International Orthopaedics (SICOT) (2014) 38:2469–2472 DOI 10.1007/s00264-014-2464-1

ORIGINAL PAPER

Clinical and radiological results of patients treated with orthogonal double plating for periprosthetic femoral fractures Franz Josef Müller & Michael Galler & Bernd Füchtmeier

Received: 11 May 2014 / Accepted: 8 July 2014 / Published online: 12 August 2014 # SICOT aisbl 2014

Abstract Purpose The aim of this study was to determine the outcome of surgically-treated periprosthetic femoral fractures with an orthogonal double plate system. Methods We performed a retrospective study of ten patients (mean age 79.5 years) surgically treated for periprosthetic femoral fractures using orthogonal double plating (lateral and additional anterior plate position) from 2010 to 2013. The patients’ demographic characteristics, complications and initial follow-up data were retrieved from our institutional database. After a minimum of six months post-surgery, we performed a radiological and clinical follow-up. Results The surgical indications for orthogonal plating were heterogenic; five patients were treated for periprosthetic fractures around their total hip prosthesis. One was treated for a fracture around a total knee prosthesis and one for an interprosthetic fracture. Additionally, three patients were treated for postoperative implant failure after the stabilisation of periprosthetic fractures around a total hip prosthesis (one) or total knee prosthesis (two). Osteosynthesis was performed using locking compression plates exclusively (length between eight and 20 holes). After a mean follow-up of 22.6 months (range, six to 42 months), two patients died, but their deaths were due to old age morbidity and were unrelated to the surgery. Surgical revision for implant failure was necessary for only one female patient due to a breakage of the lateral plate. In addition, no other failures, such as infection or non-union, were observed. At the time of follow-up, seven out of ten patients were mobile and subjectively satisfied in regards to their outcome. Conclusions Based on a small number of cases, we were able to show for the first time that the use of orthogonal double F. J. Müller (*) : M. Galler : B. Füchtmeier Clinic for Trauma, Orthopaedics and Sports Medicine, Hospital Barmherzige Brüder, 93049 Regensburg, Germany e-mail: [email protected]

plating is not associated with an increased rate of complications in patients with periprosthetic femoral fractures and stable components. Moreover, orthogonal double plating can be used successfully as a salvage procedure. At the time of follow up, seven out of ten patients were mobile. More cases must be investigated to validate our findings. Keywords Periprosthetic femoral fracture . Osteosynthesis . Double plate

Introduction Periprosthetic femoral fractures in patients with hip implants in situ are commonly classified using the Vancouver classification system [1], which allows an algorithm of treatment options to be derived [2]. Generally, osteosynthesis can be performed in cases of solid bony integration of the femoral component (well-fixed femoral component) (type B1 or C), and revision arthroplasty can be performed in patients with loose femoral components (type B2, B3) [3–6]. For periprosthetic fractures in patients with total knee arthroplasty, the classifications suggested by Su et al. [7] and Rorabeck et al. [8] can be used, though they do not take into account the modularity of the primary and revision prostheses. In regards to osteosynthesis, different locking plate systems (e.g., NBC®, LISS®, LCP®) are used for the stabilisation of femoral fractures, and they are usually positioned on the lateral side. However, the osteosynthesis of periprosthetic femoral fractures may be unstable during the procedure despite a stable stem component and the use of additional wires or cables. In such cases, the additional attachment of an anterior plate may help to achieve increased primary stability at a sufficient level as has been shown in biomechanical tests [9, 10]. This arrangement of the plates at a 90° angle from each other is also called “orthogonal” alignment.

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To the best of our knowledge, previous studies reported results with orthogonal plating for intra-articular distal femoral fractures but not periprosthetic femoral fractures [11, 12]. Thus, the primary objective of this study was to evaluate clinical data after orthogonal double plating in patients with periprosthetic femoral fractures.

Patients and methods In our periprosthetic fracture registry, all surgical procedures have been prospectively documented via computer, which allows for the collection of data for specific operations at any time. The inclusion criterion for this study was the use of orthogonal double plating in patients with periprosthetic femoral fractures, including interprosthetic femoral fractures. The exclusion criteria were the presence of infections or pathological fractures due to tumours. Based on these criteria, we were able to enroll a total of ten patients from 2010 to 2013. Initially, descriptive data, such as gender, age, and implanted components (Table 1) were retrieved for the retrospective study with an evidence level of 4. Diagnostic imaging data were also available in an electronic database archive. Possible hip dislocation, haematoseroma and impaired wound healing with or without infection were considered directly dependent complications. Moreover, non-union or delayed union as well as implant failure or the need for any surgical revision were considered failures. Additionally, we documented mortality. A clinical and radiological follow-up in our outpatient department was conducted at least six months post-surgery. The study was approved by our institutional review board, and the patients gave their informed consent prior to their inclusion in the study. Because of the small number of cases, no statistical analysis was performed.

Results The retrospective analysis identified a total of ten patients between 1/1/2010 and 31/12/2013. There were seven female and three male patients with a mean age of 79.5 years (range 55–91 years) at the time of their orthogonal double plating surgery. In five cases, the right or left femur was affected. In all cases, the fracture had been caused by falling to the ground, and all of these fractures presented as isolated injuries. The initial indication for the implantation of the primary prosthesis was coxarthrosis in seven patients and gonarthrosis in three patients. The mean interval between index prosthesis implantation and periprosthetic fracture was 103 months (range four to 312 months). The surgical indication for orthogonal plating was heterogenic, namely, five patients were treated for fractures around a total hip prosthesis. One was treated for a fracture around a total knee prosthesis and one for an interprosthetic fracture (Fig. 1a–d). Moreover, three patients were treated for implant failure after the stabilisation of periprosthetic fractures around a total hip prosthesis (one) or total knee prosthesis (two) (Table 1) due to the use of lateral plating alone. All three patients with implant failures (patient numbers 1, 8 and 10 within Table 1) were initially treated outside our facility. In all cases, stable components were observed; seven patients had uncemented and three had cemented components. Double plating was performed exclusively using fixedangle implants, which were positioned in a 90° alignment (primary lateral und secondary anterior) (Table 1). The indication of orthogonal double plating was individually determined by the surgeon during the procedure as follows: if C-arm imaging indicated medial instability upon manual stress (increase of the fracture gap by at least 2 mm) following lateral femoral plating, an additional anterior plate was indicated. In every case, a different

Table 1 Descriptive data and outcome of the ten study patients Patient number

Age (years)

Sex

Femoral implant; classification of fracture type

Lateral plating

Anterior plating

Outcome at follow up

1 2

89 87

Female Female

13 NCB 18 LCP

10 LCP 12 LCP

Alive, full weight bearing Alive, full weight bearing,

3 4 5 6 7 8 9 10

88 87 66 90 91 65 55 77

Male Female Female Female Male Female Male Female

TKA; SU 2 TKA and THA; interprosthetic fracture Vancouver C THA; Vancouver B1 THA; Vancouver B1 THA; Vancouver B1 THA; Vancouver C TKA; SU 2 THA; Vancouver C THA; Vancouver B1 TKA; SU 2

20 LCP 16 LCP 20 LCP 15 NCB 20 LCP 13 LISS 20 LCP 15 LISS

10 LCP 14 LCP 10 LCP 10 LCP 10 LCP 12 LCP 8 LCP 12 LCP

Alive, full weight bearing Alive, full weight bearing Alive, full weight bearing Dead, 53rd day postop; ileus Dead, 69th day postop; heart failure Revision, 348th day due to implant failure Alive, full weight bearing Alive, full weight bearing

TKA total knee arthroplasty, THA total hip arthroplasty

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patient) died 53 days post-surgery due to intestinal adhesions/bowel obstruction (Table 1). None of the patients needed surgical revision due to haematoseroma, impaired wound healing or infection. However, one implant failure with a lateral plate break occurred in a female patient who was abusing nicotine and alcohol and necessitated surgical knee revision arthroplasty 348 days postsurgery. Therefore, seven out of ten patients presented with the femoral double plating in situ at the time of follow-up. At follow-up visits in the outpatient department, after a mean period of 22.6 months post-surgery (range six to 42 months), those seven patients presented with radiologically confirmed bony consolidation with the repaired extremity bearing their full weight. All patients were subjectively satisfied with their clinical outcome. Therefore, seven out ten patients (70 %) showed excellent results according to Beals and Tower [13].

Discussion

Fig. 1 a Native radiographic view of 87-year-old female patient (Table 1, patient number 2) with interprosthetic femoral fracture, both primary stems are cementless, and there are no signs of implant loosening. b Native radiographic lateral view of the interprosthetic femoral fracture. c Postoperative native radiographic view shows stabilisation of interprosthetic femoral fracture with orthogonal double plating (lateral 18 hole LCP, anterior 12 hole LCP, additionally five cables). d Native radiographic view 23 months postoperatively demonstrates complete fracture consolidation

number of wires or cables (one to five) were used in addition to double plating. Additional allografts (e.g., strut grafts) or autografts were not used in any cases. The mean duration of surgery was 208 min (range 115–320 min). A total of two out of ten patients had deceased at the time of the retrospective follow-up; the eldest patient in the study (and the only one suffering from severe dementia) died 69 days post-surgery, and the second eldest (a 90-year-old female

To the best of our knowledge, this retrospective study with an evidence level of 4 is the first to provide clinical and radiological results on the surgical treatment of periprosthetic femoral fractures stabilised using orthogonal double plating. Only fixed-angle plate systems were used for these procedures. It is generally accepted that B1- and C-type fractures (according to the Vancouver classification) with a hip arthroplasty in situ, i.e., with stable stem components, represent an indication for osteosynthesis [3, 4]. The same procedure may be used for periprosthetic distal femoral fractures with a knee arthroplasty in situ as well as for interprosthetic fractures [14]. Our algorithm also states to perform osteosynthesis in patients with stable stems only. Therefore, it should be emphasised that all ten patients presented with radiologically and clinically stable intramedullary components. Biomechanical testing has shown that additional cables should be used to support fixed-angle osteosynthesis—particularly in patients with osteoporotic bones—in order to increase primary stability [15]. In patients with a good bone structure, the positioning of the plating at the lateral femur is usually sufficient; thus, that is the standard procedure. However, the optimal plate length is still unclear. Several recent studies have shown that longer implants should be selected, possibly even extending over the entire femur [16]. In our procedures, we usually test osteosynthesis stability in patients with radiologically confirmed cortical thinning under C-arm imaging by applying manual valgus stress to the femur via the lateral plating; there is no prior evidence for the effectiveness of this test. If a medial elastic increase of the fracture gap of at least 2 mm is observed, we consider this an indication for increasing stability using additional anterior fixed-angle plating.

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It must be emphasised, however, that the majority of our patients treated within this period received only lateral locking plates for stabilisation of their periprosthetic femoral fractures. Primary femoral stability can be achieved using other techniques [17, 18]. There is some evidence supporting the use of an additional attachment of so-called cortical allograft struts to the femur [19]. However, sufficient data in regards to the appropriate size of those struts and possible risks associated with their use—such as increased rates of necrosis and infections—are currently unavailable. Thus, we have not yet used these strut grafts. Furthermore, the amount of distal and proximal bi- or mono-cortical bolts of fixed-angle implants which plays a role in stability has not yet been sufficiently evaluated. This also applies to the use of additional cables, wires or claws. From our point of view, however, additional cables or wires are essential and were used in all of our patients. It is also important to identify the weaknesses of our retrospective study. The evidence level is low (level 4), the number of cases in this heterogenic population is small, and the results are based on short- to medium-term observations. With regard to the bone structure, it remains unclear when orthogonal double plating is truly indicated and when lateral plating alone offers sufficient primary stability during the bone healing period.

Conclusions Based on a small number of cases, we were able to show radiologically and clinically that the use of orthogonal double plating in patients with periprosthetic femoral fractures with well-fixed femoral components is not associated with an increased rate of complications. Additionally, it is a successful salvage procedure after implant failure. In individual cases, one may decide to perform an additional anterior plating for increased stability and to counteract any possible postoperative implant failures. More cases must be investigated to increase the validity of these results.

Conflicts of interest No outside funding was received in support of this research or in the preparation of this article. Neither author has received financial or any other support relevant to the implant used in this study or in this study’s preparation. The authors declare that they have no conflict of interest.

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