No Revisions Attributable to Wear of Highly Cross-Linked Polyethylene Liners: A Long-Term Follow-Up Study.

BACKGROUND: There is a paucity of data beyond 15 years on the survivorship of total hip arthroplasty since the introduction of highly cross-linked polyethylene (HXLPE) liners. Our aim was to evaluate implant survivorship, liner wear rates, and clinical outcomes after primary total hip arthroplasty using HXLPE liners implanted between 1999 and 2002. METHODS: Between 1999 and 2002, 690 primary total hip arthroplasties utilizing 28-mm femoral heads and HXLPE liners of a single design were identified using our institutional total joint registry. Femoral heads were made of metal in 96% of cases and ceramic in 4%. The mean age was 56 years, 48% were women, and the mean body mass index was 30. Survivorship analyses were performed for the outcomes of implant revision, reoperation, and complications for the entire cohort. Linear HXLPE liner wear rates were determined on 197 hips with radiographs with more than 18.5 years of follow-up. RESULTS: At 20 years, survivorship free of revision was 94%, free of reoperation was 92%, and free of any complication was 81%. There were no documented wear-related revisions. The linear wear rate at a mean of 20.3 years postoperatively was 0.02 mm/y. There was no statistically significant difference in measured wear observed between the first available postoperative radiographs and those taken at the final follow-up. The use of elevated liners, patient body mass index, age, preoperative diagnosis, acetabular component inclination, and anteversion angles were not associated with increased wear rates. Mean Harris hip scores improved from 52 preoperatively to 90 at greater than 18.5 years CONCLUSIONS: Primary total hip arthroplasties using a single first-generation HXLPE liner demonstrated excellent survivorship and clinical outcomes at long-term follow-up with no wear-related revisions. Wear rates of HXLPE liners at 20 years are exceedingly low and are not significantly impacted by acetabular component position or patient-dependent variables such as BMI. LEVEL OF EVIDENCE: IV.

The Frank Stinchfield Award: Assembly and Dissociation Forces Differ Between Commonly Used Dual Mobility Implants: A Biomechanical Study.

BACKGROUND: Intraprosthetic dissociation (IPD) is a complication unique to dual mobility (DM) implants where the outer polyethylene head dissociates from the inner femoral head. Increasing reports of IPD at the time of closed reduction of large head DM dislocations prompted this biomechanical study evaluating the assembly and dissociation forces of DM heads. METHODS: We tested 17 polyethylene DM heads from 5 vendors. Of the heads, 12 were highly cross-linked polyethylene (4 vendors) and 5 were infused with vitamin E (2 vendors). Heads were between 46 and 47 mm in diameter, accepting a 28 mm-inner ceramic head. Implants were assembled and disassembled using a servohydraulic machine that recorded the forces and torques applied during testing. Dissociation was tested via both axial pull-out and lever-out techniques, where lever-out simulated stem-on-acetabular component impingement. RESULTS: The initial maximum assembly force was significantly different between all vendors (P < .01) and decreased for all implants with subsequent assembly. Vendor 4-E (Link with vitamin E) heads required the highest assembly force (1,831.9 ± 81.95 N), followed by Vendor 3 (Smith & Nephew), Vendor 5 (DePuy Synthes), Vendor 1-E (Zimmer Biomet with vitamin E), Vendor 2 (Stryker), and Vendor 1 (Zimmer Biomet Arcom). Vendor 4-E implants showed the greatest dissociation resistance in both pull-out (2,059.89 N, n = 1) and lever-out (38.95 ± 2.79 Nm) tests. Vendor 1-E implants with vitamin E required higher assembly force, dissociation force, and energy than Vendor 1 heads without vitamin E. CONCLUSIONS: There were notable differences in DM assembly and dissociation forces between implants. Diminishing force was required for assembly with each additional trial across vendors. Vendor 4-E DM heads required the highest assembly and dissociation forces. Vitamin E appeared to increase the assembly and dissociation forces. Based on these results, DM polyethylene heads should not be reimplanted after dissociation, and there may be a role for establishing a minimum dissociation energy standard to minimize IPD risk.

Femur-First Technique for Mobile Bearing Unicompartmental Knee Arthroplasty Results in Decreased Implant Variability and Early Improvements in Function and Survivorship.

BACKGROUND: Higher failure rates of unicompartmental knee arthroplasty (UKA) are seen with lower surgical volume. Surgical techniques that introduce less variability improving implant positioning may lead to improved survivorship. A femur-first (FF) technique has been described, but survivorship data compared to traditional tibia-first (TF) technique are under-reported. We report the results of mobile-bearing UKA using the FF technique compared to the TF technique with emphasis on implant position and survivorship. METHODS: A total of 430 UKAs were performed by a single surgeon between 2007 and 2020. After 2012, there were 141 consecutive UKAs performed with the FF technique which were compared with 147 consecutive UKAs prior. Mean follow-up was 6 years (range, 2 to 13 years), average age was 63 years (range, 23 to 92 years), and there were 132 women. Postoperative radiographs were reviewed to determine implant positioning. Survivorship analyses were performed using Kaplan-Meier curves. RESULTS: The FF resulted in significantly thinner polyethylene (3.4 ± 0.7 mm versus 3.7 ± 0.9 mm) (P = .002) and 4 mm or less bearing thickness in 94% of cases. At 5 years, there was an early trend toward improved survivorship free from component revision (98% for the FF group and 94% for the TF [P = .35]). The FF cohort had higher Knee Society Functional scores at final follow-up (P < .001). CONCLUSION: Compared to traditional TF technique, the FF was more bone-preserving and improved radiographic positioning. The FF technique is an alternative method for mobile-bearing UKA and was associated with an improvement in implant survivorship and function.

Comparative Survival of Contemporary Cementless Acetabular Components Following Revision Total Hip Arthroplasty.

BACKGROUND: The advent of highly porous ingrowth surfaces and highly crosslinked polyethylene has been expected to improve implant survivorship in revision total hip arthroplasty. Therefore, we sought to evaluate the survival of several contemporary acetabular designs following revision total hip arthroplasty. METHODS: Acetabular revisions performed from 2000 to 2019 were identified from our institutional total joint registry. We studied 3,348 revision hips, implanted with 1 of 7 cementless acetabular designs. These were paired with highly crosslinked polyethylene or dual-mobility liners. A historical series of 258 Harris-Galante-1 components, paired with conventional polyethylene, was used as reference. Survivorship analyses were performed. For the 2,976 hips with minimum 2-year follow-up, the median follow-up was 8 years (range, 2 to 35 years). RESULTS: Contemporary components with adequate follow-up had survivorship free of acetabular rerevision of ≥95% at 10-year follow-up. Relative to Harris-Galante-1 components, 10-year survivorship free of all-cause acetabular cup rerevision was significantly higher in Zimmer Trabecular Metarevision (hazard ratio (HR) 0.3, 95% confidence interval (CI) 0.2-0.45), Zimmer Trabecular MetaModular (HR 0.34, 95% CI 0.13-0.89), Zimmer Trilogy (HR 0.4, 95% CI 0.24-0.69), DePuy Pinnacle Porocoat (HR 0.24, 95% CI 0.11-0.51), and Stryker Tritanium revision (HR 0.46, 95% CI 0.24-0.91) shells. Among contemporary components, there were only 23 rerevisions for acetabular aseptic loosening and no rerevisions for polyethylene wear. CONCLUSION: Contemporary acetabular ingrowth and bearing surfaces were associated with no rerevisions for wear and aseptic loosening was uncommon, particularly with highly porous designs. Therefore, it appears that contemporary revision acetabular components have dramatically improved upon historical results at available follow-up.

Cobalt and Chromium Ion Release in Metal-on-Polyethylene and Ceramic-on-Polyethylene THA: A Simulator Study With Cellular and Microbiological Correlations.

BACKGROUND: The aims of this study were to determine the levels of cobalt (Co) and chromium (Cr) ions generated in simulators from metal-on-polyethylene (MoP) and ceramic-on-polyethylene (CoP) constructs. Furthermore, we aimed to investigate the cytotoxic effect of these ion levels on native tissues and their potential to modify periprosthetic joint infection risk. METHODS: We used in vitro culture of human adipose-derived mesenchymal stem cells (AMSCs) and Staphylococcus epidermidis cultures, respectively. Ten hip simulator constructs (5 MoP and 5 CoP) were assembled and run for 1,000,000 cycles in bovine serum and evaluated for CoCr concentration. Cytotoxicity and growth impact on AMSCs and S. epidermidis was compared between CoCr and inert silicon dioxide. RESULTS: After 1,000,000 cycles, mean MoP and CoP Co concentration was 2264 and 0.6 ng/mL, respectively (P < .001). Mean MoP and CoP Cr concentration was 217 and 4.3 ng/mL, respectively (P < .001). Mean MoP Co:Cr ratio was 10:1. Co ions were significantly more toxic to human AMSCs than control silicon dioxide in a dose-response manner (P < .001). S. epidermidis growth was not significantly impacted by Co concentrations observed in the simulators. CONCLUSION: MoP constructs built in ideal conditions generated substantial CoCr debris, highlighting a baseline risk with these implants that may be exacerbated by host factors or imperfect surgical technique. Evaluation of impact on AMSCs suggests that debris levels produced under simulator conditions can be cytotoxic. In addition, these concentrations did not potentiate or inhibit S. epidermidis growth, suggesting that elevated periprosthetic joint infection rates with adverse local tissue reaction are related to other factors potentially associated with tissue necrosis.

The Lawrence D. Dorr Surgical Techniques & Technologies Award: Why Are Contemporary Revision Total Hip Arthroplasties Failing? An Analysis of 2500 Cases.

BACKGROUND: As revision implants and techniques have evolved and improved, understanding why contemporary revision total hip arthroplasties (THAs) fail is important to direct further improvement and innovation. As such, the goals of this study are to determine the implant survivorship of contemporary revision THAs, as well as the most common indications for re-revision. METHODS: We retrospectively reviewed 2589 aseptic revision THAs completed at our academic institution between 2005 and 2015 through our total joint registry. Thirty-nine percent were isolated acetabular revisions, 22% isolated femoral revisions, 18% both component revisions, and 21% head/liner component exchanges. The mean age at index revision THA was 66 years, and 46% were male. The indications for the index revision THA were aseptic loosening (21% acetabular, 15% femoral, 5% both components), polyethylene wear and osteolysis (18%), instability (13%), fracture (11%), and other (17%). Mean follow-up was 6 years. RESULTS: There were 211 re-revision THAs during the study period. The overall survivorship free of any re-revision at 2, 5, and 10 years was 94%, 92%, and 88%, respectively. The most common reasons for re-revision were hip instability (52%), peri-prosthetic fracture (11%), femoral aseptic loosening (11%), acetabular aseptic loosening (9%), infection (6%), polyethylene wear (3%), and other (8%). CONCLUSION: Compared to historical series, the 88% survivorship free of any re-revision at 10 years in a revision cohort at a referral center is notably improved. As implant fixation has improved, aseptic loosening has become much less common after revision THA, and instability has come to account for more than half of re-revisions.

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.

Cementation of a Dual Mobility Construct in Recurrently Dislocating and High Risk Patients Undergoing Revision Total Arthroplasty.

BACKGROUND: Recurrent instability remains a challenge after revision total hip arthroplasty (THA). We report the outcomes of cementing a cementless dual mobility (DM) component into a stable acetabular shell for the treatment and/or prevention of instability in revision THA. METHODS: Eighteen patients (18 THAs) undergoing revision THA with a specific monoblock DM construct cemented into a new acetabular component or an existing well-fixed component from 2011 to 2014 were retrospectively reviewed. Tumor prostheses and total femoral replacements were excluded. In 9 patients (50%), components were implanted specifically for recurrent dislocations. Mean age was 64 years; mean follow-up was 3 years. Patients underwent an average of 4 prior hip operations (range 2-6). RESULTS: No cemented DM cups dissociated at the cement-cup interface. Three patients (17%) experienced a postoperative dislocation. One required a revision to constrained liner and 2 underwent open reduction with retention of the DM construct. Harris Hip Scores improved from 53 to 82 postoperatively (P < .001). CONCLUSION: Cementation of a monoblock cup DM construct, an off-label use as the construct is not specifically made for cementation, into a well-fixed acetabular component provides an alternative to enhance prosthetic stability in (1) recurrently dislocating THAs with well fixed, well-positioned acetabular components and (2) complex acetabular reconstructions in which constraint should be avoided. While not a perfect solution in this series, DM constructs provide a number of advantages including no added constraint at the interface and a large effective femoral head to diminish prosthetic impingement.

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.

Satisfactory Results of the Exeter Revision Femoral Stem Used for Primary Total Hip Arthroplasty.

BACKGROUND: The Exeter cemented femoral stem has demonstrated excellent clinical and radiographic outcomes as well as long-term survivorship free from aseptic loosening. A shorter revision stem (125 mm) with a 44 offset became available for the purpose of cement-in-cement revision situations. In certain cases, this shorter revision stem may be used for various primary total hip arthroplasties (THAs) where the standard length stem would require distally reaming the femoral canal. We sought to report on the early to midterm results of this specific stem when used for primary THA regarding (1) clinical and radiographic outcomes, (2) complications, and (3) survivorship. METHODS: Twenty-nine patients (33 hips) underwent a hybrid THA using the smaller revision Exeter cemented femoral stem. Twenty-five patients (28 hips) had at least 2 years of follow-up and were assessed for clinical and radiographic outcomes. All 33 hips were included in the analysis of complications and survivorship. The Kaplan-Meier survivorship was performed using revision for all causes and for aseptic loosening as the end points. RESULTS: The average clinical follow-up was 4 years (range, 2-7). Harris Hip Scores improved from a mean preoperative value of 56 (range, 23-96) to 90 (range, 51-100) at the latest follow-up. All patients demonstrated superior cement mantles with no signs of loosening. One patient suffered a B2 periprosthetic fracture and 1 patient experienced 2 episodes of instability. The 5-year Kaplan-Meier survivorship was 96.7% for all causes of revision and was 100% using aseptic loosening as the end point. CONCLUSION: The shorter Exeter revision cemented femoral stem has favorable early to midterm clinical and radiographic outcomes when used for primary THA with a low complication rate and is a viable option in patients with narrow femoral canals where uncemented stem fixation is not desired.

Characterizing the Diagnosis and Treatment of Allergic Contact Dermatitis to 2-Octyl Cyanoacrylate Used for Skin Closure in Elective Orthopedic Surgery.

BACKGROUND: While studies have shown that postoperative wound complications can predispose to deep infection following orthopedic surgery, the best form of skin closure has not been elucidated. Furthermore, the unique risks and benefits of each type of wound closure have not been studied. The goal of this study is to present the diagnosis and treatment of patients with allergic contact dermatitis (ACD) from 2-octyl cyanoacrylate, a skin adhesive commonly used in wound closure. METHODS: Twenty-nine patients with ACD to 2-octyl cyanoacrylate (Prineo, Ethicon, NJ) following elective orthopedic surgeries from 2013 to 2016 were retrospectively reviewed; this occurred in 29 of 6088 units of Prineo used at our institution, for an estimated incidence of 0.5%. Nineteen patients (66%) had knee operations. Mean age was 55 years (range, 15-92 years). We classified patients by symptom severity and treatment requirements into mild, moderate, and severe reactions. RESULTS: Most reactions were moderate (48%) or severe (38%) reactions. Mean time from surgery to diagnosis was 11.8 days (range, 2-42 days). All patients underwent removal of the Prineo dressing and daily dressing changes with a specific protocol. Twenty patients (69%) received oral antihistamines, 16 patients (55%) required topical corticosteroids, and 5 patients (17%) required oral corticosteroids. All cases of ACD ultimately resolved at a mean of 22 days (range, 13-56 days) postoperatively. CONCLUSION: 2-Octyl cyanoacrylate skin adhesive occurs in an estimated 0.5% of cases and can lead to severe postoperative ACD when used following orthopedic operations. However, with early recognition and appropriate treatment, patients' symptoms resolve without a significant impact on wound healing.

There Are No Differences in Short- to Mid-term Survivorship Among Total Hip-bearing Surface Options: A Network Meta-analysis.

BACKGROUND: Total hip arthroplasty (THA) is increasingly being performed in patients with long life expectancies and active lifestyles. Newer implant bearing surfaces, with superior wear characteristics, often are used in this cohort with the goal of improving longevity of the prosthesis, but comparisons across the numerous available bearing surfaces are limited, so the surgeon and patient may have difficulty deciding which implants to use. QUESTIONS/PURPOSES: The purpose of this study was to answer the following question: Is there a short- to mid-term survivorship difference between common THA bearings used in patients younger than age 65 years? METHODS: We conducted a systematic review to identify randomized clinical trials (RCTs) published after 2000 that reported survivorship of ceramic-on-ceramic (CoC), ceramic-on-highly crosslinked polyethylene (CoPxl), or metal-on-highly crosslinked polyethylene (MoPxl) bearings. To qualify for our review, RCTs had to have a minimum 2-year followup and study patients were required to have an average age younger than 65 years. Direct-comparison meta-analysis and network meta-analysis were performed to combine direct and indirect evidence. RESULTS: Direct-comparison meta-analysis found no differences among the bearing surfaces in terms of the risk of revision; this approach demonstrated a risk ratio for revision of 0.65 (95% confidence interval [CI], 0.19-2.23; p = 0.50) between CoC and CoPxl and a risk ratio for revision of 0.40 (95% CI, 0.06-2.63; p = 0.34) between CoC and MoPxl. Network meta-analysis (with post hoc modification) likewise found no differences in survivorship across the three implant types, demonstrating the following probabilities of most effective implant with 95% credible intervals (CrI): CoC = 64.6% (0%-100%); CoPxl = 24.9% (0%-100%); and MoPxl = 9.9% (0%-100%). The CrIs ranged from 0% to 100% for all three bearing surfaces. Direct-comparison meta-analysis allowed for pooling of five RCTs, including 779 THAs, whereas network meta-analysis (before post hoc analysis) enabled pooling of 18 RCTs, including 2599 THAs. CONCLUSIONS: Current published evidence does not support survivorship differences among commonly used bearing surfaces in patients younger than age 65 years undergoing THA at short- to mid-term followup. Long-term RCT data will be needed to determine if a survivorship benefit is realized in younger, more active patients over time. LEVEL OF EVIDENCE: Level I, therapeutic study.

Long-term results of the uncemented acetabular component in a primary total hip arthroplasty performed for protrusio acetabuli: a fifteen year median follow-up.

PURPOSE: Protrusio acetabuli is an uncommon finding that can be seen in patients undergoing primary total hip arthroplasty for arthritis. Uncemented fixation of the acetabular component and bone grafting of the protrusio defect is commonly used as a reconstruction method and has shown good mid-term results. The long-term outcome of these reconstructions warrants further study. The objective of this study was to determine the results of primary total hip arthroplasty (THA) with use of an uncemented acetabular component for protrusio acetabuli in patients followed for a minimum of ten years. METHODS: Sixty-five hips in 53 patients had a primary THA with uncemented acetabular component for the protrusio acetabuli between 1984 and 2001. There were 53 procedures performed in females (82%) and 12 in males (18%). The mean age at the procedure was 66 years. Acetabular floor reconstruction with use of bone graft was performed in 58 hips (89%). Four patients (five hips) were lost to follow-up less than ten years after the procedure and 25 patients (31 hips) had died during the follow-up period. The median follow-up of living patients that did not have revisions for acetabular component was 15.4 years (range, ten to 24 years). RESULTS: During the study duration, six hips underwent acetabular component revision: aseptic loosening (three hips), polyethylene wear (two hips), and recurrent instability (one hip). The median Harris hip score for the living patients who did not have an acetabular component revision improved from 55 points pre-operatively to 82 points at the latest follow-up. At 15 years, the estimated survival rate from revision was 70% for the THA: 85.4% for the acetabular component, and 83% for the femoral component. Five unrevised acetabular components had evidence of non-progressive radiolucency. CONCLUSIONS: In patients undergoing THA with acetabular protrusio, fixation of an uncemented hemispherical shell and use of bone graft as necessary provided satisfactory clinical and radiographic results as well as satisfactory survivorship rates at a median follow-up of 15 years.

Diaphyseal Impaction Grafting Combined with Metaphyseal Cones: Outcomes in 88 Revision Total Knee Arthroplasties.

BACKGROUND: Metaphyseal cones with cemented stems can be successfully utilized in most revision total knee arthroplasties (TKAs). However, if the diaphysis has been previously violated, fixation of the cemented stem, which is important for cone ingrowth and construct survival, can be compromised. The initial results of our novel technique combining diaphyseal impaction bone-grafting with a metaphyseal cone were promising but required additional study. The purpose of the present study was to assess results of this technique in a larger cohort. METHODS: A metaphyseal cone combined with diaphyseal impaction grafting and a cemented stem was utilized in 88 revision TKAs at our institution, including 35 from our prior study. The mean age at the time of revision was 67 years, and 67% of patients were male. Patients had had a mean of 4 prior knee arthroplasty procedures. The 2 most common reasons for revision were aseptic loosening (78%) and 2-stage reimplantation for periprosthetic joint infection (PJI) (19%). The mean follow-up was 4 years. RESULTS: At the time of the latest follow-up, no cone-impaction grafting constructs required re-revision for aseptic loosening. Five-year survivorship free from any revision of the cone-impaction grafting construct and free from any reoperation was 95% and 65%, respectively. A total of 25 knees (28%) underwent reoperation, with the 2 most common indications being PJI and periprosthetic fracture. All cones were osseointegrated, and all bone graft appeared stable or incorporated. One patient had radiographic evidence of tibial component loosening despite a well-fixed cone; however, this patient was asymptomatic and had not undergone revision at 9 years. CONCLUSIONS: When presented with a sclerotic, polished diaphyseal canal with deficient cancellous bone and concomitant metaphyseal bone loss, our technique of combining diaphyseal impaction grafting with a metaphyseal cone proved extremely durable in this larger series of patients. No cone-impaction grafting constructs required re-revision for aseptic loosening. 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.

Contemporary outcomes of primary total hip arthroplasty in patients with inflammatory arthritis.

Aims: Contemporary outcomes of primary total hip arthroplasties (THAs) with highly cross-linked polyethylene (HXLPE) liners in patients with inflammatory arthritis have not been well studied. This study examined the implant survivorship, complications, radiological results, and clinical outcomes of THA in patients with inflammatory arthritis. Methods: We identified 418 hips (350 patients) with a primary diagnosis of inflammatory arthritis who underwent primary THA with HXLPE liners from January 2000 to December 2017. Of these hips, 68% had rheumatoid arthritis (n = 286), 13% ankylosing spondylitis (n = 53), 7% juvenile rheumatoid arthritis (n = 29), 6% psoriatic arthritis (n = 24), 5% systemic lupus erythematosus (n = 23), and 1% scleroderma (n = 3). Mean age was 58 years (SD 14.8), 66.3% were female (n = 277), and mean BMI was 29 kg/m2 (SD 7). Uncemented femoral components were used in 77% of cases (n = 320). Uncemented acetabular components were used in all patients. Competing risk analysis was used accounting for death. Mean follow-up was 4.5 years (2 to 18). Results: The ten-year cumulative incidence of any revision was 3%, and was highest in psoriatic arthritis patients (16%). The most common indications for the 15 revisions were dislocations (n = 8) and periprosthetic joint infections (PJI; n = 4, all on disease-modifying antirheumatic drugs (DMARDs)). The ten-year cumulative incidence of reoperation was 6.1%, with the most common indications being wound infections (six cases, four on DMARDs) and postoperative periprosthetic femur fractures (two cases, both uncemented femoral components). The ten-year cumulative incidence of complications not requiring reoperation was 13.1%, with the most common being intraoperative periprosthetic femur fracture (15 cases, 14 uncemented femoral components; p = 0.13). Radiological evidence of early femoral component subsidence was observed in six cases (all uncemented). Only one femoral component ultimately developed aseptic loosening. Harris Hip Scores substantially improved (p < 0.001). Conclusion: Contemporary primary THAs with HXLPE in patients with inflammatory arthritis had excellent survivorship and good functional outcomes regardless of fixation method. Dislocation, PJI, and periprosthetic fracture were the most common complications in this cohort with inflammatory arthritis.

Midterm Results of Primary Exeter Cemented Stem in a Select Patient Population.

BACKGROUND: Most North American surgeons predominantly use uncemented stems in primary total hip arthroplasties (THAs) and reserve cemented stems for selected older patients and those with poor bone quality. However, data on this "selective use" strategy for cemented stems in the population at risk for periprosthetic fracture and implant loosening are limited. The purpose of this study was to describe implant survivorship, complications, and radiographic results of a specific collarless, polished, tapered cemented stem (Exeter; Stryker) used selectively in a predominantly elderly population undergoing primary THA. METHODS: We identified 386 patients who underwent a total of 423 primary THAs with selectively utilized Exeter stems for the treatment of osteoarthritis between 2006 and 2017. In the same time period, 11,010 primary THAs were performed with uncemented stems and 961 with non-Exeter cemented stems. The mean patient age was 77 years, 71% were female, and the mean body mass index was 29 kg/m2. Competing risk analysis accounting for death was utilized to determine cumulative incidences of revision and reoperation. The mean follow-up was 5 years (range, 2 to 12 years). RESULTS: The 10-year cumulative incidence of any femoral component revision in this patient cohort was 4%, with 10 stems revised at the time of the latest follow-up. There were no intraoperative femoral fractures. The indications for revision were postoperative periprosthetic femoral fracture (n = 6), dislocation (n = 3), and infection (n = 1). There were no revisions for femoral loosening. The 10-year cumulative incidence of reoperation was 10%. The 10-year cumulative incidence of Vancouver B periprosthetic femoral fracture was 2%. Radiographically, there were no cases of aseptic loosening or osteolysis. There was a significant improvement in median Harris hip score, from 53 preoperatively to 92 at a mean follow-up of 5 years (p < 0.001). CONCLUSIONS: The strategy of selectively utilizing a collarless, polished, tapered cemented stem produced a low (4%) cumulative incidence of stem revision at 10 years postoperatively and resulted in no cases of aseptic loosening. The use of the Exeter stem did not eliminate postoperative femoral fractures in this predominantly elderly, female patient population. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Streptococcus bovis Hip and Knee Periprosthetic Joint Infections: A Series of 9 Cases.

Introduction: Prosthetic joint infection (PJI) due to Streptococcus bovis group (SBG), specifically S. bovis biotype I (S. gallolyticus), is rare and associated with colorectal carcinoma. Little has been published regarding SBG PJI. We analyzed nine cases of SBG PJI at our institution, the largest series to date. Methods: The medical records of patients diagnosed with SBG PJI between 2000-2017 were reviewed. Patients were followed until death, failure, or loss to follow-up. Mean follow-up was 37 months (range 0.5-74 months). Results: Nine PJI in 8 patients with mean prosthesis age at diagnosis of 8 years (range 4 weeks-17 years) were identified. The median duration between symptom onset and treatment was 38 weeks (range 0.3 weeks-175 weeks). 8/9 had their PJI eradicated with treatment based on acuity of symptoms. Acute PJI (2) was treated with DAIR, and chronic PJI (7) was treated with 2-stage revision arthroplasty. 1 PJI with chronic PJI developed recurrent infection after initial treatment. All patients received post-operative IV antibiotics. 7/8 patients received Ceftriaxone. Three patients received lifelong oral antibiotics. 7/8 patients underwent colonoscopy. 5/7 patients were found to have polyps following PJI diagnosis with one carcinoma and two dysplastic polyps. The two patients without polyps had identifiable gastrointestinal (GI) mucosal abnormality: tooth extraction prior to symptom onset and diverticulosis on chronic anticoagulation. Conclusion: SBG PJI is typically due to hematologic seeding. Colonoscopy should be pursued for patients with SBG PJI. Surgical treatment dictated by infection acuity and 6-week course of Ceftriaxone seems sufficient to control infection.

Contemporary cementing technique and mortality during and after Exeter total hip arthroplasty.

The Exeter universal stem implanted with contemporary cementing technique has shown an excellent survivorship at 15 years. The technique used for implantation calls for prolonged pressurization preventing blood from the femur exiting into the femoral canal, but this technique is not accepted widely as some surgeons believe it is associated with significant morbidity. This concern prompted this review. From 1988 to 2005, 9082 primary total hip arthroplasty (THA) were implanted. We identified all patients who died within 30 days from surgery. When available, the postmortem results were reviewed. Twenty-one patients died within 30 days from their primary THA (prevalence, 0.23%). There was one intraoperative death (prevalence, 0.01%). The postmortem report was consistent with fat embolism. Two additional patients died the same day of surgery from cardiac processes. No other deaths could be linked to cement. Sudden death during cemented THA with a current contemporary cementing technique and a specialized anesthetic protocol is nearly zero.