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Revision Total Hip Arthroplasty Using a Modular Femoral Implant in Paprosky Type III and IV Femoral Bone Loss
The Journal of Arthroplasty Vol. 27 No. 8 2012
Revision Total Hip Arthroplasty Using a Modular Femoral Implant in Paprosky Type III and IV Femoral Bone Loss Rasesh R. Desai, MD,* Arthur L. Malkani, MD,* Kirby D. Hitt, MD,y Fredrick F. Jaffe, MD,z John R. Schurman II, MD,§ and Jianhua Shen, MS‖
Abstract: The purpose of this study was to compare results of patients with Paprosky type I and II femoral defects vs type IIIA, IIIB, and IV defects in patients undergoing revision hip arthroplasty. There were 64 patients in the group with type I and II defects with an average age of 68 years. There were 52 patients with Paprosky type IIIA, IIIB, and IV defects with an average age of 67 years. There were 8 intraoperative fractures in the type III and IV group, whereas there were 9 in the type I and II group. There were no differences between the 2 groups with respect to subsidence, loosening, dislocation, infection, and medical complications. Survivorship for the whole group was 96.9% at 5 years. Modular femoral implants provide several intraoperative options to restore leg length, offset, and stability despite femoral defects. We did not realize a higher failure rate in patients with type III or IV defects. Keywords: revision THA, Paprosky type III and IV defect, modular femoral stem. © 2012 Elsevier Inc. All rights reserved.
With the increase in number of total hip arthroplasties performed in United States, the number of revisions performed is also on the rise. The rate of primary total hip arthroplasties have increased by approximately 50% per 100 000 persons from 1990 to 2002, whereas revision total hip arthroplasties have increased by approximately 3.7 procedures per 100 000 persons per decade [1]. Revision of the femoral component can be a challenging problem for a surgeon especially when there is significant bone loss and poor bone quality. The goals of the revision surgery are to alleviate the pain and provide stable fixation of the revision stem and restore joint mechanics. Della Valle and Paprosky [2] developed a classification scheme and an algorithmic approach to the reconstruction of femoral deficiency in revision total hip arthroplasty. Depending on the extent of the femoral bone loss, different surgical options are available for implant fixation including long stem with or without From the *Department of Orthopaedic Surgery, University of Louisville, Louisville, Kentucky; yScott and White Clinic, Temple, Texas; zNYU Hospital for Joint Diseases, New York, New York; §Advanced Orthopedic Associates PA, Wichita, Kansas; and ‖Stryker Orthopaedics, Mahwah, New Jersey. Submitted May 4, 2011; accepted March 19, 2012. Supplementary material available at www.arthroplastyjournal.org. The Conflict of Interest statement associated with this article can be found at doi:10.1016/j.arth.2012.03.039. Reprint requests: Arthur L. Malkani, MD, Department of Orthopaedic Surgery, 210 E. Gray Street, Suite 1003, Louisville, KY 40202. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2708-0013$36.00/0 doi:10.1016/j.arth.2012.03.039
calcar replacement cemented implants [3]; porous, extensively coated implants [4]; modular, extensively coated, or fluted stems [5], impaction grafting [6]; allograft-prosthetic composites [7]; or tumor type mega prosthesis [8]. Modular femoral stems are gaining popularity especially for the Paprosky type II, III, or IV defects. Modular stems allow independent sizing in the metaphyseal/ diaphyseal component, variable stem-to-neck length options, and option of change in the version and offset. Although there are studies published on outcomes of modular femoral implants on revision total hip arthroplasty [9,10], there are very few studies that focus on the results of modular femoral implants with Paprosky type III or IV severe femoral bone loss [11]. The purpose of this study was to compare the clinical and radiographic results of Paprosky types I and II defects to type III and IV defects from a multicenter prospective database of patients undergoing femoral component revision with a modular femoral implant.
Materials and Methods The data from this study were obtained from a prospective, multicenter, institutional review board– approved study from 13 centers evaluating the use of a Restoration modular implant (Stryker, Mahwah, NJ) in patients undergoing revision total hip arthroplasty. There were a total of 64 patients with type I and type II Paprosky bone loss with an average age of 68 years
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Table 1. Patient Demographics Characteristic Gender Males Females Age (y) Weight (lb) Height (in) Body mass index (kg/m2) No. of previous joint surgery 1 2 3 N3 Diagnosis Osteoarthritis Rheumatoid arthritis Post-traumatic arthritis Avascular necrosis Other
Type 1 and 2 Group (n = 64)
Type 3A, 3B, and 4 Group (n = 52)
50% 50% 68.05 ± 11.82 (range, 41-85 y) 174.73 ± 41.14 66.65 ± 3.53 27.49 ± 5.20
48% 52% 67.56 ± 11.85 (range, 43-85 y) 175.5 ± 44.53 65.96 ± 5.00 28.32 ± 6.38
84.38% 12.50% 0% 3.13%
61.54% 25.00% 8% 5.77%
54.70% 4.70% 4.70% 14.00% 21.90%
48.08% 7.69% 13.46% 5.77% 25.00%
and an average body mass index of 28. All cases were enrolled to the study from March 11, 2004, to March 27, 2007. There were 52 patients with Paprosky III and IV defects: 34 patients (65.3%) were classified as Paprosky type IIIA defect; 13 (25%), with Paprosky type III B defect; and 5 (9.6%), with Paprosky type IV defects. Baseline characteristics and surgical details were summarized and compared between groups using Wilcoxon rank sum test for non–normally distributed numerical data or χ 2 test for discrete data. All P values were 2 tailed, and a P value of .05 or less was considered to be statistically significant. SAS/STAT software version 9.1.3 (SAS Institute, Cary, NC) was used for all data analyses (Tables 1, 2 and 3). Patients had follow-up at 6 weeks, 3 months, 1 year, 2 years, and 5 years. Standard pelvis anteroposterior (AP) as well as AP and lateral radiographs of the affected hip
Statistical Test
Significance
χ2
P = .84
Wilcoxon rank sum test
P = .90
Wilcoxon rank sum test Wilcoxon rank sum test Wilcoxon rank sum test χ2
P = .93 P = .24 P = .51 P = .02
χ2
P = .26
were taken at follow-up visits for evaluation. Subsidence was determined by measuring the distance between a fixed point on the stem (body-stem junction) and a fixed bony point on femur. A difference of 3 mm or more in the measured distance between the immediate postoperative radiograph and the radiograph taken at the latest follow-up was considered as subsidence [9,12]. Surgical Technique Preoperative planning included radiographic assessment of femoral bone loss and templating to achieve the desired leg length and offset. Extended trochanteric osteotomy was performed in 18 cases (34.6%) in the type III and IV cases and 15 extended trochanteric osteotomies in the type I and II group. Posterior approach was used in 22 patients, and direct lateral approach, in 30 patients. A Restoration Modular Revision Hip System
Table 2. Surgical Data Characteristic Approach Anterolateral Posterior Duration of surgery (min) Estimated blood loss (mL)
Type 1 and 2 Group Type 3A, 3B, and 4 Group
Statistical Test χ2
42.20% 57.80% 154.95 ± 54.88 (range, 60-331) 729.33 ± 499.90 (range, 150-3000)
Was an attempt made to correct leg length? Yes 81.25% No 18.75% Correct leg length (amount attempted in millimeters) 12.94 ± 6.98 (range, 0.3-34) Correct leg length (amount achieved in millimeters) 11.92± 6.49 (range, 0.3-28) Stem inserted: (bone graft used) Yes 26.56% No 73.44%
57.70% 42.30% 194.52 ± 69.10 (range, 50-385) 1240.77 ± 1206.61 (range, 20-6000)
Wilcoxon rank sum test P b .01 P = .41
Wilcoxon rank sum test P = .04 Wilcoxon rank sum test P = .01 χ2
59.62% 40.38%
P = .01
Wilcoxon rank sum test P b .01
χ2 84.62% 13.46% 19.7 ± 14.38 (range, 0.5-63) 19.03 ± 13.68 (range, 0.5-63)
Significance
P b .01
1494 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 Table 3. Results (Harris Hip Score)
Visits Preoperative 6 wk 3 mo 1y 2y 5y Mean length of follow-up (y)
Type 1 and 2 Group (Mean Length of Follow-Up = 2.2 y)
Type 3A, 3B, and 4 Group (Mean Length of Follow-Up = 2.1 y)
47.62 62.71 73.29 87.06 86.98 83.89 2.2
43.44 63.14 74.82 85.33 84.03 84 2.1
used (Fig. 2A and B). A tapered stem was commonly used (Table 4). In Paprosky type I and II defects, a modular tapered fluted stem was used in 80% of the cases, whereas in type III and IV defects, the usage was 73%. In most cases, the medullary canal was first reamed with flexible reamers to remove debris and sclerotic bone. Rigid reamers were then used to obtain cortical contact. When plasma-sprayed cylindrical stems were used, the femoral canal was underreamed by 0.5 to 1 mm. When fluted tapered stems were inserted, conical reamers with line-to-line reaming were used. Cables were used for fixation of strut grafts, repair of extended trochanteric osteotomies, or fixation of intraoperative fractures. Allografts were used in 24 cases, and autografts, in 7 cases.
Results
(Stryker) was used in all the cases (Fig. 1A and B). Depending on the quality of the proximal bone, either porous-coated cylindrical or tapered fluted stem were
Fig. 1. (A) Restoration modular femoral implant with a cone body and conical tapered stem. (B) Restoration modular femoral stem with cone body and cylindrical plasma stem.
The mean follow-up in type I and II was 3.5 years (range, 2-5.8 years), and the mean follow-up in types III and IV group was 3.8 years (range, 2-5.7 years). In the Paprosky type I and II group, the average preoperative Harris Hip Score was 48 points, which improved to 84 points at latest follow-up. In Paprosky type III and IV defects, the average preoperative Harris Hip Score was 43 points, which improved to 84 points at latest followup. The duration of surgery in the group with type I and II defects was 155 vs 195 minutes in type III and IV defects (P b .01). The estimated blood loss in type I and II defects was 729 mL, whereas in type III and IV defects, the blood loss was 1240 mL (P b .01). The desired leglength correction in type III and IV defects was greater than the amount required in types I and II defects (P b .05). There were a total of 8 (15.3%) intraoperative periprosthetic fractures in the Paprosky type III and IV group. Of these fractures, 5 were femoral shaft fractures and 3 trochanteric fractures. Of the 8 fractures in the Paprosky type III and IV group, 3 were also in the extended trochanteric osteotomy (ETO) group. In the Paprosky type I and II group, there were 5 femoral shaft fractures and 4 trochanteric fractures. Of the 9 fractures in the type I and II groups, 5 were also in the ETO group. In the type III and IV group, there were 2 superficial wound infections and 2 hematomas; 3 patients had other wound-related problems; and there were 2 deep infections requiring irrigation, debridement, and exchange of the polyethylene liner and femoral head. Subsidence occurred in 1 patient in the group with type III and IV defects, which was clinically asymptomatic. There were no cases of aseptic femoral component loosening for the type III and IV group, but there was 1 loosening in those with type I and II bone defects. There were 3 dislocations in each group, and in those with type III and IV defects, 2 of them required closed reduction and bracing, whereas 1 underwent open operative treatment of a greater trochanteric fracture along with an acetabular liner exchange due to recurrent dislocation.
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Fig. 2. (A) Preoperative AP hip with loose femoral component with type III Paprosky bone loss extending into diaphysis. (B) Postoperative AP hip with 3-year follow-up demonstrating stable distal fixation.
Overall, in type III and IV defects, there were a total of 3 reoperations including 2 for deep joint infection and 1 for open reduction internal fixation (ORIF) of a trochanteric fracture and instability. The overall incidence of reoperation in the type III and IV group was 5.7%, which was similar to the group with type I and II bone defects. Overall survivorship using the Kaplan-Meier method analysis in groups with type I and II defects was 94.36% at 5 years, whereas in the type III and IV defects, it was 100%.
Discussion Femoral component revision poses a challenging problem primarily because of compromised soft tissue and bone deficiency encountered at the time of revision. Because of the proximal bone loss at the time of femoral component revision, distal fixation has been advocated providing more predictable results [13]. The advantages of modular femoral implants with distal fixation include intraoperative versatility that allows the surgeon to use the appropriate size of distal stems for diaphyseal fixation and appropriate sizes of proximal bodies that can best fit and fill the metaphysis. The proximal metaphyseal body is porous coated, which promotes ingrowth, and proximal loading, which can potentially minimize proximal stress shielding as well as decrease the stresses placed on the morse taper junction [14]. Modularity also provides a variety of stem and neck length options to restore leg length and offset, which also helps to restore mechanics. Such intraoperative customization has led to the increasing popularity of
modular femoral stems for femoral component revision. There have been disadvantages through the use of modular femoral implants such as high stresses at the taper junction leading to fracture of the first-generation modular implants, which has led to design changes and biomechanical improvements leading to a second generation of modular femoral implants, which is the subject of this study [15,16]. Results of proximally coated monobloc stems for femoral component revision have demonstrated higher failure rates as compared with modular stems. Mulliken et al [17] reported 10% revision rate at 4 to 6 years of follow-up. Malkani et al [18] reported 8.7% revision rate in 69 patients at midterm follow-up. Woolson and Delaney et al [19], in their study of 28 hips, reported a 20% revision rate and 45% mechanical failure rate. There are several studies demonstrating success of modular femoral implants in revision surgeries [9,10,2024] (Table 5; available online at www.arthroplastyjournal. org). Garbuz et al [25] compared modular fluted and tapered titanium stems with cylindrical extensively coated cobalt chrome stems with single modularity. At follow-up, all quality of life measures favored the modular titanium stems. Koster et al [24] showed 96% survival rate with aseptic loosening as an end point over an average of 10 years for a modular uncemented revision stem. Christie et al [10] noted approximately 99% survival rate from revision with a modular femoral stem. Several other studies [21,23,26] also have reported a high midterm success rate.
1496 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 Table 4. Restoration Modular Stem and Body Type Used Stem type
Body type
Bone Type 1 and 2 (n = 64)
Bone Type 3A, 3B and 4 (n = 52)
12 50 1 1 58 5 0 1
14 37 1 0 47 2 3 0
Plasma Conical Fluted Other Cone Broached Calcar Other
However, the survival of the modular stems also depends on the degree or severity of the bone defects. McCarthy and Lee [11] retrospectively reviewed 92 hips that underwent revision surgery with proximally coated modular femoral component and demonstrated that there was no aseptic loosening in Paprosky type II and III
A group at mean follow-up of 14 years. However, there was 9% failure rate because of aseptic loosening in Paprosky type III B and IV group. Kwong et al [20] reported their experience with modular distal fixation option for proximal femoral bone loss. Their series consisted of 143 patients. In this series, 70% of the
Revision Hip Arthroplasty Using a Modular Femoral Implant Desai et al
patients were Mallory type III, and 25% were type II. At average follow-up of 40 months, the survival rate was 97.2%. Sporer and Paprosky [13] noted that 2 (18%) of 11 Paprosky type III B and 3 (37.5%) of 8 patients with Paprosky type IV defects had to be revised because of failure suggesting risk of higher failure rates in such patients. The risk of failure was greater in patients with femoral stem diameters greater than 19 mm. The purpose of our study was to specifically review and compare the clinical and radiologic outcomes in patients undergoing femoral component revision with Paprosky type I and II defects vs type III and IV defects using modular femoral stems. We used the Restoration Modular Hip System (Stryker) in all patients. There were no cases of aseptic femoral component loosening at latest follow-up in the type III and IV group, whereas there was one case in the type I and II groups. However, there were 8 cases of intraoperative fractures of 52 patients (15.3%) in the type III and IV group. Of the fractures, 5 involved the femoral shaft. Some of the other studies in literature have also reported high intraoperative fracture rates in femoral component revision. Mulliken et al reported a 40% intraoperative fracture rate [17]. Christie et al [10] reported 22.5% intraoperative fracture rate. The patients in this series were a high-risk group with type III and IV femoral bone defects. We felt that our fracture incidence would lead to a higher overall failure rate. We were surprised that despite having intraoperative fractures, the implants were still able to obtain biologic ingrowth. From our experience, we recommend the use of prophylactic cerclage cables in patients with poor bone quality before reaming and distal fixation. Dislocation is a common complication after revision total hip arthroplasty. The incidence of dislocation has been reported in the literature from 4% to 25% after revision hip arthroplasty because of several reasons including compromised soft tissue [13]. In this current series, with a difficult group of patients undergoing femoral component revision, we feel that the dislocation was minimized given the ability of the modular femoral hip system to provide optimum offset, leg length, and fixation using the various sizes available. In addition, the use of large head sizes also, in all likelihood, played a role in minimizing dislocation [27]. In addition to trying to obtain the maximum canal fit, fixation can lead to a fracture, and undersizing can lead to subsidence. In those deficiencies where a patulous femoral canal is encountered with thin cortical bone, impaction grafting may be a reasonable option vs distal fixation to minimize the incidence of fracture. Pierson et al [15] reported on a series of 40 cases of fracture at the modular junction. However, with current design implants, the biomechanical properties of the morse taper junction have been significantly improved with the use of nitride impregnation, burnishing, and
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shot peening [16]. There was no case of modular junction failure in our series. There are several limitations to our study. This was a prospective multicenter study with different surgeons bringing their own surgical technique, experience, and perspective, which introduces a significant variable. The size of the cohort is relatively small, patients were not randomized, and the results are short term. This series is different from other revision hip arthroplasty studies looking at modular implants because it specifically concentrates on a difficult group of patients, those with type III and IV defects and comparing them to type I and II defects. We are encouraged with the clinical results of this study with the ability of this implant system to help restore offset and achieve leg-length correction in 91% of patients. In conclusion, based on our series, we feel that modular implants for femoral component revision provide excellent results with respect to achieving leglength, offset, version, and implant stability. Fixation can be reproducibly achieved despite Paprosky type III and IV defects. However, greater attention and work needs to be undertaken to minimize the rate of complications and, specifically, intraoperative fractures. Modular femoral implants do have limitations; and in those patients with a large patulous femoral canal, alternative implant options such as impaction grafting may need to be considered.
References 1. Kurtz S, Mowat F, Ong K, et al. Prevalence of primary and revision total hip and knee arthroplasty in the United States from 1990 through 2002. J Bone Joint Surg Am 2005;87:1487. 2. Della Valle CJ, Paprosky WG. Classification and an algorithmic approach to the reconstruction of femoral deficiency in revision total hip arthroplasty. J Bone Joint Surg Am 2003;85-A(Suppl 4):1. 3. Gramkow J, Jensen TH, Varmarken JE, et al. Long-term results after cemented revision of the femoral component in total hip arthroplasty. J Arthroplasty 2001;16:777. 4. Engh Jr CA, Ellis TJ, Koralewicz LM, et al. Extensively porous-coated femoral revision for severe femoral bone loss: minimum 10-year follow-up. J Arthroplasty 2002;17:955. 5. Sporer SM, Paprosky WG. Femoral fixation in the face of considerable bone loss: the use of modular stems. Clin Orthop Relat Res 2004;429:227. 6. Hostner J, Hultmark P, Karrholm J, et al. Impaction technique and graft treatment in revisions of the femoral component: laboratory studies and clinical validation. J Arthroplasty 2001;16:76. 7. Blackley HR, Davis AM, Hutchison CR, et al. Proximal femoral allograft for reconstruction of bone stock in revision arthroplasty of the hip. A nine to fifteen-year follow-up. J Bone Joint Surg Am 2001;83-A:346. 8. Malkani AL, Settecerri JJ, Sim FH, et al. Long-term results of proximal femoral replacement for non-neoplastic disorders. J Bone Joint Surg Br 1995;77:351.
1498 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 9. Kang MN, Huddleston JI, Hwang K, et al. Early outcome of a modular femoral component in revision total hip arthroplasty. J Arthroplasty 2008;23:220. 10. Christie MJ, DeBoer DK, Tingstad EM, et al. Clinical experience with a modular non- cemented femoral component in revision total hip arthroplasty: 4- to 7-year results. J Arthroplasty 2000;15:840. 11. McCarthy JC, Lee JA. Complex revision total hip arthroplasty with modular stems at a mean of 14 years. Clin Orthop Relat Res 2007;465:166. 12. Callaghan JJ, Salvati EA, Pellicci PM, et al. Results of revision for mechanical failure after cemented total hip replacement, 1979 to 1982. A two to five years follow up. JBJS Am 1985;67:1074. 13. Sporer SM, Paprosky WG. Revision total hip arthroplasty: the limits of fully coated stems. Clin Orthop Relat Res 2003;417:203. 14. Hnat WP, Conway JS, Malkani AL, et al. The effect of modular tapered fluted stems on proximal stress shielding in the human femur. J Arthroplasty 2009;24:957. 15. Pierson JL, Crowninshield RD, Earles DR. Fatigue fracture of a modular revision femoral component: a report of forty cases. Annual Meeting, February; Am Acad Orthop Surg, Washington, DC; 2005. 16. Malkani AL, Yakkanti MR. In: Hozack WJ, Parvisi J, Bendon B, editors. Surgical options for femoral reconstruction: the use of modular stems in surgical treatment of hip arthritis: reconstruction, replacement and revision. Philadelphia (Pa): Saunders Elsevier; 2010; p. 318. 17. Mulliken BD, Rorabeck CH, Bourne RB. Uncemented revision total hip arthroplasty: a 4-to-6-year review. Clin Orthop Relat Res 1996;325:156. 18. Malkani AL, Lewallen DG, Cabanela ME, et al. Femoral component revision using an uncemented, proximally
19.
20.
21.
22.
23.
24.
25.
26.
27.
coated, long-stem prosthesis. J Arthroplasty 1996;11: 411. Woolson ST, Delaney TJ. Failure of a proximally porouscoated femoral prosthesis in revision total hip arthroplasty. J Arthroplasty 1995;10(Suppl):S22. Kwong LM, Miller AJ, Lubinus P. A modular distal fixation option for proximal bone loss in revision total hip arthroplasty: a 2- to 6-year follow-up study. J Arthroplasty 2003;18(3 Suppl 1):94. Rodriguez J, Fada R, Murphy SB, et al. Two-year to fiveyear follow up of femoral defects in femoral revision treated with the Link MP modular stem. J Arthroplasty 2009;24:751. Wirtz DC, Heller KD, Holzwarth U, et al. A modular femoral implant for uncemented stem revision in THR. Int Orthop 2000;24:134. Schuh A, Werber S, Holzwarth U, et al. Cementless modular hip revision arthroplasty using the MRP Titan Revision Stem: outcome of 79 hips after an average of 4 years' follow-up. Arch Orthop Trauma Surg 2004;124: 306. Koster G, Walde TA, Willert HG. Five- to 10-year results using a noncemented modular revision stem without bone grafting. J Arthroplasty 2008;23:964. Garbuz DS, Toms A, Masri BA, et al. Improved outcome in femoral revision arthroplasty with tapered fluted modular titanium stems. Clin Orthop Relat Res 2006;453:199. Cameron HU. The long-term success of modular proximal fixation stems in revision total hip arthroplasty. J Arthroplasty 2002;17(4 Suppl 1):138. Hummel M, Malkani AL, Yakkanti MR, et al. Decreased dislocations following revision THA using larger femoral head size and posterior capsular repair. J Arthroplasty 2009;24(6 Suppl):73.
Revision Hip Arthroplasty Using a Modular Femoral Implant Desai et al
1498.e1
Table 5. Survivorship of Modular Femoral Implants Study Kang et al [9]
Kwong et al [20]
Rodriguez et al [21]
No. of Hips 39
143
97
Wirtz et al [22]
142
Schuh et al [23]
79
Koster et al [24]
73
Christie et al [10] 102 (Paprosky type IV excluded) Desai et al. Current Series 52 (Only Paprosky type III and IV cases)
Implant ZMR: Zimmer (Warsaw, IN)
Follow-Up
Revision
5 (1 for instability, 1 for aseptic loosening, 1 for periprosthetic fracture, 1 for subsidence, 1 for late infection) Link MP: Wright Medical 2-6 y (mean, 3.33 y) 4 (1 for infection, (Arlington, TN) 1 for stem fracture, 1 for leg length discrepancy, 1 for loose head-neck segment) Link MP; Wright Medical 2-6 y (mean, 3.75 y) 4 revised (2 for migration, 1 for fractured stem, 1 for periprosthetic facture) MRP-Titan; Peter-Brehm 2.3 y 7 (5 for dislocation, (Weisendorf, Germany) 2 for aseptic loosening) MRP-Titan; Peter-Brehm 4y 3 (1 for periprosthetic fracture, 2 for infection) Profemur-R revision stem; 5-10 y (mean, 6.2 y) 3 (2 for migration, Wright Medical 1 for infection) S-ROM; Depuy (Warsaw, IN) 4-7 y (mean, 6.2 y) 1 (for mechanical loosening) Restoration Modular: Stryker
2-5 y
2-5 y (mean, 2.1 y)
3 (2 for infection, 1 for postoperative periprosthetic trochanteric fracture and instability)
Survivorship 87.1%
97.2%
95.8%
95.0% 96.2% 95.8% 99.01% 94.2%
Revision Total Hip Arthroplasty Using a Modular Femoral Implant in Paprosky Type III and IV Femoral Bone Loss Rasesh R. Desai, MD,* Arthur L. Malkani, MD,* Kirby D. Hitt, MD,y Fredrick F. Jaffe, MD,z John R. Schurman II, MD,§ and Jianhua Shen, MS‖
Abstract: The purpose of this study was to compare results of patients with Paprosky type I and II femoral defects vs type IIIA, IIIB, and IV defects in patients undergoing revision hip arthroplasty. There were 64 patients in the group with type I and II defects with an average age of 68 years. There were 52 patients with Paprosky type IIIA, IIIB, and IV defects with an average age of 67 years. There were 8 intraoperative fractures in the type III and IV group, whereas there were 9 in the type I and II group. There were no differences between the 2 groups with respect to subsidence, loosening, dislocation, infection, and medical complications. Survivorship for the whole group was 96.9% at 5 years. Modular femoral implants provide several intraoperative options to restore leg length, offset, and stability despite femoral defects. We did not realize a higher failure rate in patients with type III or IV defects. Keywords: revision THA, Paprosky type III and IV defect, modular femoral stem. © 2012 Elsevier Inc. All rights reserved.
With the increase in number of total hip arthroplasties performed in United States, the number of revisions performed is also on the rise. The rate of primary total hip arthroplasties have increased by approximately 50% per 100 000 persons from 1990 to 2002, whereas revision total hip arthroplasties have increased by approximately 3.7 procedures per 100 000 persons per decade [1]. Revision of the femoral component can be a challenging problem for a surgeon especially when there is significant bone loss and poor bone quality. The goals of the revision surgery are to alleviate the pain and provide stable fixation of the revision stem and restore joint mechanics. Della Valle and Paprosky [2] developed a classification scheme and an algorithmic approach to the reconstruction of femoral deficiency in revision total hip arthroplasty. Depending on the extent of the femoral bone loss, different surgical options are available for implant fixation including long stem with or without From the *Department of Orthopaedic Surgery, University of Louisville, Louisville, Kentucky; yScott and White Clinic, Temple, Texas; zNYU Hospital for Joint Diseases, New York, New York; §Advanced Orthopedic Associates PA, Wichita, Kansas; and ‖Stryker Orthopaedics, Mahwah, New Jersey. Submitted May 4, 2011; accepted March 19, 2012. Supplementary material available at www.arthroplastyjournal.org. The Conflict of Interest statement associated with this article can be found at doi:10.1016/j.arth.2012.03.039. Reprint requests: Arthur L. Malkani, MD, Department of Orthopaedic Surgery, 210 E. Gray Street, Suite 1003, Louisville, KY 40202. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2708-0013$36.00/0 doi:10.1016/j.arth.2012.03.039
calcar replacement cemented implants [3]; porous, extensively coated implants [4]; modular, extensively coated, or fluted stems [5], impaction grafting [6]; allograft-prosthetic composites [7]; or tumor type mega prosthesis [8]. Modular femoral stems are gaining popularity especially for the Paprosky type II, III, or IV defects. Modular stems allow independent sizing in the metaphyseal/ diaphyseal component, variable stem-to-neck length options, and option of change in the version and offset. Although there are studies published on outcomes of modular femoral implants on revision total hip arthroplasty [9,10], there are very few studies that focus on the results of modular femoral implants with Paprosky type III or IV severe femoral bone loss [11]. The purpose of this study was to compare the clinical and radiographic results of Paprosky types I and II defects to type III and IV defects from a multicenter prospective database of patients undergoing femoral component revision with a modular femoral implant.
Materials and Methods The data from this study were obtained from a prospective, multicenter, institutional review board– approved study from 13 centers evaluating the use of a Restoration modular implant (Stryker, Mahwah, NJ) in patients undergoing revision total hip arthroplasty. There were a total of 64 patients with type I and type II Paprosky bone loss with an average age of 68 years
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Table 1. Patient Demographics Characteristic Gender Males Females Age (y) Weight (lb) Height (in) Body mass index (kg/m2) No. of previous joint surgery 1 2 3 N3 Diagnosis Osteoarthritis Rheumatoid arthritis Post-traumatic arthritis Avascular necrosis Other
Type 1 and 2 Group (n = 64)
Type 3A, 3B, and 4 Group (n = 52)
50% 50% 68.05 ± 11.82 (range, 41-85 y) 174.73 ± 41.14 66.65 ± 3.53 27.49 ± 5.20
48% 52% 67.56 ± 11.85 (range, 43-85 y) 175.5 ± 44.53 65.96 ± 5.00 28.32 ± 6.38
84.38% 12.50% 0% 3.13%
61.54% 25.00% 8% 5.77%
54.70% 4.70% 4.70% 14.00% 21.90%
48.08% 7.69% 13.46% 5.77% 25.00%
and an average body mass index of 28. All cases were enrolled to the study from March 11, 2004, to March 27, 2007. There were 52 patients with Paprosky III and IV defects: 34 patients (65.3%) were classified as Paprosky type IIIA defect; 13 (25%), with Paprosky type III B defect; and 5 (9.6%), with Paprosky type IV defects. Baseline characteristics and surgical details were summarized and compared between groups using Wilcoxon rank sum test for non–normally distributed numerical data or χ 2 test for discrete data. All P values were 2 tailed, and a P value of .05 or less was considered to be statistically significant. SAS/STAT software version 9.1.3 (SAS Institute, Cary, NC) was used for all data analyses (Tables 1, 2 and 3). Patients had follow-up at 6 weeks, 3 months, 1 year, 2 years, and 5 years. Standard pelvis anteroposterior (AP) as well as AP and lateral radiographs of the affected hip
Statistical Test
Significance
χ2
P = .84
Wilcoxon rank sum test
P = .90
Wilcoxon rank sum test Wilcoxon rank sum test Wilcoxon rank sum test χ2
P = .93 P = .24 P = .51 P = .02
χ2
P = .26
were taken at follow-up visits for evaluation. Subsidence was determined by measuring the distance between a fixed point on the stem (body-stem junction) and a fixed bony point on femur. A difference of 3 mm or more in the measured distance between the immediate postoperative radiograph and the radiograph taken at the latest follow-up was considered as subsidence [9,12]. Surgical Technique Preoperative planning included radiographic assessment of femoral bone loss and templating to achieve the desired leg length and offset. Extended trochanteric osteotomy was performed in 18 cases (34.6%) in the type III and IV cases and 15 extended trochanteric osteotomies in the type I and II group. Posterior approach was used in 22 patients, and direct lateral approach, in 30 patients. A Restoration Modular Revision Hip System
Table 2. Surgical Data Characteristic Approach Anterolateral Posterior Duration of surgery (min) Estimated blood loss (mL)
Type 1 and 2 Group Type 3A, 3B, and 4 Group
Statistical Test χ2
42.20% 57.80% 154.95 ± 54.88 (range, 60-331) 729.33 ± 499.90 (range, 150-3000)
Was an attempt made to correct leg length? Yes 81.25% No 18.75% Correct leg length (amount attempted in millimeters) 12.94 ± 6.98 (range, 0.3-34) Correct leg length (amount achieved in millimeters) 11.92± 6.49 (range, 0.3-28) Stem inserted: (bone graft used) Yes 26.56% No 73.44%
57.70% 42.30% 194.52 ± 69.10 (range, 50-385) 1240.77 ± 1206.61 (range, 20-6000)
Wilcoxon rank sum test P b .01 P = .41
Wilcoxon rank sum test P = .04 Wilcoxon rank sum test P = .01 χ2
59.62% 40.38%
P = .01
Wilcoxon rank sum test P b .01
χ2 84.62% 13.46% 19.7 ± 14.38 (range, 0.5-63) 19.03 ± 13.68 (range, 0.5-63)
Significance
P b .01
1494 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 Table 3. Results (Harris Hip Score)
Visits Preoperative 6 wk 3 mo 1y 2y 5y Mean length of follow-up (y)
Type 1 and 2 Group (Mean Length of Follow-Up = 2.2 y)
Type 3A, 3B, and 4 Group (Mean Length of Follow-Up = 2.1 y)
47.62 62.71 73.29 87.06 86.98 83.89 2.2
43.44 63.14 74.82 85.33 84.03 84 2.1
used (Fig. 2A and B). A tapered stem was commonly used (Table 4). In Paprosky type I and II defects, a modular tapered fluted stem was used in 80% of the cases, whereas in type III and IV defects, the usage was 73%. In most cases, the medullary canal was first reamed with flexible reamers to remove debris and sclerotic bone. Rigid reamers were then used to obtain cortical contact. When plasma-sprayed cylindrical stems were used, the femoral canal was underreamed by 0.5 to 1 mm. When fluted tapered stems were inserted, conical reamers with line-to-line reaming were used. Cables were used for fixation of strut grafts, repair of extended trochanteric osteotomies, or fixation of intraoperative fractures. Allografts were used in 24 cases, and autografts, in 7 cases.
Results
(Stryker) was used in all the cases (Fig. 1A and B). Depending on the quality of the proximal bone, either porous-coated cylindrical or tapered fluted stem were
Fig. 1. (A) Restoration modular femoral implant with a cone body and conical tapered stem. (B) Restoration modular femoral stem with cone body and cylindrical plasma stem.
The mean follow-up in type I and II was 3.5 years (range, 2-5.8 years), and the mean follow-up in types III and IV group was 3.8 years (range, 2-5.7 years). In the Paprosky type I and II group, the average preoperative Harris Hip Score was 48 points, which improved to 84 points at latest follow-up. In Paprosky type III and IV defects, the average preoperative Harris Hip Score was 43 points, which improved to 84 points at latest followup. The duration of surgery in the group with type I and II defects was 155 vs 195 minutes in type III and IV defects (P b .01). The estimated blood loss in type I and II defects was 729 mL, whereas in type III and IV defects, the blood loss was 1240 mL (P b .01). The desired leglength correction in type III and IV defects was greater than the amount required in types I and II defects (P b .05). There were a total of 8 (15.3%) intraoperative periprosthetic fractures in the Paprosky type III and IV group. Of these fractures, 5 were femoral shaft fractures and 3 trochanteric fractures. Of the 8 fractures in the Paprosky type III and IV group, 3 were also in the extended trochanteric osteotomy (ETO) group. In the Paprosky type I and II group, there were 5 femoral shaft fractures and 4 trochanteric fractures. Of the 9 fractures in the type I and II groups, 5 were also in the ETO group. In the type III and IV group, there were 2 superficial wound infections and 2 hematomas; 3 patients had other wound-related problems; and there were 2 deep infections requiring irrigation, debridement, and exchange of the polyethylene liner and femoral head. Subsidence occurred in 1 patient in the group with type III and IV defects, which was clinically asymptomatic. There were no cases of aseptic femoral component loosening for the type III and IV group, but there was 1 loosening in those with type I and II bone defects. There were 3 dislocations in each group, and in those with type III and IV defects, 2 of them required closed reduction and bracing, whereas 1 underwent open operative treatment of a greater trochanteric fracture along with an acetabular liner exchange due to recurrent dislocation.
Revision Hip Arthroplasty Using a Modular Femoral Implant Desai et al
1495
Fig. 2. (A) Preoperative AP hip with loose femoral component with type III Paprosky bone loss extending into diaphysis. (B) Postoperative AP hip with 3-year follow-up demonstrating stable distal fixation.
Overall, in type III and IV defects, there were a total of 3 reoperations including 2 for deep joint infection and 1 for open reduction internal fixation (ORIF) of a trochanteric fracture and instability. The overall incidence of reoperation in the type III and IV group was 5.7%, which was similar to the group with type I and II bone defects. Overall survivorship using the Kaplan-Meier method analysis in groups with type I and II defects was 94.36% at 5 years, whereas in the type III and IV defects, it was 100%.
Discussion Femoral component revision poses a challenging problem primarily because of compromised soft tissue and bone deficiency encountered at the time of revision. Because of the proximal bone loss at the time of femoral component revision, distal fixation has been advocated providing more predictable results [13]. The advantages of modular femoral implants with distal fixation include intraoperative versatility that allows the surgeon to use the appropriate size of distal stems for diaphyseal fixation and appropriate sizes of proximal bodies that can best fit and fill the metaphysis. The proximal metaphyseal body is porous coated, which promotes ingrowth, and proximal loading, which can potentially minimize proximal stress shielding as well as decrease the stresses placed on the morse taper junction [14]. Modularity also provides a variety of stem and neck length options to restore leg length and offset, which also helps to restore mechanics. Such intraoperative customization has led to the increasing popularity of
modular femoral stems for femoral component revision. There have been disadvantages through the use of modular femoral implants such as high stresses at the taper junction leading to fracture of the first-generation modular implants, which has led to design changes and biomechanical improvements leading to a second generation of modular femoral implants, which is the subject of this study [15,16]. Results of proximally coated monobloc stems for femoral component revision have demonstrated higher failure rates as compared with modular stems. Mulliken et al [17] reported 10% revision rate at 4 to 6 years of follow-up. Malkani et al [18] reported 8.7% revision rate in 69 patients at midterm follow-up. Woolson and Delaney et al [19], in their study of 28 hips, reported a 20% revision rate and 45% mechanical failure rate. There are several studies demonstrating success of modular femoral implants in revision surgeries [9,10,2024] (Table 5; available online at www.arthroplastyjournal. org). Garbuz et al [25] compared modular fluted and tapered titanium stems with cylindrical extensively coated cobalt chrome stems with single modularity. At follow-up, all quality of life measures favored the modular titanium stems. Koster et al [24] showed 96% survival rate with aseptic loosening as an end point over an average of 10 years for a modular uncemented revision stem. Christie et al [10] noted approximately 99% survival rate from revision with a modular femoral stem. Several other studies [21,23,26] also have reported a high midterm success rate.
1496 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 Table 4. Restoration Modular Stem and Body Type Used Stem type
Body type
Bone Type 1 and 2 (n = 64)
Bone Type 3A, 3B and 4 (n = 52)
12 50 1 1 58 5 0 1
14 37 1 0 47 2 3 0
Plasma Conical Fluted Other Cone Broached Calcar Other
However, the survival of the modular stems also depends on the degree or severity of the bone defects. McCarthy and Lee [11] retrospectively reviewed 92 hips that underwent revision surgery with proximally coated modular femoral component and demonstrated that there was no aseptic loosening in Paprosky type II and III
A group at mean follow-up of 14 years. However, there was 9% failure rate because of aseptic loosening in Paprosky type III B and IV group. Kwong et al [20] reported their experience with modular distal fixation option for proximal femoral bone loss. Their series consisted of 143 patients. In this series, 70% of the
Revision Hip Arthroplasty Using a Modular Femoral Implant Desai et al
patients were Mallory type III, and 25% were type II. At average follow-up of 40 months, the survival rate was 97.2%. Sporer and Paprosky [13] noted that 2 (18%) of 11 Paprosky type III B and 3 (37.5%) of 8 patients with Paprosky type IV defects had to be revised because of failure suggesting risk of higher failure rates in such patients. The risk of failure was greater in patients with femoral stem diameters greater than 19 mm. The purpose of our study was to specifically review and compare the clinical and radiologic outcomes in patients undergoing femoral component revision with Paprosky type I and II defects vs type III and IV defects using modular femoral stems. We used the Restoration Modular Hip System (Stryker) in all patients. There were no cases of aseptic femoral component loosening at latest follow-up in the type III and IV group, whereas there was one case in the type I and II groups. However, there were 8 cases of intraoperative fractures of 52 patients (15.3%) in the type III and IV group. Of the fractures, 5 involved the femoral shaft. Some of the other studies in literature have also reported high intraoperative fracture rates in femoral component revision. Mulliken et al reported a 40% intraoperative fracture rate [17]. Christie et al [10] reported 22.5% intraoperative fracture rate. The patients in this series were a high-risk group with type III and IV femoral bone defects. We felt that our fracture incidence would lead to a higher overall failure rate. We were surprised that despite having intraoperative fractures, the implants were still able to obtain biologic ingrowth. From our experience, we recommend the use of prophylactic cerclage cables in patients with poor bone quality before reaming and distal fixation. Dislocation is a common complication after revision total hip arthroplasty. The incidence of dislocation has been reported in the literature from 4% to 25% after revision hip arthroplasty because of several reasons including compromised soft tissue [13]. In this current series, with a difficult group of patients undergoing femoral component revision, we feel that the dislocation was minimized given the ability of the modular femoral hip system to provide optimum offset, leg length, and fixation using the various sizes available. In addition, the use of large head sizes also, in all likelihood, played a role in minimizing dislocation [27]. In addition to trying to obtain the maximum canal fit, fixation can lead to a fracture, and undersizing can lead to subsidence. In those deficiencies where a patulous femoral canal is encountered with thin cortical bone, impaction grafting may be a reasonable option vs distal fixation to minimize the incidence of fracture. Pierson et al [15] reported on a series of 40 cases of fracture at the modular junction. However, with current design implants, the biomechanical properties of the morse taper junction have been significantly improved with the use of nitride impregnation, burnishing, and
1497
shot peening [16]. There was no case of modular junction failure in our series. There are several limitations to our study. This was a prospective multicenter study with different surgeons bringing their own surgical technique, experience, and perspective, which introduces a significant variable. The size of the cohort is relatively small, patients were not randomized, and the results are short term. This series is different from other revision hip arthroplasty studies looking at modular implants because it specifically concentrates on a difficult group of patients, those with type III and IV defects and comparing them to type I and II defects. We are encouraged with the clinical results of this study with the ability of this implant system to help restore offset and achieve leg-length correction in 91% of patients. In conclusion, based on our series, we feel that modular implants for femoral component revision provide excellent results with respect to achieving leglength, offset, version, and implant stability. Fixation can be reproducibly achieved despite Paprosky type III and IV defects. However, greater attention and work needs to be undertaken to minimize the rate of complications and, specifically, intraoperative fractures. Modular femoral implants do have limitations; and in those patients with a large patulous femoral canal, alternative implant options such as impaction grafting may need to be considered.
References 1. Kurtz S, Mowat F, Ong K, et al. Prevalence of primary and revision total hip and knee arthroplasty in the United States from 1990 through 2002. J Bone Joint Surg Am 2005;87:1487. 2. Della Valle CJ, Paprosky WG. Classification and an algorithmic approach to the reconstruction of femoral deficiency in revision total hip arthroplasty. J Bone Joint Surg Am 2003;85-A(Suppl 4):1. 3. Gramkow J, Jensen TH, Varmarken JE, et al. Long-term results after cemented revision of the femoral component in total hip arthroplasty. J Arthroplasty 2001;16:777. 4. Engh Jr CA, Ellis TJ, Koralewicz LM, et al. Extensively porous-coated femoral revision for severe femoral bone loss: minimum 10-year follow-up. J Arthroplasty 2002;17:955. 5. Sporer SM, Paprosky WG. Femoral fixation in the face of considerable bone loss: the use of modular stems. Clin Orthop Relat Res 2004;429:227. 6. Hostner J, Hultmark P, Karrholm J, et al. Impaction technique and graft treatment in revisions of the femoral component: laboratory studies and clinical validation. J Arthroplasty 2001;16:76. 7. Blackley HR, Davis AM, Hutchison CR, et al. Proximal femoral allograft for reconstruction of bone stock in revision arthroplasty of the hip. A nine to fifteen-year follow-up. J Bone Joint Surg Am 2001;83-A:346. 8. Malkani AL, Settecerri JJ, Sim FH, et al. Long-term results of proximal femoral replacement for non-neoplastic disorders. J Bone Joint Surg Br 1995;77:351.
1498 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 9. Kang MN, Huddleston JI, Hwang K, et al. Early outcome of a modular femoral component in revision total hip arthroplasty. J Arthroplasty 2008;23:220. 10. Christie MJ, DeBoer DK, Tingstad EM, et al. Clinical experience with a modular non- cemented femoral component in revision total hip arthroplasty: 4- to 7-year results. J Arthroplasty 2000;15:840. 11. McCarthy JC, Lee JA. Complex revision total hip arthroplasty with modular stems at a mean of 14 years. Clin Orthop Relat Res 2007;465:166. 12. Callaghan JJ, Salvati EA, Pellicci PM, et al. Results of revision for mechanical failure after cemented total hip replacement, 1979 to 1982. A two to five years follow up. JBJS Am 1985;67:1074. 13. Sporer SM, Paprosky WG. Revision total hip arthroplasty: the limits of fully coated stems. Clin Orthop Relat Res 2003;417:203. 14. Hnat WP, Conway JS, Malkani AL, et al. The effect of modular tapered fluted stems on proximal stress shielding in the human femur. J Arthroplasty 2009;24:957. 15. Pierson JL, Crowninshield RD, Earles DR. Fatigue fracture of a modular revision femoral component: a report of forty cases. Annual Meeting, February; Am Acad Orthop Surg, Washington, DC; 2005. 16. Malkani AL, Yakkanti MR. In: Hozack WJ, Parvisi J, Bendon B, editors. Surgical options for femoral reconstruction: the use of modular stems in surgical treatment of hip arthritis: reconstruction, replacement and revision. Philadelphia (Pa): Saunders Elsevier; 2010; p. 318. 17. Mulliken BD, Rorabeck CH, Bourne RB. Uncemented revision total hip arthroplasty: a 4-to-6-year review. Clin Orthop Relat Res 1996;325:156. 18. Malkani AL, Lewallen DG, Cabanela ME, et al. Femoral component revision using an uncemented, proximally
19.
20.
21.
22.
23.
24.
25.
26.
27.
coated, long-stem prosthesis. J Arthroplasty 1996;11: 411. Woolson ST, Delaney TJ. Failure of a proximally porouscoated femoral prosthesis in revision total hip arthroplasty. J Arthroplasty 1995;10(Suppl):S22. Kwong LM, Miller AJ, Lubinus P. A modular distal fixation option for proximal bone loss in revision total hip arthroplasty: a 2- to 6-year follow-up study. J Arthroplasty 2003;18(3 Suppl 1):94. Rodriguez J, Fada R, Murphy SB, et al. Two-year to fiveyear follow up of femoral defects in femoral revision treated with the Link MP modular stem. J Arthroplasty 2009;24:751. Wirtz DC, Heller KD, Holzwarth U, et al. A modular femoral implant for uncemented stem revision in THR. Int Orthop 2000;24:134. Schuh A, Werber S, Holzwarth U, et al. Cementless modular hip revision arthroplasty using the MRP Titan Revision Stem: outcome of 79 hips after an average of 4 years' follow-up. Arch Orthop Trauma Surg 2004;124: 306. Koster G, Walde TA, Willert HG. Five- to 10-year results using a noncemented modular revision stem without bone grafting. J Arthroplasty 2008;23:964. Garbuz DS, Toms A, Masri BA, et al. Improved outcome in femoral revision arthroplasty with tapered fluted modular titanium stems. Clin Orthop Relat Res 2006;453:199. Cameron HU. The long-term success of modular proximal fixation stems in revision total hip arthroplasty. J Arthroplasty 2002;17(4 Suppl 1):138. Hummel M, Malkani AL, Yakkanti MR, et al. Decreased dislocations following revision THA using larger femoral head size and posterior capsular repair. J Arthroplasty 2009;24(6 Suppl):73.
Revision Hip Arthroplasty Using a Modular Femoral Implant Desai et al
1498.e1
Table 5. Survivorship of Modular Femoral Implants Study Kang et al [9]
Kwong et al [20]
Rodriguez et al [21]
No. of Hips 39
143
97
Wirtz et al [22]
142
Schuh et al [23]
79
Koster et al [24]
73
Christie et al [10] 102 (Paprosky type IV excluded) Desai et al. Current Series 52 (Only Paprosky type III and IV cases)
Implant ZMR: Zimmer (Warsaw, IN)
Follow-Up
Revision
5 (1 for instability, 1 for aseptic loosening, 1 for periprosthetic fracture, 1 for subsidence, 1 for late infection) Link MP: Wright Medical 2-6 y (mean, 3.33 y) 4 (1 for infection, (Arlington, TN) 1 for stem fracture, 1 for leg length discrepancy, 1 for loose head-neck segment) Link MP; Wright Medical 2-6 y (mean, 3.75 y) 4 revised (2 for migration, 1 for fractured stem, 1 for periprosthetic facture) MRP-Titan; Peter-Brehm 2.3 y 7 (5 for dislocation, (Weisendorf, Germany) 2 for aseptic loosening) MRP-Titan; Peter-Brehm 4y 3 (1 for periprosthetic fracture, 2 for infection) Profemur-R revision stem; 5-10 y (mean, 6.2 y) 3 (2 for migration, Wright Medical 1 for infection) S-ROM; Depuy (Warsaw, IN) 4-7 y (mean, 6.2 y) 1 (for mechanical loosening) Restoration Modular: Stryker
2-5 y
2-5 y (mean, 2.1 y)
3 (2 for infection, 1 for postoperative periprosthetic trochanteric fracture and instability)
Survivorship 87.1%
97.2%
95.8%
95.0% 96.2% 95.8% 99.01% 94.2%