Review Article
Periprosthetic Fractures Around Loose Femoral Components Abstract Roshan P. Shah, MD, JD Neil P. Sheth, MD Chancellor Gray, MD Hassan Alosh, MD Jonathan P. Garino, MD
From Columbia University, New York, NY (Dr. Shah), the University of Pennsylvania, Philadelphia, PA (Dr. Sheth, Dr. Gray, and Dr. Alosh), and the Pennsylvania Orthopedic Center, Alvern, PA (Dr. Garino). Dr. Shah or an immediate family member has stock or stock options held in Pfizer, Merck, GlaxoSmithKline, Alnylam, and Intuitive Surgical. Dr. Sheth or an immediate family member serves as a paid consultant to Zimmer. Dr. Garino or an immediate family member has received royalties from Smith & Nephew; is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew; serves as a paid consultant to Smith & Nephew and DePuy; has received research or institutional support from Zimmer; and serves as a board member, owner, officer, or committee member of the Pennsylvania Orthopedic Society. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Gray and Dr. Alosh. J Am Acad Orthop Surg 2014;22: 482-490 http://dx.doi.org/10.5435/ JAAOS-22-08-482 Copyright 2014 by the American Academy of Orthopaedic Surgeons.
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The development of periprosthetic fractures around loose femoral components can be a devastating event for patients who have undergone total hip arthroplasty (THA). As indications for THA expand in an aging population and to use in younger patients, these fractures are increasing in incidence. This review covers the epidemiology, risk factors, prevention, and clinical management of periprosthetic femoral fractures. Treatment principles and reconstructive options are discussed, along with outcomes and complications. Femoral revision with a long-stem prosthesis or a modular tapered stem is the mainstay of treatment and has demonstrated good outcomes in the literature. Other reconstruction options are available, depending on bone quality. Surgeons must have a sound understanding of the diagnosis and treatment of periprosthetic femoral fractures.
T
otal hip arthroplasty (THA) reliably treats hip pain caused by articular cartilage degeneration; however, the development of periprosthetic femoral fractures after THA is a devastating complication. Two registry studies form the foundation of our understanding of these fractures. Between 1969 and 1999, 1,249 fractures out of 30,329 hip arthroplasty cases were studied in the Mayo Clinic Joint Registry.1 Periprosthetic fractures in the Swedish National Hip Arthroplasty Registry were studied retrospectively between 1979 and 19982 and prospectively between 1999 and 2000.3 The latter study found that femoral periprosthetic fractures were the third most frequently reported reason for reoperation after THA, accounting for 9.5% of the revisions between 1999 and 2000.3 Other studies have reported the prevalence of late periprosthetic hip fractures to be between 0.1% and 18%,4 with an annual incidence of between 0.045% and 0.13%.2
The incidence of periprosthetic hip fractures is increasing. Bhattacharyya et al5 found a 216% increase between 2002 and 2006. Several reasons for the increase have been proposed.1,2 First, the total prevalence of patients living with THA is increasing. Second, with time, the number of patients experiencing osteolysis to a varying degree, as well as component loosening, will increase. Third, as patients age, there is a greater risk for the development of osteoporosis and periprosthetic fracture caused by minor trauma. Fourth, with the success of THA and its expanding indications, more patients are young and active; consequently, this patient population has a greater exposure to higher energy trauma and therefore an increased risk of periprosthetic fracture. Fifth, the expanding class of patients with THA logically leads to a greater number of patients requiring revision THA. Several treatment options have been proposed based on an accurate classification of the fracture type and
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implant stability. Preoperatively differentiating between a loose and a stable femoral implant can be challenging, but certain signs and symptoms can be helpful. Fractures occurring around loose implants require femoral stem revision.
Vancouver Classification The Vancouver classification is the most common classification system used to describe periprosthetic fractures. This classification is based on fracture location, implant stability, and integrity of the residual bone stock.6,7 Type B fractures occur along the length of the femoral stem. Type B fractures are further subdivided by stem stability and bone stock. Type B1 fractures are fractures with a stable femoral component. Type B2 fractures are fractures with a loose femoral component but with supportive femoral bone stock. Type B3 fractures are fractures with a loose femoral component and associated poor integrity bone stock, wherein the metaphyseal and diaphyseal bone stock is deficient and unsupportive. The incidence and prevalence of each Vancouver type are not well known, for the same reasons that make the true incidence of all periprosthetic fractures elusive. In the Swedish registry report, 53% of the fractures were type B2 and only 4% were type B3.8 When the group examined whether the index surgery was a primary THA or a revision THA, they found that fractures occurring after primary THA were more commonly type B2, whereas fractures occurring after revision THA were more commonly type B1.2
technique, and the type of implant used.9,10 Osteolysis and loosening are most directly related to Vancouver type B2 and B3 fractures. Routine clinical follow-up is necessary to identify patients at risk for loosening, and regular radiographic evaluations have been shown to be cost effective.11 Biomechanical studies have demonstrated that loose femoral stems have a nearly 60% reduction in the torque to failure compared with well-fixed stems.12 In a study by Beals and Tower,13 27% of patients with fractures had evidence of loosening preoperatively. The Swedish registry showed that 70% of fractures involved loose prostheses, with 23% known to be loose and 47% first identified as loose at the time of surgery.2 It is unclear what contribution infection has to loosening and subsequent fracture. The inflammatory markers erythrocyte sedimentation rate and C-reactive protein have poor specificity in the setting of a fracture.14,15 However, intraoperative aspiration for cell count and culture studies provides valuable information when the suspicion for infection is high. We use standard cut-off values of 3,000 WBC/mL and 80% polymorphonuclear cells for diagnosing infection. Because of fracture bleeding, we correct for the contribution of serum white blood cells with the following formula:
WBCcorrected 5 WBCobserved 2 WBCserum · RBCfluid = RBCserum ;16 where WBC is white bloods cells and RBC is red blood cells.
Risk Factors General risk factors for the development of periprosthetic fractures after THA include osteolysis and loosening, trauma, age, gender, osteoporosis, index diagnosis, revision surgery, August 2014, Vol 22, No 8
Management Preoperative Evaluation Patients with periprosthetic fractures generally present to the emergency
department after sustaining spontaneous or low-energy trauma and may be seen in the trauma bay after sustaining high-energy trauma. Advanced Trauma Life Support guidelines should always be used for initial patient evaluation following trauma. Conducting an appropriate physical examination will help reveal associated musculoskeletal injuries. A thorough history provides information about the medical causes of spontaneous or low-energy injury, such as syncope, cardiopulmonary compromise, or stroke; any underlying disorders should then be managed by the appropriate specialist. As with any femur fracture, significant blood loss may occur, requiring close monitoring of cardiopulmonary vital signs and volume status. Medical co-management is the most effective method by which to optimize care of patients with periprosthetic fractures before surgical intervention. Previous surgical notes should be obtained, especially if the index procedure was performed at an outside institution, to properly identify the currently implanted devices. If prior records are unavailable, consultation with other surgeons and industry representatives can help determine the components and the manufacturers. Finally, preoperative surgical planning is critical in achieving clinical success. Arrange to have all extraction devices and revision equipment available for the implanted components. In addition, a thorough and systematic evaluation of the acetabular component should be conducted intraoperatively because an acetabular revision requiring more than a liner exchange may be necessary (ie, loose component, poor component position, poor implant track record, shell or locking mechanism damage, extensive corrosion). Radiographic studies consisting of an AP pelvis and AP and cross-table lateral views of the hip should be obtained to assess for fracture
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Periprosthetic Fractures Around Loose Femoral Components
morphology, prosthetic stability, component malposition, bone stock, the location of any osteolysis, and the presence of wear. Lateral frog-leg views are also valuable in patients who can tolerate the positioning of the leg. Full-length femur radiographs can reveal bony deformities, such as proximal femoral varus remodeling, total knee arthroplasty, or the presence of other hardware that may interfere with the planned reconstruction. In some circumstances, CT may be used as an adjunct for assessing the fracture, areas of bone spotwelding, regions of bone loss, and the position of the component.
Distinguishing Vancouver Type B1 From Type B2/B3 Historically, outcomes were poor for periprosthetic fractures.13,17,18 However, with the advent of the Vancouver classification in 1995, results have improved, thus reinforcing the importance of the system in guiding diagnosis and treatment. It is not uncommon for type B2 fractures to be mistaken for type B1 fractures. Determining whether a stem is wellfixed or loose is critical; this is likely the most important step when managing these patients. When fractures are misclassified, failure rates are higher. In the Swedish registry, a 30% reoperation rate was found for B1 fractures treated with open reduction and internal fixation (ORIF), whereas the failure rate for B2 fractures treated with revision was only 18.5%.3,8 The authors inferred that some of their B1 fractures were actually B2 fractures and should have been revised for optimal treatment. Relevant history that contributes to making this determination includes preexisting groin or thigh pain, pain with non–weight-bearing range of motion, progressive limb shortening, and persistent symptoms or signs of infection. Radiographic comparison with immediate post-arthroplasty
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radiographs can show signs of loosening (eg, subsidence, circumferential radiolucent lines, evidence of a supportive pedestal in a proximally fixed stem, and cement mantle fracture).19 Ultimately, evidence of loosening may not be revealed until the intraoperative assessment is conducted; therefore, all implants and revision instrumentation must be made available for all periprosthetic fracture surgeries. Although others have recommended routine hip dislocation and stability testing, the trade-off of extra soft-tissue dissection is not trivial. When preoperative evaluation suggests that a type B1 fracture is present, we rely on thorough testing of the prosthesis-bone interface through the fracture site to determine implant stability.
Surgical Principles for Loose Stems The diagnosis of a loose femoral stem in the face of a periprosthetic fracture necessitates femoral component revision. Surgical treatment principles for loose femoral components are based on several factors, including fracture morphology, the host bone quality, patient age, and functional status.20 When adequate bone stock remains, the principles of reconstruction require the removal of the loose device, cement, and biomembrane; reconstruction of the host femoral shaft; and the implantation of a long-stemmed prosthesis to obtain stable distal fixation. In the past, extensively porous-coated devices have been considered the most dependable for the management of these fractures; however, modular stems are becoming more popular. With fractures occurring in the setting of major bone loss (ie, Vancouver type B3), reconstruction typically entails device removal and débridement. This is followed by the use of a modular tapered stem that requires ,4 to 6 cm of interference fit; the
splines on the stem provide rotational stability. Severely ectatic femoral canals may require proximal bone reconstitution with either structural allograft (ie, allograft prosthesis composite) or a mega prosthesis (ie, proximal femoral replacement). The complexity of the fracture and the degree of proximal femoral remodeling determines whether the fracture is reduced and fixed first or whether the prosthesis is implanted and the proximal bone is wrapped around the implant. In the presence of little comminution and few fracture fragments, it may be preferable to reduce and fix the fracture before implantation. This optimizes compression and bony contact, thus adhering to standard fracture treatment principles. In certain situations, the best strategy may require the implantation of a distally fixed revision prosthesis first while exploiting the fracture as a window. An extended trochanteric osteotomy of the proximal fracture fragment may be required when the proximal femur demonstrates varus and retroversion remodeling.21 Severe proximal femoral remodeling will not allow for the insertion of a long stem through the deformity without destroying the proximal femur. In this scenario, the diaphyseal preparation is facilitated through direct visualization of the femoral canal and bypassing the proximal deformity. After the stem is implanted, the proximal fragments can be debulked and reduced around the proximal stem with cables or Luque wires. Proximal femoral remodeling is a more common occurrence with loose cemented femoral stems.22
Implant Selection for Vancouver Type B2 Fractures Extensively Porous-coated Stems The monoblock, extensively porouscoated, noncemented prosthesis has
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Figure 1
Monoblock, extensively coated, noncemented stem for a type B2 fracture. A, Hip radiograph showing fracture and stem subsidence. B, Postoperative radiograph showing satisfactory stem position and fracture reduction; offset is overcorrected.
been the reliable implant for femoral reconstruction in type B2 fractures (Figure 1). These devices bypass the fracture and achieve distal diaphyseal fixation, with at least 4 to 6 cm of interference fit, which is recommended for optimal stability of the implant.23 Monoblock stems are available in either a straight or a bowed geometry. Straight stems confer three-point fixation in a bowed femur; however, there is a risk of anterior distal cortical perforation when the stem length exceeds the tolerance of the native femur’s radius of curvature. Bowed stems may be necessary when the stems surpass a length of 8 inches; however, limitations exist regarding the ability to change the anteversion of the prosthesis because of the bow. The inability to change the anteversion August 2014, Vol 22, No 8
of the neck independently of the stem may result in hip instability. Noncemented, extensively porouscoated long stems have had favorable results in the literature. Garcia-Rey et al24 reported on 20 type B2 and 15 type B3 fractures treated with these devices without allograft. All fractures united, and no patients reported thigh pain at an average of 8.3 years. Average Merle d’Aubigné and Postel scores were 5.8 for pain, 5.2 for function, and 4.9 for range of motion. Interestingly, the authors reported an increase in the cortical index and cortical bone thickness despite the use of diaphyseal fixation and concerns for stress shielding. This effect was greater for stems smaller than 16 mm and in patients with mild or moderate preoperative osteoporosis. A review of five studies
using extensively porous-coated stems showed that 111 of 113 fractures (98%) had united by a mean follow-up of 5.6 years, whereas only 6 showed evidence of loosening.24 Complications associated with these implants have been described. GarciaRey et al24 reported subsidence of .1 cm in 19 patients (48%) between 6 and 12 weeks. Twelve of 23 treated Vancouver type B2 fractures (52%) and 10 of 17 treated Vancouver type B3 fractures (59%) subsided more than 1 cm. Clinically, six patients (15%) had a limb-length discrepancy of .1 cm, and two patients had a discrepancy of .2 cm. Nine patients (23%) required the use of one crutch for a limp. There were no dislocations, three postoperative hematomas (8%), three intraoperative greater trochanter fractures (8%), two missed fractures (5%) at the distal stem tip (one of which resulted in a displaced fracture), one supracondylar femoral fracture (3%), and two reoperations (5%) for removal of cerclage wires because of superficial infection. Sheth et al10 reported on 21 type B2 and B3 fractures treated with extensively coated, diaphyseal implants and found complications in seven patients (33%), including instability, subsidence, infection, heterotopic ossification, and osteotomy nonunion.
Modular Tapered Stems Both monoblock tapered stems (ie, Wagner-type stems) and modular tapered stems allow for diaphyseal fixation, rotational stability through splines, reduced risk of anterior perforation, and independent control of component anteversion. Modular tapered stems are more commonly used than monoblock designs and have become the new dependable implant of femoral reconstruction.25-27 These devices comprise a distal component that engages the diaphysis and a modular proximal component that mates via a Morse taper, allowing
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Periprosthetic Fractures Around Loose Femoral Components
for 4 to 6 weeks. Abdel et al27 reported on 25 Vancouver type B2 and 19 Vancouver type B3 fractures treated in this manner in a 4.5-year follow-up. Forty-three of 44 patients (98%) reached radiographic union with a Harris Hip score of 83. Munro et al26 reported on 38 Vancouver type B2 and 17 Vancouver type B3 fractures with a 4.5-year follow-up. Fiftyfour fractures (98%) healed by 24 months, with an average WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score of 76 for B2 fractures and 77 for B3 fractures. There were two stem revisions and eight reoperations. Complications reported in both studies included instability, subsidence, and infection.26,27
Figure 2
Long-stem Cemented Prosthesis
Modular tapered stem for a type B2 periprosthetic fracture. A, Hip radiograph showing fracture and stem subsidence. B, Postoperative radiograph showing satisfactory position of the modular tapered stem with good fracture reduction.
independent control of anteversion, length, and offset (Figure 2). Modular tapered stems can obtain stability with ,4 cm of interference fit within the diaphysis and rely on splines for rotational stability of the implant.26 Proper sizing of these implants is important for axial stability because subsidence is a frequent mechanical complication; the tendency is to undersize the stem because of the risk of creating an intraoperative femoral fracture.26 Our preferred technique when using a modular tapered stem is to reconstruct the femur first, followed by fracture reduction. Under manual reaming, a conical support is created with sequential tapered reamers, based on the template diameter and the length of the stem. Manual reaming reduces the risk of femoral blow-out
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with poor bone stock. A prophylactic cable should be placed around the intact femur distal to the fracture to prevent propagation. The modular, fluted, tapered stem is then impacted into the distal femur, and modular components are trialed on the proximal aspect of the stem until the desired leg length and hip stability are obtained. The rotational orientation of the modular components are marked using a standard reference with electrocautery. Final implants are impacted onto the stem, with attention paid to recreating the desired rotation. The proximal fracture fragments are then debulked, using a highspeed burr, and wrapped around the stem using cables or Luque wires. Typically, patient rehabilitation consists of protected weight bearing following surgery and no abduction
In rare circumstances, when the surgeon predicts a low likelihood of biologic fixation (eg, postradiation therapy, severe osteoporosis, severe femoral bone loss), reconstruction may be best addressed with a cemented long-stem prosthesis. The surgeon should achieve anatomic fracture reduction, optimally with compression, before reconstruction to minimize cement extrusion through the fracture site, which can impede fracture healing. Haidukewych et al28 recommended fracture reduction and fixation with cables, gentle cement pressurization, and intraoperative radiographs after implantation to search for extruded cement.
Cortical Strut Allografts First described in 1989, cortical strut grafts can restore bone stock and improve the structural mechanics of the reconstruction. Historically, good results were reported for periprosthetic fractures treated with cortical strut allograft and cerclage wires.29,30 In a study of 19 patients by Chandler et al,31 16 patients (84%) had bony
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Figure 3
Proximal femoral replacement for a type B3 periprosthetic fracture. A, Hip radiograph showing deficient proximal and lateral bone with multiple fracture lines and stem subsidence. B and C, Postoperative radiographs showing a well-positioned proximal femoral replacement with retention and healing of the deficient proximal bone. (Courtesy of Brett Levine, MD, Rush University, Chicago, IL)
union and good clinical function after 5 months. In a study by Head et al,32 results of .90% bony union with cortical struts were reported with a follow-up of .10 years. Cortical strut grafts are used infrequently and only for support of host bone stock, specifically on the tension surfaces of the femur (ie, anterior and lateral). Park et al20 described an overall union rate of 94% in a series of 18 patients. In type B2 fractures, union times dropped from 52 weeks with revision alone to 17 weeks if a plate or strut-onlay was used. The use of cortical strut grafts remains controversial because of concerns over soft-tissue stripping and its impact on healing.
Vancouver Type B3 Fractures Fractures of severely deficient bone can cause extensive comminution and devascularized bone fragments, resulting in a deficient and unsupportive proximal femur. This necessitates August 2014, Vol 22, No 8
augmentation with a cortical strut allograft and/or impaction grafting, or replacement with an allograftprosthetic composite (APC) or mega prosthesis. This scenario is seen in the multiply revised hip, with repeated devascularization from canal reaming, multiple cable applications, and prior osteotomies. Proximal replacement is also a reasonable choice whenever a distal press-fit stem requires additional proximal support or in the setting of an oncologic pathologic periprosthetic fracture.
Impaction Grafting Impaction grafting has been described for Vancouver type B2 and B3 periprosthetic fractures33 and for revision THA generally.34 Although rarely used, this technique may be used successfully in severely ectatic bone and simple fracture patterns. Grafting can address areas of fracture comminution, as well as reconstitute a capacious canal. We recommend fracture reduction with cables for oblique or spiral
patterns, augmented with a circumferential wire mesh for transverse fracture patterns. The mesh should span at least two cortical diameters above and below the fracture site. The canal is prepared and a suitable prosthesis is selected that will extend at least two cortical diameters below the fracture. A cement restrictor is placed in the canal, and corticocancellous bone is impacted into the canal. Reamers are used to recreate the canal and further impact the bone graft, followed by broaches and special tamps to reconstitute the metaphyseal bone stock. The stem is then cemented into place. Lee et al33 found fracture healing and reconstitution of bone stock in all seven patients in their report, with good clinical results in six patients (86%).
Allograft Prosthesis Composite Allograft prosthesis composite (APC) reconstructions involve cementing the proximal portion of a long stem into an allograft, and then impacting
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Periprosthetic Fractures Around Loose Femoral Components
Table 1 Summary of Reporting on Type B2 Periprosthetic Fractures
Study
No. of Subjects at Final Follow-Up
Fracture Type
Study Type
Springer et al39
111
76 B2 and 35 B3
Case series
Bhattacharyya et al5
51
43 B2 and 8 B3
Case-control
Mukundan et al40
59
42 B2 and 17 B3
Case series
Corten et al41
31
B2
Case series
Fink et al42
32
Case series
Matharu et al43
46
22 B2 and 10 B3 33 B2 and 13 B3
Marx et al44
29
Case series
Neumann et al45
55
15 B2 and 14 B3 35 B2 and 20 B3
Garcia-Rey et al24
35
20 B2 and 15 B3
Case series
Sheth et al10
21
18 B2, 1 B3, Case-control 2 B2/A(g)
Case series
Case series
Mean Patient Age in Years (Range)
Treatment Method Cemented stem, proximally porouscoated stem, extensively porouscoated stem, allograftprosthesis composite, or endoprosthesis Long stem revision 1/2plate or allograft strut, ORIF alone Long stem revision 1/2 plate, distallocking long stem revision Cemented long stem prosthesis with allograft strut Long stem noncemented modular revision Noncemented, fully porous-coated long stem revision, or femoral endoprosthesis Noncemented Wagner long stem revision Noncemented modular tapered long stem revision Noncemented, fully porous-coated long stem revision Noncemented, fully porous-coated long stem revision
65.3 (37 to 91)
Mean Follow-up in Months (Range) 64.9 (2 to 185)
79.1 (range NS)
26 (range NS)
74.2 (57 to 100)
24 (range NS)
82 (56 to 93)
33 (0 to 132)
67.4 (39 to 90)
32.2 (24 to 60)
76.7 (57 to 94)
24 (6 to 73)
67.8 (40 to 82)
74 (range NS)
74 (45 to 84)
67 (60 to 144)
80 (51 to 86)
100 (36 to 204)
66.5 (47 to 82)
NS
NS = not specified, ORIF = open reduction and internal fixation
the distal stem into the host distal femur. For optimal fixation, the distal femur is prepared with a step cut, and a reciprocal cut is made in the allograft. The remaining proximal host bone and soft-tissue attachments can be wrapped around the construct as vascularized autograft and fixed with cerclage cables. Finally, any residual host greater trochanter or abductor tissue is fixed to this construct.35 APC outcomes have demonstrated reasonable clinical outcomes in the
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literature. In a series of 25 Vancouver type B3 hips treated with APCs, 20 hips (80%) demonstrated healing between the allograft and host bone at 5 years, and 21 patients (84%) had no or only mild pain.35,36 Radiographic graft resorption was mild in four hips (16%) and moderate in two hips (8%). This technique is time consuming and falling out of favor. The allograft canal may require substantial reaming to match an ectactic distal host
femur for an appropriately sized stem. The allograft, once thought to incorporate and allow soft-tissue healing, resorbs with time. Ultimately, the allograft conveys a mechanically weaker construct (ie, the bone can fracture) compared with that of a metal mega prosthesis.
Mega Prosthesis Proximal bone stock can be replaced with a tumor prosthesis37,38 (Figure 3).
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After prosthesis removal and débridement, the femur is cut transversely, as proximally as possible to provide a good circumferential bony shelf. The canal preparation and stem placement depends on whether the proximal femoral replacement is cemented or press-fit. Anteversion is controlled by the orientation of the implantation, and offset can be varied based on the implant modularity. Leg length can be controlled using modular body segments in varying sizes. Proximal femoral replacements have had mixed clinical results at 4 years.38 McLean et al38 reported the results of 15 proximal femoral replacement prostheses in a series of Vancouver type B3 periprosthetic fractures and patients with failed ORIF of femoral fractures with poor bone stock. They reported Medical Outcomes Study 12-Item Short Form scores of approximately 50 for both the physical and mental components. Their complications included three dislocations, two failures of seven one-stage procedures for infection, and one refracture below the proximal femur replacement.
Outcomes and Complications Table 1 summarizes the treatment outcomes for Vancouver B2 and B3 fractures.5,10,24,39-45 Mortality is high following periprosthetic hip fractures. The Swedish registry found that 1.2% of patients died within the first week postoperatively, and 9.4% of patients died within 12 months of surgery.2 Bhattacharyya et al5 found a cumulative mortality rate of 21% and a 1-year mortality rate of 11%. This was similar to mortality following hip fractures generally and significantly higher than the mortality following primary total joint arthroplasty. For all type B fractures in the report by Bhattacharyya et al,5 the mortality rates after ORIF and revision were August 2014, Vol 22, No 8
33% and 12%, respectively. Subdividing further, a higher mortality rate for ORIF than that for revision arthroplasty approached significance for both type B1 and B2 fractures. Part of the benefit may be explained by the mobility and full weight bearing following revision compared with the restricted weight bearing following ORIF. Eighteen percent of patients experienced a postoperative complication, including bleeding (3.4%), dislocation (3.2%), wound infection (2.7%), and deep vein thrombosis (0.8%).2 Early reoperations were common, with 10.4% of patients undergoing reoperation within the first 12 months.8 In total, 23% of patients underwent reoperation at a mean interval of 22 months.8 Thirteen percent of the reoperations were the result of loosening.
Summary Periprosthetic fractures are increasing in incidence as the number of patients undergoing primary THA increases. The goal of treatment is to obtain stable fracture fixation and distal stem fixation. A long, fully coated stem was historically the mainstay of treatment, although modular tapered stems are gaining in popularity. Other reconstructive options also exist based on the bone quality. Despite significant first-year mortality rates and other complications, patients who sustain a periprosthetic fracture can have good outcomes when the appropriate treatment is chosen. It is imperative that the treating surgeon have a high level of suspicion that a stem may be loose and, if confirmed, appropriate implants and special equipment must be available to revise the femoral component.
References Evidence-based Medicine: Levels of evidence are described in the table of
contents. In this article, references 3, 5, and 22 are level II studies. References 1, 2, 4, 8, 10, 15, 16, 19, and 24 are level III studies. References 6, 7, 13, 17, 18, 20, 21, 23, 26, 27, and 29-45 are level IV studies. References 9, 14, 25, and 28 are level V expert opinions. References printed in bold type are those published within the past 5 years. 1. Berry DJ: Epidemiology: hip and knee. Orthop Clin North Am 1999;30(2): 183-190. 2. Lindahl H, Malchau H, Herberts P, Garellick G: Periprosthetic femoral fractures classification and demographics of 1049 periprosthetic femoral fractures from the Swedish National Hip Arthroplasty Register. J Arthroplasty 2005; 20(7):857-865. 3. Lindahl H, Garellick G, Regnér H, Herberts P, Malchau H: Three hundred and twenty-one periprosthetic femoral fractures. J Bone Joint Surg Am 2006;88(6): 1215-1222. 4. Sarvilinna R, Huhtala HS, Sovelius RT, Halonen PJ, Nevalainen JK, Pajamäki KJ: Factors predisposing to periprosthetic fracture after hip arthroplasty: A case (n = 31)-control study. Acta Orthop Scand 2004;75(1):16-20. 5. Bhattacharyya T, Chang D, Meigs JB, Estok DM II, Malchau H: Mortality after periprosthetic fracture of the femur. J Bone Joint Surg Am 2007;89(12):2658-2662. 6. Duncan CP, Masri BA: Fractures of the femur after hip replacement. Instr Course Lect 1995;44:293-304. 7. Masri BA, Meek RM, Duncan CP: Periprosthetic fractures evaluation and treatment. Clin Orthop Relat Res 2004; 420:80-95. 8. Lindahl H, Malchau H, Odén A, Garellick G: Risk factors for failure after treatment of a periprosthetic fracture of the femur. J Bone Joint Surg Br 2006;88(1): 26-30. 9. Franklin J, Malchau H: Risk factors for periprosthetic femoral fracture. Injury 2007;38(6):655-660. 10.
Sheth NP, Brown NM, Moric M, Berger RA, Della Valle CJ: Operative treatment of early peri-prosthetic femur fractures following primary total hip arthroplasty. J Arthroplasty 2013;28(2): 286-291.
11. Lavernia CJ: Cost-effectiveness of early surgical intervention in silent osteolysis. J Arthroplasty 1998;13(3):277-279.
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Periprosthetic Fractures Around Loose Femoral Components 12. Harris B, Owen JR, Wayne JS, Jiranek WA: Does femoral component loosening predispose to femoral fracture? An in vitro comparison of cemented hips. Clin Orthop Relat Res 2010;468(2):497-503. 13. Beals RK, Tower SS: Periprosthetic fractures of the femur. An analysis of 93 fractures. Clin Orthop Relat Res 1996;327: 238-246. 14. Pike J, Davidson D, Garbuz D, Duncan CP, O’Brien PJ, Masri BA: Principles of treatment for periprosthetic femoral shaft fractures around well-fixed total hip arthroplasty. J Am Acad Orthop Surg 2009;17(11):677-688. 15. Chevillotte CJ, Ali MH, Trousdale RT, Larson DR, Gullerud RE, Berry DJ: Inflammatory laboratory markers in periprosthetic hip fractures. J Arthroplasty 2009;24(5):722-727. 16. Ghanem E, Houssock C, Pulido L, Han S, Jaberi FM, Parvizi J: Determining “true” leukocytosis in bloody joint aspiration. J Arthroplasty 2008;23(2):182-187. 17. Johansson JE, McBroom R, Barrington TW, Hunter GA: Fracture of the ipsilateral femur in patients wih total hip replacement. J Bone Joint Surg Am 1981;63 (9):1435-1442. 18. Lewallen DG, Berry DJ: Periprosthetic fracture of the femur after total hip arthroplasty: Treatment and results to date. Instr Course Lect 1998;47:243-249. 19. Engh CA, Massin P, Suthers KE: Roentgenographic assessment of the biologic fixation of porous-surfaced femoral components. Clin Orthop Relat Res 1990;257:107-128. 20. Park SK, Kim YG, Kim SY: Treatment of periprosthetic femoral fractures in hip arthroplasty. Clin Orthop Surg 2011;3(2): 101-106. 21. Levine BR, Della Valle CJ, Lewis P, Berger RA, Sporer SM, Paprosky W: Extended trochanteric osteotomy for the treatment of vancouver B2/B3 periprosthetic fractures of the femur. J Arthroplasty 2008;23(4):527-533. 22. Foran JR, Brown NM, Della Valle CJ, Levine BR, Sporer SM, Paprosky WG: Prevalence, risk factors, and management of proximal femoral remodeling in revision hip arthroplasty. J Arthroplasty 2013;28 (5):877-881. 23. Weeden SH, Paprosky WG: Minimal 11-year follow-up of extensively porous-coated stems
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in femoral revision total hip arthroplasty. J Arthroplasty 2002;17(4, suppl 1)134-137. 24. García-Rey E, García-Cimbrelo E, CruzPardos A, Madero R: Increase of cortical bone after a cementless long stem in periprosthetic fractures. Clin Orthop Relat Res 2013;471(12):3912-3921. 25. Srinivasan A, Jung E, Levine BR: Modularity of the femoral component in total hip arthroplasty. J Am Acad Orthop Surg 2012;20(4):214-222. 26. Munro JT, Garbuz DS, Masri BA, Duncan CP: Tapered fluted titanium stems in the management of Vancouver B2 and B3 periprosthetic femoral fractures. Clin Orthop Relat Res 2014; 472(2):590-598. 27. Abdel MP, Lewallen DG, Berry DJ: Periprosthetic femur fractures treated with modular fluted, tapered stems. Clin Orthop Relat Res 2014;472(2):599-603. 28. Haidukewych GJ, Langford JR, Liporace FA: Revision for periprosthetic fractures of the hip and knee. Instr Course Lect 2013;62:333-340.
35. Maury AC, Pressman A, Cayen B, Zalzal P, Backstein D, Gross A: Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty. J Bone Joint Surg Am 2006;88(5):953-958. 36. Haddad FS, Garbuz DS, Masri BA, Duncan CP: Structural proximal femoral allografts for failed total hip replacements: A minimum review of five years. J Bone Joint Surg Br 2000;82(6):830-836. 37. Klein GR, Parvizi J, Rapuri V, et al: Proximal femoral replacement for the treatment of periprosthetic fractures. J Bone Joint Surg Am 2005;87(8): 1777-1781. 38.
39. Springer BD, Berry DJ, Lewallen DG: Treatment of periprosthetic femoral fractures following total hip arthroplasty with femoral component revision. J Bone Joint Surg Am 2003;85-A(11):2156-2162. 40.
Mukundan C, Rayan F, Kheir E, Macdonald D: Management of late periprosthetic femur fractures: A retrospective cohort of 72 patients. Int Orthop 2010;34(4):485-489.
41.
Corten K, Macdonald SJ, McCalden RW, Bourne RB, Naudie DD: Results of cemented femoral revisions for periprosthetic femoral fractures in the elderly. J Arthroplasty 2012;27(2): 220-225.
42.
Fink B, Grossmann A, Singer J: Hip revision arthroplasty in periprosthetic fractures of vancouver type B2 and B3. J Orthop Trauma 2012;26(4):206-211.
43.
Matharu GS, Pynsent PB, Dunlop DJ, Revell MP: Clinical outcome following surgical intervention for periprosthetic hip fractures at a tertiary referral centre. Hip Int 2012;22(5):494-499.
44.
Marx A, Beier A, Jung L, Lohmann CH, Halder AM: Peri-prosthetic femoral fractures treated with the uncemented Wagner revision stem. Hip Int 2012;22(3): 286-291.
45.
Neumann D, Thaler C, Dorn U: Management of Vancouver B2 and B3 femoral periprosthetic fractures using a modular cementless stem without allografting. Int Orthop 2012;36(5): 1045-1050.
29. Pak JH, Paprosky WG, Jablonsky WS, Lawrence JM: Femoral strut allografts in cementless revision total hip arthroplasty. Clin Orthop Relat Res 1993;295: 172-178. 30. Brady OH, Garbuz DS, Masri BA, Duncan CP: The treatment of periprosthetic fractures of the femur using cortical onlay allograft struts. Orthop Clin North Am 1999;30(2):249-257. 31. Chandler HP, King D, Limbird R, et al: The use of cortical allograft struts for fixation of fractures associated with well-fixed total joint prostheses. Semin Arthroplasty 1993; 4(2):99-107. 32. Head WC, Malinin TI, Emerson RH Jr, Mallory TH: Restoration of bone stock in revision surgery of the femur. Int Orthop 2000;24(1):9-14. 33. Lee GC, Nelson CL, Virmani S, Manikonda K, Israelite CL, Garino JP: Management of periprosthetic femur fractures with severe bone loss using impaction bone grafting technique. J Arthroplasty 2010;25(3):405-409. 34. Gie GA, Linder L, Ling RS, Simon JP, Slooff TJ, Timperley AJ: Impacted cancellous allografts and cement for revision total hip arthroplasty. J Bone Joint Surg Br 1993;75(1):14-21.
McLean AL, Patton JT, Moran M: Femoral replacement for salvage of periprosthetic fracture around a total hip replacement. Injury 2012;43(7):1166-1169.
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Periprosthetic Fractures Around Loose Femoral Components Abstract Roshan P. Shah, MD, JD Neil P. Sheth, MD Chancellor Gray, MD Hassan Alosh, MD Jonathan P. Garino, MD
From Columbia University, New York, NY (Dr. Shah), the University of Pennsylvania, Philadelphia, PA (Dr. Sheth, Dr. Gray, and Dr. Alosh), and the Pennsylvania Orthopedic Center, Alvern, PA (Dr. Garino). Dr. Shah or an immediate family member has stock or stock options held in Pfizer, Merck, GlaxoSmithKline, Alnylam, and Intuitive Surgical. Dr. Sheth or an immediate family member serves as a paid consultant to Zimmer. Dr. Garino or an immediate family member has received royalties from Smith & Nephew; is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew; serves as a paid consultant to Smith & Nephew and DePuy; has received research or institutional support from Zimmer; and serves as a board member, owner, officer, or committee member of the Pennsylvania Orthopedic Society. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Gray and Dr. Alosh. J Am Acad Orthop Surg 2014;22: 482-490 http://dx.doi.org/10.5435/ JAAOS-22-08-482 Copyright 2014 by the American Academy of Orthopaedic Surgeons.
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The development of periprosthetic fractures around loose femoral components can be a devastating event for patients who have undergone total hip arthroplasty (THA). As indications for THA expand in an aging population and to use in younger patients, these fractures are increasing in incidence. This review covers the epidemiology, risk factors, prevention, and clinical management of periprosthetic femoral fractures. Treatment principles and reconstructive options are discussed, along with outcomes and complications. Femoral revision with a long-stem prosthesis or a modular tapered stem is the mainstay of treatment and has demonstrated good outcomes in the literature. Other reconstruction options are available, depending on bone quality. Surgeons must have a sound understanding of the diagnosis and treatment of periprosthetic femoral fractures.
T
otal hip arthroplasty (THA) reliably treats hip pain caused by articular cartilage degeneration; however, the development of periprosthetic femoral fractures after THA is a devastating complication. Two registry studies form the foundation of our understanding of these fractures. Between 1969 and 1999, 1,249 fractures out of 30,329 hip arthroplasty cases were studied in the Mayo Clinic Joint Registry.1 Periprosthetic fractures in the Swedish National Hip Arthroplasty Registry were studied retrospectively between 1979 and 19982 and prospectively between 1999 and 2000.3 The latter study found that femoral periprosthetic fractures were the third most frequently reported reason for reoperation after THA, accounting for 9.5% of the revisions between 1999 and 2000.3 Other studies have reported the prevalence of late periprosthetic hip fractures to be between 0.1% and 18%,4 with an annual incidence of between 0.045% and 0.13%.2
The incidence of periprosthetic hip fractures is increasing. Bhattacharyya et al5 found a 216% increase between 2002 and 2006. Several reasons for the increase have been proposed.1,2 First, the total prevalence of patients living with THA is increasing. Second, with time, the number of patients experiencing osteolysis to a varying degree, as well as component loosening, will increase. Third, as patients age, there is a greater risk for the development of osteoporosis and periprosthetic fracture caused by minor trauma. Fourth, with the success of THA and its expanding indications, more patients are young and active; consequently, this patient population has a greater exposure to higher energy trauma and therefore an increased risk of periprosthetic fracture. Fifth, the expanding class of patients with THA logically leads to a greater number of patients requiring revision THA. Several treatment options have been proposed based on an accurate classification of the fracture type and
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implant stability. Preoperatively differentiating between a loose and a stable femoral implant can be challenging, but certain signs and symptoms can be helpful. Fractures occurring around loose implants require femoral stem revision.
Vancouver Classification The Vancouver classification is the most common classification system used to describe periprosthetic fractures. This classification is based on fracture location, implant stability, and integrity of the residual bone stock.6,7 Type B fractures occur along the length of the femoral stem. Type B fractures are further subdivided by stem stability and bone stock. Type B1 fractures are fractures with a stable femoral component. Type B2 fractures are fractures with a loose femoral component but with supportive femoral bone stock. Type B3 fractures are fractures with a loose femoral component and associated poor integrity bone stock, wherein the metaphyseal and diaphyseal bone stock is deficient and unsupportive. The incidence and prevalence of each Vancouver type are not well known, for the same reasons that make the true incidence of all periprosthetic fractures elusive. In the Swedish registry report, 53% of the fractures were type B2 and only 4% were type B3.8 When the group examined whether the index surgery was a primary THA or a revision THA, they found that fractures occurring after primary THA were more commonly type B2, whereas fractures occurring after revision THA were more commonly type B1.2
technique, and the type of implant used.9,10 Osteolysis and loosening are most directly related to Vancouver type B2 and B3 fractures. Routine clinical follow-up is necessary to identify patients at risk for loosening, and regular radiographic evaluations have been shown to be cost effective.11 Biomechanical studies have demonstrated that loose femoral stems have a nearly 60% reduction in the torque to failure compared with well-fixed stems.12 In a study by Beals and Tower,13 27% of patients with fractures had evidence of loosening preoperatively. The Swedish registry showed that 70% of fractures involved loose prostheses, with 23% known to be loose and 47% first identified as loose at the time of surgery.2 It is unclear what contribution infection has to loosening and subsequent fracture. The inflammatory markers erythrocyte sedimentation rate and C-reactive protein have poor specificity in the setting of a fracture.14,15 However, intraoperative aspiration for cell count and culture studies provides valuable information when the suspicion for infection is high. We use standard cut-off values of 3,000 WBC/mL and 80% polymorphonuclear cells for diagnosing infection. Because of fracture bleeding, we correct for the contribution of serum white blood cells with the following formula:
WBCcorrected 5 WBCobserved 2 WBCserum · RBCfluid = RBCserum ;16 where WBC is white bloods cells and RBC is red blood cells.
Risk Factors General risk factors for the development of periprosthetic fractures after THA include osteolysis and loosening, trauma, age, gender, osteoporosis, index diagnosis, revision surgery, August 2014, Vol 22, No 8
Management Preoperative Evaluation Patients with periprosthetic fractures generally present to the emergency
department after sustaining spontaneous or low-energy trauma and may be seen in the trauma bay after sustaining high-energy trauma. Advanced Trauma Life Support guidelines should always be used for initial patient evaluation following trauma. Conducting an appropriate physical examination will help reveal associated musculoskeletal injuries. A thorough history provides information about the medical causes of spontaneous or low-energy injury, such as syncope, cardiopulmonary compromise, or stroke; any underlying disorders should then be managed by the appropriate specialist. As with any femur fracture, significant blood loss may occur, requiring close monitoring of cardiopulmonary vital signs and volume status. Medical co-management is the most effective method by which to optimize care of patients with periprosthetic fractures before surgical intervention. Previous surgical notes should be obtained, especially if the index procedure was performed at an outside institution, to properly identify the currently implanted devices. If prior records are unavailable, consultation with other surgeons and industry representatives can help determine the components and the manufacturers. Finally, preoperative surgical planning is critical in achieving clinical success. Arrange to have all extraction devices and revision equipment available for the implanted components. In addition, a thorough and systematic evaluation of the acetabular component should be conducted intraoperatively because an acetabular revision requiring more than a liner exchange may be necessary (ie, loose component, poor component position, poor implant track record, shell or locking mechanism damage, extensive corrosion). Radiographic studies consisting of an AP pelvis and AP and cross-table lateral views of the hip should be obtained to assess for fracture
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Periprosthetic Fractures Around Loose Femoral Components
morphology, prosthetic stability, component malposition, bone stock, the location of any osteolysis, and the presence of wear. Lateral frog-leg views are also valuable in patients who can tolerate the positioning of the leg. Full-length femur radiographs can reveal bony deformities, such as proximal femoral varus remodeling, total knee arthroplasty, or the presence of other hardware that may interfere with the planned reconstruction. In some circumstances, CT may be used as an adjunct for assessing the fracture, areas of bone spotwelding, regions of bone loss, and the position of the component.
Distinguishing Vancouver Type B1 From Type B2/B3 Historically, outcomes were poor for periprosthetic fractures.13,17,18 However, with the advent of the Vancouver classification in 1995, results have improved, thus reinforcing the importance of the system in guiding diagnosis and treatment. It is not uncommon for type B2 fractures to be mistaken for type B1 fractures. Determining whether a stem is wellfixed or loose is critical; this is likely the most important step when managing these patients. When fractures are misclassified, failure rates are higher. In the Swedish registry, a 30% reoperation rate was found for B1 fractures treated with open reduction and internal fixation (ORIF), whereas the failure rate for B2 fractures treated with revision was only 18.5%.3,8 The authors inferred that some of their B1 fractures were actually B2 fractures and should have been revised for optimal treatment. Relevant history that contributes to making this determination includes preexisting groin or thigh pain, pain with non–weight-bearing range of motion, progressive limb shortening, and persistent symptoms or signs of infection. Radiographic comparison with immediate post-arthroplasty
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radiographs can show signs of loosening (eg, subsidence, circumferential radiolucent lines, evidence of a supportive pedestal in a proximally fixed stem, and cement mantle fracture).19 Ultimately, evidence of loosening may not be revealed until the intraoperative assessment is conducted; therefore, all implants and revision instrumentation must be made available for all periprosthetic fracture surgeries. Although others have recommended routine hip dislocation and stability testing, the trade-off of extra soft-tissue dissection is not trivial. When preoperative evaluation suggests that a type B1 fracture is present, we rely on thorough testing of the prosthesis-bone interface through the fracture site to determine implant stability.
Surgical Principles for Loose Stems The diagnosis of a loose femoral stem in the face of a periprosthetic fracture necessitates femoral component revision. Surgical treatment principles for loose femoral components are based on several factors, including fracture morphology, the host bone quality, patient age, and functional status.20 When adequate bone stock remains, the principles of reconstruction require the removal of the loose device, cement, and biomembrane; reconstruction of the host femoral shaft; and the implantation of a long-stemmed prosthesis to obtain stable distal fixation. In the past, extensively porous-coated devices have been considered the most dependable for the management of these fractures; however, modular stems are becoming more popular. With fractures occurring in the setting of major bone loss (ie, Vancouver type B3), reconstruction typically entails device removal and débridement. This is followed by the use of a modular tapered stem that requires ,4 to 6 cm of interference fit; the
splines on the stem provide rotational stability. Severely ectatic femoral canals may require proximal bone reconstitution with either structural allograft (ie, allograft prosthesis composite) or a mega prosthesis (ie, proximal femoral replacement). The complexity of the fracture and the degree of proximal femoral remodeling determines whether the fracture is reduced and fixed first or whether the prosthesis is implanted and the proximal bone is wrapped around the implant. In the presence of little comminution and few fracture fragments, it may be preferable to reduce and fix the fracture before implantation. This optimizes compression and bony contact, thus adhering to standard fracture treatment principles. In certain situations, the best strategy may require the implantation of a distally fixed revision prosthesis first while exploiting the fracture as a window. An extended trochanteric osteotomy of the proximal fracture fragment may be required when the proximal femur demonstrates varus and retroversion remodeling.21 Severe proximal femoral remodeling will not allow for the insertion of a long stem through the deformity without destroying the proximal femur. In this scenario, the diaphyseal preparation is facilitated through direct visualization of the femoral canal and bypassing the proximal deformity. After the stem is implanted, the proximal fragments can be debulked and reduced around the proximal stem with cables or Luque wires. Proximal femoral remodeling is a more common occurrence with loose cemented femoral stems.22
Implant Selection for Vancouver Type B2 Fractures Extensively Porous-coated Stems The monoblock, extensively porouscoated, noncemented prosthesis has
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Figure 1
Monoblock, extensively coated, noncemented stem for a type B2 fracture. A, Hip radiograph showing fracture and stem subsidence. B, Postoperative radiograph showing satisfactory stem position and fracture reduction; offset is overcorrected.
been the reliable implant for femoral reconstruction in type B2 fractures (Figure 1). These devices bypass the fracture and achieve distal diaphyseal fixation, with at least 4 to 6 cm of interference fit, which is recommended for optimal stability of the implant.23 Monoblock stems are available in either a straight or a bowed geometry. Straight stems confer three-point fixation in a bowed femur; however, there is a risk of anterior distal cortical perforation when the stem length exceeds the tolerance of the native femur’s radius of curvature. Bowed stems may be necessary when the stems surpass a length of 8 inches; however, limitations exist regarding the ability to change the anteversion of the prosthesis because of the bow. The inability to change the anteversion August 2014, Vol 22, No 8
of the neck independently of the stem may result in hip instability. Noncemented, extensively porouscoated long stems have had favorable results in the literature. Garcia-Rey et al24 reported on 20 type B2 and 15 type B3 fractures treated with these devices without allograft. All fractures united, and no patients reported thigh pain at an average of 8.3 years. Average Merle d’Aubigné and Postel scores were 5.8 for pain, 5.2 for function, and 4.9 for range of motion. Interestingly, the authors reported an increase in the cortical index and cortical bone thickness despite the use of diaphyseal fixation and concerns for stress shielding. This effect was greater for stems smaller than 16 mm and in patients with mild or moderate preoperative osteoporosis. A review of five studies
using extensively porous-coated stems showed that 111 of 113 fractures (98%) had united by a mean follow-up of 5.6 years, whereas only 6 showed evidence of loosening.24 Complications associated with these implants have been described. GarciaRey et al24 reported subsidence of .1 cm in 19 patients (48%) between 6 and 12 weeks. Twelve of 23 treated Vancouver type B2 fractures (52%) and 10 of 17 treated Vancouver type B3 fractures (59%) subsided more than 1 cm. Clinically, six patients (15%) had a limb-length discrepancy of .1 cm, and two patients had a discrepancy of .2 cm. Nine patients (23%) required the use of one crutch for a limp. There were no dislocations, three postoperative hematomas (8%), three intraoperative greater trochanter fractures (8%), two missed fractures (5%) at the distal stem tip (one of which resulted in a displaced fracture), one supracondylar femoral fracture (3%), and two reoperations (5%) for removal of cerclage wires because of superficial infection. Sheth et al10 reported on 21 type B2 and B3 fractures treated with extensively coated, diaphyseal implants and found complications in seven patients (33%), including instability, subsidence, infection, heterotopic ossification, and osteotomy nonunion.
Modular Tapered Stems Both monoblock tapered stems (ie, Wagner-type stems) and modular tapered stems allow for diaphyseal fixation, rotational stability through splines, reduced risk of anterior perforation, and independent control of component anteversion. Modular tapered stems are more commonly used than monoblock designs and have become the new dependable implant of femoral reconstruction.25-27 These devices comprise a distal component that engages the diaphysis and a modular proximal component that mates via a Morse taper, allowing
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Periprosthetic Fractures Around Loose Femoral Components
for 4 to 6 weeks. Abdel et al27 reported on 25 Vancouver type B2 and 19 Vancouver type B3 fractures treated in this manner in a 4.5-year follow-up. Forty-three of 44 patients (98%) reached radiographic union with a Harris Hip score of 83. Munro et al26 reported on 38 Vancouver type B2 and 17 Vancouver type B3 fractures with a 4.5-year follow-up. Fiftyfour fractures (98%) healed by 24 months, with an average WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score of 76 for B2 fractures and 77 for B3 fractures. There were two stem revisions and eight reoperations. Complications reported in both studies included instability, subsidence, and infection.26,27
Figure 2
Long-stem Cemented Prosthesis
Modular tapered stem for a type B2 periprosthetic fracture. A, Hip radiograph showing fracture and stem subsidence. B, Postoperative radiograph showing satisfactory position of the modular tapered stem with good fracture reduction.
independent control of anteversion, length, and offset (Figure 2). Modular tapered stems can obtain stability with ,4 cm of interference fit within the diaphysis and rely on splines for rotational stability of the implant.26 Proper sizing of these implants is important for axial stability because subsidence is a frequent mechanical complication; the tendency is to undersize the stem because of the risk of creating an intraoperative femoral fracture.26 Our preferred technique when using a modular tapered stem is to reconstruct the femur first, followed by fracture reduction. Under manual reaming, a conical support is created with sequential tapered reamers, based on the template diameter and the length of the stem. Manual reaming reduces the risk of femoral blow-out
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with poor bone stock. A prophylactic cable should be placed around the intact femur distal to the fracture to prevent propagation. The modular, fluted, tapered stem is then impacted into the distal femur, and modular components are trialed on the proximal aspect of the stem until the desired leg length and hip stability are obtained. The rotational orientation of the modular components are marked using a standard reference with electrocautery. Final implants are impacted onto the stem, with attention paid to recreating the desired rotation. The proximal fracture fragments are then debulked, using a highspeed burr, and wrapped around the stem using cables or Luque wires. Typically, patient rehabilitation consists of protected weight bearing following surgery and no abduction
In rare circumstances, when the surgeon predicts a low likelihood of biologic fixation (eg, postradiation therapy, severe osteoporosis, severe femoral bone loss), reconstruction may be best addressed with a cemented long-stem prosthesis. The surgeon should achieve anatomic fracture reduction, optimally with compression, before reconstruction to minimize cement extrusion through the fracture site, which can impede fracture healing. Haidukewych et al28 recommended fracture reduction and fixation with cables, gentle cement pressurization, and intraoperative radiographs after implantation to search for extruded cement.
Cortical Strut Allografts First described in 1989, cortical strut grafts can restore bone stock and improve the structural mechanics of the reconstruction. Historically, good results were reported for periprosthetic fractures treated with cortical strut allograft and cerclage wires.29,30 In a study of 19 patients by Chandler et al,31 16 patients (84%) had bony
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Figure 3
Proximal femoral replacement for a type B3 periprosthetic fracture. A, Hip radiograph showing deficient proximal and lateral bone with multiple fracture lines and stem subsidence. B and C, Postoperative radiographs showing a well-positioned proximal femoral replacement with retention and healing of the deficient proximal bone. (Courtesy of Brett Levine, MD, Rush University, Chicago, IL)
union and good clinical function after 5 months. In a study by Head et al,32 results of .90% bony union with cortical struts were reported with a follow-up of .10 years. Cortical strut grafts are used infrequently and only for support of host bone stock, specifically on the tension surfaces of the femur (ie, anterior and lateral). Park et al20 described an overall union rate of 94% in a series of 18 patients. In type B2 fractures, union times dropped from 52 weeks with revision alone to 17 weeks if a plate or strut-onlay was used. The use of cortical strut grafts remains controversial because of concerns over soft-tissue stripping and its impact on healing.
Vancouver Type B3 Fractures Fractures of severely deficient bone can cause extensive comminution and devascularized bone fragments, resulting in a deficient and unsupportive proximal femur. This necessitates August 2014, Vol 22, No 8
augmentation with a cortical strut allograft and/or impaction grafting, or replacement with an allograftprosthetic composite (APC) or mega prosthesis. This scenario is seen in the multiply revised hip, with repeated devascularization from canal reaming, multiple cable applications, and prior osteotomies. Proximal replacement is also a reasonable choice whenever a distal press-fit stem requires additional proximal support or in the setting of an oncologic pathologic periprosthetic fracture.
Impaction Grafting Impaction grafting has been described for Vancouver type B2 and B3 periprosthetic fractures33 and for revision THA generally.34 Although rarely used, this technique may be used successfully in severely ectatic bone and simple fracture patterns. Grafting can address areas of fracture comminution, as well as reconstitute a capacious canal. We recommend fracture reduction with cables for oblique or spiral
patterns, augmented with a circumferential wire mesh for transverse fracture patterns. The mesh should span at least two cortical diameters above and below the fracture site. The canal is prepared and a suitable prosthesis is selected that will extend at least two cortical diameters below the fracture. A cement restrictor is placed in the canal, and corticocancellous bone is impacted into the canal. Reamers are used to recreate the canal and further impact the bone graft, followed by broaches and special tamps to reconstitute the metaphyseal bone stock. The stem is then cemented into place. Lee et al33 found fracture healing and reconstitution of bone stock in all seven patients in their report, with good clinical results in six patients (86%).
Allograft Prosthesis Composite Allograft prosthesis composite (APC) reconstructions involve cementing the proximal portion of a long stem into an allograft, and then impacting
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Periprosthetic Fractures Around Loose Femoral Components
Table 1 Summary of Reporting on Type B2 Periprosthetic Fractures
Study
No. of Subjects at Final Follow-Up
Fracture Type
Study Type
Springer et al39
111
76 B2 and 35 B3
Case series
Bhattacharyya et al5
51
43 B2 and 8 B3
Case-control
Mukundan et al40
59
42 B2 and 17 B3
Case series
Corten et al41
31
B2
Case series
Fink et al42
32
Case series
Matharu et al43
46
22 B2 and 10 B3 33 B2 and 13 B3
Marx et al44
29
Case series
Neumann et al45
55
15 B2 and 14 B3 35 B2 and 20 B3
Garcia-Rey et al24
35
20 B2 and 15 B3
Case series
Sheth et al10
21
18 B2, 1 B3, Case-control 2 B2/A(g)
Case series
Case series
Mean Patient Age in Years (Range)
Treatment Method Cemented stem, proximally porouscoated stem, extensively porouscoated stem, allograftprosthesis composite, or endoprosthesis Long stem revision 1/2plate or allograft strut, ORIF alone Long stem revision 1/2 plate, distallocking long stem revision Cemented long stem prosthesis with allograft strut Long stem noncemented modular revision Noncemented, fully porous-coated long stem revision, or femoral endoprosthesis Noncemented Wagner long stem revision Noncemented modular tapered long stem revision Noncemented, fully porous-coated long stem revision Noncemented, fully porous-coated long stem revision
65.3 (37 to 91)
Mean Follow-up in Months (Range) 64.9 (2 to 185)
79.1 (range NS)
26 (range NS)
74.2 (57 to 100)
24 (range NS)
82 (56 to 93)
33 (0 to 132)
67.4 (39 to 90)
32.2 (24 to 60)
76.7 (57 to 94)
24 (6 to 73)
67.8 (40 to 82)
74 (range NS)
74 (45 to 84)
67 (60 to 144)
80 (51 to 86)
100 (36 to 204)
66.5 (47 to 82)
NS
NS = not specified, ORIF = open reduction and internal fixation
the distal stem into the host distal femur. For optimal fixation, the distal femur is prepared with a step cut, and a reciprocal cut is made in the allograft. The remaining proximal host bone and soft-tissue attachments can be wrapped around the construct as vascularized autograft and fixed with cerclage cables. Finally, any residual host greater trochanter or abductor tissue is fixed to this construct.35 APC outcomes have demonstrated reasonable clinical outcomes in the
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literature. In a series of 25 Vancouver type B3 hips treated with APCs, 20 hips (80%) demonstrated healing between the allograft and host bone at 5 years, and 21 patients (84%) had no or only mild pain.35,36 Radiographic graft resorption was mild in four hips (16%) and moderate in two hips (8%). This technique is time consuming and falling out of favor. The allograft canal may require substantial reaming to match an ectactic distal host
femur for an appropriately sized stem. The allograft, once thought to incorporate and allow soft-tissue healing, resorbs with time. Ultimately, the allograft conveys a mechanically weaker construct (ie, the bone can fracture) compared with that of a metal mega prosthesis.
Mega Prosthesis Proximal bone stock can be replaced with a tumor prosthesis37,38 (Figure 3).
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Roshan P. Shah, MD, JD, et al
After prosthesis removal and débridement, the femur is cut transversely, as proximally as possible to provide a good circumferential bony shelf. The canal preparation and stem placement depends on whether the proximal femoral replacement is cemented or press-fit. Anteversion is controlled by the orientation of the implantation, and offset can be varied based on the implant modularity. Leg length can be controlled using modular body segments in varying sizes. Proximal femoral replacements have had mixed clinical results at 4 years.38 McLean et al38 reported the results of 15 proximal femoral replacement prostheses in a series of Vancouver type B3 periprosthetic fractures and patients with failed ORIF of femoral fractures with poor bone stock. They reported Medical Outcomes Study 12-Item Short Form scores of approximately 50 for both the physical and mental components. Their complications included three dislocations, two failures of seven one-stage procedures for infection, and one refracture below the proximal femur replacement.
Outcomes and Complications Table 1 summarizes the treatment outcomes for Vancouver B2 and B3 fractures.5,10,24,39-45 Mortality is high following periprosthetic hip fractures. The Swedish registry found that 1.2% of patients died within the first week postoperatively, and 9.4% of patients died within 12 months of surgery.2 Bhattacharyya et al5 found a cumulative mortality rate of 21% and a 1-year mortality rate of 11%. This was similar to mortality following hip fractures generally and significantly higher than the mortality following primary total joint arthroplasty. For all type B fractures in the report by Bhattacharyya et al,5 the mortality rates after ORIF and revision were August 2014, Vol 22, No 8
33% and 12%, respectively. Subdividing further, a higher mortality rate for ORIF than that for revision arthroplasty approached significance for both type B1 and B2 fractures. Part of the benefit may be explained by the mobility and full weight bearing following revision compared with the restricted weight bearing following ORIF. Eighteen percent of patients experienced a postoperative complication, including bleeding (3.4%), dislocation (3.2%), wound infection (2.7%), and deep vein thrombosis (0.8%).2 Early reoperations were common, with 10.4% of patients undergoing reoperation within the first 12 months.8 In total, 23% of patients underwent reoperation at a mean interval of 22 months.8 Thirteen percent of the reoperations were the result of loosening.
Summary Periprosthetic fractures are increasing in incidence as the number of patients undergoing primary THA increases. The goal of treatment is to obtain stable fracture fixation and distal stem fixation. A long, fully coated stem was historically the mainstay of treatment, although modular tapered stems are gaining in popularity. Other reconstructive options also exist based on the bone quality. Despite significant first-year mortality rates and other complications, patients who sustain a periprosthetic fracture can have good outcomes when the appropriate treatment is chosen. It is imperative that the treating surgeon have a high level of suspicion that a stem may be loose and, if confirmed, appropriate implants and special equipment must be available to revise the femoral component.
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