Compared with previous generations, the geriatric population is growing rapidly, with these individuals having prolonged life expectancies and more active lifestyles. Many of these patients have already undergone primary total hip arthroplasty (THA) and are presenting with aseptic loosening, polyethylene wear, osteolysis, or periprosthetic fractures. Therefore, an increasing number of geriatric patients are undergoing revision THA. The demand for hip revision procedures is projected to double by the year 2026.1
Osteolysis from polyethylene wear and proximal femoral bone loss can be a challenging clinical problem, bringing additional complexity to revision THA. Additionally, hip fracture is a serious and costly public health problem. Compared with monoblock stems, modular femoral revision stems offer surgeons the ability to separate the tasks of achieving distal fixation and restoring leg length, offset, and version, which are critical steps in a successful hip reconstruction. One in 2 women and 1 in 4 men older than 50 years will have a fracture related to osteoporosis.2 It is estimated that more than 61 million individuals will be at risk by the year 2020. As the number of hip fractures continues to increase, most patients will heal uneventfully after undergoing open reduction and internal fixation with pinning, cephalomedullary nail, or hemiarthroplasty. However, failures do occur and require a conversion hip surgery, which often requires the use of revision components.3,4 Failed open reduction and internal fixation is a challenging complication of proximal femur fractures. In these cases, modular femoral revision stems can be helpful.
The early results of modular femoral revision systems are promising for the treatment of the deficient proximal femur in complex primary and revision THA, with these components having a 100% survival rate at a mean follow-up of 1.5 to 3.7 years.5 The Arcos Modular Femoral Revision System (Zimmer Biomet, Warsaw, Indiana) offers surgeons the ability to customize both the hip implant and its corresponding instruments (Figure 1).
Arcos Modular Femoral Revision System (Zimmer Biomet, Warsaw, Indiana). (Image courtesy of Zimmer Biomet.)
The primary objective of this retrospective review was to describe survivorship of all Arcos Modular Femoral Revision System implanted components at 2 years and to use the Kaplan–Meier survivorship curve to project survivorship at 60 months. Secondary objectives were to summarize radiographic findings at 2-year survivorship and to measure radiographic subsidence. The authors hypothesized that the Arcos Modular Femoral Revision System would have excellent survivorship at 2 years.
Materials and Methods
This retrospective, single-center study included a cohort of adult patients who underwent revision THA with the Arcos Modular Femoral Revision System between 2010 and 2014 performed by 1 of 3 orthopedic surgeons (R.R.S., A.C.G., W.M.G.) at 1 of 2 urban, community-based teaching hospitals. All patients received follow-up treatment at a single orthopedic practice site. Follow-up data and radiographs were obtained through 2016. After institutional review board approval was obtained, the electronic health records and radiographs of all patients meeting these criteria were reviewed.
Using the diagnostic codes (27132, 27134, 27137, 27138) representing revision of THA, a list of patients surgically treated by the 3 surgeons from 2010 to 2014 was generated by the practice's billing company. This included patients with previous open reduction and internal fixation of the hip that was converted to THA (27132). Using this list, electronic health records from the hospitals and orthopedic practice were reviewed using the Power-Chart (Cerner Corporation, Kansas City, Missouri) and SRSsoft (SRS Software, LLC, Montvale, New Jersey) electronic health record systems, respectively, to validate patient inclusion and collect study data. The patients' radiographs were obtained through the orthopedic practice's picture archiving and communication system to assess availability of essential radiographs and radiographic data collection.
Radiographic review included assessment of bone defect level and radiographic subsidence by an independent reviewer (F.W.P., M.G.R.). Bone defect assessment was based on the Paprosky femoral classification system.6,7 Radiographic subsidence was evaluated via anteroposterior radiographs: 1 obtained immediately after revision surgery and the others at 1- and 2-year follow-up. The most distal cerclage wire or the middle of the lesser trochanter (if there was no metal wire) was used as the reference point. The reference point for the stem was the rim of the component. Calibration of measurements was standardized based on the fixed diameter of the metaphyseal–diaphyseal assembly area of the component (fixed diameter of 19 mm). Measurement of the distance between the femoral reference point and the rim of the stem was calculated on the radiographs, and the difference represented subsidence in millimeters.8,9
Descriptive statistics were calculated for all continuous and categorical data on all patient characteristics. Continuous data were reported as mean±SD, and categorical data were reported as number (percent). The proportion of patients undergoing re-revision with 95% confidence interval was reported. A Kaplan–Meier survival analysis was used to estimate the cumulative incidence of the re-revision of the femoral component for any reason after the first revision of the femoral component for any reason. Radiographic subsidence in millimeters at 1 and 2 years was reported as mean±SD. Interval comparisons were made within patients via paired t test. A 2-tailed P value of .05 was considered statistically significant. Analysis was performed using SPSS for Windows version 22.0 software (IBM Corp, Armonk, New York). On the basis of previously published studies,10,11 the authors anticipated a mean re-revision (second revision) rate, expected proportion (P), of 0.10±0.05 (width=0.10) with a 90% confidence level, which required approximately 98 patient records.12
Fifty-one THA revisions were included in this study. Of the 51 revision procedures, 7 underwent a re-revision THA. Kaplan–Meier survivorship using re-revision for any reason was 86.3% at 60 months (mean follow-up, 24.3±18.5 months; range, 1–64 months). The cumulative incidence of re-revision was 13.7% (95% confidence interval, 4%–23%) (Figure 2). Mean time to re-revision was 4.88±3.9 months. The most common diagnosis for repeat revision was aseptic loosening (3 [42.9%]), followed by infection (2 [28.6%]) and periprosthetic fracture (2 [28.6%]). Three (42.9%) of 7 patients had Paprosky type 3 bone defects. Mean age at re-revision was 68.6±11.2 years. Two patients (28.6%) were male. Mean body mass index was 29.3±8.8 kg/m2. Six patients (85.7%) had right side surgery. All patients underwent posterior surgical approach. There was no significant difference in 1- and 2-year subsidence within patients (P=.224; paired t test) (Table 1). Table 2 outlines individual re-revision patients. Figure 3 and Figure 4 show 5-year revision radiographs for 2 patients who had staged revisions. Figure 3 shows an 83-year-old woman with a Paprosky type 3 bone defect at the time of right-side revision, diagnosed with polyethylene wear and osteolysis. This patient had a well-aligned, well-fixed arthroplasty with no evidence of mechanical complication or wear. Figure 4 shows a 61-year-old man with a Paprosky type 2 bone defect at the time of left-side revision, diagnosed with a resolved infection. The left hip showed an extensive acetabular and femoral revision with solid bone ingrowth and no evidence of mechanical complication or wear.
Kaplan–Meier survival analysis was used to estimate the cumulative incidence of the second revision of the femoral component in all patients after the first revision of the femur component attributable to any reason.
Anteroposterior radiograph of an 83-year-old woman 5 years after staged right total hip arthroplasty revision with the Arcos Modular Femoral Revision System (Zimmer Biomet, Warsaw, Indiana) showing a well-aligned, well-fixed arthroplasty with no evidence of mechanical complication or wear.
Anteroposterior radiograph of a 61-year-old man 5 years after staged left total hip arthroplasty revision with the Arcos Modular Femoral Revision System (Zimmer Biomet, Warsaw, Indiana) with greater trochanter claw plate and screws showing extensive acetabular and femoral revision with solid bone ingrowth and no evidence of mechanical complication or wear.
With the increased prevalence of THA, prolonged life expectancies, and increasing activity, the rates of revision THA are projected to grow exponentially.1 Aseptic loosening, instability, infection, and periprosthetic fractures are all common causes of revision hip surgery.3,4 Failure of revision THA has similar causes and often leads to an increasingly complex re-revision THA. Proximal femoral bone deficiency from polyethylene wear and osteolysis increasingly can complicate revision THA. The authors sought to examine component survivorship for a single modular femoral revision system after initial revision THA. Their secondary objective was to examine radiographic subsidence.
This study showed a component survivorship of 86.3% at 60-month follow-up when estimating the incidence of re-revision THA for any reason after initial revision THA. Two failures occurred due to postoperative periprosthetic femur fracture, 2 occurred due to infection. and 3 occurred due to aseptic femoral component loosening. The mean age at failed revision was 68.6 years. Radiographic review showed a mean subsidence of −0.509 mm at 1 year and −1.022 mm at 2 years, which is comparable with subsidence rates of other revision stems reported in the literature.8 Most (6 of 7) failures of revision THA occurred in patients with a Paprosky type 2 or 3 proximal femoral bone defect.
This study had several limitations. First, this was a retrospective, single-center cohort study with no comparison group, and only 51 patients were included. In addition, the study lacked patient outcome or satisfaction scores. Future prospective, multicenter studies are needed to examine reasons for revision failures, long-term component survivorship, patient-reported outcomes, and radiographic subsidence.
This study showed excellent results for this particular modular femoral revision system. Component survivorship was 93.2% at 60 months when excluding infection and postoperative femur fractures due to falls, and all-included component survivorship was 86.3% at 60 months. This study showed promising early results in survivorship and subsidence for the Arcos Modular Femoral Revision System.
- Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007;89(4):780–785.
- Andersson GBJ, Bouchard J, Bozic KJ, et al. Osteoporosis and bone health. In: American Academy of Orthopaedic Surgeons, ed. The Burden of Musculoskeletal Diseases in the United States: Prevalence, Societal and Economic Cost. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2008:97–122.
- Kyle RF, Cabanela ME, Russell TA, et al. Fractures of the proximal part of the femur. Instr Course Lect. 1995;44:227–253.
- Kyle RF, Gustilo RB, Premer RF. Analysis of six hundred and twenty-two intertrochanteric hip fractures. J Bone Joint Surg Am. 1979;61(2):216–221. doi:10.2106/00004623-197961020-00009 [CrossRef]
- Frye BM, Berend KR, Morris MJ, Adams JB, Lombardi AV Jr, . Modular femoral tapered revision stems in total hip arthroplasty. JISRF. 2013;3(3):32–37.
- Telleria JJM, Gee AO. Classifications in brief: Paprosky classification of acetabular bone loss. Clin Orthop Relat Res. 2013;471(11):3725–3730. doi:10.1007/s11999-013-3264-4 [CrossRef]
- Paprosky WG, Perona PG, Lawrence JM. Acetabular defect classification and surgical reconstruction in revision arthroplasty: a 6-year follow-up evaluation. J Arthroplasty. 1994;9(1):33–44. doi:10.1016/0883-5403(94)90135-X [CrossRef]
- Girard O, Roche O, Wavreille G, Canovas F, Le Béguec P. Stem subsidence after total hip revision: 183 cases at 5.9 years follow-up. Orthop Traumatol Surg Res. 2011;97(2):121–126. doi:10.1016/j.otsr.2010.10.006 [CrossRef]
- Loudon JR, Charnley J. Subsidence of the femoral prosthesis in total hip replacement in relation to the design of the stem. J Bone Joint Surg Br. 1980;62(4):450–453. doi:10.1302/0301-620X.62B4.7430222 [CrossRef]
- Ong KL, Lau E, Suggs J, Kurtz SM, Manley MT. Risk of subsequent revision after primary and revision total joint arthroplasty. Clin Orthop Relat Res. 2010;468(11):3070–3076. doi:10.1007/s11999-010-1399-0 [CrossRef]
- Wong JM, Liu YL, Graves S, de Steiger R. What is the rerevision rate after revising a hip resurfacing arthroplasty? Analysis from the AOANJRR. Clin Orthop Relat Res. 2015;473(11):3458–3464. doi:10.1007/s11999-015-4215-z [CrossRef]
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|Characteristic||First Revision (N=51)||Second Revision (N=7)|
|Age at surgery, mean±SD, y||70.4±11.8||68.6±11.2|
|Male, No. (%)||30 (58.8)||2 (28.6)|
|Body mass index, mean±SD, kg/m2||29.6±6.6||29.3±8.8|
|Right side, No. (%)||30 (58.8)||6 (85.7)|
|Revision diagnosis, No. (%)|
| Aseptic loosening||20 (39.2)||3 (42.9)|
| Periprosthetic fracture||14 (27.5)||2 (28.6)|
| Infection||8 (15.7)||2 (28.6)|
| Implant failure||2 (3.9)|
| Other||7 (13.7)|
|Posterior approach, No. (%)||47 (92.2)||7 (100.0)|
|1-year subsidence, mean±SD, mm||−0.509±4.04b||-c|
|2-year subsidence, mean±SD, mm||−1.022±6.9b||-|
|Paprosky bone defect classification, No. (%)|
| Mild (1)||14 (27.5)||1 (14.3)|
| Moderate (2)||21 (41.2)||3 (42.9)|
| Severe (3)||16 (31.4)||3 (42.9)|
| Follow-up, mean±SD, mo||24.3±18.5||5.29±4.3|
|Patient No./Sex/Age, y||Body Mass Index, kg/m2||Side||Diagnosis||Paprosky Bone Defect Classification||Approach||Time to Re-revision, mo|