Reaming allows the surgeon to enlarge the intramedullary canal and, thus, the diameter of the nail. This improves nail fit and increases the rigidity of the nail.

    However, if the diameter of the intramedullary nail is too small it will obtain less fit within the canal. If the nail is so small that there is no frictional fit within the canal, the working length of the nail becomes very large, essentially from the proximal interlocking bolt to the distal interlocking bolt. The implant goes from a “load-sharing” device to a “load-bearing” device. Thus, over time, the interlocking bolts break and the nail reaches its plastic deformation point, bending into varus.

    Revision Procedure

    The patient agreed to undergo revision surgery. Prior to surgery, laboratory studies were obtained to assist in ruling out metabolic abnormality or infection. With any non-union, there are concerns about infection possibly causing early fixation failure. Metabolic abnormality should be investigated but is unlikely to be the main culprit in a construct that fails by the 6 week mark after surgery.

    Laboratory studies included C-reactive protein, erythrocyte sedimentation rate, white blood cell count, and a panel of endocrine (vitamin D, thyroid stimulating hormone, parathyroid hormone, alkaline phosphatase, calcium, and phosphorus). All were within normal limits.

    With the patient cleared for surgery, the procedure was scheduled. It was planned to include exchange antegrade medullary nailing of the fracture (Figure 4). As stated above, the key step in this revision procedure would be enlarging the diameter of the nail to obtain good endosteal fit through the fracture site.

    Figure 4. Fluoroscopic images depict removal of the broken interlocking bolt and cannulation of the proximal end of the nail.

    After removal of the prior nail, multiple cultures were obtained from the intramedullary canal; all were ultimately negative for infection.

    The canal was then reamed up to 12 mm to accept an 11-mm intramedullary nail, which obtained excellent fit within the canal. The nail was locked distally with 2 static interlocking bolts and then back-slapped to compress the fracture site. This was followed by placement of 2 proximal interlocking bolts (Figure 5). Careful attention was paid to ensuring that the rotation of the limb was not altered during the operation.

    Figure 5. Fluoroscopic images depict reaming of the canal and insertion of an 11-mm intramedullary nail, and fixation with interlocking bolts.

    Postoperative radiographs demonstrate improved alignment of the fracture, achieved solely by enlarging the diameter of the intramedullary implant (Figure 6). The fracture site was neither exposed nor bone-grafted. The patient was allowed to bear weight as tolerated postoperatively.

    Figure 6. Radiographs taken postoperatively show that enlarging the diameter of the intramedullary implant allowed for improved fracture alignment.

    Ten months after the revision procedure, the patient was back to 100% of her pre-injury activities. Radiographs demonstrate osseous union of the fracture without complication (Figure 7).

    Figure 7. Radiographs show osseous union of the fracture, with no complications noted.

    Key Points

    • Closed femoral shaft fractures represent significant, high-energy injuries in young patients, and are often best treated with intramedullary nailing. Improvements in technique and implant design have led to very high union rates and relatively low rates of complication for patients with simple diaphyseal fractures. However, the principles of intramedullary nailing must be followed.
    • Reaming enlarges the intramedullary canal, increasing the diameter of the intramedullary nail that can be utilized (and thus its rigidity) and improving endosteal fit of the nail, leading to improved rates of union. [2]
    • Interlocking nails allow for improved rotational and axial stability and for successful treatment of metaphyseal fractures with intramedullary implants. However, for the non-comminuted isthmal fracture, the primary method by which the intramedullary nail imparts stability is by endosteal fit. Placement of only 1 interlocking bolt on either side of a mid-shaft femur fracture is acceptable as long as the nail has excellent fit at the isthmus.
    • Preoperative imaging can be helpful in determining the appropriate nail diameter; however, tactile feedback from the reamers themselves should be utilized to confirm the nail diameter that will fill the canal.

    Author Information

    Brendan J. Yuan, MD, is an Assistant Professor in the Division of Orthopedic Trauma, Mayo Clinic, Rochester, Minnesota.

    Disclosures: Dr. Yuan has no disclosures relevant to this article.

    References

    1. Brumback RJ, Uwagie-Ero S, Lakatos RP, Poka A, Bathon GH, Burgess AR. Intramedullary nailing of femoral shaft fractures. Part II: Fracture-healing with static interlocking fixation. J Bone Joint Surg Am; 1988;70: 1453–1462
    2. Canadian Orthopaedic Trauma Society. Nonunion following intramedullary nailing of the femur with and without reaming. Results of a multicenter randomized clinical trial. J Bone Joint Surg Am. 2003;85:2093-2096.
    3. Winquist RA, Hansen ST, Clawson DK. Closed intramedullary nailing of femoral fractures. A report of five hundred and twenty cases. J Bone Joint Surg Am. 1984;66:529 –539.
    4. Langer JS, Gardner MJ, Ricci WM. The cortical step sign as a tool for assessing and correcting rotational deformity in femoral shaft fractures. J Orthop Trauma. 2010 Feb;24(2):82-8.
    5. Taitsman LA, Lynch JR, Agel J, Barei DP, Nork SE. Risk factors for femoral nonunion after femoral shaft fracture. J Trauma. 2009 Dec;67(6):1389-92.