Total Femur Antibiotic Spacers: Effective Salvage for Complex Periprosthetic Joint Infections.

BACKGROUND: A simultaneous periprosthetic joint infection (PJI) of an ipsilateral hip and knee arthroplasty is a challenging complication of lower extremity reconstructive surgery. We evaluated the use of total femur antibiotic-impregnated polymethylmethacrylate (PMMA) bone cement spacers in the staged treatment of such limb-threatening PJIs. METHODS: Thirteen patients were treated with a total femur antibiotic spacer. The mean age at the time of spacer placement was 65 years. Nine patients had polymicrobial PJIs. All spacers incorporated vancomycin (3.0 g/40 g PMMA) and gentamicin (3.6 g/40 g PMMA), while 8 also included amphotericin (150 mg/40 g PMMA). Eleven spacers were biarticular. Twelve spacers were implanted through one longitudinal incision, while 8 of 12 reimplantations occurred through 2 smaller, separate hip and knee incisions. Mean follow-up after reimplantation was 3 years. RESULTS: Twelve (92%) patients underwent reimplantation of a total femur prosthesis at a mean of 26 weeks. One patient died of medical complications 41 days after spacer placement. At latest follow-up, 3 patients had experienced PJI recurrence managed with irrigation and debridement. One required acetabular component revision for instability. All 12 reimplanted patients retained the total femur prosthesis with no amputations. Eleven (91%) were ambulatory, and 7 (58%) remained on suppressive antibiotics. CONCLUSION: Total femur antibiotic spacers are a viable, but technically demanding, limb-salvage option for complex PJIs involving the ipsilateral hip and knee. In the largest series to date, there were no amputations and 75% of reimplanted patients remained infection-free. Radical debridement, antimicrobial diversity, prolonged spacer retention, and limiting recurrent soft tissue violation are potential tenets of success. LEVEL OF EVIDENCE: IV.

Mild Coronal Stem Malalignment Does Not Negatively Impact Survivorship or Clinical Results in Uncemented Primary Total Hip Arthroplasties With Dual-Tapered Implants.

BACKGROUND: Proper component positioning in total hip arthroplasty (THA) is crucial for implant fixation and hip stability. The purpose of this study is to assess if neutral coronal stem alignment (0° ± 3°) improved long-term survivorship in uncemented femoral components. METHODS: Between 2005 and 2010, 1028 primary THAs were performed with 2 contemporary dual-tapered, proximally coated uncemented stem types. Alignment was measured immediately postoperatively and at most recent follow-up. In total, 978 femoral stems (95%) were within 0° ± 3° of the neutral anatomic coronal axis, and the 50 stems (5%) outside that range were considered outliers (3.1° of valgus to 4.8° of varus). Outcomes analyzed included implant survivorship, Harris Hip Scores, and incidence of dislocation. Mean follow-up was 5 years. RESULTS: Survivorship free of aseptic femoral component loosening was 99.3% and 98.2% at 5 and 8 years in the neutral group vs 100% at 5 and 8 years in the outlier group (P = .98). Survivorship free of femoral component revision for any reason was 99.1% and 97.3% at 5 and 8 years vs 100% at 5 and 8 years, respectively (P = .80). Harris Hip Scores were similar (89 in both groups; P = .84) at most recent follow-up. The incidence of mild to moderate thigh pain was also similar in both groups (6.1% vs 6%, P = .85). The incidence of dislocation was 1.5% at 8 years, and similar between both groups (P = .77). CONCLUSION: Slight malalignment of contemporary dual-tapered uncemented THA femoral components does not appear to negatively impact survivorship or clinical outcomes, which is in contrast to cemented femoral components. LEVEL OF EVIDENCE III: Case-control study.

Two-Stage Revision Total Hip Arthroplasty With a Specific Articulating Antibiotic Spacer Design: Reliable Periprosthetic Joint Infection Eradication and Functional Improvement.

BACKGROUND: Two-stage revision utilizing spacers loaded with high-dose antibiotic cement prior to reimplantation remains the gold standard for treatment of periprosthetic joint infections (PJI) in total hip arthroplasty (THA) in North America, but there is a paucity of data on mid-term outcomes. We sought to analyze the survivorship free of infection, clinical outcomes, and complications of a specific articulating spacer utilized during 2-stage revision. METHODS: One hundred thirty-five hips (131 patients) undergoing a 2-stage revision THA for PJI with a specific articulating antibiotic spacer design from 2005 to 2013 were retrospectively reviewed. Infections were classified according to the Musculoskeletal Infection Society criteria. Mean age at resection was 65 years and mean follow-up was 5 years (rang, 2-10). RESULTS: Survivorship free of any infection after reimplantation was 92% and 88% at 2 and 5 years, respectively. Patients with a host-extremity grade of C3 compared to all patients with a host grade of A [hazard ratio (HR) 4.1, P = .05] were significant risk factors for poorer infection-free survivorship after reimplantation. Harris hip scores improved from a mean of 58 to a mean of 71 in the spacer phase (P = .002) and a mean of 81 post-reimplantation (P = .001). Fourteen (10%) patients dislocated after reimplantation, 9 (7%) of which required re-revision. Trochanteric deficiency (HR 19, P < .0001), dislocation of the articulating spacer prior to reimplantation [which occurred in 7 (5%) patients, 5 of whom subsequently dislocated the definitive implant] (HR 16, P < .0001), and female gender (HR 5, P = .002) were significant risk factors for post-reimplantation dislocation. CONCLUSION: Insertion of an articulating antibiotic spacer during a 2-stage revision THA for PJI demonstrates reliable infection eradication and improvement in clinical function, including the spacer phase. Patients with trochanteric deficiency and an articulating spacer dislocation are at high risk of post-reimplantation dislocation; judicial use of a dual-mobility or constrained device should be considered in these patients.

High Rate of Positive Cultures in Patients Referred With Antibiotic Spacers as Part of 2-Stage Exchange.

BACKGROUND: Two-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains the gold standard treatment in North America. Occasionally, patients with knee PJI are referred for definitive management after resection and antibiotic spacer placement. Currently, little literature exists to suggest how these patients should be managed. The purpose of this study is to report the clinical outcomes of these patients. METHODS: We retrospectively identified 54 patients (54 knees) from 2000 to 2012 treated for PJI with initial TKA resection and spacer placement performed somewhere other than the definitive treatment center. The mean age at reimplantation was 64 years, with 59% being male. Redebridement and antibiotic spacer exchange was performed for all patients. Mean follow-up was 6.5 years. RESULTS: Of the 54 knees, 22 (41%) grew an organism from a culture taken at the time of redebridement and spacer exchange. The most common organism identified at redebridement was Staphylococcus aureus (41%). Obtaining positive cultures at redebridement was not associated with presenting erythrocyte sedimentation rate (P = .46), C-reactive protein (P = .57), or the presence of retained cement (P = .13). Forty-nine of 54 (91%) knees were ultimately reimplanted. Two-year survivorship free of infection in reimplanted knees was 98%. CONCLUSION: Patients referred with an antibiotic knee spacer for PJI have a high rate of positive cultures at the time of redebridement. Neither the presenting serology nor the identification of retained cement was associated with obtaining positive cultures at the time of redebridement. Nevertheless, this unique cohort of patients has favorable outcomes when redebrided with spacer exchange prior to reimplantation.

Antibacterial and Biocompatible Titanium-Copper Oxide Coating May Be a Potential Strategy to Reduce Periprosthetic Infection: An In Vitro Study.

BACKGROUND: Periprosthetic infections are devastating for patients and more efficacious preventive strategies are needed. Surface-modified implants using antibacterial coatings represent an option to cope with this problem; however, manufacturing limitations and cytotoxicity have curbed clinical translation. Among metals with antibacterial properties, copper has shown superior in vitro antibacterial performance while maintaining an acceptable cytotoxicity profile. A thin film containing copper could prevent early biofilm formation to limit periprosthetic infections. This pilot study presents the in vitro antibacterial effect, cytotoxicity, and copper ion elution pattern of a thin film of titanium-copper oxide (TiCuO). QUESTIONS/PURPOSES: (1) Do titanium alloy (Ti6Al4V) discs coated with a thin film of TiCuO reduce Staphylococcus epidermidis biofilm and planktonic cell density compared with uncoated discs? (2) Do Ti6Al4V discs coated with a thin film of TiCuO affect normal human osteoblast viability compared with untreated cells? (3) Is copper ion concentration generated by coated discs lower than previously published copper ion concentrations that cause 50% toxicity in similar human cell lines in vitro (TC50)? METHODS: Ninety Ti6Al4V discs (12.5 mm diameter; 1.25 mm thick) were used in this study. Seventy-two Ti6Al4V discs were coated with a thin film of either titanium oxide (TiO) or TiCuO containing 20%, 40%, or 80% copper using high-power impulse magnetron sputtering (HiPIMS). Eighteen Ti6Al4V discs remained uncoated for control purposes. We tested antibacterial properties of S epidermidis grown on discs in wells containing growth medium. After 24 hours, planktonic bacteria as well as biofilms removed by sonication were quantitatively cultured. Annexin/Pi staining was used to quantify in vitro normal human osteoblast cell viability at 24 hours and Day 7, respectively. Copper elution was measured at Days 1, 2, 3, 7, 14, and 28 using an inductively coupled plasma mass spectrometer to analyze aliquots of culture medium. Copper ion concentration achieved at 24 hours was compared with previously published TC50 for gingival fibroblast, a phenotypically similar cell line with available data regarding copper ion exposure. RESULTS: Discs coated with TiCuO 80% copper showed greater biofilm and planktonic cell density reduction when compared with other tested compositions (analysis of variance [ANOVA]; p < 0.001). Discs coated with TiCuO 80% copper showed mean biofilm and planktonic cell density of 4.0 log10 (SD = 0.4) and 5.7 log10 (SD = 0.2). Discs coated with TiCuO 80% showed a mean difference in biofilm and planktonic cell density of 2.5 log10 (95% confidence interval [CI], 1.9-3.1 log10; p < 0.001) and 1.2 (95% CI, 0.6-1.8; p < 0.001), respectively, when compared with uncoated discs. Normal human osteoblast viability did not differ among all groups at 24 hours (ANOVA; p = 0.2) and Day 7 (ANOVA; p = 0.7). Discs coated with TiCuO 80% copper showed a mean difference (95% CI) in relative cell viability (%) at 24 hours and Day 7 of 31.1 (95% CI, -19.4 to 81.7; p = 0.4) and -5.0 (95% CI, -7.8 to 17.9; p = 0.9), respectively, when compared with untreated cells. For all TiCuO-coated discs, copper ion elution peaked at 24 hours and slowly decreased in a curvilinear fashion to nearly undetectable levels by Day 28. Discs coated with TiCuO 80% copper showed mean copper ion concentration at 24 hours of 269.4 µmol/L (SD = 25.2 µmol/L) and this concentration was lower than previously published TC50 for similar human cell lines at 24 hours (344 µmol/L, SEM = 44 µmol/L). CONCLUSIONS: This pilot study demonstrates a proof of concept that a thin-film implant coating with TiCuO can provide a potent local antibacterial environment while remaining relatively nontoxic to a human osteoblast cell line. Further research in an animal model will be necessary to establish efficacy and safety of this technique and whether it might be useful in the design of implants. CLINICAL RELEVANCE: A thin film coating with TiCuO demonstrates high antibacterial activity and low cellular cytotoxicity to human osteoblasts in vitro. Taken together, these properties represent a potential strategy for preventing periprosthetic infection if further work in animal models can confirm these results in vivo.

Disclosing Agents for the Intraoperative Identification of Biofilms on Orthopedic Implants.

BACKGROUND: Disclosing agents are dyes used in dentistry to colorize plaque (biofilm) and may offer a means for intraoperative detection of biofilms on orthopedic implants. Methylene blue (MB) stains biofilm and is safely used in orthopedic applications. Injection of MB into acutely infected prosthetic knees before debridement may enable visualization of biofilm, which could influence treatment decisions. The aims of this study were to determine if MB could be used to visualize biofilm on total knee arthroplasty (TKA) implants and to determine if MB staining has an antimicrobial effect that might interfere with subsequent culture. METHODS: Staphylococcus epidermidis biofilms were formed on TKA polyethylene liners and polymethylmethacrylate (PMMA) and Teflon discs. After staining biofilms on these implants, the bacterial densities were determined through sonication and quantitative culture. The antimicrobial activity of MB staining was determined by measuring the bacterial density of S. epidermidis biofilms on PMMA discs incubated in 0.05% MB for 24 hours vs 30 seconds and comparing it with controls unexposed to MB. RESULTS: MB stained S. epidermidis biofilms grown on TKA implants and Teflon and PMMA discs in vitro. Sonication and quantitative culture of the stained implants showed that bacterial densities were at supraphysiological levels. Staining did not affect the ability to culture the organism. CONCLUSION: MB is a possible cost-effective and novel method to expeditiously identify intraoperative biofilm. To further evaluate MB staining and its potential clinical usefulness, future studies are needed to assess the ability of MB to stain physiological levels of biofilm.

Antimicrobial-Loaded Bone Cement Does Not Negatively Influence Sonicate Fluid Culture Positivity for Diagnosis of Prosthetic Joint Infection.

We compared culture results to investigate the influence of antimicrobial-loaded cement on sonicate fluid culture positivity for the diagnosis of prosthetic joint infection. Fifty-four subjects were assessed. The sensitivities of sonicate fluid culture were 77.8% (14 of 18) in subjects with an antimicrobial-loaded cemented prosthesis and 58.3% (21 of 36) in subjects with an antimicrobial-free prosthesis.

The Mark Coventry Award: Trabecular metal tibial components were durable and reliable in primary total knee arthroplasty: a randomized clinical trial.

BACKGROUND: Although highly porous metals have demonstrated excellent bone ingrowth properties and so are an intriguing option for fixation in total knee arthroplasty (TKA), some surgeons are skeptical about the durability of uncemented tibial fixation and the potential for soft tissues to adhere to these porous metals and perhaps cause knee stiffness or pain. QUESTIONS/PURPOSES: The purpose of this study was to compare, in the context of a randomized clinical trial, a highly porous metal tibia compared with a traditional modular cemented tibia in terms of survivorship, Knee Society scores, range of motion (ROM), and complications. METHODS: From 2003 to 2006, 397 patients (age 67.8 ± 8.7 years; 54% female) were randomized to three groups: (1) traditional modular cemented tibia; (2) cemented highly porous metal tibia; and (3) uncemented highly porous metal tibia. The same posterior-stabilized femoral component and patella component were cemented in every case. Stratified randomization was done for surgeon, patient's age, sex, and body mass index. Survivorship at 5 years was compared between the groups, as were Knee Society scores, ROM, and complications. Radiographic assessment included alignment, radiolucency, and implant migration/loosening. Patients were followed until death, revision, or for a minimum of 2 years (mean, 5 years; range, 2-9 years). Four patients were lost to followup before 2 years. RESULTS: Highly porous metal tibias (both uncemented and cemented) were no different from traditional cemented modular tibial modular components in terms of survivorship at 5 years using a intention-to-treat analysis (96.8% [1]; 97.6% [2]; 96.7% [3]; p = 0.59). A per-protocol analysis revealed that no highly porous metal tibia was revised for aseptic loosening. Highly porous metal tibias performed comparably to traditional cemented modular tibias in terms of Knee Society scores, ROM, and the frequency of complications. CONCLUSIONS: At 5 years this randomized clinical trial demonstrated that highly porous metal tibias provided comparably durable fixation and reliable pain relief and restoration of function when compared with a traditional cemented modular tibia in TKA. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Elution of High Dose Amphotericin B Deoxycholate From Polymethylmethacrylate.

Fungal periprosthetic joint infections are rare, devastating complications of arthroplasty. There is conflicting evidence as to the efficacy of amphotericin B elution from cement spacers. The purpose of this study was to determine whether concentrations of amphotericin B released from bone cement over time would be efficacious in treating a periprosthetic infection. A continuous flow chamber was used to evaluate the in vitro release of amphotericin from cement beads containing 7.5% amphotericin. Following polymerization, 3.3% of the initially loaded amphotericin B was detected. The peak mean concentration eluted from the bone cement was 0.33 µg/mL at 8 hours. The AUC0-24 was 2.79 µg/mL/h; 0.20% of the amphotericin B was released. In conclusion, amphotericin B is released from bone cement at a clinically useful concentration.

Uncemented porous tantalum acetabular components: early follow-up and failures in 613 primary total hip arthroplasties.

Uncemented tantalum acetabular components were introduced in 1997. The purpose was to determine the 2- to 10-year results with this implant material in primary total hip arthroplasty. Our registry identified all primary total hip cases with porous tantalum cups implanted from 1997 to 2004. Clinical outcomes and radiographs were studied. 613 cases were identified. Seventeen percent of patients were lost to follow-up. Twenty-five reoperations were performed (4.4%). Acetabular cup removal occurred in 6 cases (1.2%). No cups were revised for aseptic loosening. Incomplete radiolucent lines were found on 9.3% of initial postoperative radiographs. At 2 years, 67% had resolved. Zero new radiolucent lines were detected. Two- to 10-year results of porous tantalum acetabular components for primary total hip arthroplasty demonstrate high rates of initial stability and apparent ingrowth.

Marlex Mesh Reconstruction of the Extensor Mechanism: A Concise 5-Year Follow-up of 2 Previous Reports.

LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Aseptic tibial debonding as a cause of early failure in a modern total knee arthroplasty design.

BACKGROUND: We observed isolated tibial component debonding from the cement in one modern primary TKA design (NexGen LPS 3° tibial tray; Zimmer, Warsaw, IN, USA). This failure mechanism is sparsely reported in the literature. QUESTIONS/PURPOSES: We (1) assessed survivorship of this tibial tray with special emphasis on debonding; (2) described clinical and radiographic features associated with tibial failure; and (3) compared patient and radiographic features of the failures with a matched cohort. METHODS: A total of 1337 primary TKAs were performed with a cemented NexGen LPS 3° tibial tray over an 11-year period. Twenty-five knees (1.9%) were revised for tibial debonding. BMI and radiographic alignment in the tibial debonding group were compared with a matched control group. Implant survivorship was assessed using tibial debonding as the end point. RESULTS: Survival free of revision from tibial debonding was 100% at 1 year and 97.8% at 5 years. The tibial failures shared a typical radiographic pattern with debonding at the cement-implant interface and subsidence into varus and flexion. We found no link between limb alignment or individual component alignment and failure because 22 of the 25 failures occurred in well-aligned knees. CONCLUSIONS: Our standardized followup of patients undergoing TKA at routine intervals allowed us to discover a higher rate of revision resulting from tibial debonding. We have discontinued the use of this particular tibial tray for primary TKA and surveillance for patients undergoing TKA continues to be warranted.

Dental procedures as risk factors for prosthetic hip or knee infection: a hospital-based prospective case-control study.

BACKGROUND: The actual risk of prosthetic joint infection as a result of dental procedures and the role of antibiotic prophylaxis have not been defined. METHODS: To examine the association between dental procedures with or without antibiotic prophylaxis and prosthetic hip or knee infection, a prospective, single-center, case-control study for the period 2001-2006 was performed at a 1200-bed tertiary care hospital in Rochester, Minnesota. Case patients were patients hospitalized with total hip or knee infection. Control subjects were patients who underwent a total hip or knee arthroplasty but without a prosthetic joint infection who were hospitalized during the same period on the same orthopedic floor. Data regarding demographic features and potential risk factors were collected. Logistic regression was used to assess the association of variables with the odds of infection. RESULTS: A total of 339 case patients and 339 control subjects were enrolled in the study. There was no increased risk of prosthetic hip or knee infection for patients undergoing a high-risk or low-risk dental procedure who were not administered antibiotic prophylaxis (adjusted odds ratio [OR], 0.8; 95% confidence interval [CI], 0.4-1.6), compared with the risk for patients not undergoing a dental procedure (adjusted OR, 0.6; 95% CI, 0.4-1.1) respectively. Antibiotic prophylaxis in high-risk or low-risk dental procedures did not decrease the risk of subsequent total hip or knee infection (adjusted OR, 0.9 [95% CI, 0.5-1.6] and 1.2 [95% CI, 0.7-2.2], respectively). CONCLUSIONS: Dental procedures were not risk factors for subsequent total hip or knee infection. The use of antibiotic prophylaxis prior to dental procedures did not decrease the risk of subsequent total hip or knee infection.

Varus-valgus constraint in 416 revision total knee arthroplasties with cemented stems provides a reliable reconstruction with a low subsequent revision rate at early to mid-term review.

AIMS: Varus-valgus constrained (VVC) implants are often used during revision total knee arthroplasty (TKA) to gain coronal plane stability. However, the increased mechanical torque applied to the bone-cement interface theoretically increases the risk of aseptic loosening. We assessed mid-term survivorship, complications, and clinical outcomes of a fixed-bearing VVC device in revision TKAs. METHODS: A total of 416 consecutive revision TKAs (398 patients) were performed at our institution using a single fixed-bearing VVC TKA from 2007 to 2015. Mean age was 64 years (33 to 88) with 50% male (199). Index revision TKA diagnoses were: instability (n = 122, 29%), aseptic loosening (n = 105, 25%), and prosthetic joint infection (PJI) (n = 97, 23%). All devices were cemented on the epiphyseal surfaces. Femoral stems were used in 97% (n = 402) of cases, tibial stems in 95% (n = 394) of cases; all were cemented. In total, 93% (n = 389) of cases required a stemmed femoral and tibial component. Femoral cones were used in 29%, and tibial cones in 40%. Survivorship was assessed via competing risk analysis; clinical outcomes were determined using Knee Society Scores (KSSs) and range of movement (ROM). Mean follow-up was four years (2 to 10). RESULTS: The five-year cumulative incidence of subsequent revision for aseptic loosening and instability were 2% (95% confidence interval (CI) 0.2 to 3, number at risk = 154) and 4% (95% CI 2 to 6, number at risk = 153), respectively. The five-year cumulative incidence of any subsequent revision was 14% (95% CI 10 to 18, number at risk = 150). Reasons for subsequent revision included PJI (n = 23, of whom 12 had previous PJI), instability (n = 13), and aseptic loosening (n = 11). The use of this implant without stems was found to be a significant risk factor for subsequent revision (hazard ratio (HR) 7.58 (95% CI 3.98 to 16.03); p = 0.007). KSS improved from 46 preoperatively to 81 at latest follow-up (p < 0.001). ROM improved from 96° prerevision to 108° at latest follow-up (p = 0.016). CONCLUSION: The cumulative incidence of subsequent revision for aseptic loosening and instability was very low at five years with this fixed-bearing VVC implant in revision TKAs. Routine use of cemented and stemmed components with targeted use of metaphyseal cones likely contributed to this low rate of aseptic loosening. Cite this article: Bone Joint J 2020;102-B(4):458-462.

Intermediate to Long-Term Follow-up of Cementing Liners into Well-Fixed Acetabular Components.

BACKGROUND: The cementation of a new liner into a well-fixed acetabular component is common during revision total hip arthroplasty (THA) for many indications, but most commonly for lack of a modern, compatible, highly cross-linked polyethylene (HXLPE) liner. However, little is known about the intermediate-term to long-term durability of this strategy. The purpose of this study was to evaluate the implant survivorship, risk of complications, clinical outcomes, and radiographic results of cementing a new HXLPE liner into a well-fixed acetabular component. METHODS: We retrospectively identified 323 revision THAs in which a nonconstrained HXLPE liner was cemented into a well-fixed acetabular component. The mean age at the time of the revision THA was 63 years, and 50% of patients were female. The most common indications for revision THA were polyethylene wear and osteolysis (48%), aseptic femoral loosening (35%), and hip instability (8%). The mean follow-up was 9 years. RESULTS: Polyethylene liner failure occurred in 11 cases (3%). In all cases, the cemented liner dissociated from the acetabular component. At 10 years, the survivorship free from any revision was 80% (95% confidence interval [CI], 75% to 84%) and the survivorship free from any reoperation was 77% (95% CI, 72% to 82%). The most common reason for re-revision was dislocation (45% of reoperations). A dislocation occurred in 17% of cases. Hips that underwent revision for instability were significantly more likely to dislocate compared with hips that underwent revision for liner wear (hazard ratio [HR], 2.3 [95% CI, 1.2 to 4.5]; p = 0.02). Elevated rim or face-changing liners were significantly more likely to dissociate than flat liners (HR, 9.0 [95% CI, 1.2 to 70.6]; p = 0.04). CONCLUSIONS: Cementation of a nonconstrained HXLPE liner into a well-fixed acetabular component during revision THA provided durable fixation with only a small number of failures at the cement interface (3%). Instability after this procedure remains a concern, but this is multifactorial in nature. These data support the continued use of this technique, when necessary, during revision THA. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Midterm to long-term followup of staged reimplantation for infected hip arthroplasty.

UNLABELLED: Most reports on two-stage reimplantation have focused on the short-term cure rate of infection, but little is known about long-term reinfection-free survival or mechanical durability. We retrospectively reviewed 168 patients (169 hips) with infected arthroplasty, all of whom had two-stage reimplantation for the treatment of an infected total hip arthroplasty between 1988 and 1998. In the second stage, the femoral component was fixed with antibiotic-loaded bone cement in 121 hips; the remaining femoral components and all acetabular components were uncemented. The minimum followup time was 2 years (mean, 7 years; range, 2-16 years). At most recent followup, 12 hips (7.1%) were reoperated on for reinfection and 13 hips (7.7%) were revised for aseptic loosening or osteolysis. Apparently aseptic loosening occurred on one or both sides of the joint in 24 hips (14.2%). The 10-year survivals free of reinfection and mechanical failure were 87.5% and 75.2% respectively. Nineteen hips dislocated and eight underwent revision surgery for instability. The method of femoral component fixation, either with or without cement, did not correlate with risk of infection, loosening, or mechanical failure. Based on these results, the method of fixation used for the femoral component during two-stage reimplantation surgery should be based on the surgeon's preference for fixation combined with the assessment of femoral bone stock. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Long-Term Outcomes of Constrained Liners Cemented into Retained, Well-Fixed Acetabular Components.

BACKGROUND: Cementation of a constrained liner is a viable option for treating instability after total hip arthroplasty (THA) when the acetabular component is well fixed and well aligned. However, concerns regarding long-term mechanical failure and recurrent instability remain. The aim of this study was to evaluate the long-term survivorship, complications, and clinical and radiographic outcomes of constrained polyethylene liners cemented into well-fixed acetabular components at the time of revision THA. METHODS: We identified 125 cases in which a constrained liner of 1 design was cemented into a retained, osseointegrated acetabular component during revision THA between 1998 and 2006. The mean patient age at revision was 70 years. Mean follow-up was 7 years. Survivorship data, risk of instability, and clinical and radiographic outcomes were analyzed. RESULTS: Survivorship free from revision for instability was 86% at 5 years and 81% at 10 years. Survivorship free from aseptic acetabular component revision was 78% at 5 years and 65% at 10 years, with the most common failure mechanism being dissociation of the constrained liner from the acetabular component. Survivorship free from revision for any reason was 76% at 5 years and 60% at 10 years. The most common complications were instability and periprosthetic joint infection, with cumulative incidences at 7 years of 18% and 11%, respectively. Harris hip scores did not significantly improve. Cup position did not affect implant survivorship or risk of dislocation. CONCLUSIONS: Cementing a constrained liner into a retained acetabular shell at the time of revision THA has durable long-term results, with 8 in 10 patients free from instability at 10 years. Aseptic acetabular survivorship was worse (65%) at 10 years, primarily due to dissociation of the constrained liner from the acetabular component. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Povidone-Iodine Wound Lavage to Prevent Infection After Revision Total Hip and Knee Arthroplasty: An Analysis of 2,884 Cases.

BACKGROUND: Postoperative infection remains a major challenge in revision total hip arthroplasty (THA) and revision total knee arthroplasty (TKA). Wound irrigation with dilute povidone-iodine (PI) solution has emerged as a simple, inexpensive, and potentially successful means of reducing postoperative infections. The aim of this study was to assess its effectiveness in reducing infection following revision THA and TKA in, to our knowledge, the largest revision cohort to date. METHODS: Using our institution's total joint registry, we identified 1,402 revision THAs and 1,482 revision TKAs performed during the study period (2013, when the PI irrigation protocol was first implemented, to 2017). The PI lavage protocol was employed in 27% of the revision THA cases and 34% of the revision TKA cases; in the remaining cases, the protocol was not used. Demographics, comorbid conditions, underlying surgical diagnoses, and whether the revision was for a septic or an aseptic etiology were compared between the groups (use or no use of PI irrigation). Any reoperation due to infection, as assessed at 3 and 12 months following revision arthroplasty, was compared between the groups and propensity scores were calculated to account for differences in baseline characteristics between the groups. RESULTS: After adjusting for baseline differences between the groups using the propensity-score weighted models, we found no significant difference in the rate of reoperation for infection at 3 months (p = 0.58 for revision THA, and p = 0.06 for revision TKA) and at 12 months (p = 0.78 for revision THA, and p = 0.06 for revision TKA). Nonetheless, the hazard ratios from the propensity-score model trended higher for patients who received PI lavage: 1.6 and 1.3 for revision THA at 3 and 12 months, respectively, and 2.9 at both 3 and 12 months for revision TKA. CONCLUSIONS: PI wound lavage demonstrated no benefit in reducing any reoperation for infection following revision THA and TKA. Moreover, the trend toward higher rates for reoperation for infection among patients who received PI irrigation merit further consideration. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Cementless fixation in total knee arthroplasty: past, present, and future.

Cementless fixation in total knee arthroplasty (TKA) has had limited use in recent decades due to past failures in the early generation of cementless designs. Screw track osteolysis, poor polyethylene, and metal-backed patellar component failures contributed to a controversial track record and created a reluctance to embrace cementless fixation in TKA; however, these failure mechanisms are correctable. In addition, there is renewed interest in cementless fixation due to the recent development of improved biomaterials, particularly highly porous metals and highly crosslinked polyethylene, as well as time-saving advantages and long-term osseointegration of cementless fixation. There are long-term reports of successful designs of cementless knee arthroplasty that are nearly equal to the results of cemented designs. This article discusses the past history, current long-term results, and future of cementless fixation in TKA.

Two-Stage Exchange and Marlex-Mesh Reconstruction for Infection with Extensor Mechanism Disruption After Total Knee Arthroplasty.

BACKGROUND: Periprosthetic joint infection (PJI) of the knee with concurrent disruption of the extensor mechanism is a devastating complication. Historically, knees with such complications have been salvaged with use of an arthrodesis or amputation. The purpose of this study was to assess the survival and functional outcomes of a 2-stage exchange arthroplasty combined with knitted monofilament polypropylene (Marlex; C.R. Bard) mesh reconstruction of the extensor mechanism. METHODS: From 2000 to 2015, 16 patients underwent a 2-stage exchange arthroplasty and Marlex-mesh reconstruction for PJI with an extensor mechanism disruption. The study included 9 male patients and 7 female patients with a mean age at the time of reimplantation and mesh reconstruction of 64 years. The mean follow-up was 4 years. PJI was diagnosed on the basis of the Musculoskeletal Infection Society criteria. Clinical outcomes, including survivorship, Knee Society Score (KSS) results, and complications, were assessed. RESULTS: Of 16 reconstructions, 13 were in place at the time of the latest follow-up. At 2 years, survivorship free of mesh failure was 86%, survivorship free of PJI was 87%, and survivorship free of PJI or mesh failure was 75%. The mean KSS improved from 48 prior to resection to 74 after mesh reconstruction and reimplantation. The mean extensor lag improved from 31° prior to resection to 3° after mesh reconstruction. Two patients required mesh revision, 1 patient required an above-the-knee amputation for complex wound complications related to reinfection, 1 patient developed a reinfection requiring irrigation and debridement, and 1 patient developed a superficial infection that required debridement. CONCLUSIONS: Two-stage exchange arthroplasty combined with Marlex-mesh reconstruction of the extensor mechanism is a viable alternative to knee arthrodesis or amputation. At 2 years, 75% of mesh reconstructions were in place and without evidence of PJI. Moreover, the functional outcomes were improved, with a negligible extensor lag. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.