ABSTRACT Proximal femur fractures are a common orthopedic injury, and it is estimated that their prevalence will continue to increase over the next twenty years. There has been much debate over the optimal management of basicervical fractures, which can be difficult to identify radiographically. There is also a role for conversion total hip arthroplasty in patients where fracture fixation fails. We present a case report of a proximal femur fracture managed as a basicervical fracture, and subsequently needing a conversion arthroplasty and revision surgery. We also review the literature to identify the complexities of basicervical fractures and conversion arthroplasty. Key Words: fracture, basicervical, neck, conversion, arthroplasty INTRODUCTION Proximal femur fractures are becoming increasingly common as the patient population ages. There were approximately 340,000 hip fractures in 2008, with this number projected to increase to 580,000 by 20201. These injuries often require operative management given the pain and functional limitations they cause for patients. Over half of these fractures are classified as intertrochanteric and approximately 1.8% are basicervical2,3. Basicervical fractures can be difficult to diagnose given their location, and as a result, they have varying definitions in the literature. Diagnostic descriptions include fractures that run along the anterior capsular attachment of the hip, to a fracture that runs through the base of the femoral neck where it meets the intertrochanteric region 4,5. Another important consideration is the femoral

Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA 2 Yale New Haven Hospital, New Haven, CT, USA Corresponding Author: Vineet Tyagi 800 Howard Avenue New Haven, CT 06519 (551) 358-1959 [email protected] The authors have no conflicts of interest to disclose. 1

calcar, which sits at the convergence of vertically-aligned trabeculae which travel superiorly and are involved with load-bearing in the femoral head6. This section of cortical bone is anisotropic and can withstand high loading forces in a longitudinal direction but is relatively weak when subjected to shear or tension forces in the transverse plane7. Fractures are classified as stable or unstable, with stability based on the structural integrity of the posterior femoral calcar. There is also some debate whether these fractures are classified as intracapsular or extracapsular, and due to the difficulties in classification, there is considerable debate regarding the optimal surgical fixation of basicervical fractures. Intracapsular fractures can be treated with hemiarthroplasty or osteosynthesis screws. The main complications with intracapsular fractures are based on the vascularization of the femoral head and the lack of periosteum, which can contribute to impaired fracture healing and avascular necrosis8. Extracapsular fractures can be treated with sliding hip screws or cephalomedullary nails. In extracapsular fractures, the fixation construct is typically load-bearing as opposed to load-sharing. As a result, the main complication is typically screw cut-out9. The primary factors that predispose a patient to screw cut-out include low bone density, inadequate reductions, and fracture instability10. Certain radiographic features, such as lack of reduction in the sagittal plane and/or lack of medial support in patients with intramedullary fixation, may predispose to failure. Patients over 75 years old were also found to have rates of fixation failure and reoperation, possibly indicating that these patients should undergo hemiarthroplasty instead11. Conversion to total hip arthroplasty (THA) is typically a viable option in cases where there is osteonecrosis, nonunion, malunion, failure of fracture fixation, or post-traumatic arthritis12. CASE PRESENTATION A 58-year-old male with a significant history of alcohol, polysubstance abuse, and suicidal attempts initially presented after sustaining a fall. He was diagnosed with a left basicervical femoral fracture and underwent surgical stabilization with a trochanteric cephalomedullary nail (Figure 1). He was subsequently lost to follow up until 10 months after his index surgery. Symptoms at this time Volume 37   29

V. Tyagi, O. Akinbo

Figure 1. Radiographs showing the left hip (A) at time of fracture; (B) after placement of cephalomedullary nail.

Figure 2. Radiograph showing the left hip nine months postoperatively.

included pain with ambulation; ambulation was assisted with a cane. There was suspicion for a fracture non-union with plan to obtain confirmatory CT scan and surgical planning as necessary. A CT scan confirmed non-union,

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but did not show screw cut-out. He later presented to the medical intensive care unit for a suicidal attempt. During this admission the patient noted that his left hip pain had worsened and he had been nearly bedridden for the past few months. Radiographs revealed an impending screw cut-out of his fracture fixation (Figure 2). ESR, CRP levels were elevated (60mm/hr and 76.6mg/L respectively); he subsequently had a hip aspiration that was negative (no growth, no organisms seen on Gram stain). Following appropriate clearance, he was taken to the operating room for a conversion total hip arthroplasty through a posterior approach. Pre-operative plan was to implant a Stryker restoration modular stem to by-pass the distal screw hole of the nail, and a primary cup with revision shells and liner options available as necessary. Intraoperatively, he had cut out of his lag screw with multiple defects were noted in the anterior, posterior, and medial walls of the acetabulum. The femur was reconstructed with a Stryker restoration modular stem. The bone stock was poor, and good fixation could not be gotten in the acetabulum. A posterior wall fracture was then noted. Plan at this point was to fix the fracture, bone graft the defects, and obtain fixation with a revision shell with adjunct screw fixation. However, the fracture could not be fixed due to poor bone stock. Given this, adequate shell stability could not be obtained. As such, plan became to return at another time to perform a stable total hip arthroplasty utilizing an antiprotrusio cage for acetabular stability. Our facility does not keep antiprotrusio cages on shelf, and available pre-operative imaging studies did not indicate the need for one. Of note, radiographic studies performed days before surgery did not show cut-out or evidence of acetabular defects as encountered during surgery. Postoperative CT scan confirmed a posterior wall fracture (Figure 3). A pre-operative CT scan just prior to surgery might have evidenced findings encountered during surgery. The patient was brought back to the OR five days later for an implantation of an antiprotrusio cage. The defects were bone grafted. Multiple screws were used to affix the cage to the pelvis. The fixation was stable. A liner was then cemented in place. Fixation could not be achieved in the ischium because of an extremely poor bone stock (Figure 4). Post-operatively, he was made toe-touch weight bearing with posterior hip precautions. He was subsequently discharged home after approximately 2 weeks. He returned to the hospital within a month from discharge, and was admitted for suicidal ideation. His course since surgery has been complicated by multiple and frequent admissions for various psychiatric issues including suicidal ideations, major depression, bipolar disorder, altered mental status, and substance abuse issues. However, he has done well with his hip. He

Conversion Total Hip Arthroplasty After Failed Basicervical Hip Fracture Fixation

Figure 3: Images of the left hip (A) after conversion THA and (B) postoperative CT scan showing acetabular posterior wall defect.

Figure 4: Image of the left hip after removal of THA and implantation of acetabular cage and revision modular stem.

A had physical therapy, and gradually progressed in his ambulatory status. At over a year from surgery, he has minimal pain, and ambulates with a cane. DISCUSSION Biomechanics of Treatments for Basicervical Femoral Fractures Biomechanics play an important role in implant selection for basicervical fractures. Intramedullary devices such as gamma nails distribute loads from the hip through the entire femoral shaft, reducing concentrated forces that can cause implant failure. This provides the benefit of allowing patients to bear full weight in the immediate postoperative period. A cadaveric study of 24 femurs placed under hydraulic compression found

that cephalomedullary nails were able to sustain more cycles of loading and a higher absolute load than DHS systems prior to failure13. Another study of six pairs of cadaveric femurs found that intramedullary constructs had no significant benefits over DHS systems with cyclical loading, but were superior in terms of varus/ valgus angulation and rotation at the fracture site14. The stability of the fracture pattern has also been shown to play a significant role in the success of the implant. Intramedullary nails in unstable fracture patterns have been shown to fail with loads 28% lower than nails in stable fractures15. In addition, nails with multiple neck screws had less displacement under loads than those with one screw16. Another study of twelve cadaveric femurs found no difference in construct stiffness or failure under loading when comparing DHS and intramedullary nails, but recommended that intramedullary nails may be more suitable in unstable fracture patterns without medial support17. Extramedullary devices have also been analyzed for their effectiveness in fixation of femoral fractures. An experimental study of compression hip screws found that the load required to overcome the static frictional force between the plate and the femur was significantly higher with screw-plate angle of 130 degrees than with an angle of 150 degrees18. Therefore, the lower the screw-plate angle, the greater the compressive force that could be applied and provide fracture stability. In a study of twenty artificial femurs with stable and unstable intracapsular fractures, it was shown that sliding hip screw systems are not as effective as compression plates in unstable fractures when subjected to cyclic axial and torque loads. The screw systems which failed typically showed posterior rotation and retroverted varus deviation of the femoral head19. This may be due to the low rotational stability of DHS systems, which may be improved through additional cancellous screw placement20. Outcomes and Complications of Basicervical Fracture Fixation The operative management of basicervical fractures varies based on whether they are approached as femoral neck fractures and treated with cancellous screws or hemiarthroplasty, or approached as intertrochanteric fractures and treated with DHS. Basicervical fractures, however, typically are more unstable than intertrochanteric fractures21. As a result, basicervical fractures treated with sliding hip screws do not address rotational stability22,23. A prospective study of 42 patients reported outcomes of patients with basicervical fractures, or equivalent fractures defined as trochanteric fractures where the head-neck section does not remain connected to the trochanters24. These patients, who were treated with a DHS and a derotational screw, were followed at Volume 37   31

V. Tyagi, O. Akinbo preset intervals for 12 months postoperatively. 93% of patients had adequate reductions, defined as displacement less than 3 millimeters between fragments, and femoral neck angulation less than 10 degrees of varus or less than 15 degrees of valgus angulation compared to the contralateral side. There were no screw cut-outs, pull-outs, or breakage, and no patients required reoperation. In addition, 98% of patients reported no difference in range of motion compared to their other hip. A retrospective study of 28 basicervical fractures and 38 intertrochanteric fractures treated with DHS found that use of a derotational screw did not significantly affect fracture stability or clinical outcome25. Basicervical fractures had a higher rate of radiographic collapse than stable intertrochanteric fractures, but not unstable A intertrochanteric fractures. These B findings are likely secondary to the instability of basicervical fractures as shown in the above biomechanical studies. A retrospective two-institution study of 28 patients concluded that cephalomedullary nail fixation had strong clinical outcomes in basicervical fractures26. With a mean follow-up time of 29 months, no screw cut-outs, femur fractures, or reoperations were required. Harris hip scores were good or very good in 67.9% of patients. The average time to clinical fracture healing, defined as no pain in the hip with mobilization, was six weeks. The study also found that the mean age of patients with a good reduction as defined by the Singh index on radiographs27 was significantly lower than those with a poor reduction. These findings were confirmed by a retrospective review of 32 basicervical fractures treated with cephalomedullary nails28. 84% of fractures had no displacement or loss of reduction one year postoperatively. No patients had avascular necrosis of the femoral head or cut-out. Pascarella et al looked at 321 intertrochanteric and basicervical fractures and found that the most common intraoperative complications were either incorrect fracture reduction or incorrect lag screw positioning. It was recommended that patients be appropriately positioned on a fracture table and reduction achieved preoperatively to avoid inadequate reductions. Another recommendation was 10 degrees of internal rotation of the extremity to aid with reduction. The femoral canal should be reamed 2 mm larger than the distal nail diameter to avoid intraoperative fractures. Axial fluoroscopic views were deemed essential to aid in lag screw position. Poor lag screw positioning led to the most common postoperative complication, which was implant cut-out. Ideal lag screw position is in the lower portion of the femoral head on the frontal plane and in the midline on the lateral plane. Entry points that are lateral to the tip of the greater trochanter can lead to medial cortex stress when the nail is inserted, leading to fractures. In obese patients, 32   The Iowa Orthopedic Journal

it may be useful to mark the greater trochanter with a Kirschner wire under fluoroscopy29. Other recommendations to improve outcomes include using tibial or distal femoral traction to aid with reduction and minimize soft tissue tension28. Outcomes and Complications of Conversion Total Hip Arthroplasty In patients with non-displaced fractures or younger patients with displaced fractures, internal fixation has been shown to be highly successful30. Internal fixation, however, can still fail secondary to osteonecrosis, nonunion, infection, or symptomatic hardware. In cases of failure, conversion total hip arthroplasty can be a viable treatment option. A study of 102 conversion THAs for failed femoral C neck fracture fixation found that clinical outcomes were promising, with a mean Harris hip score of 81.8 with an average follow-up of 3.2 years12. The study found that about 12% of patients suffered from early surgical complications, with the most common being infections and periprosthetic fractures. A retrospective review by Bercik et al compared outcomes of conversion THAs for femoral neck fractures initially fixed with DHS versus cephalomedullary nails. There was no difference in mean length of hospital stay or blood products used, but operative time was longer and blood loss was higher for patients in the CMN group. The study also found that that significantly more patients in the DHS group were implanted with metaphyseal-fit stems, compared to more diaphyseal-fit stems in CMN patients31. To implant an intramedullary nail, the metaphyseal cancellous bone must be reamed, often times precluding future metaphyseal fixation of a femoral stem if a conversion THA is necessary. Therefore, the authors concluded that conversions from CMN are similar to revision stem placement, and may be technically more difficult. CMN placement violates the abductor mechanism and this can cause persistent hip pain which may persist even after conversion THA32,33. CONCLUSION Conversion total hip arthroplasties are complex surgical procedures now being increasingly recognized as revision arthroplasties12. Proper identification of fracture patterns and proper fixation could help reduce the incidence or need for conversion THA. In our case, a hemiarthroplasty might have been a better construct for a fracture that is arguably an intracapsular femoral neck fracture. Obtaining preoperative CT scans soon before surgery can aid in assessment of bone stock or the presence of fractures or acetabular defects. Typically, it can be expected that the bone stock in these cases will be deficient because these patients have been restricted weight bearing. A very strong press-fit might not be

Conversion Total Hip Arthroplasty After Failed Basicervical Hip Fracture Fixation feasible, and screw fixation might be very important. Bipolar hemiarthroplasty should be a consideration. Lastly, cephalomedullary nails are difficult to remove and their removal can result in complications during conversion THA; as such it might be prudent to use sliding hip screw constructs in stable fracture patterns31. REFERENCES 1. Pui, C.M., et al., Increased complication rate following conversion total hip arthroplasty after cephalomedullary fixation for intertrochanteric hip fractures: a multi-center study. J Arthroplasty, 2013. 28(8 Suppl): p. 45-7. 2. Koval, K.J., et al., Patients with femoral neck and intertrochanteric fractures. Are they the same? Clin Orthop Relat Res, 1996(330): p. 166-72. 3. Saarenpaa, I., J. Partanen, and P. Jalovaara, Basicervical fracture--a rare type of hip fracture. Arch Orthop Trauma Surg, 2002. 122(2): p. 69-72. 4. Blair, B., et al., Basicervical fractures of the proximal femur. A biomechanical study of 3 internal fixation techniques. Clin Orthop Relat Res, 1994(306): p. 256-63. 5. Parker MJ, P.G., Thorngren K-G, Extramedullary fixation of extracapsular fractures, in Handbook of hip fracture surgery. 1997, Butterworth-Heinemann: Oxford. p. 63-90. 6. Lotz, J.C., E.J. Cheal, and W.C. Hayes, Stress distributions within the proximal femur during gait and falls: implications for osteoporotic fracture. Osteoporos Int, 1995. 5(4): p. 252-61. 7. Sheehan, S.E., et al., Proximal Femoral Fractures: What the Orthopedic Surgeon Wants to Know. Radiographics, 2015. 35(5): p. 1563-84. 8. Damany, D.S., M.J. Parker, and A. Chojnowski, Complications after intracapsular hip fractures in young adults. A meta-analysis of 18 published studies involving 564 fractures. Injury, 2005. 36(1): p. 131-41. 9. Anglen, J.O. and J.N. Weinstein, Nail or plate fixation of intertrochanteric hip fractures: changing pattern of practice. A review of the American Board of Orthopaedic Surgery Database. J Bone Joint Surg Am, 2008. 90(4): p. 700-7. 10. Barrios, C., et al., Healing complications after internal fixation of trochanteric hip fractures: the prognostic value of osteoporosis. J Orthop Trauma, 1993. 7(5): p. 438-42. 11. Weil, N.L., D. van Embden, and J.M. Hoogendoorn, Radiographic fracture features predicting failure of internal fixation of displaced femoral neck fractures. Eur J Trauma Emerg Surg, 2015. 41(5): p. 501-7.

12. Archibeck, M.J., et al., Total hip arthroplasty after failed internal fixation of proximal femoral fractures. J Arthroplasty, 2013. 28(1): p. 168-71. 13. Rupprecht, M., et al., A comparative biomechanical analysis of fixation devices for unstable femoral neck fractures: the Intertan versus cannulated screws or a dynamic hip screw. J Trauma, 2011. 71(3): p. 625-34. 14. Roderer, G., et al., Side plate fixation vs. intramedullary nailing in an unstable medial femoral neck fracture model: A comparative biomechanical study. Clin Biomech (Bristol, Avon), 2011. 26(2): p. 141-6. 15. Eberle, S., et al., The stability of a hip fracture determines the fatigue of an intramedullary nail. Proc Inst Mech Eng H, 2010. 224(4): p. 577-84. 16. Vidyadhara, S. and S.K. Rao, Cephalomedullary nails in the management of ipsilateral neck and shaft fractures of the femur--one or two femoral neck screws? Injury, 2009. 40(3): p. 296-303. 17. Weiser, L., et al., Extra- vs. intramedullary treatment of pertrochanteric fractures: a biomechanical in vitro study comparing dynamic hip screw and intramedullary nail. Arch Orthop Trauma Surg, 2015. 135(8): p. 1101-6. 18. Kyle, R.F., T.M. Wright, and A.H. Burstein, Biomechanical analysis of the sliding characteristics of compression hip screws. J Bone Joint Surg Am, 1980. 62(8): p. 1308-14. 19. Brandt, E., et al., Biomechanical analysis of the percutaneous compression plate and sliding hip screw in intracapsular hip fractures: experimental assessment using synthetic and cadaver bones. Injury, 2006. 37(10): p. 979-83. 20. Swiontkowski, M.F., et al., Torsion and bending analysis of internal fixation techniques for femoral neck fractures: the role of implant design and bone density. J Orthop Res, 1987. 5(3): p. 433-44. 21. Gill, J.M., et al., Biomechanical aspects of the repair of intertrochanteric fractures. J Biomed Eng, 1989. 11(3): p. 235-9. 22. Ort, P.J. and J. LaMont, Treatment of femoral neck fractures with a sliding compression screw and two Knowles pins. Clin Orthop Relat Res, 1984(190): p. 158-62. 23. Ly, T.V. and M.F. Swiontkowski, Management of femoral neck fractures in young adults. Indian J Orthop, 2008. 42(1): p. 3-12. 24. Massoud, E.I.E., Fixation of basicervical and related fractures. Int Orthop, 2010. 34(4): p. 577-82. 25. Su, B.W., et al., Basicervical versus intertrochanteric fractures: an analysis of radiographic and functional outcomes. Orthopedics, 2006. 29(10): p. 919-25.

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V. Tyagi, O. Akinbo 26. Tasyikan, L., et al., Short-term results of surgical treatment with cephalomedullary nails for basicervical proximal femoral fractures. Acta Orthop Belg, 2015. 81(3): p. 427-34. 27. BD Browner, J.J., AM Levine, PG Trafton, C Krettek, Skeletal trauma. 4th ed, ed. S.E. Press. 2009, Philadelphia. 28. Hu, S.-j., G.-r. Yu, and S.-m. Zhang, Surgical Treatment of Basicervical Intertrochanteric Fractures of the Proximal Femur with Cephalomeduallary Hip Nails. Orthopaedic Surgery, 2013. 5(2): p. 124-129. 29. Pascarella, R., et al., Methods to avoid gamma nail complications. Chir Organi Mov, 2008. 91(3): p. 133-9.

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30. Schmidt, A.H., et al., Femoral neck fractures. Instr Course Lect, 2005. 54: p. 417-45. 31. Bercik, M.J., et al., Conversion total hip arthroplasty: a reason not to use cephalomedullary nails. J Arthroplasty, 2012. 27(8 Suppl): p. 117-21. 32. Gardner, M.J., et al., Anatomy of the greater trochanteric ‘bald spot’: a potential portal for abductor sparing femoral nailing? Clin Orthop Relat Res, 2008. 466(9): p. 2196-200. 33. Hesse, B. and A. Gachter, Complications following the treatment of trochanteric fractures with the gamma nail. Arch Orthop Trauma Surg, 2004. 124(10): p. 692-8.

Conversion Total Hip Arthroplasty After Failed Basicervical Hip Fracture Fixation: A Case Report and Review of Literature.

Proximal femur fractures are a common orthopedic injury, and it is estimated that their prevalence will continue to increase over the next twenty year...
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