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    Neglected Femoral Neck Fracture and Delayed Union of the Femoral Shaft

    Six months after a repair of a closed diaphyseal femur fracture, a 35-year-old patient presents with severe groin pain and the inability to bear weight. What went wrong – and what should be done to fix it?

    Author

    Brandon J. Yuan, MD

    Disclosures

    The author has no disclosures relevant to this article.

    Case Presentation

    A 35-year-old female patient with a history of nicotine use sustains a closed diaphyseal femur fracture in a high-speed motor vehicle collision. She was initially seen at a local hospital for definitive management of this injury.

    As part of the initial evaluation, 1 portable radiograph of the femur was obtained (Figure 1), as were CT scans of the patient’s chest, abdomen, and pelvis. Figure 2 shows a representative image from the coronal reconstructions of the CT scans.

    Figure 1. Radiograph showing a closed diaphyseal femur fracture sustained in a high-speed motor vehicle collision.

    Figure 2. Coronal reconstructions of the CT scans of the patient’s pelvis.

    Previous studies have demonstrated that femoral neck fractures occur in association with femoral shaft fractures in approximately 9% of cases, and that the diagnosis may be missed 20% to 50% of the time. [1] In one study, CT of the pelvis reduced the rate of missed femoral neck fractures; [1] however, other studies have demonstrated poor sensitivity (64%) of CT scans in diagnosing associated femoral neck fractures. [2]

    Review of this patient’s CT scan does not show evidence of a femoral neck fracture.

    Initial Treatment

    The surgeon opted for treatment with an antegrade medullary nail. Although not commented on in the operative report, the presence of skin staples at the fracture site implies an open reduction.

    Two distal and 2 proximal interlocking screws were placed. The proximal interlocking screws included an antegrade screw into the lesser trochanter and a transverse interlocking screw.

    Mild translation and flexion at the fracture site are noted, but no femoral neck fracture is visualized on the postoperative radiographs (Figure 3), which do not include views of the uninjured hip for comparison.

    Figure 3. Radiographs taken after repair of the femur fracture show mild translation and flexion at the fracture site.

    The patient was made weight-bearing as tolerated after surgery.

    At our institution, the femoral neck is evaluated in patients with femoral shaft fractures at 3 different time points, with distinct radiographic views.

    Preoperatively: Axial and reformatted coronal CT images of the ipsilateral femoral neck are reviewed to check for the presence of a femoral neck fracture. In the absence of a CT scan, a high-quality anteroposterior (AP) pelvis radiograph is acceptable. We prefer an AP pelvis radiograph (as opposed to an AP hip radiograph) to compare the injured proximal femur with the uninjured side, although differences in leg position and rotation will be present.

    Intraoperatively: The femoral neck is assessed fluoroscopically via a 15 internal rotation view after seating of the nail and before placement of proximal interlocking screws. This allows the surgeon to decide if placement of reconstruction-type screws into the femoral head is necessary, as many non-displaced femoral neck fractures may only become apparent after manipulation of the limb and seating of the nail. In the case of a retrograde femoral nail, this fluoroscopic view is obtained after proximal interlocking screws are placed.

    Postoperatively: While the patient is still in the operating room and before the sterile back table has been torn down, a true AP pelvis radiograph is obtained with both patellae facing directly anteriorly. The higher-quality images obtained with plain radiography allow the surgeon to critically assess the femoral neck one more time prior to leaving the operating room.

    Outcome of Initial Treatment

    The patient began complaining of significant groin pain, and 5 days after the initial surgery, radiographs of the right hip were obtained (Figure 4). Careful evaluation reveals mild displacement of a femoral neck fracture.

    Figure 4. Radiograph of the hip 5 days after surgery shows mild displacement of a femoral neck fracture.

    By 4 weeks after surgery, the patient had still not put any weight on the right lower extremity due to continued groin pain. Radiographs demonstrate further displacement of the femoral neck fracture, with no callus formation at the femoral shaft fracture (Figure 5). The patient was still smoking.

    Figure 5. Radiograph of the hip 4 weeks after surgery shows further displacement of the femoral neck fracture, with no callus formation at the femoral shaft fracture.

    What went wrong with the initial treatment?

    • No femoral neck fracture was seen on the preoperative CT scan, and intraoperative fluoroscopic images and immediate postoperative radiographs did not include a view taken perpendicular to the femoral neck – either with the leg internally rotated or the fluoroscopic beam arced over the top of the body. Femoral neck fractures associated with femoral shaft fractures are often minimally displaced and may not become radiographically apparent until after manipulation of the limb intraoperatively. Even with appropriate imaging of the proximal femur, some fractures will not displace until 2 to 3 weeks after surgery. [1-3]
    • Although in retrospect the fracture does appear to be present in the views obtained 5 days after surgery, the difference in the femoral neck may have been more readily apparent on an AP pelvis radiograph to allow comparison to the contralateral side.

    Second Opinion: Revision Recommended

    The patient presented to our institution 6 months after the injury complaining of disabling groin pain and the inability to bear weight. On examination, her right lower leg was shortened and externally rotated. The patient has stopped smoking.

    Radiographs reveal a delayed union of the femoral shaft fracture and a displaced femoral neck non-union (Figure 6).

    Figure 6. Radiographs of the hip 6 months after surgery show delayed union of the femoral shaft fracture and a displaced femoral neck non-union.

    We obtained preoperative CT scans, which reveal a chronic non-union of the femoral neck with bone loss, most noted posteromedially (Figure 7).

    Figure 7. CT scan of the hip 6 months after surgery shows a chronic non-union of the femoral neck with bone loss, most noted posteromedially.

    The CT scan also demonstrates adequate femoral head bone with no evidence of avascular necrosis (AVN) or post-traumatic arthritis. The absence of AVN was confirmed on bone scan.

    We recommended a revision procedure to address several concerns for both the neglected femoral neck fracture and the delayed union of the femoral shaft fracture.

    It was important to rule out underlying infection or endocrine abnormality that may have contributed to delayed bone healing. A C-reactive protein level, erythrocyte sedimentation rate, white blood cell count, and panel of endocrine labs (vitamin D, thyroid-stimulating hormone, parathyroid hormone, alkaline phosphatase, calcium, and phosphorus levels) were obtained preoperatively and were unremarkable.

    Treatment of femoral shaft delayed union can be accomplished with revision fixation with a laterally based plate or exchange medullary nailing. The delayed union may also be augmented with autologous bone graft.

    Hip arthroplasty is typically considered to treat delayed femoral neck fracture. However, given this patient’s young age and a presumed viable femoral head, joint salvage is preferred, as it will preserve the option for salvage with hip arthroplasty if necessary at a later date. [4]

    Salvage of the femoral neck fracture involves addressing both the biologic and biomechanical reasons for possible failure. Treatment options include open reduction and internal fixation and bone grafting of the femoral neck, with or without intertrochanteric osteotomy.

    Intertrochanteric osteotomy offers the advantage of neutralizing most of the shear forces present at the femoral neck fracture, at the expense of altering the proximal femoral anatomy.

    Bone graft in this case should be autologous to maximize osteogenic potential, and may be obtained from the iliac crest, proximal tibia, or femoral shaft.

    Our treatment algorithm to address these concerns included:

    • Removal of the implants and harvest of an autologous bone graft from the ipsilateral femur
    • Exchange medullary nailing with conversion to a retrograde medullary implant
    • Open reduction and bone grafting of the femoral neck
    • Intertrochanteric osteotomy to neutralize shear forces across the femoral neck

    Revision Procedure: Solving the Problem

    • The patient was positioned supine on a flat radiolucent table.
    • The previous nail was removed, and the distal femur was opened in preparation for a retrograde medullary nail (Figure 8).
    • The medullary canal was reamed up by 1 mm to clean out any potential rind from the previous implant (Figure 9) and cultures were obtained. All were negative for infection.
    • Intramedullary bone graft was harvested from the femoral canal and distal femoral metaphysis by passing a Reamer-Irrigator-Aspirator (RIA) antegrade down the femur, utilizing a reamer at least 3 mm larger than the previous nail (Figure 10).
    • A retrograde medullary nail 2 mm larger than the previous nail was placed, and the femoral shaft delayed union was compressed via “forward” slapping the nail (Figure 11).
    • The nail was left intentionally short at the proximal femur to allow room for the subsequent osteotomy (Figure 12).
    • Autologous bone graft was added to the femoral shaft fracture through a small, open approach.
    • Following open reduction, bone grafting, and provisional fixation of the femoral neck fracture, the osteotomy was planned. It should be noted that the apex of the osteotomy was moved more medially to avoid lengthening the leg too much (Figure 13).
    • The chisel for the double-angled blade plate was seated into the femoral head and a 20 lateral closing wedge osteotomy was performed (Figure 14).
    • The 135 blade plate was inserted into the femoral head and reduced to the femoral shaft, closing the osteotomy (Figure 15).
    • The oblique osteotomy was compressed via offset compression (Figure 16).

    Figure 8. The distal femur is prepared for a retrograde medullary nail.

    Figure 9. The medullary canal was reamed up by 1 mm to clean out any potential rind from the previous implant.

    Figure 10. A Reamer-Irrigator-Aspirator was used to harvest an intramedullary bone graft from the femoral canal and distal femoral metaphysis.

    Figure 11. After placement of a retrograde medullary nail the femoral shaft delayed union was compressed via “forward” slapping the nail.

    Figure 12. Room is left in the proximal femur for an osteotomy.

    Figure 13. The femoral neck was reduced and bone grafted via an open approach.

    Figure 14. The chisel for the double-angled blade plate was seated into the femoral head prior to a 20 lateral closing wedge osteotomy. The apex of the osteotomy was moved more medially to avoid lengthening the leg too much.

    Figure 15. A 135 blade plate was inserted into the femoral head and reduced to the femoral shaft to close the osteotomy.

    Figure 16. The oblique osteotomy was compressed via offset compression.

    Postoperatively, the patient was kept touch-down weight-bearing for 6 weeks, and then advanced to weight-bearing as tolerated.

    Outcome of the Revision Procedure

    Twelve months after the revision surgery, the patient’s radiographs show union of the femoral neck, osteotomy, and femoral shaft (Figure 17). One of the distal interlocking screws in the retrograde nail broke prior to union.

    Figure 17. Radiographs 12 months after the revision procedure show union of the femoral neck, osteotomy, and femoral shaft.

    The patient walks with a mild Trendelenburg gait, but has minimal hip and no thigh pain. Her leg lengths are equal, but she has notable asymmetric abductor weakness on examination.

    Radiographs also clearly demonstrate the alteration of her proximal femoral anatomy, with reduced hip offset, distalization of the trochanter, medialization of the femoral shaft, and iatrogenic coxa-valga.

    Key Points

    • Careful analysis of the femoral neck is necessary in any patient with a femoral shaft fracture. The femoral neck should be assessed radiographically preoperatively, intraoperatively, and postoperatively for fracture. If any doubt exists and an antegrade medullary nail is planned, consider use of a reconstruction-type nail to ”protect” the femoral neck.
    • Delayed union of a femoral shaft fracture can be managed effectively with exchange medullary nailing or lateral compression plating. An antegrade nail may be exchanged for a retrograde nail if necessary.
    • The neglected femoral neck fracture in a patient with a viable femoral head is best managed with joint salvage.
    • An intertrochanteric osteotomy to reduce shear forces across the fracture site is an option, but is not necessary in every case. Consideration to the alteration of proximal femoral anatomy is important.
    • Adding biologic supplementation to selected non-unions is an important consideration. Options include use of iliac crest, proximal tibia, or calcaneus bone. Bone graft may also be harvested from the medullary canal of long bones with the use of the RIA.

    References

    • Tornetta P III, Kain MS, Creevy WR. Diagnosis of femoral neck fractures in patients with a femoral shaft fracture: improvement with a standard protocol. J Bone Joint Surg Am. 2007;89:39–43.
    • O’Toole R, et al. Diagnosis of femoral neck fracture associated with femoral shaft fracture: blinded comparison of computed tomography and plain radiography. J Orthop Trauma. 2013;27(6).
    • Alho A. Concurrent ipsilateral fractures of the hip and shaft of the femur: a systematic review of 722 cases. Ann Chir Gynaecol. 1997;86:326–336.
    • Magu N, et al., Modified pauwels’ intertrochanteric osteotomy in neglected femoral neck fracture. Clin Orthop Relat Res. 2009; 467:1064–1073.

    Author Information

    Brandon J. Yuan, MD, is Assistant Professor of Orthopedic Surgery, Division of Orthopedic Trauma, at Mayo Clinic, Rochester, Minnesota.