Abstract:
Periprosthetic pertrochanteric femur fractures following hip resurfacing arthroplasty are uncommon. Operative treatments for these fractures have ranged from percutaneous lag screws, large fragment plates, blade plates, and cephalomedullary devices. We describe internal fixation of an isolated periprosthetic intertrochanteric fracture following hip resurfacing arthroplasty with a lateral entry femoral recon nail.
Key Words: intertrochanteric hip fracture; hip resurfacing arthroplasty; peri-prosthetic fracture
Introduction
Proximal femur fractures following hip resurfacing arthroplasty are uncommon and can pose significant treatment challenges. Periprosthetic femoral neck (pPFF) fractures should be divided into intra-capsular and extra-capsular hip fractures when reading the literature. Intra-capsular femoral neck fractures occur with an incidence of 1-2%, and the risk factors for such injuries are well-characterized in the literature [1]. Less is known about extra-capsular, but its incidence may be on the rise as hip resurfacing arthroplasty has become increasingly popular option for physiologically young patients.
Different types of internal fixation have been described for pPFF. In a recently published case series, Peskun and colleagues demonstrate the successful treatment of two pPFF with cephalomedullary devices (CMD)[2]. Other implants that have been used with success include percutaneous AO lag scews [3], blade plate fixation [4], and a contoured, large dynamic compression plate [5]. We describe successful fixation of an intertrochanteric hip fracture following hip resurfacing arthroplasty with a Synthes (Paoli, PA) lateral entry femoral recon nail (LFN).
Case
A 62 year old male underwent left hip resurfacing with a Birmingham Hip System (Smith & Nephew, Memphis, Tenn) using metal-on-metal components through a posterior approach in November 2008 without complications. The patient subsequently developed metastatic prostate cancer in 2009 and underwent prophylactic intramedullary nailing (Gamma Nail 3; Stryker, Mahwah, NJ) of the right hip and femur for impending pathologic right hip fracture in September 2010. In September 2011, the patient fell while getting into his truck and sustained a left intertrochanteric hip fracture (Figure 1).
The patient was brought to the operating room within 24 hours of injury. After discussion with the patient’s oncology team, the decision was made to retain the hip resurfacing components and to use an intramedullary implant because of concern for future pathologic fracture. A Synthes LFN was selected so that two proximal locking screws could be placed without making contact with the prosthesis.
The patient’s fracture was reduced using traction on a fracture table. A 6cm incision was made in line with the femur proximal to the tip of the greater trochanter. A guide wire was placed into the appropriate entry point on the greater trochanter using fluoroscopy and opened manually with an awl. This was followed by a ball-tipped guide that was positioned into the distal femoral metaphysis. Serial reaming was performed up to 14mm; reamings were sent to pathology; and a 13mm x 420mm LFN was passed over the guide wire. Two proximal locking screws measuring 105mm and 100mm were placed using the targeting guide without contacting the resurfacing implant.
The duration of surgery was 95 minutes. Post-operative radiographs showed satisfactory implant placement and alignment of the fracture (Figure 2). The patient was discharged to an acute rehabilitation facility on post-operative day four and instructed to remain partial weight bearing for 12 weeks. Pathology report of the reamings was consistent with prostatic adenocarcinoma, and the patient was subsequently treated with both chemotherapy and radiation at two months post-operatively.
Radiographs at 3 month follow-up demonstrated good overall alignment of the fracture and implant (Figure 3). The patient was ambulating well with a walker and did not complain of hip pain. He was progressed to weight bearing as tolerated at this point. The patient was seen six months after surgery by his orthopaedic oncologist. No left hip radiographs were obtained at that time, because the patient was not complaining of hip pain. Unfortunately, the patient became increasingly ill and was admitted to hospice care seven months after surgery. He passed away shortly thereafter.
Discussion.
Treatment of pPFF with a femoral recon nail may offer several advantages. One advantage is the ability to have two points of fixation around the stem of the femoral component, which may reduce the risk of implant or fracture displacement. In most commercially available CMD, a single screw or blade should be placed into the center of the femoral head on both the coronal and lateral views with a tip-apex distance <25mm. Optimal placement of the lag screw or blade in a patient with a hip resurfacing is limited by two factors. First, the stem of the hip resurfacing femoral component may interfere with the correct positioning of the screw. Second, visualization of the tip-apex distance is difficult in the presence of a radio-opaque femoral head.
These two factors could theoretically increase the risk of femoral component loosening or malalignment of fracture with attempts at achieving optimal screw placement.
A second potential advantage of a LFN is that it may offer a more stable construct than a CMD in patients with pPFFs. The total screw diameter in our patient was 13.0mm as each proximal screw measured 6.5mm is diameter. The proximal screw diameter in both the Styker and Synthes CMD is 11.0mm. The LFN allows for the placement of longer screws. In our case, our screw lengths measure 100 and 105mm. In the case series using CMD, the screw lengths measured 90 and 95mm [2]. The use of a construct with greater overall screw diameter and screw length increases the surface area contact with cancellous bone and may confer greater strength than a construct that uses only a single point of fixation.
One disadvantage to using a femoral recon nail in treatment of an intertrochanteric fracture is that it is a rigid construct that theoretically does not allow for controlled collapse and compression of the fracture. A CMD is a fixed angle device that is designed to allow stable collapse of such fractures. In our patient, stable collapse of the fracture is demonstrated at the three month post-operative visit (Figure 3) and is a testament to the overall strength of this construct.
Conclusion
Our case report highlights the use of a LFN to treat an intertrochantic fracture in a patient with a stable hip resurfacing implant. We believe that the ability to place two screws across the fracture through this device offers several advantages that may lead to greater stability and that a LFN should be considered an option for the treatment of pPFF. .
References.
Marker DR, Seyler TM, RH Jinnah, et al. Femoral neck fractures after metal-on-metal total hip resurfacing: A prospective cohort study. J Arthroplasty 2007;22:66.
Peskun CJ, Townley JB, Shemitsch EH, et al. Treatment of periprosthetic fractures around hip resurfacings with cephalomedullary nails. J Arthroplasty 2012;27:494.
Lein T, Schlee J, Kothe M, et al. Periprosthetic intertrochanteric fracture of the femur following articular resurfacing of the hip joint: treatment with lag screw osteosynthesis. Unfallchirurg 2010;113:944.
Weinrauch P, Krikler S. Proximal femoral fracture after hip resurfacing managed with blade-plate fixation. A case report. J Bone Joint Surg Am 2008;90:1345.
Whittingham-Jones P, Charnley G, Francis J, et al. Internal fixation after subtrochanteric femoral fracture after hip resurfacing arthroplasty. J Arthroplasty 2010;25:334.
Figure Legend
Figure 1. Injury AP pelvis radiograph demonstrating left intertrochanteric femur fracture with stable Birmingham hip resurfacing components.
Figure 2. Immedaite post-operative AP femur films demonstrating successful placement of a Synthes LFN and femoral head screws around the stem of a Birmingham hip resurfacing femoral component.
Figure 3. Three month post-operative films demonstrating appropriate fracture healing and good overall alignment of the implant.
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