Outcomes of Liner Exchange Versus Component Revision for the Treatment of Stiffness Following Primary Total Knee Arthroplasty.

BACKGROUND: This study aimed to compare outcomes of revision total knee arthroplasty (rTKA) with liner exchange (LE) versus component revision (CRev) for stiffness post-TKA. METHODS: We retrospectively identified all rTKA performed for stiffness after primary TKA using our institutional database (2003 to 2021). Cases with infection, loosening, or < two years follow-up were excluded. There were 129 rTKA included, 91 in the LE, and 38 in the CRev cohorts. The mean follow-up was 8.5 years (range, two to 21). The LE and CRev cohorts had similar baseline demographics (P > 0.05), previous manipulation (P = 0.45), time from primary TKA (P = 0.14), and pre-rTKA arc of motion (AOM) (P = 0.08). The primary outcomes were the achievement of a successful range of movement (ROM), defined as flexion ≥ 90° with an extension deficit of ≤ 10°, and AOM improvement. Kaplan-Meier analysis was used to compare survival free from re-revision between cohorts. RESULTS: For the entire cohort, 69% achieved a successful ROM, and the mean AOM improved (P < 0.001). Achievement of successful ROM was comparable between LE (72%) and CRev (62%) cohorts (P = 0.29). The mean gain in AOM was similar between LE (24.9°) and CRev (25.4°) cohorts (P = 0.45). Preoperative extension deficit was associated with poorer outcomes (P = 0.006). The 10-year re-revision-free survival was similar between the LE (86.2%) and CRev (81.1%) cohorts (P = 0.55). Survival from re-revision for stiffness at 10-years was also similar (P = 0.6). The CRev group had increased surgical times (P < 0.0001), blood loss (P < 0.0001), and length of stay (P = 0.01). CONCLUSIONS: LE resulted in similar achievement of a successful ROM and re-revision-free survival compared with CRev. In properly selected patients, LE is a reasonable option for the treatment of stiffness after TKA.

Clinical Outcomes and Risk Factors for Re-Revision Due to Trunnion Corrosion in Primary Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: There is a paucity of literature regarding the mid-term (greater than 2 years) outcomes of revision for adverse local tissue reaction to metal debris due to corrosion at the head-neck junction (trunnionosis) in metal-on-polyethylene total hip arthroplasty (THA), and risk factors for re-revision remain largely unknown. We aimed to report the re-revision-free survival and functional outcomes for this patient population and to identify risk factors for re-revision. METHODS: A total of 80 hips (79 patients) with a metal-on-polyethylene THA who had undergone revision for trunnionosis at our institution were included. The mean study follow-up from index trunnionosis revision was 4.6 years (range, 2.0 to 9.4). Kaplan-Meier survival analysis was performed with all-cause re-revision as the end point, and multivariate logistic regression was used to identify risk factors for re-revision. RESULTS: We saw that twenty-one hips (26%) underwent re-revision at a mean of 8.0 months (range, 0.03 to 36.3) after the index trunnionosis revision, most commonly for instability and infection. The two- and five-year all-cause re-revision-free survival rates were 75.0 and 73.2%, respectively. The mean Oxford Hip Score was 33.7 (range, 11 to 48); 76% were satisfied, and 24% were dissatisfied with their hip. Multivariate analysis identified not undergoing a cup revision (odds ratio: 4.5; 95% confidence interval: 1.03 to 19.7) and time from primary THA to the index trunnionosis revision (odds ratio: 0.77; 95% confidence interval: 0.62 to 0.97) as risk factors for undergoing re-revision. CONCLUSIONS: The risk of early re-revision for these patients is high (26%), mostly due to infection and instability, and functional outcomes are fair. Not performing a cup revision appears to be a risk factor for re-revision, as is the shorter time from primary THA to trunnionosis revision. LEVEL OF EVIDENCE: III.

Porous Tantalum Metaphyseal Cones for Severe Femoral and Tibial Bone Defects in Revision Total Knee Arthroplasty are Reliable for Fixation at Mean 5-Year Follow-Up.

BACKGROUND: Porous tantalum metaphyseal cones may facilitate reconstructions of severe bone defects during revision total knee arthroplasty (TKA), but there remains a paucity of data on their outcomes at mean 5 years of follow-up. This study reports the component survivorship, patient satisfaction, functional outcomes, radiographic osseointegration, and complications of revision TKA with porous tantalum metaphyseal cones at mid-term (mean 5-year) follow-up. METHODS: This study included 152 patients who had a mean age of 66 years (range, 33 to 86 years) undergoing revision TKA with porous tantalum metaphyseal cones. Indications for surgery included aseptic loosening (n = 87, 57.3%), second-stage reimplantation for infection (n = 42, 27.6%), osteolysis with well-fixed components (n = 20, 13.2%), and periprosthetic fracture (n = 3, 2.0%). Component survivorship, clinical outcomes, radiographic outcomes, and any complications were recorded. The mean follow-up time was 5.6 years (range, 2.2 to 13.7). RESULTS: Survivorship was 100% when the end point was revision of the metaphyseal cone (no cones were revised) and 83.8% (95% confidence interval: 77.9 to 90.2%) when the end point was reoperation for any reason at 5-year follow-up. Reoperations were performed for infection (n = 10), instability (n = 4), periprosthetic fracture (n = 2), and quadriceps rupture/dehiscence (n = 3). The mean patient satisfaction score was 78.8 ± 11.3 and the mean Forgotten Joint Score was 62.2 ± 16.7 at the final follow-up. The preoperative median University of California at Los Angeles score improved from 2 (interquartile range 2 to 3) to 6 points (interquartile range 5 to 6) (P < .001), and the preoperative Oxford knee score improved from 15.2 ± 3.8 to 39.4 ± 5.1 points (P < .001) at the final follow-up. All metaphyseal cones showed radiographic evidence of osteointegration without any subsidence or loosening. CONCLUSIONS: Porous tantalum metaphyseal cones enabled robust reconstructions of severe femoral and tibial bone defects during revision TKA. These reconstructions were associated with excellent survivorship, improvements in functional outcomes, and reproducible radiographic osseointegration at mean 5-year follow-up. The most common reasons for reoperation were infection and instability.

The John Charnley Award: The Impact of Human Leukocyte Antigen Genotype on Bacterial Infection Rates and Successful Eradication in Total Hip Arthroplasty.

BACKGROUND: Genetics play an important role in several medical domains; however, the influence of human leukocyte antigen (HLA) genotype on the development of periprosthetic joint infection (PJI) in total hip arthroplasty (THA) remains unknown. The primary aim of this study was to determine if HLA genotype is associated with the development of bacterial PJI in THA. Secondarily, we evaluated the association between HLA genotype and PJI treatment success. METHODS: A retrospective, matched, case-control study was performed using prospectively collected data from a single institution. A total of 49 patients who underwent primary THA were included, with a mean follow-up of 8.5 years (range, 4.2 to 12.9). The 23 cases (PJI) and 26 controls (no PJI) were matched for age, sex, follow-up, body mass index, primary diagnosis, and comorbidities (P > .05). High-resolution genetic analysis targeting 11 separate HLA loci was performed in all patients using serum samples. The HLA gene frequencies and carriage rates were determined and compared between cohorts. A subgroup analysis of PJI treatment success (18) and failure (5) was performed. Statistical significance was set at P = .10 for genetic analysis and at 0.05 for all other analyses. RESULTS: There were 4 HLA alleles that were significantly associated with the development of PJI. The 3 at-risk alleles included HLA-C∗06:02 (odds ratio 5.25, 95% CI [confidence interval] 0.96 to 28.6, P = .064), HLA-DQA1∗04:01 (P = .096), and HLA-DQB1∗04:02 (P = .096). The single protective allele was HLA-C∗03:04 (odds ratio 0.12, 95% CI 0.01 to 1.10, P = .052). There were no specific HLA alleles that were associated with treatment success or failure. CONCLUSIONS: This study suggests that there are at-risk and protective HLA alleles associated with the development of PJI in THA. To our knowledge, this is the first study to demonstrate an association between patient HLA genotype and the development of PJI. A larger study of the subject matter is necessary and warranted.

The Diagnostic Utility of Serum Metal Ion Markers for High-Grade Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesions (ALVALs) in Revision Hip and Knee Arthroplasty: An International Multicenter Study.

BACKGROUND: Aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) are typically described in the context of metal-on-metal (MoM) hip bearings. This study explores the diagnostic utility of preoperative serum cobalt and chromium ion levels in determining the histological grade of ALVAL in revision hip and knee arthroplasty. METHODS: This was a multicenter retrospective review of 26 hips and 13 knees assessing the correlation between preoperative ion levels (mg/L (ppb)) and the histological grade of ALVAL from intraoperative specimens. The diagnostic ability of preoperative serum cobalt and chromium levels to determine high-grade ALVAL was assessed using a receiver operating characteristic (ROC) curve. RESULTS: In the knee cohort, there was a higher serum cobalt level in high-grade ALVAL cases (10.2 mg/L (ppb) versus 3.1 mg/L (ppb)) (P = .0002). The Area Under the Curve (AUC) was 1.00 (95% confidence interval (CI) 1.00 to 1.00). There was a higher serum chromium level in high-grade ALVAL cases (12.25 mg/L (ppb) versus 7.77 mg/L (ppb)) (P = .0002). The AUC was 0.806 (95% CI 0.555 to 1.00). In the hip cohort, there was a higher serum cobalt level in high-grade ALVAL cases (333.5 mg/L (ppb) versus 119.9 mg/L (ppb)) (P = .0831). The AUC was 0.619 (95% CI 0.388 to 0.849). There was a higher serum chromium level in high-grade ALVAL cases (186.4 mg/L (ppb) versus 79.3 mg/L (ppb)) (P = .183). The AUC was 0.595 (95% CI 0.365 to 0.824). CONCLUSIONS: Histologically, high-grade ALVAL has significantly higher preoperative serum cobalt and chromium ion levels in revision TKA. Preoperative serum ion levels have excellent diagnostic utility in revision TKA. Cobalt levels in revision THA have a fair diagnostic ability and chromium levels had a poor diagnostic ability.

Short-term survival of the cementless triathlon total knee arthroplasty in a young patient cohort.

BACKGROUND: The purpose of this study is to assess the short-term survivorship of a new cementless total knee arthroplasty (TKA) design in comparison to its cemented predecessor design in a young patient cohort less than 65 years of age. METHODS: We performed a retrospective cohort study of all primary TKAs (cemented and cementless) in patients under the age of 65 at the time of the index procedure, in a single institution between May 2018 and May 2019. Primary outcome variables included aseptic revision and all-cause revision. Operative time was a secondary variable. Independent variables considered included age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) grade, implant type (cruciate-retaining (CR) or posterior-stabilised (PS)) and the use of cemented or cementless implants. RESULTS: There were 106 cemented TKAs and 152 cementless TKAs (Triathlon, Stryker Inc, Mahwah, NJ ) implanted. The minimum follow-up for all cases was 2 years (mean cementless 32.5 months, mean cemented 34.9 months). Of the entire 258 implants only 2 were revised. Both revisions occurred in the cemented cohort for prosthetic joint infection (PJI). The all-cause revision rate in the cementless cohort was 0% compared to 1.8% in the cemented cohort (p = 0.168). Operative times were significantly reduced from 62 min in the cemented cohort to 52.2 min in the cementless cohort (p < 0.001). CONCLUSION: In a young patient cohort, the cementless Triathlon TKA demonstrates excellent survivorship at short-term follow-up with significant reductions in operative times when compared to the cemented Triathlon TKA.

Risk factors for failure of manipulation under anesthesia after total knee arthroplasty.

BACKGROUND: Manipulation under anesthesia (MUA) is a well-established treatment for stiffness after total knee arthroplasty (TKA). Risk factors for failure of MUA remain largely unknown. The primary aim of this study was to identify risk factors for failure of MUA after TKA. METHODS: We performed a retrospective cohort study including 470 patients who underwent MUA after primary TKA with minimum 2 year follow-up. Patients were grouped into success (n = 412) or failure (n = 58) cohorts; failure was defined as flexion < 90° at most recent follow-up or revision for stiffness. The increase in flexion post-MUA for the cohort was calculated. Several clinical, patient, and surgical factors were analyzed using univariate, followed by multivariable logistic regression models to identify independent risk factors associated with failure. RESULTS: The mean increase in flexion was 42° (range 0-115). BMI 30-35 (p = 0.01, odds ratio (OR) 2.42; 95% CI 1.25-4.68) and poorer pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.23-1.67) were risk factors for failure. When considering revision for stiffness only, BMI 30-35 (p = 0.01, OR 3.27; 95% CI 1.41-7.61), lower pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.18-1.75), and history of prior knee surgery (p = 0.04, OR 2.31; 95% CI 1.06-5.04) were predictors of failure. Time to MUA (p = 0.48), thromboprophylaxis (p = 0.44), pre-operative opioid use (p = 0.34), depression/anxiety (p = 1.0), and several other factors analyzed were not associated with failure. CONCLUSION: In this large cohort, elevated BMI and lower pre-MUA flexion were risk factors for failure of MUA. History of prior knee surgery was an additional predictor of requiring revision for stiffness.

Developing rights-based standards for children having tests, treatments, examinations and interventions: using a collaborative, multi-phased, multi-method and multi-stakeholder approach to build consensus.

Children continue to experience harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. The international ISupport collaboration aimed to develop standards to outline and explain good procedural practice and the rights of children within the context of a clinical procedure. The rights-based standards for children undergoing tests, treatments, investigations, examinations and interventions were developed using an iterative, multi-phased, multi-method and multi-stakeholder consensus building approach. This consensus approach used a range of online and face to face methods across three phases to ensure ongoing engagement with multiple stakeholders. The views and perspectives of 203 children and young people, 78 parents and 418 multi-disciplinary professionals gathered over a two year period (2020-2022) informed the development of international rights-based standards for the care of children having tests, treatments, examinations and interventions. The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds.    Conclusion: This is the first study of its kind which outlines international rights-based procedural care standards from multi-stakeholder perspectives. The standards offer health professionals and educators clear evidence-based tools to support discussions and practice changes to challenge prevailing assumptions about holding or restraining children and instead encourage a focus on the interests and rights of the child. What is Known: • Children continue to experience short and long-term harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. • Professionals report uncertainty and tensions in applying evidence-based practice to children's procedural care. What is New: • This is the first study of its kind which has developed international rights-based procedural care standards from multi-stakeholder perspectives. • The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds.

Malseating of Modular Dual Mobility Liners: High Prevalence in Revision Total Hip Arthroplasty.

BACKGROUND: Modular dual mobility (MDM) acetabular components have become increasingly more popular in total hip arthroplasty (THA). Uncertainty remains regarding liner malseating and its consequences after 5 to 10 years, especially in patients who undergo revision THA. The objective of this study was to analyze the prevalence of malseating and implant survivorship of patients who underwent revision THA using an MDM liner. METHODS: We retrospectively identified patients who had a minimum 2-year follow-up and underwent revision THA using an MDM liner. Patient demographics, implant details, mortality, and all-cause revisions were recorded. Patients who had radiographic follow-up were assessed for malseating. Kaplan-Meier survival was used to determine implant survivorship. We included 143 hips in 141 patients. Mean age was 70 years (35-93 years), and 86 patients (60.1%) were female. RESULTS: Overall implant survival was 89.3% (95% confidence interval (CI) 0.843-0.946) at a mean follow-up of 6 years (ranging from 2 to 10 years). There were eight patients excluded from malseating assessment. Upon radiological review, 15 liners (11.1%) were malseated. Survival for all-cause revision for patients with malseated liners was 80.0% (12/15, 95% CI 0.62 - 0.99, P = .15) versus 91.5% in patients who had nonmalseated liners (110/120, 95% CI 0.86-0.96). There were no intraprosthetic dislocations and 3.5% of the patients were revised due to instability. No liners were revised due to malseating, and no patients who had malseated liners were revised due to instability. CONCLUSIONS: Using MDM components in our cohort comprised of revision THA was associated with a high prevalence of malseating and an overall survival of 89.3% at a mean follow-up of 6 years. Malseating does not appear to impact implant survival at a mean follow-up of 6 years.

Highly Crosslinked Polyethylene Liner Thickness Does Not Influence Survival in Primary Total Hip Arthroplasty After Mean Follow-Up of 13 Years: A Study of 2,565 Hips With a Single Design Liner.

BACKGROUND: Concerns remain that thinner highly crosslinked polyethylene (HXLPE) liners in modern total hip arthroplasty (THA) may lead to premature liner-related failures or revision. The aim of this study was to evaluate the effect of liner thickness on survival and revision rates of HXLPE in primary THA after more than 10 years. METHODS: We retrospectively identified 2,565 primary THAs using HXLPE with a mean follow-up of 13 years (range, 11 to 19). Patients were grouped for each mm of polyethylene thickness. Liner thickness varied from 4.9 to 12.7 mm, with one third measuring less than 6 mm. Primary outcomes were reoperation, all-cause revision, and liner-related revision. RESULTS: The reoperation rate was 7.3%, the all-cause revision rate was 5.6%, and the liner-related revision rate was 0.04%. There was no significant difference in all-cause revision when stratified by liner thickness (P = .286) and liner thickness was not associated with liner-related revision (n = 1). There was a statistically, but not clinically significant difference in mean liner thickness for the cohort that underwent reoperation (7.09 versus 6.89 mm, P = .01) and all-cause revision (7.16 versus 6.89 mm, P = .031). CONCLUSION: In our cohort, liner thickness was not associated with all-cause revision-free survival, and there was no clinically significant difference in liner thickness between those patients who did require a reoperation or all-cause revision, and those who did not. There was only 1 liner-related failure in the entire cohort. Our results indicate that using thinner HXLPE liners to maximize femoral head size in THA is a safe practice that does not lead to increased revision rates or liner failure at a mean 13-year follow-up.

Survival analysis of one-stage exchange of infected unicompartmental knee arthroplasty: a single-center study with minimum 3 years follow-up.

PURPOSE: The rates of unicompartmental knee arthroplasty (UKA) are increasing yet little data exists regarding management of periprosthetic joint infections (PJI) after UKA, particularly utilizing one-stage revision. The aim of this study was to determine the septic and all-cause revision-free survival of UKA PJIs treated with one-stage revision, as well as functional outcomes and risk factors for failure. METHODS: A retrospective review of one-stage septic revisions with a hinged or rotating hinged implant between 2000 and 2015 at a single institution was performed. Results of 15 patients with a minimum of 3-year follow-up (mean = 93 months; range 37-217) were evaluated by means of infection control, survivorship, patient reported functional score and possible causal factors for a re-revision. Kaplan-Meier curves and Cox regression analysis were used. RESULTS: After a mean of 8 years of follow-up infection control rate was 93.3%, the survivorship free of any reoperation, including both septic and aseptic causes, was 80% at 5 years and 64.2% at ten years and average Lysholm score was 72.7 ± 21.3 (33-100). CONCLUSION: One-stage revision for PJI of UKA using a hinged knee design has excellent infection-free survival at mid to long-term follow-up. Likewise, patient reported functional outcomes are promising. However, one-third of patients required aseptic reoperation and aseptic loosening was the dominant etiology.

International primary knee arthroplasty registry review: findings from current reports.

INTRODUCTION: International joint registries provide high volumes of information in relation to the performance of total knee arthroplasty on a global scale. Distillation of this data can be challenging, particularly with the establishment of more arthroplasty registries on a yearly basis. We therefore aim to present key information from these registries in relation to primary total knee arthroplasty. The specific questions of interest include: Which fixation type is superior in TKA? Does the level of constraint impact on clinical performance? How do partial knee replacements perform in the registries? Does patellar resurfacing lead to superior results? Are there any specific implants which perform particularly well or poorly? METHODS: A comprehensive review of the major English-speaking knee arthroplasty registries across the globe was performed. Given the expanding large number of registries worldwide, it was not possible to perform a comprehensive review of all registries and so, a detailed review of the major English-speaking knee arthroplasty registries was included. Key trends and developments in implant performance were identified and presented in the current article. RESULTS: Total knee replacements have lower revision rates than both unicompartmental and patellofemoral joint replacement procedures. Patellofemoral joint replacements have the highest failure rate of all knee replacement procedures. Cruciate-Retaining (CR) TKR designs have superior outcomes to Posterior-Stabilized (PS) designs across all registries. Patellar resurfacing appears to confer an advantage over non-resurfaced patellas in primary TKR. CONCLUSION: We present current global trends in the utility and performance of TKA based on data from English-speaking arthroplasty registries.

The Prevalence and Outcomes of Unexpected Positive Intraoperative Cultures in Presumed Aseptic Revision Knee Arthroplasty.

BACKGROUND: The prevalence and outcomes of unexpected positive intraoperative cultures (UPC) in presumed aseptic revision total knee arthroplasty (TKA) are unclear. The purpose of this study was to determine the prevalence of UPC and infection-free implant survival in this patient population. Secondly, we aimed to compare the infection-free implant survival between cohorts based on number of UPCs and antibiotic treatment. METHODS: We reviewed our institutional database from 2006 to 2019 for all TKA revisions (n = 1795) to identify all presumed aseptic TKA revisions with intraoperative culture(s). After exclusions, 775 revisions were eligible and those with UPC were included in the Kaplan-Meier analysis to determine infection-free implant survival for the cohorts. RESULTS: The prevalence of UPC was 9.8%. The 2- and 5-year infection-free survival was 97.4% and 95.3%, respectively. The 5-year infection-free survival from the same microorganism as the UPC was 98.7%. Infection-free survival was similar for the 1 versus ≥2 UPC cohorts (P = .416), however was poorer for the cohort treated with antibiotics (P = .021). Only one of 3 subsequent PJI-related implant failures was caused by the same microorganism (polymicrobial) as the UPC. There were no subsequent infections in patients with a single UPC not treated with antibiotics. CONCLUSIONS: The prevalence of UPC was 9.8% and the infection-free implant survival is excellent. Infection-free survivorship from PJI caused by the same UPC microorganism is outstanding. Comparisons between cohorts must be interpreted with caution due to study limitations. A single UPC in patents without other signs of infection does not require antibiotic treatment. LEVEL OF EVIDENCE: IV.

The Impact of Changing Total Knee Arthroplasty Implants at a High-Volume Institution.

BACKGROUND: The ability of a group of high-volume arthroplasty surgeons to simultaneously change their preferred primary total knee arthroplasty (TKA) implant of choice to another, has not been explored in the literature to date. The main hypothesis was that such a change could be made with no significant impact on clinical outcomes. METHODS: This is a retrospective cohort study comparing the last 500 consecutive TKAs implanted of a routinely used TKA implant (NexGen; Zimmer, Warsaw, IN) with the first 500 consecutive TKAs implanted of a newly adopted TKA implant (Triathlon; Stryker, Mahwah, NJ) at an institutional level. Primary outcomes of importance included all complications that occurred either intraoperatively or early postoperatively, early all-cause revision rate, and early reintervention rate. RESULTS: There was a 1.2% (n = 6) complication rate in the NexGen cohort compared to 0.8% (n = 4) in the newly adopted Triathlon cohort (P = .75). The rate of intraoperative fracture was 1% in the NexGen cohort and 0.6% in the Triathlon cohort (P = .72). The early all-cause revision rate for the NexGen TKA was 1% (n = 5) compared to 0.8% (n = 4) in the Triathlon cohort (P = 1.0). The manipulation under anesthesia (MUA) rate in the NexGen cohort was 2.4% compared to 4.6% in the Triathlon cohort (P = .058). The only predictor variable associated with MUA rate was American Society of Anesthesiologists grade, where there was a significantly lower rate of MUA with a higher American Society of Anesthesiologists grade (P = .042). CONCLUSION: It is possible to implement the institution-wide adoption of an established, high-performing TKA implant without any negative implications in relation to early revision rates, perioperative complication rates, and reintervention rates. This study is the first of its kind to be reported in the literature.

Which International Consensus Meeting Preoperative Minor Criteria is the Most Accurate Marker for the Diagnosis of Periprosthetic Joint Infection in Hip and Knee Arthroplasty?

BACKGROUND: The accurate preoperative diagnosis of periprosthetic joint infection (PJI) is critical. The aim of this study was to evaluate the diagnostic accuracy and performance of the 2018 International Consensus Meeting (ICM) preoperative minor criteria for the diagnosis of chronic PJI in total hip and knee arthroplasty. METHODS: We retrospectively reviewed 260 patients that underwent a revision knee or hip arthroplasty at our institution between 2015 and 2017. All major and minor 2018 ICM criteria (except erythrocyte sedimentation rate, D-dimer) were available for all patients included. Cases with at least 1 major criterion were considered as infected. Receiver operative characteristic curve analysis was performed for preoperative minor criteria. RESULTS: The diagnostic performance of the preoperative minor criteria ranked as per the area under the curve was PMN% (0.926), alpha defensin (0.922), white blood cell count (0.916), leukocyte esterase (0.861), and serum C-reactive protein (0.860). Increasing the PMN % cutoff from 70% to 77.8% improves the diagnostic accuracy (86.5% vs 90.8%). The highest diagnostic performance was achieved by combining all 5 preoperative parameters, and at current ICM thresholds, the diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive were 93.5%, 95.4%, 92.1%, 89.7%, and 96.5%, respectively. CONCLUSION: The diagnostic performance of preoperative minor criteria was outstanding (PMN%, alpha defensin, white blood cell count) or excellent (leukocyte esterase, serum C-reactive protein). PMN% showed the best diagnostic utility (area under the curve) and should have an increased weight-adjusted score in the ICM scoring system.

A Comparison of Mobile and Fixed-Bearing Unicompartmental Knee Arthroplasty at a Minimum 10-Year Follow-up.

BACKGROUND: The long-term survivorship and functional outcomes of the mobile-bearing (MB) compared to the fixed-bearing (FB) unicompartmental knee arthroplasty (UKA) implant design remain a topic of debate. The aim of the current study was to compare the survivorship and functional outcomes of MB and FB UKA at a minimum 10-year follow-up. METHODS: We retrospectively reviewed 106 consecutive medial UKAs (89 patients) from our institution with a minimum 10-year follow-up. The 38 MB and 68 FB knees had follow-up of 14.2 years (12.9-15.5) and 11.5 years (10.2-15.1), respectively. Validated patient-reported outcomes and radiographs were evaluated as were etiology, timing, and complexity of revision. Kaplan-Meier 10-year survival was calculated with revision to total knee arthroplasty as the end point. RESULTS: The 10-year survival was 82.9% (95% confidence interval [CI] 65.8-91.9) for MB and 90.9% (95% CI 79.4-96.2) for FB UKA (P = .102), and 88.0% (95% CI 79.3-93.2) for the entire cohort. Patient outcomes were similar between groups, as were timing and etiologies for revision to total knee arthroplasty. One-third of revisions required either stems or tibial augments, and of these, all were of MB design. CONCLUSION: Survival and functional outcomes were similar between MB and FB designs. One-third of revisions required either stems or augments, all were of MB design.

Treatment of femoral bone loss in revision total hip arthroplasty: a clinical practice review.

Patient and implant selection is essential to optimize outcome. Femoral bone loss classifications such as the American Academy of Orthopaedic Surgeons, Gross, and Paprosky classifications permit surgeons to systematically manage bone stock deficiencies and guide implant selection. Here we provide a comprehensive report on the pitfalls and management of this reconstructive challenge. Preoperative planning remains vital to the treatment of femoral bone loss in revision hip arthroplasty and the authors believe it is essential and should include the entire femur. This commonly includes imaging for bone loss such as Judet views or computed tomography scan and must include the entire femur though additional radiographs such as Judet views apply more for acetabular bone loss as opposed to femoral bone loss. All patients should have pre-operative work up to exclude infection. If any of these results area elevated, an aspirate and sampling is required to guide microbiological management. Classically with regards femoral revision surgery, uncemented fixation has proven to give the best outcomes but surgeons must remain flexible and use cemented fixation when necessary. Adequate proximal bone stock permits the use of implants used in primary joint surgery. Implants with proximal modularity can be used in cases where bone stock allows for superb proximal bone support. The vast majority of femoral revisions have inadequate proximal bone stock, thus distally fixed stems should be used and have been shown to provide both axial and rotational stability provided there is an intact isthmus. Taper fluted stems can provide good outcomes even in cases of major bone loss. However, with severe bony loss, impaction grating or the use of a megaprotsthesis is sometimes necessary and is down to surgeon choice and preference. This article has been written as a guide for management and summarises the best evidence available.

Navigated Versus Conventional Total Knee Arthroplasty: A Systematic Review and Meta-analysis of Prospective Randomized Controlled Trials.

Background: Recent evidence on the cost-effectiveness of technology in total knee arthroplasty (TKA) demonstrated that navigated computer-assisted methods (N-TKA) is likely to be most cost-effective in the clinical setting. The aim of the current meta-analysis is to compare radiographic, clinical and functional outcomes between conventional TKA (C-TKA) and N-TKA methods. Methods: All prospective randomized controlled trials (pRCTs) comparing primary TKA performed using C-TKA and N-TKA techniques were eligible for inclusion. Radiographic outcomes included postoperative coronal, sagittal and axial component alignment. Clinical outcomes included all-cause revision and aseptic revision. Functional outcomes were analyzed when reported. A random-effects meta-analysis of all available cases was performed. This allowed for all missing data. Results: Normal coronal mechanical alignment of the tibial (p < 0.001) and femoral (p = 0.001) components was achieved more frequently with N-TKA. Normal sagittal mechanical alignment of the tibial component was achieved significantly more with N-TKA (p < 0.010). There was no difference in short-term clinical survivorship (all-cause, p = 0.649; aseptic, p = 0.79) or in functional outcomes reported between groups. There was a clinically significant reduction in the mean C-TKA operative time (87 min, σ = 16.6, 95% CI 76.4-98.8) compared N-TKA (97.6 min, σ = 16.9, 95% CI 86.2-109.1) (p = 0.17). Conclusion: Navigated TKA achieves superior radiographic alignment for femoral and tibial components in both the coronal and sagittal plane. Operative times are 10 min longer in the N-TKA group. Functional outcomes are similar between navigated and conventional groups. Clinical outcomes reported in Level I studies are limited to short-term follow-up so future prospective studies are required.

Articulating Spacers in Total Hip Arthroplasty: Surgical Technique and Outcomes.

Although one-stage exchange arthroplasty is gaining popularity, two-stage exchange arthroplasty remains the gold standard for the treatment of periprosthetic joint infections. Use of an articulating spacer for this procedure offers an avenue for maintaining hip motion and controlled weight-bearing, allowing local antibiotic elution. However, there is no uniform consensus on the optimal surgical protocol for using articulating spacers. This review describes the surgical technique for undertaking a first-stage exchange arthroplasty using an articulating spacer and discusses the pertinent literature on key concepts relating to periprosthetic joint infections in total hip arthroplasty to guide effective surgical decision making in these patients.