Prevalence and Impact of Unexpected Positive Intraoperative Cultures in Total Hip or Knee Revision Surgery.

BACKGROUND: Our aim was to evaluate the prevalence and impact of unexpected positive intraoperative cultures (UPICs) on the outcome of presumed aseptic total knee and hip revision surgery. METHODS: Data regarding patients who underwent elective total hip or knee revision surgery from January 2003 to July 2017 due to preoperatively presumed aseptic reasons was retrospectively reviewed. Partial revisions and patients who had follow-ups below 60 months were excluded from the study. In all surgeries, at least three intraoperative samples were taken for microbial culture. Failure was defined as the need for re-revision due to any cause at 5 years and/or the need for antibiotic suppressive therapy. Overall, 123 total hip and 431 total knee revisions were eligible for the study. All cases had at least a 5 year follow-up. RESULTS: There were 420 cases (75.8%) that had all cultures negative, 108 (19.5%) had a single UPIC, and 26 (4.7%) had either ≥ 2 UPICs for the same microorganism or 1 UPIC for a virulent microorganism. This latter group was not associated with a significantly higher failure rate (2 of 26, 7.7%) compared to those in the aseptic group (54 of 528, 10.2%). Revisions performed within the first 24 months after primary implantation had a higher 5-year re-revision rate (19.3 versus 8.4%, P = 0.01), mainly attributable to aseptic causes. CONCLUSION: Total hip and knee revisions with UPICs were not significantly associated with a higher re-revision risk at 5 years. Those revisions performed within the first 24 months after primary arthroplasty had a higher rate of any-cause failure.

Analysis of the incidence and risk factors of blood transfusion in total knee revision: a retrospective nationwide inpatient sample database study.

OBJECTIVE: This study sought to determine the incidence and risk factors of blood transfusion among patients undergoing total knee revision (TKR) using a nationwide database. METHODS: A retrospective data analysis was conducted based on the Nationwide Inpatient Sample (NIS), enrolling patients who underwent TKR from 2010 to 2019 with complete information. The patients were divided into two groups based on whether they received blood transfusion or not. The demographic characteristics (race, sex, and age), length of stay (LOS), total charge of hospitalization, hospital characteristics (admission type, insurance type, bed size, teaching status, location, and region of hospital), hospital mortality, comorbidities, and perioperative complications were analyzed. Finally, we conducted univariate and multivariate logistic regression to identify factors that were associated with TKR patients to require blood transfusion. RESULTS: The NIS database included 115,072 patients who underwent TKR. Among them, 14,899 patients received blood transfusion, and the incidence of blood transfusion was 13.0%. There was a dramatic decrease in the incidence over the years from 2010 to 2019, dropping from 20.4 to 6.5%. TKR patients requiring transfusions had experienced longer LOS, incurred higher total medical expenses, utilized Medicare more frequently, and had increased in-hospital mortality rates (all P < 0.001). Independent predictors for blood transfusion included advanced age, female gender, iron-deficiency anemia, rheumatoid disease, chronic blood loss anemia, congestive heart failure, coagulopathy, uncomplicated diabetes, lymphoma, fluid and electrolyte disorders, metastatic carcinoma, other neurological diseases, paralysis, peripheral vascular disorders, pulmonary circulation disorders, renal failure, valvular disease, and weight loss. In addition, risk factors for transfusion in TKR surgery included sepsis, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, gastrointestinal bleeding, heart failure, renal insufficiency, pneumonia, wound infection, lower limb nerve injury, hemorrhage/seroma/hematoma, wound rupture/non healing, urinary tract infection, acute renal failure, and postoperative delirium. CONCLUSIONS: Our findings highlight the importance of recognizing the risk factors of blood transfusion in TKR to reduce the occurrence of adverse events.

Revision Total Knee Arthroplasty for Catastrophic Tibial Post Failure: Rare Complication of Total Knee Replacement.

Tibial post failure is a rare but serious complication of posterior-stabilized total knee arthroplasty that requires revision surgery. Although tibial post fracture has previously been reported, this case involves an implant with a design feature that may predispose patients to the complication. The fracture also occurred later than observed in most other reports. A 72-year-old male who had undergone a posterior stabilized total knee arthroplasty seven years prior presented with knee pain and instability after a fall from standing. Although plain radiographs were not diagnostic, history and physical exam suggested failure of the tibial polyethylene post. This was confirmed during surgery when the fractured component was identified in the suprapatellar pouch. Given absence of malrotation or malalignment of the well-fixed femoral and tibial components, a polyethylene liner exchange was performed. Postoperatively, the patient had complete resolution of pain and instability with 0-120 degrees of stable ROM, which has persisted to latest follow-up at 6 months.

Bilateral Patellar Tendon Rupture Following Total Knee Arthroplasty in a Patient With Alkaptonuria: A Case Report.

Alkaptonuria (AKU) is a rare hereditary disorder of tyrosine degradation. The disorder is characterized by the accumulation of a pigment called homogentisic acid. Its accumulation can lead to the breakdown of connective tissue, including tendons. This report presents a 46-year-old male with a history of bilateral total knee arthroplasty (TKA) who sustained bilateral patellar tendon rupture after an acute injury. A single-stage bilateral knee revision with direct repair of the extensor mechanism augmented with Achilles allograft was performed. The procedure was successful, and the patient had an excellent post-operative outcome at one year post-operatively. This case attempts to highlight the possible complications from AKU in order to better counsel patients with this condition who are undergoing TKA.

Patients undergoing revisions for total knee replacement malposition are younger and more often female: An analysis of data from the Dutch Arthroplasty register.

Background: The proportion of patients who are dissatisfied with the outcome following total knee replacement (TKR) is high. Malalignment is considered a probable cause for persistent pain, but whether this reason for revision could be the result of specific patient characteristics remains unclear. Therefore, we aim to assess whether specific patient characteristics are associated with revision for symptomatic TKR malalignment. Methods: Data was obtained from the Dutch Arthroplasty Register (LROI), which contains data from all Dutch hospitals. All patients who underwent TKR revision surgery between 2008 and 2019 were included in this study. The (primary) reason for revision as well as patient characteristics (age, gender, ASA classification, and pre-operative patient-reported outcome measures) were abstracted. The Chi-square test for categorical variables, and ANOVA or Kruskal-Wallis for continuous variables were used to determine differences in patient characteristics between the subgroups based on reason for revision. Results: A total of 11,044 TKR revisions were registered in The Netherlands between 2008 and 2019. Malalignment was registered as the primary reason for revision in 13% of the patients. Subgroup analyses showed that patients who underwent TKR revisions for malalignment where younger (63.8 year, SD ± 9.3) and more often female (70%) compared to other major reasons for TKR revisions. Conclusion: Patients who had a TKR revision for malalignment were younger and more often female. This suggests that patient characteristics may play a role when reasons to perform revision surgery are considered. Surgeons should invest in the expectation management in (young) patients and inform patients of these potential risk factors as part of shared decision-making.

The Role of Single Positive Cultures in Presumed Aseptic Total Hip and Knee Revision Surgery-A Systematic Review of the Literature.

(1) Background: Prior to revision hip (THA) or knee arthroplasty (TKA), periprosthetic low-grade infection (PJI) should be ruled out. Despite advances in preoperative diagnosis, unsuspected positive cultures (UPCs) may occur in initially planned aseptic revisions. Particularly, single UPCs pose a diagnostic and therapeutic dilemma, as their impact on outcome is unclear and recommendations are heterogeneous. This review investigates the frequency of single UPCs and their impact on implant survivorship. (2) Methods: In July 2022, a comprehensive literature search was performed using PubMed and Cochrane Library search. In total, 197 articles were screened. Seven retrospective studies with a total of 5821 cases were able to be included in this review. (3) Results: Based on the cases included, UPCs were found in 794/5821 cases (14%). In 530/794 cases (67%), the majority of the UPCs were single positive. The most commonly isolated pathogens were coagulase negative Staphylococci and Cutibacterium acnes. Five of seven studies reported no influence on revision- or infection-free survival following a single positive culture. In two studies, single UPCs following THA revision were correlated with subsequent re-revision for PJI. (4) Conclusions: Single UPCs of a non-virulent pathogen following presumed aseptic TKA revision may be interpreted as contaminants. A single UPC following THA revision may be a risk factor for subsequent PJI. The role of systemic antibiotic treatment remains unclear, but it should be considered if other risk factors for PJI are present.

Porous metal block based on topology optimization to treat distal femoral bone defect in total knee revision.

Metal block augmentations are common solutions in treating bone defects of total knee revision. However, the stress shielding and poor osteointegration resulted from metal block application could not be neglected in bone defects restoration. In this study, a novel porous metal block was designed with topology optimization to improve biomechanical performance. The biomechanical difference of the topologically optimized block, solid Ti6Al4V block, and porous Ti6Al4V block in treating bone defects of total knee revision was compared by finite element analysis. The inhomogeneous femoral model was created according to the computed tomography data. Combined with porous structures, minimum compliance topology optimization subjected to the volume fraction constraint was utilized for the redesign of the metal block. The region of interest was defined as a 10 mm area of the distal femur beneath the contacting surface. The biomechanical performance of daily motions was investigated. The von Mises stress, the strain energy density of the region of interest, and the von Mises stress of metal blocks were recorded. The results were analyzed in SPSS. In terms of the region of interest, the maximum von Mises stress of the topological optimized group increased obviously, and its average stress was significantly higher than that of the other groups (p < 0.05). Moreover, the topologically optimized block group had the highest maximum strain energy density of the three groups, and the lowest maximum stress of block was also found in this group. In this study, the stress shielding reduction and stress transfer capability were found obviously improved through topology optimization. Therefore, the topological optimized porous block is recommended in treating bone defects of total knee revision. Meanwhile, this study also provided a novel approach for mechanical optimization in block designing.

Spacer exchange in persistent periprosthetic joint infection: microbiological evaluation and survivorship analysis.

PURPOSE: The purposes of this study were to determine demographics and characteristics of patients who underwent spacer exchange for persistent infection in the setting of two-stage arthroplasty for periprosthetic joint infection, to describe the microbiology of pathogens involved, to analyze survivorship free from infection in these patients. METHODS: The institutional prospectively collected database was reviewed to enroll patients with minimum 2 years follow-up. Patients who underwent two-stage procedure for septic arthritis were excluded, as were patients who had spacer fracture or dislocation. RESULTS: A total of 34 patients (41 procedures) were included. Mean age was 65.0 ± 12.8 years. Mean follow-up was 53.4 ± 24.8 months. Mean number of previous procedures was 3.6 ± 1.2. A total of 27 (79.4%) patients underwent final reimplantation. The most frequently isolated pathogen in spacer exchange was Staphylococcus epidermidis (10 cases, 28.6%). Polymicrobial cultures were obtained from 9 (25.71%) patients, 10 (28.6%) presented culture-negative infections. A total of 11 (32.4%) resistant pathogens were isolated, and 16 (47.0%) difficult to treat pathogens were detected. Eradication rate was 78.8%. Overall survivorship of implants after final reimplantation was 72.8% at 51.8 months. CONCLUSION: Surgeons should be aware that subjects necessitating spacer exchange often present multiple comorbidities, previous staged revision failures, soft-tissue impairment and difficult to treat infection. In these patients, spacer exchange provides good clinical results and infection eradication, preventing arthrodesis or amputation.

Biomechanical Comparison Between Porous Ti6Al4V Block and Tumor Prosthesis UHMWPE Block for the Treatment of Distal Femur Bone Defects.

Purpose: The management of bone defects is a crucial content of total knee revision. This study compared the biomechanical performance of porous Ti6Al4V block and tumor prosthesis UHMWPE block in treating distal femoral bone defects. Methods: The finite element models of AORI type 3 distal femoral bone defect treated with porous Ti6Al4V block and UHMWPE block were established. Sensitivity analysis was performed to obtain the appropriate mesh size. The biomechanical performance of treatment methods in bone defects were evaluated according to the peak stress, the Von Mises stress distribution, and the average stresses of regions of interest under the condition of standing on one foot and flexion of the knee. Statistical analysis was conducted by independent samples t-test in SPSS (p < 0.05). Results: In the standing on one-foot state, the peak stress of the porous Ti6Al4V block was 12.42 MPa and that of the UHMWPE block was 19.97 MPa, which is close to its yield stress (21 MPa). Meanwhile, the stress distribution of the UHMWPE block was uneven. In the flexion state, the peak stress of the porous Ti6Al4V block was 16.28 MPa, while that of the UHMWPE block was 14.82 MPa. Compared with the porous Ti6Al4V block group, the average stress of the region of interest in UHMWPE block group was higher in the standing on one foot state and lower in the flexion state (p < 0.05). Conclusion: More uniform stress distribution was identified in the porous Ti6Al4V block application which could reserve more bone. On the contrary, uneven stress distribution and a larger high-stress concentration area were found in the UHMWPE block. Hence, the porous Ti6Al4V block is recommended for the treatment of AORI type 3 distal femoral bone defect.

Dislocation of Rotating Hinged Knee Prostheses in a Patient With Extensor Mechanism Dysfunction.

Rotating hinged knee replacements are used to restore knee stability when intrinsic stability is lost in the form of soft tissue compression. With medical engineering advancements and improvements in arthroplasty, intrinsic stability can be achieved by an implant post system. We present the case of a 44-year-old female who presented with post-traumatic right knee multi-ligamentous instability and advanced secondary osteoarthritis following a traumatic knee dislocation two years ago. The patient initially underwent a hinged total knee replacement. After five years, she got dislocation of hinged total knee replacement that affected her condition and necessitated emergency admission for open reduction and revision. Most reported cases of rotating hinge prosthesis dislocation occurred during the first year of follow-up. However, our case dislocated after five years of follow-up due to dislodgement from the tibial tray with the polyethylene channel in the form of fatigue failure of the anti-dislocation mechanism.

Catastrophic Failure of the Tibial Component After Total Knee Arthroplasty: Fracture and Dissociation Between the Baseplate and Stem.

Fracture of the tibial component can be a devastating complication after primary total knee arthroplasty. While fractures of the tibial baseplate have been reported, failure at the junction between the baseplate and stem has not been well-described. We present a 49-year-old male who developed progressively worsening left knee pain and an effusion 7-8 years after an index total knee arthroplasty. Radiographs revealed component subsidence and subtle asymmetry between the baseplate and stem. At the time of revision, the tibial component was found to be fractured at the junction of the baseplate and stem, with complete dissociation between the two pieces. Clinicians should maintain a high index of suspicion for catastrophic failure, as this rare phenomenon can be subtle on radiographs and requires close monitoring for signs of component subsidence.

High Rate of Re-Revision in Patients Less Than 55 Years of Age Undergoing Aseptic Revision Total Knee Arthroplasty.

BACKGROUND: There are limited data on the outcomes of revision total knee arthroplasty in young patients. We sought to characterize the re-revision-free survival and risk factors for re-revision in patients less than 55 years who underwent aseptic revision TKA. METHODS: We retrospectively reviewed 197 revision TKAs at a mean follow-up of 5 years. Mean age was 49 years; mean body mass index was 31 kg/m2. Twenty-seven (14%) patients had at least 1 prior revision TKA. The most common indications for revision included instability (29%), arthrofibrosis (26%), and aseptic loosening (24%). Constraint included the following: 59 posterior-stabilized (30%), 123 varus-valgus constrained (62%), and 15 hinged (8%). Components revised included the following: 93 femur/tibia (47%), 68 polyethylene-only (35%), 19 femur-only (10%), and 17 other (9%). Survivorship free from re-revision was calculated via the Kaplan-Meier method and a multivariate Cox proportional regression was utilized to identify risk factors for re-revision. RESULTS: Survivorship free from any re-revision at 5 years was 80%. In the multivariate analysis, patients with a prior revision (hazard ratio [HR] = 2.78, P = .02), an isolated polyethylene exchange (HR = 3.0, P = .004), and a hinged prosthesis (HR = 3.47, P = .05) were significant risk factors for lower revision-free survival. Forty-two patients (21%) underwent re-revision, most commonly for periprosthetic joint infection (7%), instability (6%), and aseptic loosening (5%). Re-revision occurred in 18/68 (26%) patients undergoing an isolated polyethylene exchange. CONCLUSION: Patients less than 55 years undergoing revision TKA have a modest 5-year revision-free survival of 80%. Patients with prior revision TKAs (HR = 2.78), hinge type prostheses (HR = 3.47), and polyethylene-only revisions (HR = 3.0) had higher revision rates.

Early Aseptic Failure of the Tibial Component-Cement Interface in ATTUNE® Total Knee Arthroplasty: A Report of Three Cases.

Total knee arthroplasty (TKA) systems are designed to maximize the longevity of the implant. However, an unusually high rate of aseptic tibial tray loosening was observed in the DePuy ATTUNE® total knee arthroplasty system (DePuy Synthes, Warsaw, USA). Affected patients noted symptoms of instability and reproducible pain at the bone-implant interface. However, there was no radiographic evidence of lucency or implant failure. Intra-operatively, the tibial component was grossly loose and lacked adhered cement. We hypothesize that the loosening is due to the smooth architecture of the undersurface of the tibial component, lacking either grit blasting or porous coating.

Medium term clinical outcomes of tibial cones in revision knee arthroplasty.

INTRODUCTION: Trabecular metal cones are a relatively new option for reconstruction of major bone defects during revision total knee arthroplasty (TKA). The purpose of the present study was to retrospectively assess medium-term results for tibial cones in revision TKA with a severe proximal tibial bone defect. We hypothesized that revision TKA patients with bone defects treated with trabecular metal cones have excellent medium-term clinical and radiological results. PATIENTS AND METHODS: A single-center retrospective review included all consecutive cases of tibial revision using trabecular metal cones. All patients with a minimum 2-year follow-up were included in the study. There were no exclusion criteria. The primary endpoint was tibial cone survivorship. The secondary endpoints were revision TKA all-cause survivorship, patient-reported outcome measures with a Knee injury and Osteoarthritis Outcome Score (KOOS), SF 12, and radiographic analysis. RESULTS: Five of the 57 patients alive at last follow-up (8.77%) had undergone revision (4 for infection and 1 for instability). Complications comprised four cases (7.02%) of infection, 2 cases (3.51%) of tibial and femoral implant aseptic loosening that did not require revision surgery, 1 of which (1.75%) with associated patellar loosening, and 1 case (1.75%) of instability. Kaplan-Meier estimates showed 100% 5-year survivorship with tibial cone revision for aseptic loosening and 93.44% (95% CI 83.47-97.49%) for all-cause revision. DISCUSSION: The present study of cones used for tibial revision supports shows excellent results; however, longer and larger follow-up is needed to better assess results in revision TKA. LEVEL OF EVIDENCE: 4, retrospective study.

Localized cytokine responses to total knee arthroplasty and total knee revision complications.

BACKGROUND: The study of localized immune-related factors has proven beneficial for a variety of conditions, and one area of interest in the field of orthopaedics is the impact of implants and localized infections on immune response. Several cytokines have shown increased systemic concentrations (in serum/plasma) in response to implants and infection, but tissue-level cytokines have not been investigated as thoroughly. METHODS: This exploratory study investigated tissue-level cytokines in a cohort of patients (N = 17) in response to total knee arthroplasty and total knee revision to better understand the immune response to implants and localized infection (e.g., prosthetic joint infection). The overall goal of this study was to provide insight into the localized cytokine response of tissues and identify tissue-level markers specific to inflammation caused by implants vs. inflammation caused by infection. Tissues were collected across several anatomical locations and assayed with a panel of 20 human inflammatory cytokines to understand spatial differences in cytokine levels. RESULTS: In this study, six cytokines were elevated in implanted joints, as compared to native joints: IL-10, IL-12p70, IL-13, IL-17A, IL-4, and TNF-α (p < 0.05). Seven cytokines showed infection-dependent increases in localized tissues: IL-1α, IL-1ß, IL-6, IL-8, MCP-1, MIP-1α, and MIP-1ß (p < 0.05). CONCLUSIONS: This study demonstrated that differences exist in tissue-level cytokines in response to presence of implant, and some cytokines were specifically elevated for infection; these responses may be informative of overall tissue health. These results highlight the utility of investigating localized cytokine concentrations to offer novel insights for total knee arthroplasty and total knee revision procedures, as well as their complications. Ultimately, this information could provide additional, quantitative measurements of tissue to aid clinical decision making and patient treatment options.

Risk Adjustment in the California Joint Replacement Registry: Is Patient Complexity Accurately Assessed in Academic Versus Nonacademic Hospitals?

BACKGROUND: We sought to report on the differences in observed versus expected arthroplasty outcomes between academic and nonacademic hospitals in a large joint registry. We utilized the California Joint Replacement Registry's data and risk adjustment model. METHODS: Observed versus expected hip and knee arthroplasty complications were utilized to assess hospital and surgeon risk-adjusted complication rates (RACRs). Based on a hospital and surgeon RACR, each was assigned a performance rating ("worse," "expected," "better"). Associations between academic status and performance ratings, rates of individual complications, prevalence of risk factors associated with increased complication rates, and differences in complication rates were calculated. RESULTS: A higher percentage of academic providers had "worse" than expected ratings, whereas a higher percentage of nonacademic providers had "expected" and "better" than expected ratings (P = .011) based on the observed versus expected complication rates. There was a higher incidence of patients with congestive heart failure and an elevated American Society of Anesthesiologists classification in academic institutions (P = .0001). The complication rate was higher in academic institutions for all total knee arthroplasties (P < .0016). CONCLUSIONS: We identified disparities in RACRs between nonacademic and academic institutions. This may reflect the difficulty of fully adjusting for medical risk and surgical complexity in a large arthroplasty database.

Diagnosing Prosthetic Joint Infections in Patients With Inflammatory Arthritis: A Systematic Literature Review.

BACKGROUND: Patients with inflammatory arthritis (IA) are at increased risk of prosthetic joint infections (PJI), yet differentiating between septic and aseptic failure is a challenge. The aim of our systematic review is to evaluate synovial biomarkers and their efficacy at diagnosing PJI in patients with IA. METHODS: A comprehensive literature search was performed in the following databases from inception to January 2018: Ovid MEDLINE, Ovid EMBASE, and the Cochrane Library. Searches across the databases retrieved 367 results. Two of 5 reviewers independently screened a total of 298 citations. Discrepancies were resolved by a third reviewer. Twenty articles fit our criteria, but due to methodological differences findings could not be pooled for meta-analysis. For 5 studies, raw data were provided, pooled, and used to derive optimal diagnostic cut points. RESULTS: Our final analysis included 1861 non-IA patients, including 426 patients with PJI, and 90 IA patients of whom 26 had PJI. There was a significant difference among the 4 groups for serum C-reactive protein (CRP), erythrocyte sedimentation rate, and synovial CRP, polymorphonuclear neutrophil percent, white blood cells, interleukin (IL)-6, IL-8, and IL-1b. Polymorphonuclear neutrophil percent had the highest sensitivity (95.2%) and specificity (85.0%) to detect infections with an optimum threshold of 78%. CONCLUSION: While levels of synovial white blood cells, IL-6, IL-8, and serum CRP appear higher in patients with IA, there is overlap with those who are not infected. Further studies are needed to explore diagnostic tests that will better detect PJI in patients with IA.

The proper timing of second-stage revision in treating periprosthetic knee infection: reliable indicators and risk factors.

BACKGROUND: Two-stage revision is the standard procedure for periprosthetic knee infection. But when to perform the second-stage is still under debate. We attempt to search the reliable indicators, risk factors, and proper timing for the second-stage revision. METHODS: We reviewed and followed 81 infected total knee arthroplasty patients who underwent two-stage revision from January 2010 to January 2014. Our cohort included 56 males and 25 females, all patients were confirmed as PJI with the same phenotypic cultures. The average age was 64.8 ± 8.21 (range 36-78) months. The mean follow-up time was 46.5 ± 17.6 (range 12-72) months after the second-stage surgeries. The diagnostic parameters including serum C-reaction protein, erythrocyte sedimentation rate, and intraoperative frozen section at the time of re-implantation were analyzed. The spacer detention time and antibiotic treatment time were compared. RESULTS: Ten of them went through failed first- or second-stage surgeries. The overall success rate was 87.7%. The intraoperative frozen section is a good indicator at the time of re-implantation; the sensitivity and specificity is 90 and 83.1%. Serum CRP and ESR showed poor diagnostic value at time of re-implantation. Atypical pathogen infection, positive FS, and previous sinus were high-risk factors for failure of two-stage revision. Spacer detention time between 12 and 16 weeks had higher success rate than over 16 weeks. CONCLUSION: The proper timing of re-implantation should be combined with disappearance of clinical symptoms and negative intraoperative FS with spacer detention time at 12 to 16 weeks.

Comparing Inpatient Complication Rates between Octogenarians and Nonagenarians following Primary and Revision Total Knee Arthroplasty in a Nationally Representative Sample, 2010⁻2014.

We compared the inpatient postoperative complication rates between octogenarians and nonagenarians undergoing primary and revision total knee arthroplasty (TKA). We used the Nationwide Inpatient Sample (NIS) to analyze inpatient admission data from 2010⁻2014. We compared the rates at which nonagenarians and octogenarians developed each complication following both primary TKA (PTKA) and revision TKA (RTKA). A national estimate of 324,933 patients were included in our study. A total of 313,299 (96.42%) were octogenarians, and 11,634 (3.58%) were nonagenarians. 294,462 (90.62%) underwent PTKA, and 30,471 (9.38%) underwent RTKA. Nonagenarians undergoing PTKA had a higher inpatient mortality rate, and developed sepsis more frequently than octogenarians. Nonagenarians undergoing RTKA had a higher inpatient mortality rate, and developed cardiogenic shock more frequently than octogenarians. In both PTKA and RTKA, nonagenarians received transfusions more frequently, and developed urinary tract infection and acute kidney injury more frequently than octogenarians. In both PTKA and RTKA, nonagenarians sustained a higher inpatient mortality rate than octogenarians. Orthopedic surgeons should counsel nonagenarian patients undergoing both PTKA and RTKA preoperatively about this increased mortality risk, as well as the increased risks of more minor complications like transfusion, urinary tract infection, and acute kidney injury.

Revision total knee arthroplasty with porous-coated metaphyseal sleeves provides radiographic ingrowth and stable fixation.

PURPOSE: Porous-coated metaphyseal sleeves are designed to fill bone defects and facilitate osseointegration when bone loss in encountered during revision total knee arthroplasty (TKA). The purpose of this study is to evaluate short-term results of porous-coated metaphyseal sleeves with regards to implant fixation and clinical outcomes. METHODS: A retrospective review was conducted on 50 patients (79 sleeves-49 tibial and 30 femoral) who had a press-fit metaphyseal sleeve with revision TKA. Tibial and femoral bone loss was classified according to the Anderson Orthopaedic Research Institute (AORI) bone defect classification. Post-operative complications of infection, revision surgery, and dislocation were assessed. Follow-up radiographs were evaluated for signs of loosening using the criteria developed by the Knee Society. The median follow-up was 58.8 months (range 25.8-93.0 months). RESULTS: The bone loss classifications were 1 type 1, 30 type 2a, 2 type 2b, and 17 type 3, and with regards to the femur, 5 were type 1, 8 type 2a, 31 type 2b, and 6 type 3. At final follow-up, 41/45 (91.1%) tibial and 28/29 (96.6%) femoral sleeves showed radiographic evidence of ingrowth. Of these 69 patients, all showed radiographic evidence of bony ingrowth. Three sleeves were revised for infection and two for loosening. The re-operation rate for loosening was 5/74 (6.8%) and for any reason was 14/74 (18.9%). CONCLUSIONS: Modular porous-coated press fit metaphyseal sleeves fill defects and provide evidence of radiographic ingrowth. Short-term stable fixation can be achieved with sleeves, which is helpful as more patients undergo revision total knee arthroplasty with greater bone loss. Longer duration studies are needed to ascertain the survival rate of these implants. LEVEL OF EVIDENCE: IV.