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Are Prosthetic Spacers Safe to Use in 2-Stage Treatment for Infected Total Knee Arthroplasty?
The Journal of Arthroplasty Vol. 27 No. 8 2012
Are Prosthetic Spacers Safe to Use in 2-Stage Treatment for Infected Total Knee Arthroplasty? Ho-Rim Choi, MD, Henrik Malchau, MD, PhD, and Hany Bedair, MD
Abstracts: This retrospective study compares treatment results of infected total knee arthroplasty with 2-stage exchange technique using 14 articulating spacers using metallic and polyethylene components (prosthetic group) and 33 static all-cement spacer (static group). For the prosthetic and static groups, treatment success rate was 71% and 67% at 58 months of follow-up, respectively, and not significantly different. The prosthetic group required less frequent extensile surgical approaches at the second-stage reimplantation. Range of motion was significantly improved in both groups, but there was no difference at latest follow-up between the groups. Of 14 in the prosthetic group, 4 (28%) did not undergo second-stage procedure. Antibiotic spacers consisting of prosthetic components can be a safe and effective treatment option for 2-stage revision total knee arthroplasty with equivalent infection control rates. Keywords: total knee arthroplasty, infection, two-stage revision, prosthetic spacer, static spacer, comparison. © 2012 Elsevier Inc. All rights reserved.
Two-stage exchange arthroplasty with delayed reimplantation is considered the standard treatment of chronic infection after total knee arthroplasty (TKA) with an infection control rate of approximately 85% to 95% [1-5]. During the interim period between the 2 stages, different spacer options are available: resection arthroplasty (no spacer), antibiotic cement beads, static antibiotic cement block, or articulating spacer. However, there is no consensus on the optimal spacer for this interim period, and the choice can depend on many variables, including chronicity of the infection, host condition, and virulence of the infecting organism, but most likely, the choice is based upon the treating surgeons' preference. Of these treatment options, a static antibiotic cement block spacer has been widely used with satisfactory infection control rates of approximately 84% to 96% [6,7]. However, a static spacer has disadvantages of interim functional disability, soft tissue contractures that
From the Department of the Orthopaedic Surgery, Massachusetts General Hospital, Boston, Massachusetts. Submitted October 30, 2011; accepted February 24, 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.2012.02.023. Reprint requests: Hany Bedair, MD, Department of Orthopedic Surgery, Massachusetts General Hospital, 55 Fruit St, Yawkey-3B, Boston, MA 02114. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2708-0010$36.00/0 doi:10.1016/j.arth.2012.02.023
can make the subsequent second stage difficult, and compromise of bone stock [8-11]. To overcome these disadvantages, all-cement, articulating, functional spacers have been developed. This type of articulating spacers can provide joint motion and proper soft tissue tension during interim periods, which may make the second-stage procedure easier and lead to increased ultimate range of motion (ROM) [10,12]. A number of studies have reported successful infection control and improved ROM using articulating antibiotic-loaded cement spacers [5,11]. In a similar technique, Hofmann et al used the removed and resterilized femoral component and a new all-polyethylene tibial component, which were fixed with antibiotic-laden cement as the spacer. They reported no recurrence of infection and increased ROM by this technique in their series of 26 chronic infections of TKA [13]. Other studies of articulating spacers using similar techniques to Hofmann et al [13] also reported successful treatment outcome [3,4,14,15]. However, this method of an articulating prosthetic spacer is not widely used and likely due to the concern about reimplanting metallic and polyethylene components in an infected bed, which may hinder effective infection control by harboring bacteria on these foreign bodies. Furthermore, although articulating spacers are known to show improved ROM and to demonstrate an infection control comparable with that of static spacers, few studies directly compare prosthetic spacers and static cement spacers [8].
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Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al
The purpose of this study was to compare the characteristics and treatment results of articulating prosthetic spacers with that of static, all-cement spacers and outline the role of articulating prosthetic spacers in infected TKA. We hypothesized that prosthetic spacers not only would provide effective control of infection but would also allow better ROM and less need for extensile approach and constrained type implants at the time of reimplantation.
Materials and Methods Between January 2000 and January 2009, 65 patients with an infected TKA were managed by 2stage revision arthroplasty at our institution. Of these, 4 died of unrelated disease within 1 year, 6 were lost to follow-up, and 8 were referred from an outside center and received only the second-stage reimplantation (n = 6) or fusion (n = 2) as the first procedure at our institution. Excluding these 18 patients, the remaining 47 patients were treated by spacer insertion with planned delayed reimplantation and included in this retrospective analysis. There were 23 males and 24 females, and the mean age at the first-stage operation was 64 years (range, 38-85 years). The diagnosis for the primary arthroplasty was osteoarthritis in 39, posttraumatic arthritis in 4, rheumatoid arthritis in 2, congenital dislocation in 1, and unknown in 1. The primary TKA was performed at our institution in 9 knees and elsewhere in 38 knees. Twentynine patients had more than 2 operations on the knee before the first-stage operation. The mean follow-up period was 58 months (range, 14-118 months). Infection was diagnosed by positive culture results from a preoperative joint aspirate or intraoperative tissue specimens. With culture negative results, the diagnosis was made based on the presence of an abscess or draining sinus communicating to the joint, signs of acute inflammation consistent with infection on histopathologic examination (N5 neutrophils per high-powered field), or purulence surrounding the prosthesis at the time of surgery in conjunction with abnormal laboratory studies for erythrocyte sedimentation rate (ESR) (≥25 mm/h), C-reactive protein (CRP) (N8.0 mg/L), synovial fluid white blood cell (WBC) count (≥2000/μL), and synovial fluid polymorphonuclear differential count (N65%) [16-18]. Infection type was classified as early postoperative, acute hematogenous, and chronic infection based on suggestion of Tsukayama et al [19], and the patients were classified according to the method of McPherson et al [20] to characterize their host status (uncompromised, compromised, and significantly compromised). Any additional surgery to control persistent or recurrent infection other than the planned secondstage reimplantation was considered treatment failure. All patients were divided into 2 groups based on the type of interim spacer; (1) articulating prosthetic spacer
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(prosthetic group, n = 14) and (2) static cement block spacer (static group, n = 33). Selection of the spacer option was based on the treating surgeons' preference and not related to any specific patient factors. The each surgeon in this series consistently chose the same type of interim spacer with 2 surgeons using the prosthetic spacer and 3 surgeons using the static spacer. The firststage operation in both groups involved removal of all components and cement and a thorough irrigation and extensive debridement for all nonviable soft tissues and bone. For the prosthetic group, a new (n = 6) or removed and sterilized (n = 8) femoral component was used for the femoral side, and a new all-polyethylene tibial component (n = 7), removed and sterilized polyethylene insert (n = 3), or molded cement block (n = 4) was used for the tibial articulating surface. Reused components were sent for autoclave sterilization during the course of the surgery and reinserted as the spacer. The undersurface of these prosthetic spacers was coated with antibiotic cement and inserted into the resected femur and tibia without pressurization to avoid excessive interdigitation of the cement into the cancellous bone. For the static group, the spacer was made with a cylindrical-shaped cement puck when the antibiotic cement reached very doughy state and then inserted between the extension gap of the resected bone while the limb was manually distracted. In both groups, the antibiotic-loaded bone cement containing 1.0 g of vancomycin and 2.4 g of tobramycin in each 40 g of cement was used. After surgery, weight bearing as tolerated was allowed in both groups, with unrestricted ROM in for the prosthetic group. Patients received 6 weeks of intravenous antibiotic therapy based on culture results and consultation of infectious disease service. Patients were followed up at 2 weeks, 1 to 3 months, and 6 months after surgery. Wound conditions were evaluated, and spacer status was examined by radiographs. Serologic study for ESR, CRP was performed at regular intervals. The second-stage reimplantation was performed when the infection was judged to be controlled by a negative culture result on follow-up aspiration after at least 2 weeks of discontinuation of antibiotics and a normalizing trend of the laboratory findings (ESR, CRP, and joint aspirate WBC count with differential count). The final decision to proceed with reimplantation was made at the surgeons' discretion in the operating room in conjunction with intraoperative frozen section results. The second-stage operation was performed through the same skin incision as the first stage, and extensile approach was used at the surgeons' discretion. All patients were asked to follow up at 2 weeks, 1 to 3 months, 1 year, and the 2 to 3 years postoperatively. The mean clinical and radiographic follow-up period was 43 months (range, 17-102) for the prosthetic group and 63 months (range, 14-118) for static group (P = .02). The
1476 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 mean time between the first- and second-stage procedures was 6 months in both groups. Patients' demographics, type of infection, previous history of infection treatment, type of prior surgery, microorganisms, surgical approach and type of reimplanted prostheses (level of constraint), ROM, rates of complication, and treatment success were analyzed using SPSS Ver. 17.0 (SPSS, Chicago, Ill). χ 2 And Fisher exact tests were used to determine the differences in proportions for each variable between the prosthetic and static groups. The independent-sample t test was used to compare the means of continuous variables between the 2 study groups. P b .05 was considered statistically significant.
Results There was no significant difference between the 2 groups in terms of patients' characteristics, type of infection, prior surgery, and microorganisms (Table 1; available online at www.arthroplastyjournal.org). Preoperative laboratory data were also no different between the groups (Table 2). Staphylococcus aureus was the most common microorganism in the prosthetic group, and S aureus and coagulase-negative Staphylococcus were the most common microorganisms in the static group (Table 3). The rates of treatment success for the prosthetic and static groups were 71% and 67%, respectively. There was no significant difference in the rate of treatment success between the groups (P = 1.00) (Table 1; available online at www.arthroplastyjournal.org). For the prosthetic group, 4 patients had recurrent infections after the second-stage reimplantation. Three were managed by repeat irrigation/debridement (I/D), and 1 was treated by repeat I/D and a subsequent 2-stage revision. Two of these 4 are still being treated at latest follow-up. In the static group, 11 patients demonstrated a recurrent infection (4 after the first-stage and 7 after the secondstage procedure). Four of them were managed by I/D, and 2 of them were managed by repeat 2-stage revision. Two patients were treated by arthrodesis; 2, by amputation; and 1, by resection and repeat I/D. Table 2. Comparison of Preoperative Laboratory Data Prosthetic Group (n = 14), Mean ± SD
Variables 3
Serum WBC (/mm ) ESR (mm/h) CRP (mg/L) Joint aspirate WBC (/mm3) Neutrophil (%)
Static Group (n = 33), Mean ± SD
P
9062 ± 3839 77 ± 37 48 ± 61
9490 ± 5830 95 ± 33 81 ± 88
.33 .10 .28
18 239 (3458-45 113) 96 (91-98)
66 500 (23 350-91 700) 94 (86-97)
.05 .50
Continuous data are expressed as mean ± SD, except joint aspirate values which are median (interquartile range) due to skewness.
Table 3. Bacterial Characteristics of 47 Knees Type of Microorganism
Prosthetic Group (n = 14)
Gram-positive S aureus MSSA MRSA Coagulase-negative Staphylococcus MSCNS MRCNS Staphylococcus lugdunensis Streptococcus species Propionibacterium acnes Peptostreptococcus Actinomyces Gram-negative Escherichia coli Klebsiella Pseudomonas Polybacterial Microorganism unknown
3 1
1 1 1 1
Static Group (n = 33)
5 6 4 7 2 1 1 1
1 1 2* 2
1 1† 4
Abbreviations: MSSA; methicillin-sensitive S aureus; MRSA, methicillin-resistant S aureus; MSCNS, methicillin-sensitive coagulasenegative Staphylococcus; MRCNS, methicillin-resistant coagulase-negative Staphylococcus. * Methicillin-sensitive S aureus + methicillin-sensitive coagulasenegative Staphylococcus, methicillin-sensitive coagulase-negative Staphylococcus + Enterococcus. † Methicillin-resistant S aureus + Streptococcus mitis.
In the prosthetic group, the mean preoperative ROM was 82° (range, 30°-115°), and the most recent ROM was 100° (range, 70°-130°). In the static group, the mean preoperative ROM was 77° (range, 45°-120°), and the latest ROM was 97° (range, 75°-130°). Range of motion improved significantly (preoperative vs followup) in both prosthetic (P = .048) and static (P b .001) group, but there was no significant difference of preoperative (P = .61) and follow-up (P = .60) ROM between the 2 groups. In the prosthetic group, 2 extensile approaches (quadriceps snip; “Q-snip”) were used for the firststage operation, and 4 extensile approaches (29%) (3 Qsnips, 1 tibial tubercle osteotomy [TTO]) for the secondstage reimplantation. In the static group, 15 extensile approaches (1 Q-snip and 14 TTO) were used for the first-stage operation, and 25 extensile approaches (76%) (5 Q-snip, 1 V-Y quadricepsplasty, and 19 TTO) for the second-stage reimplantation (Table 4). A significantly Table 4. Number of Extensile Surgical Approaches Used Surgical Approach First stage Q-snip TTO Second stage Q-snip V-Y quadricepsplasty TTO
Prosthetic Group (n = 14)
Static Group (n = 33)
2
1 14
3
5 1 19
1
Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al Table 5. Implant Used in the Second-Stage Reimplantation Implant Used Posterior stabilized Condylar constrained knee Hinged Others Not reimplanted Arthrodesis
Prosthetic Group (n = 14)
Static Group (n = 33)
2 6 2
6 21 4
4 2
larger number of extensile approaches were used in the static group (P b .01). In the prosthetic group, 8 patients (57%) received a semiconstrained (n = 6) or hinged TKA (n = 2) prostheses at reimplantation. Four patients (29%) did not undergo the second-stage reimplantation as the knee was functioning well with the prosthetic spacer and the infection appeared controlled at a mean follow-up of 25 months. In the static group, 25 patients (76%) received semiconstrained (n = 21) or hinged TKAs (n = 4) at reimplantation. Two patients underwent arthrodesis for the second-stage operation (Table 5). There were no patients who retained their static spacer as the final treatment. Although statistically not significant (P = .30), the static group showed higher incidence of constrained type (semiconstrained or hinged) implant use. One patient in the prosthetic group had a noninfected hematoma formation after reimplantation, which was managed with an irrigation and debridement. In the static group, there was 1 periprosthetic femur fracture, 1 wound dehiscence, 1 spacer subluxation, and 1 arthrofibrosis. The periprosthetic fracture and spacer subluxation were managed conservatively by immobilization, and the wound dehiscence and arthrofibrosis required additional surgery for wound coverage and manipulation under anesthesia.
Discussion Although there are number of studies on the efficacy of 2-stage exchange arthroplasty, debate remains as to what type of spacer should be used between the stages. An ideal spacer should be durable, cost-effective, easily available, and effectively control infection while allowing for function during the interim periods. Traditionally, static cement spacers have been used, but recent results indicate that articulating spacers may have some benefit such as interim functionality, preservation of bone stock, and improved final ROM [8,11,21]. Various methods of preparing an articulating spacer for 2-stage revisions have been developed by many researchers; however, each method has its advantages and disadvantages. Cement-on-cement articulating spacer can be effectively fabricated by intraoperative molding [5,9,11]; however, this method does not provide an ideal articulating surface. These spacers usually demonstrate uncomfortable crepitation and ratcheting with joint
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motion. There is also concern about the particulate cement debris being generated from joint motion. On the other hand, since Duncan et al [22] reported satisfactory results of infection control using the prosthesis of antibiotic-loaded acrylic cement (PROSTALAC; DePuy, Warsaw, Ind), this system has shown acceptable infection control with a reasonable ROM between the stages [10,12]. However, this system is relatively expensive with extra costs associated with the specific molds and extra time for intraoperative fabrication. In the present study, we used new or removed, resterilized components for the femur and new or resterilized tibial polyethylene components or cement block for tibial articulating surface. This method is similar technique to the one described by Hofmann et al [13] in which resterilized femoral components and new all-polyethylene tibial inserts were used. This technique may provide an ideal articulating surface of less friction than that of cement-on-cement articulation and is potentially cost-effective and easily available compared with the commercially available molded spacers. Reusing the original autoclaved femoral or tibial component to treat infection is still controversial. A commonly stated concern in using this technique is the insertion of metal and polyethylene components within the joint in the face of infection; this theoretically could lead to bacterial adhesion to these foreign bodies [23]. The results of this study demonstrate that this type of spacer can control infection at rates comparable with the static spacer without increasing risk of infection. Moreover, 4 patients in the prosthetic group did not undergo second-stage reimplantation at the mean of 25 months follow-up as the joint was functioning well with infection control; these patients in effect have been successfully managed with a 1-stage exchange. Cuckler [3] also reported that 4 of their 44 patients treated with prosthetic spacer delayed a second-stage conversion more than 1 year because the patients were so comfortable with the articulated spacer. These findings suggest that prosthetic spacer not only effectively treat infection but could potentially obviate the need for the second stage in some cases, an option that does not appear to exist with an all-cement static or molded articulating spacer. Our overall success using either technique was lower than many previously reported series [1-5]. There may be several reasons for this. First, our definition of treatment failure of any additional surgery to control persistent or recurrent infection may contribute to a seemingly lower success rate with this technique. A recent study in which failure of 2-stage revision for infected TKAs was defined as any treated knee requiring further treatment of infection, similar to the current study, resulted in 28% of failure rate, which is comparable with the rate observed in this study [24]. In addition, as a tertiary care center, complex referrals
1478 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 might also have contributed to the lower success rate. Many of the patients in this cohort had been referred by surgeons from outside our institution with various prior treatments for infection including antibiotic therapy and/or previous irrigation and debridement procedures, both known to effect the success rate of the 2-stage exchange [25]. In most comparative studies, articulating spacers have shown better ROM than the static spacers [5,8,11]. However, Fehring et al [9] reported that mobile spacers offered no functional advantages over static spacers as the mean ROM was statistically similar (105° vs 98°). In the present study, there was no significant difference of the preoperative and final ROM between the 2 groups. This finding was inconsistent with our original hypothesis, and we attribute this result to our conservative rehabilitation for ROM in the prosthetic group. They did not receive formal physical therapy between stages and post reimplantation, which was usually emphasized in other reports [14]. Fehring et al [9] noted that 60% of the patients in the static group had bone loss, whereas the articulating group did not show any measurable bone loss. Hsu et al [5] also reported that 100% of the knees in the static group had bone loss, whereas 48% of cases in the articulating group had bone loss. In our study, a consistent evaluation of bone loss was not performed. However as a surrogate for this, we compared use of constrained implants in the 2 groups. We found that the static group required more constraint than the prosthetic group (76 % vs 57%), although statistically not significant. Moreover, we found that an extensile approach was required much less frequently in the articulating group, which was consistent with previous report of Hsu et al [5]. Our findings suggest that the prosthetic spacer can maintain soft tissue tension with ligamentous stability and conserve bone well enough to allow for less constrained types of prostheses at the time of reimplantation. However, prosthetic spacers invariably cost more than static cement spacers. Without any obvious improvement in infection control rates or clinical outcomes, this added expense should be questioned. Potential advantages, as outlined above, may include the use of fewer augments, constrained devices, extensile exposures, and increased surgical times. A cost-effectiveness analysis, while beyond the scope of this study, would need to be conducted before the recommended use of either these techniques as the most cost-effective use of resources. Limitations of our study are its retrospective study design. Our study group was established over a long period during which treatment protocols may have evolved. This might have led heterogeneity of spacer design or surgical technique, and it might have affected the treatment results. In addition, an uneven distribution of number of cases and follow-up periods between 2
groups may lead to potential bias. Finally, patients were not randomized to the 2 groups. In summary, periprosthetic knee infections can be effectively controlled by prosthetic spacers without compromising the treatment outcome compared with that of static spacer. Prosthetic spacers less frequently required extensile surgical approach and constrained type prostheses at the time of reimplantation. Articulating spacers using prosthetic metal and polyethylene components can be a safe and effective method for the management of infection after TKA.
Acknowledgments The authors thank David Zurakowski, PhD, for his statistical help and Anthony Marchie, MD, for his help for preparing the manuscript.
References 1. Windsor RE, Insall JN, Urs WK, et al. Two-stage reimplantation for the salvage of total knee arthroplasty complicated by infection. Further follow-up and refinement of indications. J Bone Joint Surg Am 1990;72:272. 2. Goldman RT, Scuderi GR, Insall JN. 2-stage reimplantation for infected total knee replacement. Clin Orthop Relat Res 1996;331:118. 3. Cuckler JM. The infected total knee: management options. J Arthroplasty 2005;20:33. 4. Hofmann AA, Goldberg T, Tanner AM, et al. Treatment of infected total knee arthroplasty using an articulating spacer: 2- to 12-year experience. Clin Orthop Relat Res 2005;430:125. 5. Hsu YC, Cheng HC, Ng TP, et al. Antibiotic-loaded cement articulating spacer for 2-stage reimplantation in infected total knee arthroplasty: a simple and economic method. J Arthroplasty 2007;22:1060. 6. Booth Jr RE, Lotke PA. The results of spacer block technique in revision of infected total knee arthroplasty. Clin Orthop Relat Res 1989;248:57. 7. Haleem AA, Berry DJ, Hanssen AD. Mid-term to long-term followup of two-stage reimplantation for infected total knee arthroplasty. Clin Orthop Relat Res 2004;428:35. 8. Emerson Jr RH, Muncie M, Tarbox TR, et al. Comparison of a static with a mobile spacer in total knee infection. Clin Orthop Relat Res 2002;404:132. 9. Fehring TK, Odum S, Calton TF, et al. Articulating versus static spacers in revision total knee arthroplasty for sepsis. The Ranawat Award. Clin Orthop Relat Res 2000; 380:9. 10. Haddad FS, Masri BA, Campbell D, et al. The PROSTALAC functional spacer in two-stage revision for infected knee replacements. Prosthesis of antibiotic-loaded acrylic cement. J Bone Joint Surg Br 2000;82:807. 11. Park SJ, Song EK, Seon JK, et al. Comparison of static and mobile antibiotic-impregnated cement spacers for the treatment of infected total knee arthroplasty. Int Orthop 2010;34:1181. 12. Meek RM, Masri BA, Dunlop D, et al. Patient satisfaction and functional status after treatment of infection at the site
Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al
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16.
17.
18.
of a total knee arthroplasty with use of the PROSTALAC articulating spacer. J Bone Joint Surg Am 2003;85-A:1888. Hofmann AA, Kane KR, Tkach TK, et al. Treatment of infected total knee arthroplasty using an articulating spacer. Clin Orthop Relat Res 1995;321:45. Anderson JA, Sculco PK, Heitkemper S, et al. An articulating spacer to treat and mobilize patients with infected total knee arthroplasty. J Arthroplasty 2009; 24:631. Jamsen E, Sheng P, Halonen P, et al. Spacer prostheses in two-stage revision of infected knee arthroplasty. Int Orthop 2006;30:257. Greidanus NV, Masri BA, Garbuz DS, et al. Use of erythrocyte sedimentation rate and C-reactive protein level to diagnose infection before revision total knee arthroplasty. A prospective evaluation. J Bone Joint Surg Am 2007;89:1409. Parvizi J, Ghanem E, Menashe S, et al. Periprosthetic infection: what are the diagnostic challenges? J Bone Joint Surg Am 2006;88(Suppl 4):138. Trampuz A, Hanssen AD, Osmon DR, et al. Synovial fluid leukocyte count and differential for the diagnosis of prosthetic knee infection. Am J Med 2004;117:556.
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19. Tsukayama DT, Estrada R, Gustilo RB. Infection after total hip arthroplasty. A study of the treatment of one hundred and six infections. J Bone Joint Surg Am 1996;78:512. 20. McPherson EJ, Woodson C, Holtom P, et al. Periprosthetic total hip infection: outcomes using a staging system. Clin Orthop Relat Res 2002;403:8. 21. Jamsen E, Stogiannidis I, Malmivaara A, et al. Outcome of prosthesis exchange for infected knee arthroplasty: the effect of treatment approach. Acta Orthop 2009;80:67. 22. Duncan CP, Beauchamp C. A temporary antibiotic-loaded joint replacement system for management of complex infections involving the hip. Orthop Clin North Am 1993; 24:751. 23. Pitto RP, Spika IA. Antibiotic-loaded bone cement spacers in two-stage management of infected total knee arthroplasty. Int Orthop 2004;28:129. 24. Mortazavi SM, Vegari D, Ho A, et al. Two-stage exchange arthroplasty for infected total knee arthroplasty: predictors of failure. Clin Orthop Relat Res 2011;469:3049. 25. Sherrell JC, Fehring TK, Odum S, et al. The Chitranjan Ranawat Award: fate of two-stage reimplantation after failed irrigation and debridement for periprosthetic knee infection. Clin Orthop Relat Res 2011;469:18.
Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al Table 1. Comparison of Baseline Demographic Data Variables Age ≤65 N65 Sex Male Female Host factor Uncompromised Compromised Diabetes mellitus Yes No Type of infection Early postoperative Acute hematogenous Chronic Preoperative treatment history Yes No Prior surgery Primary Revision Other † Microorganism S aureus Others Bacterial resistance Methicillin resistant Others Extensile approach at first stage Extensile approach at second stage Prostheses reimplanted Constrained Others ROM, degrees Preoperative Latest follow-up Time between stages, mo Follow-up, mo Complication Yes No Treatment result ‡ Success Failure
Prosthetic Group (n = 14)
Static Group (n = 33)
P .36
9 (64%) 5 (36%)
16 (48%) 17 (52%)
7 (50%) 7 (50%)
17 (52%) 16 (48%)
6 (43%) 8 (57%)
16 (48%) 17 (52%)
6 (43%) 8 (57%)
8 (24%) 25 (76%)
0 (0%) 6 (43%) 8 (57%)
0 (0%) 5 (15%) 28 (85%)
1.00
.76
.30
.06
.52 6 (43%) 8 (57%)
19 (58%) 14 (42%)
10 (71%) 4 (29%) 0 (0%)
25 (76%) 7 (21%) 1 (3%)
5 (36%) 9 (64%)
12 (36%) 21 (64%)
2 (14%) 12 (86%) 2 (14%)
14 (42%) 19 (58%) 15 (45%)
.05
4 (29%)
25 (76%)
b.01 *
8 (57%) 6 (37%)
25 (76%) 8 (24%)
82 ± 25 100 ± 26 6 (3-8)
77 ± 25 97 ± 15 6 (4-7)
.61 .60 .68
43 ± 26
63 ± 27
.02 * 1.00
1 (7%) 13 (93%)
4 (12%) 29 (88%)
10 (71%) 4 (29%)
22 (67%) 11 (33%)
.71
1.00
.09
.30
1.00
* Statistically significant. † Referred from outside hospital in resection arthroplasty state. ‡ Any type of additional surgery for recurrent or persistent infection was considered failure.
1479.e1
Are Prosthetic Spacers Safe to Use in 2-Stage Treatment for Infected Total Knee Arthroplasty? Ho-Rim Choi, MD, Henrik Malchau, MD, PhD, and Hany Bedair, MD
Abstracts: This retrospective study compares treatment results of infected total knee arthroplasty with 2-stage exchange technique using 14 articulating spacers using metallic and polyethylene components (prosthetic group) and 33 static all-cement spacer (static group). For the prosthetic and static groups, treatment success rate was 71% and 67% at 58 months of follow-up, respectively, and not significantly different. The prosthetic group required less frequent extensile surgical approaches at the second-stage reimplantation. Range of motion was significantly improved in both groups, but there was no difference at latest follow-up between the groups. Of 14 in the prosthetic group, 4 (28%) did not undergo second-stage procedure. Antibiotic spacers consisting of prosthetic components can be a safe and effective treatment option for 2-stage revision total knee arthroplasty with equivalent infection control rates. Keywords: total knee arthroplasty, infection, two-stage revision, prosthetic spacer, static spacer, comparison. © 2012 Elsevier Inc. All rights reserved.
Two-stage exchange arthroplasty with delayed reimplantation is considered the standard treatment of chronic infection after total knee arthroplasty (TKA) with an infection control rate of approximately 85% to 95% [1-5]. During the interim period between the 2 stages, different spacer options are available: resection arthroplasty (no spacer), antibiotic cement beads, static antibiotic cement block, or articulating spacer. However, there is no consensus on the optimal spacer for this interim period, and the choice can depend on many variables, including chronicity of the infection, host condition, and virulence of the infecting organism, but most likely, the choice is based upon the treating surgeons' preference. Of these treatment options, a static antibiotic cement block spacer has been widely used with satisfactory infection control rates of approximately 84% to 96% [6,7]. However, a static spacer has disadvantages of interim functional disability, soft tissue contractures that
From the Department of the Orthopaedic Surgery, Massachusetts General Hospital, Boston, Massachusetts. Submitted October 30, 2011; accepted February 24, 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.2012.02.023. Reprint requests: Hany Bedair, MD, Department of Orthopedic Surgery, Massachusetts General Hospital, 55 Fruit St, Yawkey-3B, Boston, MA 02114. © 2012 Elsevier Inc. All rights reserved. 0883-5403/2708-0010$36.00/0 doi:10.1016/j.arth.2012.02.023
can make the subsequent second stage difficult, and compromise of bone stock [8-11]. To overcome these disadvantages, all-cement, articulating, functional spacers have been developed. This type of articulating spacers can provide joint motion and proper soft tissue tension during interim periods, which may make the second-stage procedure easier and lead to increased ultimate range of motion (ROM) [10,12]. A number of studies have reported successful infection control and improved ROM using articulating antibiotic-loaded cement spacers [5,11]. In a similar technique, Hofmann et al used the removed and resterilized femoral component and a new all-polyethylene tibial component, which were fixed with antibiotic-laden cement as the spacer. They reported no recurrence of infection and increased ROM by this technique in their series of 26 chronic infections of TKA [13]. Other studies of articulating spacers using similar techniques to Hofmann et al [13] also reported successful treatment outcome [3,4,14,15]. However, this method of an articulating prosthetic spacer is not widely used and likely due to the concern about reimplanting metallic and polyethylene components in an infected bed, which may hinder effective infection control by harboring bacteria on these foreign bodies. Furthermore, although articulating spacers are known to show improved ROM and to demonstrate an infection control comparable with that of static spacers, few studies directly compare prosthetic spacers and static cement spacers [8].
1474
Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al
The purpose of this study was to compare the characteristics and treatment results of articulating prosthetic spacers with that of static, all-cement spacers and outline the role of articulating prosthetic spacers in infected TKA. We hypothesized that prosthetic spacers not only would provide effective control of infection but would also allow better ROM and less need for extensile approach and constrained type implants at the time of reimplantation.
Materials and Methods Between January 2000 and January 2009, 65 patients with an infected TKA were managed by 2stage revision arthroplasty at our institution. Of these, 4 died of unrelated disease within 1 year, 6 were lost to follow-up, and 8 were referred from an outside center and received only the second-stage reimplantation (n = 6) or fusion (n = 2) as the first procedure at our institution. Excluding these 18 patients, the remaining 47 patients were treated by spacer insertion with planned delayed reimplantation and included in this retrospective analysis. There were 23 males and 24 females, and the mean age at the first-stage operation was 64 years (range, 38-85 years). The diagnosis for the primary arthroplasty was osteoarthritis in 39, posttraumatic arthritis in 4, rheumatoid arthritis in 2, congenital dislocation in 1, and unknown in 1. The primary TKA was performed at our institution in 9 knees and elsewhere in 38 knees. Twentynine patients had more than 2 operations on the knee before the first-stage operation. The mean follow-up period was 58 months (range, 14-118 months). Infection was diagnosed by positive culture results from a preoperative joint aspirate or intraoperative tissue specimens. With culture negative results, the diagnosis was made based on the presence of an abscess or draining sinus communicating to the joint, signs of acute inflammation consistent with infection on histopathologic examination (N5 neutrophils per high-powered field), or purulence surrounding the prosthesis at the time of surgery in conjunction with abnormal laboratory studies for erythrocyte sedimentation rate (ESR) (≥25 mm/h), C-reactive protein (CRP) (N8.0 mg/L), synovial fluid white blood cell (WBC) count (≥2000/μL), and synovial fluid polymorphonuclear differential count (N65%) [16-18]. Infection type was classified as early postoperative, acute hematogenous, and chronic infection based on suggestion of Tsukayama et al [19], and the patients were classified according to the method of McPherson et al [20] to characterize their host status (uncompromised, compromised, and significantly compromised). Any additional surgery to control persistent or recurrent infection other than the planned secondstage reimplantation was considered treatment failure. All patients were divided into 2 groups based on the type of interim spacer; (1) articulating prosthetic spacer
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(prosthetic group, n = 14) and (2) static cement block spacer (static group, n = 33). Selection of the spacer option was based on the treating surgeons' preference and not related to any specific patient factors. The each surgeon in this series consistently chose the same type of interim spacer with 2 surgeons using the prosthetic spacer and 3 surgeons using the static spacer. The firststage operation in both groups involved removal of all components and cement and a thorough irrigation and extensive debridement for all nonviable soft tissues and bone. For the prosthetic group, a new (n = 6) or removed and sterilized (n = 8) femoral component was used for the femoral side, and a new all-polyethylene tibial component (n = 7), removed and sterilized polyethylene insert (n = 3), or molded cement block (n = 4) was used for the tibial articulating surface. Reused components were sent for autoclave sterilization during the course of the surgery and reinserted as the spacer. The undersurface of these prosthetic spacers was coated with antibiotic cement and inserted into the resected femur and tibia without pressurization to avoid excessive interdigitation of the cement into the cancellous bone. For the static group, the spacer was made with a cylindrical-shaped cement puck when the antibiotic cement reached very doughy state and then inserted between the extension gap of the resected bone while the limb was manually distracted. In both groups, the antibiotic-loaded bone cement containing 1.0 g of vancomycin and 2.4 g of tobramycin in each 40 g of cement was used. After surgery, weight bearing as tolerated was allowed in both groups, with unrestricted ROM in for the prosthetic group. Patients received 6 weeks of intravenous antibiotic therapy based on culture results and consultation of infectious disease service. Patients were followed up at 2 weeks, 1 to 3 months, and 6 months after surgery. Wound conditions were evaluated, and spacer status was examined by radiographs. Serologic study for ESR, CRP was performed at regular intervals. The second-stage reimplantation was performed when the infection was judged to be controlled by a negative culture result on follow-up aspiration after at least 2 weeks of discontinuation of antibiotics and a normalizing trend of the laboratory findings (ESR, CRP, and joint aspirate WBC count with differential count). The final decision to proceed with reimplantation was made at the surgeons' discretion in the operating room in conjunction with intraoperative frozen section results. The second-stage operation was performed through the same skin incision as the first stage, and extensile approach was used at the surgeons' discretion. All patients were asked to follow up at 2 weeks, 1 to 3 months, 1 year, and the 2 to 3 years postoperatively. The mean clinical and radiographic follow-up period was 43 months (range, 17-102) for the prosthetic group and 63 months (range, 14-118) for static group (P = .02). The
1476 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 mean time between the first- and second-stage procedures was 6 months in both groups. Patients' demographics, type of infection, previous history of infection treatment, type of prior surgery, microorganisms, surgical approach and type of reimplanted prostheses (level of constraint), ROM, rates of complication, and treatment success were analyzed using SPSS Ver. 17.0 (SPSS, Chicago, Ill). χ 2 And Fisher exact tests were used to determine the differences in proportions for each variable between the prosthetic and static groups. The independent-sample t test was used to compare the means of continuous variables between the 2 study groups. P b .05 was considered statistically significant.
Results There was no significant difference between the 2 groups in terms of patients' characteristics, type of infection, prior surgery, and microorganisms (Table 1; available online at www.arthroplastyjournal.org). Preoperative laboratory data were also no different between the groups (Table 2). Staphylococcus aureus was the most common microorganism in the prosthetic group, and S aureus and coagulase-negative Staphylococcus were the most common microorganisms in the static group (Table 3). The rates of treatment success for the prosthetic and static groups were 71% and 67%, respectively. There was no significant difference in the rate of treatment success between the groups (P = 1.00) (Table 1; available online at www.arthroplastyjournal.org). For the prosthetic group, 4 patients had recurrent infections after the second-stage reimplantation. Three were managed by repeat irrigation/debridement (I/D), and 1 was treated by repeat I/D and a subsequent 2-stage revision. Two of these 4 are still being treated at latest follow-up. In the static group, 11 patients demonstrated a recurrent infection (4 after the first-stage and 7 after the secondstage procedure). Four of them were managed by I/D, and 2 of them were managed by repeat 2-stage revision. Two patients were treated by arthrodesis; 2, by amputation; and 1, by resection and repeat I/D. Table 2. Comparison of Preoperative Laboratory Data Prosthetic Group (n = 14), Mean ± SD
Variables 3
Serum WBC (/mm ) ESR (mm/h) CRP (mg/L) Joint aspirate WBC (/mm3) Neutrophil (%)
Static Group (n = 33), Mean ± SD
P
9062 ± 3839 77 ± 37 48 ± 61
9490 ± 5830 95 ± 33 81 ± 88
.33 .10 .28
18 239 (3458-45 113) 96 (91-98)
66 500 (23 350-91 700) 94 (86-97)
.05 .50
Continuous data are expressed as mean ± SD, except joint aspirate values which are median (interquartile range) due to skewness.
Table 3. Bacterial Characteristics of 47 Knees Type of Microorganism
Prosthetic Group (n = 14)
Gram-positive S aureus MSSA MRSA Coagulase-negative Staphylococcus MSCNS MRCNS Staphylococcus lugdunensis Streptococcus species Propionibacterium acnes Peptostreptococcus Actinomyces Gram-negative Escherichia coli Klebsiella Pseudomonas Polybacterial Microorganism unknown
3 1
1 1 1 1
Static Group (n = 33)
5 6 4 7 2 1 1 1
1 1 2* 2
1 1† 4
Abbreviations: MSSA; methicillin-sensitive S aureus; MRSA, methicillin-resistant S aureus; MSCNS, methicillin-sensitive coagulasenegative Staphylococcus; MRCNS, methicillin-resistant coagulase-negative Staphylococcus. * Methicillin-sensitive S aureus + methicillin-sensitive coagulasenegative Staphylococcus, methicillin-sensitive coagulase-negative Staphylococcus + Enterococcus. † Methicillin-resistant S aureus + Streptococcus mitis.
In the prosthetic group, the mean preoperative ROM was 82° (range, 30°-115°), and the most recent ROM was 100° (range, 70°-130°). In the static group, the mean preoperative ROM was 77° (range, 45°-120°), and the latest ROM was 97° (range, 75°-130°). Range of motion improved significantly (preoperative vs followup) in both prosthetic (P = .048) and static (P b .001) group, but there was no significant difference of preoperative (P = .61) and follow-up (P = .60) ROM between the 2 groups. In the prosthetic group, 2 extensile approaches (quadriceps snip; “Q-snip”) were used for the firststage operation, and 4 extensile approaches (29%) (3 Qsnips, 1 tibial tubercle osteotomy [TTO]) for the secondstage reimplantation. In the static group, 15 extensile approaches (1 Q-snip and 14 TTO) were used for the first-stage operation, and 25 extensile approaches (76%) (5 Q-snip, 1 V-Y quadricepsplasty, and 19 TTO) for the second-stage reimplantation (Table 4). A significantly Table 4. Number of Extensile Surgical Approaches Used Surgical Approach First stage Q-snip TTO Second stage Q-snip V-Y quadricepsplasty TTO
Prosthetic Group (n = 14)
Static Group (n = 33)
2
1 14
3
5 1 19
1
Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al Table 5. Implant Used in the Second-Stage Reimplantation Implant Used Posterior stabilized Condylar constrained knee Hinged Others Not reimplanted Arthrodesis
Prosthetic Group (n = 14)
Static Group (n = 33)
2 6 2
6 21 4
4 2
larger number of extensile approaches were used in the static group (P b .01). In the prosthetic group, 8 patients (57%) received a semiconstrained (n = 6) or hinged TKA (n = 2) prostheses at reimplantation. Four patients (29%) did not undergo the second-stage reimplantation as the knee was functioning well with the prosthetic spacer and the infection appeared controlled at a mean follow-up of 25 months. In the static group, 25 patients (76%) received semiconstrained (n = 21) or hinged TKAs (n = 4) at reimplantation. Two patients underwent arthrodesis for the second-stage operation (Table 5). There were no patients who retained their static spacer as the final treatment. Although statistically not significant (P = .30), the static group showed higher incidence of constrained type (semiconstrained or hinged) implant use. One patient in the prosthetic group had a noninfected hematoma formation after reimplantation, which was managed with an irrigation and debridement. In the static group, there was 1 periprosthetic femur fracture, 1 wound dehiscence, 1 spacer subluxation, and 1 arthrofibrosis. The periprosthetic fracture and spacer subluxation were managed conservatively by immobilization, and the wound dehiscence and arthrofibrosis required additional surgery for wound coverage and manipulation under anesthesia.
Discussion Although there are number of studies on the efficacy of 2-stage exchange arthroplasty, debate remains as to what type of spacer should be used between the stages. An ideal spacer should be durable, cost-effective, easily available, and effectively control infection while allowing for function during the interim periods. Traditionally, static cement spacers have been used, but recent results indicate that articulating spacers may have some benefit such as interim functionality, preservation of bone stock, and improved final ROM [8,11,21]. Various methods of preparing an articulating spacer for 2-stage revisions have been developed by many researchers; however, each method has its advantages and disadvantages. Cement-on-cement articulating spacer can be effectively fabricated by intraoperative molding [5,9,11]; however, this method does not provide an ideal articulating surface. These spacers usually demonstrate uncomfortable crepitation and ratcheting with joint
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motion. There is also concern about the particulate cement debris being generated from joint motion. On the other hand, since Duncan et al [22] reported satisfactory results of infection control using the prosthesis of antibiotic-loaded acrylic cement (PROSTALAC; DePuy, Warsaw, Ind), this system has shown acceptable infection control with a reasonable ROM between the stages [10,12]. However, this system is relatively expensive with extra costs associated with the specific molds and extra time for intraoperative fabrication. In the present study, we used new or removed, resterilized components for the femur and new or resterilized tibial polyethylene components or cement block for tibial articulating surface. This method is similar technique to the one described by Hofmann et al [13] in which resterilized femoral components and new all-polyethylene tibial inserts were used. This technique may provide an ideal articulating surface of less friction than that of cement-on-cement articulation and is potentially cost-effective and easily available compared with the commercially available molded spacers. Reusing the original autoclaved femoral or tibial component to treat infection is still controversial. A commonly stated concern in using this technique is the insertion of metal and polyethylene components within the joint in the face of infection; this theoretically could lead to bacterial adhesion to these foreign bodies [23]. The results of this study demonstrate that this type of spacer can control infection at rates comparable with the static spacer without increasing risk of infection. Moreover, 4 patients in the prosthetic group did not undergo second-stage reimplantation at the mean of 25 months follow-up as the joint was functioning well with infection control; these patients in effect have been successfully managed with a 1-stage exchange. Cuckler [3] also reported that 4 of their 44 patients treated with prosthetic spacer delayed a second-stage conversion more than 1 year because the patients were so comfortable with the articulated spacer. These findings suggest that prosthetic spacer not only effectively treat infection but could potentially obviate the need for the second stage in some cases, an option that does not appear to exist with an all-cement static or molded articulating spacer. Our overall success using either technique was lower than many previously reported series [1-5]. There may be several reasons for this. First, our definition of treatment failure of any additional surgery to control persistent or recurrent infection may contribute to a seemingly lower success rate with this technique. A recent study in which failure of 2-stage revision for infected TKAs was defined as any treated knee requiring further treatment of infection, similar to the current study, resulted in 28% of failure rate, which is comparable with the rate observed in this study [24]. In addition, as a tertiary care center, complex referrals
1478 The Journal of Arthroplasty Vol. 27 No. 8 September 2012 might also have contributed to the lower success rate. Many of the patients in this cohort had been referred by surgeons from outside our institution with various prior treatments for infection including antibiotic therapy and/or previous irrigation and debridement procedures, both known to effect the success rate of the 2-stage exchange [25]. In most comparative studies, articulating spacers have shown better ROM than the static spacers [5,8,11]. However, Fehring et al [9] reported that mobile spacers offered no functional advantages over static spacers as the mean ROM was statistically similar (105° vs 98°). In the present study, there was no significant difference of the preoperative and final ROM between the 2 groups. This finding was inconsistent with our original hypothesis, and we attribute this result to our conservative rehabilitation for ROM in the prosthetic group. They did not receive formal physical therapy between stages and post reimplantation, which was usually emphasized in other reports [14]. Fehring et al [9] noted that 60% of the patients in the static group had bone loss, whereas the articulating group did not show any measurable bone loss. Hsu et al [5] also reported that 100% of the knees in the static group had bone loss, whereas 48% of cases in the articulating group had bone loss. In our study, a consistent evaluation of bone loss was not performed. However as a surrogate for this, we compared use of constrained implants in the 2 groups. We found that the static group required more constraint than the prosthetic group (76 % vs 57%), although statistically not significant. Moreover, we found that an extensile approach was required much less frequently in the articulating group, which was consistent with previous report of Hsu et al [5]. Our findings suggest that the prosthetic spacer can maintain soft tissue tension with ligamentous stability and conserve bone well enough to allow for less constrained types of prostheses at the time of reimplantation. However, prosthetic spacers invariably cost more than static cement spacers. Without any obvious improvement in infection control rates or clinical outcomes, this added expense should be questioned. Potential advantages, as outlined above, may include the use of fewer augments, constrained devices, extensile exposures, and increased surgical times. A cost-effectiveness analysis, while beyond the scope of this study, would need to be conducted before the recommended use of either these techniques as the most cost-effective use of resources. Limitations of our study are its retrospective study design. Our study group was established over a long period during which treatment protocols may have evolved. This might have led heterogeneity of spacer design or surgical technique, and it might have affected the treatment results. In addition, an uneven distribution of number of cases and follow-up periods between 2
groups may lead to potential bias. Finally, patients were not randomized to the 2 groups. In summary, periprosthetic knee infections can be effectively controlled by prosthetic spacers without compromising the treatment outcome compared with that of static spacer. Prosthetic spacers less frequently required extensile surgical approach and constrained type prostheses at the time of reimplantation. Articulating spacers using prosthetic metal and polyethylene components can be a safe and effective method for the management of infection after TKA.
Acknowledgments The authors thank David Zurakowski, PhD, for his statistical help and Anthony Marchie, MD, for his help for preparing the manuscript.
References 1. Windsor RE, Insall JN, Urs WK, et al. Two-stage reimplantation for the salvage of total knee arthroplasty complicated by infection. Further follow-up and refinement of indications. J Bone Joint Surg Am 1990;72:272. 2. Goldman RT, Scuderi GR, Insall JN. 2-stage reimplantation for infected total knee replacement. Clin Orthop Relat Res 1996;331:118. 3. Cuckler JM. The infected total knee: management options. J Arthroplasty 2005;20:33. 4. Hofmann AA, Goldberg T, Tanner AM, et al. Treatment of infected total knee arthroplasty using an articulating spacer: 2- to 12-year experience. Clin Orthop Relat Res 2005;430:125. 5. Hsu YC, Cheng HC, Ng TP, et al. Antibiotic-loaded cement articulating spacer for 2-stage reimplantation in infected total knee arthroplasty: a simple and economic method. J Arthroplasty 2007;22:1060. 6. Booth Jr RE, Lotke PA. The results of spacer block technique in revision of infected total knee arthroplasty. Clin Orthop Relat Res 1989;248:57. 7. Haleem AA, Berry DJ, Hanssen AD. Mid-term to long-term followup of two-stage reimplantation for infected total knee arthroplasty. Clin Orthop Relat Res 2004;428:35. 8. Emerson Jr RH, Muncie M, Tarbox TR, et al. Comparison of a static with a mobile spacer in total knee infection. Clin Orthop Relat Res 2002;404:132. 9. Fehring TK, Odum S, Calton TF, et al. Articulating versus static spacers in revision total knee arthroplasty for sepsis. The Ranawat Award. Clin Orthop Relat Res 2000; 380:9. 10. Haddad FS, Masri BA, Campbell D, et al. The PROSTALAC functional spacer in two-stage revision for infected knee replacements. Prosthesis of antibiotic-loaded acrylic cement. J Bone Joint Surg Br 2000;82:807. 11. Park SJ, Song EK, Seon JK, et al. Comparison of static and mobile antibiotic-impregnated cement spacers for the treatment of infected total knee arthroplasty. Int Orthop 2010;34:1181. 12. Meek RM, Masri BA, Dunlop D, et al. Patient satisfaction and functional status after treatment of infection at the site
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of a total knee arthroplasty with use of the PROSTALAC articulating spacer. J Bone Joint Surg Am 2003;85-A:1888. Hofmann AA, Kane KR, Tkach TK, et al. Treatment of infected total knee arthroplasty using an articulating spacer. Clin Orthop Relat Res 1995;321:45. Anderson JA, Sculco PK, Heitkemper S, et al. An articulating spacer to treat and mobilize patients with infected total knee arthroplasty. J Arthroplasty 2009; 24:631. Jamsen E, Sheng P, Halonen P, et al. Spacer prostheses in two-stage revision of infected knee arthroplasty. Int Orthop 2006;30:257. Greidanus NV, Masri BA, Garbuz DS, et al. Use of erythrocyte sedimentation rate and C-reactive protein level to diagnose infection before revision total knee arthroplasty. A prospective evaluation. J Bone Joint Surg Am 2007;89:1409. Parvizi J, Ghanem E, Menashe S, et al. Periprosthetic infection: what are the diagnostic challenges? J Bone Joint Surg Am 2006;88(Suppl 4):138. Trampuz A, Hanssen AD, Osmon DR, et al. Synovial fluid leukocyte count and differential for the diagnosis of prosthetic knee infection. Am J Med 2004;117:556.
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19. Tsukayama DT, Estrada R, Gustilo RB. Infection after total hip arthroplasty. A study of the treatment of one hundred and six infections. J Bone Joint Surg Am 1996;78:512. 20. McPherson EJ, Woodson C, Holtom P, et al. Periprosthetic total hip infection: outcomes using a staging system. Clin Orthop Relat Res 2002;403:8. 21. Jamsen E, Stogiannidis I, Malmivaara A, et al. Outcome of prosthesis exchange for infected knee arthroplasty: the effect of treatment approach. Acta Orthop 2009;80:67. 22. Duncan CP, Beauchamp C. A temporary antibiotic-loaded joint replacement system for management of complex infections involving the hip. Orthop Clin North Am 1993; 24:751. 23. Pitto RP, Spika IA. Antibiotic-loaded bone cement spacers in two-stage management of infected total knee arthroplasty. Int Orthop 2004;28:129. 24. Mortazavi SM, Vegari D, Ho A, et al. Two-stage exchange arthroplasty for infected total knee arthroplasty: predictors of failure. Clin Orthop Relat Res 2011;469:3049. 25. Sherrell JC, Fehring TK, Odum S, et al. The Chitranjan Ranawat Award: fate of two-stage reimplantation after failed irrigation and debridement for periprosthetic knee infection. Clin Orthop Relat Res 2011;469:18.
Prosthetic Spacer for Infected Total Knee Arthroplasty Choi et al Table 1. Comparison of Baseline Demographic Data Variables Age ≤65 N65 Sex Male Female Host factor Uncompromised Compromised Diabetes mellitus Yes No Type of infection Early postoperative Acute hematogenous Chronic Preoperative treatment history Yes No Prior surgery Primary Revision Other † Microorganism S aureus Others Bacterial resistance Methicillin resistant Others Extensile approach at first stage Extensile approach at second stage Prostheses reimplanted Constrained Others ROM, degrees Preoperative Latest follow-up Time between stages, mo Follow-up, mo Complication Yes No Treatment result ‡ Success Failure
Prosthetic Group (n = 14)
Static Group (n = 33)
P .36
9 (64%) 5 (36%)
16 (48%) 17 (52%)
7 (50%) 7 (50%)
17 (52%) 16 (48%)
6 (43%) 8 (57%)
16 (48%) 17 (52%)
6 (43%) 8 (57%)
8 (24%) 25 (76%)
0 (0%) 6 (43%) 8 (57%)
0 (0%) 5 (15%) 28 (85%)
1.00
.76
.30
.06
.52 6 (43%) 8 (57%)
19 (58%) 14 (42%)
10 (71%) 4 (29%) 0 (0%)
25 (76%) 7 (21%) 1 (3%)
5 (36%) 9 (64%)
12 (36%) 21 (64%)
2 (14%) 12 (86%) 2 (14%)
14 (42%) 19 (58%) 15 (45%)
.05
4 (29%)
25 (76%)
b.01 *
8 (57%) 6 (37%)
25 (76%) 8 (24%)
82 ± 25 100 ± 26 6 (3-8)
77 ± 25 97 ± 15 6 (4-7)
.61 .60 .68
43 ± 26
63 ± 27
.02 * 1.00
1 (7%) 13 (93%)
4 (12%) 29 (88%)
10 (71%) 4 (29%)
22 (67%) 11 (33%)
.71
1.00
.09
.30
1.00
* Statistically significant. † Referred from outside hospital in resection arthroplasty state. ‡ Any type of additional surgery for recurrent or persistent infection was considered failure.
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