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A 58-year-old female with right hip pain
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A 58-year-woman with history of dyslipidemia, hypertension, obesity and gastroesophageal reflux disease presented to our office with a chief complaint of right hip pain. Roughly 18 months prior to presentation, she sustained a closed right subtrochanteric femur fracture treated at an outside facility with a long cephalomedullary nail. The mechanism of injury was a low-energy fall coupled with a history of bisphosphonate therapy for approximately 7 years. Since the time of surgery, the patient had been using a walker though had not done so prior to injury. She complained of lateral thigh numbness and diffuse right-sided hip pain, the latter localized to the fracture site which was exacerbated by standing. Bisphosphonate therapy was initially stopped then re-started 2 months postoperatively.
Upon physical examination, the surgical incision was well-healed without surrounding erythema or fluctuance. The patient walked with an antalgic gait and had tenderness to palpation diffusely about the hip. She had preserved motor strength in all peripheral nerve distributions but had decreased sensation to both sharp and dull stimuli over the lateral aspect of the hip.
Laboratory work-up completed at time of presentation (Figure 1) revealed white blood cell count of 5.6 K/microliter (ref: 3.7-11.4), C-reactive protein of 5 mg/L (ref: 0-9), and erythrocyte sedimentation rate of 24 mm/hr (ref: 0-20 mm/hr).
Images: Liporace FA
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Right subtrochanteric femur nonunion in setting of bisphosphonate use
The patient sustained a nonunion of her subtrochanteric femur fracture initially treated with intramedullary fixation. Further compromising the healing capacity was her prolonged use of bisphosphonates pre-injury and resumption 2 months postoperatively. Presentation is typical of a subtrochanteric femoral nonunion, as most patients will have marked pain and functional disability. Save those with medical contraindications, revision surgery is indicated in almost all patients. Revision options include bone grafting, revision of internal fixation or replacement with a prosthesis.
Subtrochanteric femoral fractures are subject to high nonunion rates due to both mechanical and biological factors, often cited between 7% to 20% in studies. The cortical bone in the subtrochanteric region endures the largest stresses in the body with large medial compressive forces and lateral tensile stresses compromising healing capacity in a malreduced fracture. High varus stresses and poor cortical vascularity in the subtrochanteric region can lead to nonunion when proximal femoral alignment is not restored. In addition, due to the high energy required to induce a subtrochanteric femur fracture, there is also often extensive comminution, further increasing the chance of nonunion. Other risk factors for nonunion include poor bone quality, unfavorable fracture patterns and poor implant position.
Initial postoperative imaging demonstrated less than ideal alignment of the right proximal femur, a common precursor to nonunion in this anatomic region. Implication of bisphosphonates in atypical femur fractures has led to awareness of significantly worse outcomes when associated with subtrochanteric femur fractures compared to bisphosphonate-naïve patients. While bisphosphonates are potent inhibitors of bone resorption, they have been recognized as a potential cause of delayed fracture union by decreasing bone turnover.
Multiple authors have noted significant increases in implant failure and need for revision surgery after fixation of subtrochanteric femur fractures in the setting of bisphosphonate use, as high as a 30% to 46% failure rate in some studies. One study in particular noted a 71% failure rate of subtrochanteric fracture treatment in the setting of bisphosphonate use with a 13% nonunion rate (compared to 0% in bisphosphonate-naïve patients). In a separate study, only one of four patients on bisphosphonate therapy undergoing intramedullary nailing of a subtrochanteric femur fracture went on to heal while the other three patients required revision surgery. Although the exact time to healing and nonunion rates of subtrochanteric femur fractures in the setting of bisphosphonate therapy are unknown, the literature confirms complications and nonunion rates are significantly increased.
Treatment
The patient underwent diagnostic laboratory workup to rule out infection as a cause of the patient’s atrophic nonunion. The lab values were not concerning for an infectious process, suggesting poor fracture alignment after index surgery and continued use of bisphosphonates were primary causes. Given these findings, the decision was made to perform a removal of the cephalomedullary nail (CMN) and nonunion repair. The stiff fibrous nonunion was taken down and bone marrow aspirate from iliac crest was combined with demineralized bone matrix and cancellous chips to augment the repair. With goals of achieving anatomic alignment, removal of the CMN left a large bony void.
To ensure more medialized placement of the CMN, an anterolateral plate was placed. The purpose and placement of the plate not only helped obtain and maintain alignment following reduction, strategic screw placement along the lateral aspect of the femur (within the bony void left by the prior CMN), acted as “blocking screws” to ensure ideal CMN placement (Figure 2). Intraoperative cultures were taken from both bone and the nonunion site, and later confirmed to be negative for any infectious process. The patient was allowed to immediately bear weight on the operative extremity as tolerated and bisphosphonate therapy ceased. The patient progressed well with therapy and was discharged to inpatient rehabilitation 4 days postoperatively.
At her first follow-up 3 weeks after surgery, the patient stated her pain was considerably improved from preoperative levels. She was also ambulating well with the assistance of a walker. Ten weeks after surgery, the patient noted significantly improved pain and function with radiographs exhibiting abundant callus (Figure 3). By that point, her wounds had healed and she was walking with a mild abductor gait without assistance. At 6 months after her nonunion surgery, she was pain-free, ambulating without an assistive device and had returned to work (Figure 4).
- References:
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- Grady MK, et al. Orthopedics. 2012;doi:10.3928/01477447-20120525-51.
- Haidukewych GJ, et al. Clin Orthop Relat Res. 2004;419:185-188.
- O’Neill BJ, et al. BMJ Case Rep. 2014;doi:10.1136/bcr-2013-203519.
- Prasarn ML, et al. Clin Orthop Relat Res. 2012;doi:10.1007/s11999-012-2412-6.
- Teo BJX, et al. Bone Joint J. 2014;doi:10.1302/0301-620X.96B5.32887.
- Weil YA, et al. J Trauma. 2011;doi:10.1097/TA.0b013e31821957e3.
- For more information:
- Nima Eftekhary, MD, Frank A. Liporace, MD, and Richard S. Yoon, MD, are from NYU Langone Medical Center, 550 First Ave., New York, NY 10016. Eftekhary can be reached at nima.eftekhary@nyumc.org; Liporace can be reached at liporace33@gmail.com; Yoon can be reached at yoonrich@gmail.com.
Disclosures: Liporace reports he is an unpaid consultant for Zimmer Biomet, receives royalties from and is a paid speaker and consultant for Medtronic and is a paid consultant for Stryker and DePuy Synthes. Eftekhary and Yoon report no financial disclosures.