Visible fluid motion on manipulation as the new threshold for intraoperatively determined knee arthroplasty component loosening: A Delphi study.

PURPOSE: There is a lack of a clear, uniform definition for intraoperatively assessed component loosening of a knee arthroplasty component, complicating the interpretation and interchangeability of results of diagnostic studies using an intraoperative observation as the reference test. The purpose of this study was to establish a consensus among specialised knee revision surgeons regarding the definition of intraoperatively determined loosening of total or unicondylar knee arthroplasty components. METHODS: Utilising the Delphi consensus method, an international panel of highly specialised knee revision surgeons was invited to participate in a three-round process. The initiation of the first round involved the exploration of possible criteria for intraoperatively determined loosening with open questions. The second round focused on rating these criteria importance on a five-point Likert scale. For the third round, criteria that reached consensus were summarised in consecutive definitions for intraoperatively determined loosening and proposed to the panel. Consensus was established when over 70% of participants agreed with a definition for intraoperatively determined loosening. RESULTS: The 34 responding panel members described in total 60 different criteria in the first round of which 34 criteria received consensus in the second round. Summarising these criteria resulted in four different definitions as minimal requirements for intraoperatively determined loosening. Eighty-eight percent of the panel members agreed on defining a component as loose if there is visible fluid motion at the interface observed during specific movements or when gently applying direct force. CONCLUSION: This study successfully established a consensus using a Delphi method among knee revision surgeons on the definition of intraoperatively determined component loosening. By agreeing on the visibility of fluid motion as new definition, this study provides a standardised reference for future diagnostic research. This definition will enhance the interpretability and interchangeability of future diagnostic studies evaluating knee arthroplasty component loosening. LEVEL OF EVIDENCE: Level V.

Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Knee Arthroplasty.

BACKGROUND: Frailty can predict adverse outcomes after various orthopaedic procedures, but is not well-studied in revision total knee arthroplasty (rTKA). We investigated the correlation between the Hospital Frailty Risk Score (HFRS) and post-rTKA outcomes. METHODS: Using the Nationwide Readmissions Database, we identified rTKA patients discharged from January 2017 to November 2019 for the most common diagnoses (mechanical loosening, infection, and instability). Using HFRS, we compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients with multivariate and binomial regressions. The 30-day complication and reoperation rates were compared using univariate analyses. We identified 25,177 mechanical loosening patients, 12,712 infection patients, and 9,458 instability patients. RESULTS: Frail patients had higher rates of 30-day readmission (7.8 versus 3.7% for loosening, 13.5 versus 8.1% for infection, 8.7 versus 3.9% for instability; P < .01), longer length of stay (4.1 versus 2.4 days for loosening, 8.1 versus 4.4 days for infection, 4.9 versus 2.4 days for instability; P < .01), and greater cost ($32,082 versus $27,582 for loosening, $32,898 versus $28,115 for infection, $29,790 versus $24,164 for instability; P < .01). Frail loosening patients had higher 30-day complication (6.8 versus 2.9%, P < .01) and reoperation rates (1.8 versus 1.2%, P = .01). Frail infection patients had higher 30-day complication rates (14.0 versus 8.3%, P < .01). Frail instability patients had higher 30-day complication (8.0 versus 3.5%, P < .01) and reoperation rates (3.2 versus 1.6%, P < .01). CONCLUSIONS: The HFRS may identify patients at risk for adverse events and increased costs after rTKA. Further research is needed to determine causation and mitigate complications and costs.

Revision Total Knee Arthroplasty With an Imageless, Second-Generation Robotic System.

BACKGROUND: Robotic-assisted total knee arthroplasty is increasingly used in revision total knee arthroplasty (rTKA), with imageless systems recently receiving Food and Drug Administration (FDA) approval. However, there remains a paucity of literature on the use of robotic assistance in revision total knee arthroplasty (TKA). This paper describes the imageless surgical technique for robotic revision TKA using a second-generation robotic system and details both intraoperative and 90-day outcomes. METHODS: This was a retrospective review of 115 robotic revision TKAs from March 2021 to May 2023 at 3 tertiary academic centers. Patient demographics, perioperative surgical data, and 90-day outcomes were collected. Pain and Patient-Reported Outcomes Measurement Information System scores preoperatively and postoperatively were recorded. All-cause reoperations at the final follow-up were detailed. The mean patient age was 65 years (range, 43 to 88), and 58% were women. The mean follow-up time was 13 months (range, 3 to 51). RESULTS: The most common indications for rTKA were instability (n = 37, 32%) and aseptic loosening (n = 42, 37%). There were 83 rTKAs to a posterior-stabilized liner, 22 to a varus-valgus constrained liner, and 5 to a hinged construct. The median polyethylene size was 11 (interquartile range, 10 to 13), and 93% of patients had their joint line restored within 5 millimeters of the native contralateral knee. Within the 90-day postoperative window, there were 8 emergency department visits and 2 readmissions. At the final follow-up, there were 5 reoperations and 2 manipulations under anesthesia. There were 4 patients who required irrigation and debridement after superficial wound dehiscence, and one had an arthrotomy disruption after a fall. CONCLUSIONS: This review demonstrates favorable intraoperative and 90-day outcomes and suggests that imageless robotic surgery is a promising modality in rTKA. Further studies comparing the longitudinal outcomes after robotic and conventional rTKA are warranted.

Outcomes of Metaphyseal Cones and Stem Fixation Following Rotating Hinge in Complex Primary and Revision Total Knee Arthroplasty.

BACKGROUND: Although hinged prostheses have been used successfully in complex revision total knee arthroplasty (TKA), concerns exist regarding early failure due to aseptic loosening and other mechanical complications. The use of metaphyseal cones and hybrid cement fixation have been studied in unlinked constrained primary or revision TKA, but their impact on the survivorship of hinged prostheses has yet to be investigated. METHODS: We identified a consecutive series of 164 hinged prostheses and collected data on demographics, indications, complications, and re-revisions in patients who had fully cemented versus hybrid stems, with and without metaphyseal cones. A multivariate analysis was performed to identify independent variables associated with re-revision as the primary end point. RESULTS: In total, 84 patients (51.2%) had fully cemented stems, and 80 patients (48.8%) had hybrid stems. Cones were used in 73 patients (44.5%). At a mean follow-up of 3.4 ± 2.2 years, 42 patients underwent re-revision (25.8%), most commonly for infection (12.2%), followed by loosening (6.7%) and periprosthetic fracture (3.7%). Patients who had fully cemented stems had lower re-revision rates than hybrid fixation constructs (19 versus 26%, P = .043). Using multivariable regression, a construct with hybrid fixation with cones (odds ratio = 2.39; P = .037) was an independent risk factor for failure. Utilization of cones alone did not have an effect on re-revision rates at 3.4-year follow-up. CONCLUSIONS: While we found no difference with the use of cones, patients undergoing revision TKA with a hinge prosthesis and fully cemented stems had better overall survivorship than hybrid stems.

Medicaid Patients Travel Disproportionately Farther for Revision Total Joint Arthroplasty.

BACKGROUND: Access to high-quality care for revision total joint arthroplasty (rTJA) is poorly understood but may vary based on insurance type. This study investigated distance traveled for hip and knee rTJA based on insurance type. METHODS: A total of 317 revision hips and 431 revision knees performed between 2010 and 2020 were retrospectively reviewed. Cluster sampling was used to select primary hips and knees for comparison. Median driving distance was compared based upon procedure and insurance type. RESULTS: Revision hip and knee patients traveled 18.2 and 11.0 miles farther for surgery compared to primary hip and knee patients (P ≤ .001). For hip rTJA, Medicaid patients traveled farther than Medicare patients followed by commercially insured patients with median distances traveled of 98.4, 67.2, and 35.6 miles, respectively (P = .016). Primary hip patients traveled the same distance regardless of insurance type (P = .397). For knee rTJA, Medicaid patients traveled twice as far as Medicare and commercially insured patients (medians of 85.0, 43.5, and 42.2 miles respectively, P ≤ .046). Primary knee patients showed a similar pattern (P = .264). Age and ASA-PS classification did not indicate greater comorbidity in Medicaid patients. CONCLUSION: Insurance type may influence rTJA referrals, with disproportionate referral of Medicaid and Medicare patients to nonlocal care centers. In addition to patient burden, these patterns potentially present a financial burden to facilities accepting referrals. Strategies to improve equitable access to rTJA, while maintaining the highest and most economical standards of care for patients, providers, and hospitals, are encouraged.

Decreased Patellar Fractures and Subluxation With Patellar Component Replacement at Stage-One Spacer.

BACKGROUND: Periprosthetic joint infection is a devastating complication of total knee arthroplasty and is often treated with 2-stage revision. We retrospectively assessed whether replacing the patellar component with articulating stage-one spacers was associated with improved outcomes compared to spacers without patellar component replacement. METHODS: A total of 139 patients from a single academic institution were identified who underwent an articulating stage-one revision total knee arthroplasty and had at least 1-year follow-up. Of the 139 patients, 91 underwent patellar component removal without replacement, while 48 had a patellar component replaced at stage-one revision. Patellar fracture and reinfection at any point after stage-one were recorded. Knee range of motion (ROM), patellar thickness, lateral tilt, and lateral displacement were measured at 6-weeks post stage-one. Chi-square, Fisher's exact, and t-tests were utilized for comparisons. There were no significant demographic differences between groups. RESULTS: Patellar component replacement at stage-one revision was associated with fewer patellar fractures (2.1 versus 12.1%, P = .046), less lateral patellar displacement (1.7 versus 16.0 mm, P < .01), and improved pre to postoperative knee ROM 6 weeks after stage-one (+5.9 versus -11.4°, P = .03). There was no difference in reinfections after stage-2 revision for the replaced or unreplaced patellar groups (15.4 versus 15%, P = 1.000). While the mean time between stage-one and stage-2 was not different (5.2 versus 4.5 months, P = .50), at one-year follow-up, significantly more patients in the patellar component replacement group were satisfied and refused stage-2 revision (45.8 versus 3.3%, P < .001). CONCLUSIONS: Replacing the patellar component at stage-one revision is associated with a decreased rate of patellar fracture and lateral patellar subluxation, improved ROM, and possible increased patient satisfaction, as reflected by nearly half of these patients electing to keep their spacer. There was no difference in reinfection rates between the cohorts.

Fellowship-Trained Surgeons Experience a Learning Curve Performing Revision Total Joint Arthroplasty.

BACKGROUND: Revision hip (rTHA) and knee (rTKA) arthroplasties require considerable surgical proficiency, but are frequently delegated to the least experienced surgeons. This study examined the influence of surgeon experience on revision outcomes. METHODS: Prospective data on confirmed aseptic rTHAs (n=122) and rTKAs (n=195) performed by four fellowship-trained surgeons in the same practice were retrospectively analyzed. Surgeons were grouped based on years in practice (inexperienced [IE] first two years, early experience [EE) 4 to 6 years, senior experience [SE] 15 to 17 years). Procedure duration, estimated blood loss (EBL), and reoperation rates were compared, controlling for potential covariates. RESULTS: Procedure durations varied based on surgeon experience for three of four rTHA diagnoses (P≤0.001). Relative to the SE surgeon, procedure duration was 80.0 (95% CI [confidence interval] 61.7 to 98.4, P<0.001) minutes longer for IE surgeons and 30.9 (95% CI 17.5 to 44.3, P < 0.001) minutes longer for the EE surgeon. Procedure durations also varied based on surgeon experience for three of four rTKA diagnoses (P<0.001), with the longest durations for IE surgeons. Procedure durations varied based on the interaction of surgeon experience, patient age, and body mass index (BMI). The EBL did not differ in rTHA based on surgeon experience (P=0.978), but did differ for rTKA (P=0.004). There were 25% of rTHAs performed by IE surgeons compared to 15.5% for the EE surgeon and 3.6% for the SE surgeon that underwent reoperation within a year of the index procedure (P=0.064), with significantly more reoperations for the same indication among IE and EE surgeons (P=0.046). CONCLUSIONS: Complex procedures completed by less experienced surgeons may result in longer procedures, higher EBL, and more early reoperations. Study findings implicate a learning curve for revision arthroplasty that continues for several years, warranting consideration of existing patient allocation and referral patterns.

Patient-reported outcomes and satisfaction after revisions of medial unicompartmental knee arthroplasties for unexplained pain vs aseptic loosening.

PURPOSE: Does patients revised for unexplained pain after mUKA present the same PROM and satisfaction scores 1-3 years after revision as patients revised for aseptic loosening?". METHODS: 104 patients undergoing revision of mUKA's for the indications unexplained pain and aseptic loosening were included in the period January 1, 2018 to December 31, 2020. from the Danish Knee Arthroplasty Register. 52 patients were revised for unexplained pain and 52 for aseptic loosening. Patient demographics did not differ between the two groups. PROMs [Oxford Knee Score (OKS), EQ-5D-5L, Forgotten Joint Score (FJS)] and questions about satisfaction with the surgery were sent to digitally secured mailboxes. Pearson's Chi-square test and Wilcoxon Rank Sum test were used to test for statistical differences between groups. RESULTS: The median OKS 1-3 years after revision was 26 (IQR 22) for unexplained pain vs 34 (IQR 12) for aseptic loosening, p = 0.033. The median EQ-5D-5L Index after revision was 0.7 (IQR 0.6) for unexplained vs 0.8 (IQR 0.1) for aseptic loosening, p = 0.014. The median FJS after revision was 48 (IQR 10) for unexplained pain vs 52 (IQR 14) for aseptic loosening, p = 0.1. The mean satisfaction with the surgery on a 0-100 scale (100 = not satisfied; 0 = very satisfied) was 55 (IQR 60) for unexplained pain vs 50 (IQR 67) for aseptic loosening, p = 0.087, and patients revised for unexplained pain were less likely to find their knee problem importantly improved (p = 0.032). CONCLUSION: Patients undergoing revision of mUKAs for unexplained pain presented poor postoperative PROM scores, and PROM scores were worse compared to those of patients revised for aseptic loosening. Patients revised for unexplained pain were less likely to find their knee problem importantly improved. This study support the evidence against revisions for unexplained pain. LEVEL OF EVIDENCE: Level III.

Alpha-defensin as a diagnostic tool in revision total knee arthroplasties with unexpected positive intraoperative cultures and unexpected culture negative intraoperative cultures.

PURPOSE: Unexpected-positive-intraoperative-cultures (UPIC) are common in presumed aseptic revision-total-knee-arthroplasties (rTKA). However, the clinical significance is not entirely clear. In contrast, in some presumably septic rTKA, identification of an underlying pathogen was not possible, so-called unexpected-negative-intraoperative-cultures (UNIC). The purpose of this study was to evaluate the potential use of synovial alpha-defensin (AD) levels in these patients. METHODS: Synovial AD levels from 143 rTKAs were evaluated retrospectively from our prospectively maintained institutional periprostetic joint infection (PJI) biobank and database. The 2018-International Consensus Meeting (ICM) criteria was used to define the study groups. Samples from UPICs with a minimum of one positive intraoperative culture (ICM 2- ≥ 6) (n = 20) and UNIC's (ICM ≥ 6) (n = 14) were compared to 34 septic culture-positive samples (ICM ≥ 6) and 75 aseptic culture-negative (ICM 0-1). Moreover, AD-lateral-flow-assay (ADLF) and an enzyme-linked-immunosorbent-assay (ELISA) in detecting the presence of AD in native and centrifuged synovial fluid specimens was performed. Concentration of AD determined by ELISA and ADLF methods, as well as microbiological, and histopathological results, serum and synovial parameters along with demographic factors were analysed. RESULTS: AD was positive in 31/34 (91.2%) samples from the septic culture-positive group and in 14/14 (100%) samples in the UNIC group. All UPIC samples showed a negative AD result. Positive AD samples were highly associated with culture positive and histopathological results (p < 0.001). No high-virulent microorganisms (0/20) were present in the UPIC group, compared to infected-group (19/34; 55.9%). High virulent microorganisms showed a positive AD result in 89.5% (17/19) of the cases. Methicillin resistant Staphylococcus epidermis (MRSE) infections had significantly higher AD levels than with methicillin susceptible S. epidermdis (MSSE) (p = 0.003). ELISA and ADLF tests were positive with centrifuged (8/8) and native (8/8) synovial fluid. CONCLUSION: AD showed a solid diagnostic performance in infected and non-infected revisions, and it provided an additional value in the diagnosis of UPIC and UNIC associated to rTKAs. Pathogen virulence as well as antibiotic resistance pattern may have an effect on AD levels. Centrifugation of synovial fluid had no influence on ADLF results.

Patient-Reported Outcomes and Satisfaction 1 to 3 Years After Revisions of Total Knee Arthroplasties for Unexplained Pain Versus Aseptic Loosening.

BACKGROUND: It is unknown if patients are relieved of pain after knee arthroplasty revision for unexplained pain. The aim of this cross-sectional case-control study was to compare patient-reported outcome measures (PROMs) and satisfaction 1 to 3 years after revision of total knee arthroplasties (TKAs) for the indications of unexplained pain versus aseptic loosening. METHODS: We included 384 patients undergoing TKA revision for the indications of unexplained pain and aseptic loosening from January 1, 2018 to December 31, 2020 from the Danish Knee Arthroplasty Register. A total of 81 patients were revised for unexplained pain and 303 for aseptic loosening. Questionnaires including PROMs (Oxford Knee Score, EQ-5D-5L, and Forgotten Joint Score) and satisfaction with the surgery on a 0-100 scale (100 = not satisfied; 0 = very satisfied) were sent to digitally secured mailboxes. Time from revision to data collection was a median 3.1 years (range, 1.4-4.4 years). RESULTS: Median Oxford Knee Score was 25 (interquartile range [IQR] 15) versus 31 (IQR 18) 1-3 years after revisions for unexplained pain versus aseptic loosening, P = .009. Median EQ-5D-5L was 0.6 (IQR 0.4) versus 0.8 (IQR 0.3) for unexplained pain versus aseptic loosening, P = .009. Median Forgotten Joint Score was 50 (IQR 7) versus 50 (IQR 16) for unexplained pain versus aseptic loosening, P = .905. Satisfaction was 75 (IQR 38) for unexplained pain and 50 (IQR 73) for aseptic loosening, P < .001. CONCLUSION: Patients undergoing TKA revision for the indication of unexplained pain had worse results on PROMs than those revised for aseptic loosening. Likewise, patients revised for unexplained pain were less satisfied compared to patients revised for aseptic loosening. This information is valuable to both surgeons and patients when candidates for revision surgery are selected, to obtain the best possible outcomes.

No Association Between Hospital Volume and Early Second Revision Rate in Revision Total Knee Arthroplasty in the Dutch Orthopaedic Register.

BACKGROUND: Revision knee arthroplasty (R-KA) is rising globally. Technical difficulty of R-KA varies from liner exchange to full revision. Centralization has been shown to reduce mortality and morbidity rates. The present study aimed to evaluate the association between hospital R-KA volume and overall second revision rate, as well as revision rate for different types of revision. METHODS: The R -KAs between 2010 and 2020 with available data on the primary KA in the Dutch Orthopaedic Arthroplasty Register were included. Minor revisions were excluded. Implant data and anonymous patient characteristics were obtained from the Dutch Orthopaedic Arthroplasty Register. Survival analyses and competing risk analysis were performed per volume category (≤12, 13 to 24, or ≥25 cases/year) at 1, 3, and 5 years following R-KA. There were 8,072 R-KA cases available. Median follow-up was 3.7 years (range 0 to 13.7 years). There were a total of 1,460 second revisions (18.1%) at the end of follow-up. RESULTS: There were no statistically significant differences between second revision rates of the three volume groups. Adjusted hazard ratio for second revision were 0.97 (Confidence Interval (CI) 0.86 to 1.11) for hospitals with 13 to 24 cases/year and 0.94 (CI 0.83 to 1.07) with ≥25 cases/year compared to low volume (≤12 cases/year). Type of revision did not influence second revision rate. CONCLUSION: Second revision rate of R-KA does not seem to be dependent on hospital volume or type of revision in the Netherlands. LEVEL OF EVIDENCE: Level IV, Observational registry study.

Classifying Bone Loss in Failed Stemmed Total Knee Arthroplasty: Determining Reliability.

BACKGROUND: Failed stemmed total knee arthroplasty (TKA) components present with varying degrees of bone loss and technical challenges. A classification system has been proposed based upon metaphyseal bone loss and diaphyseal cortical integrity. A validation study was performed to determine interobserver and intraobserver reliability at multiple institutions and with different levels of training. METHODS: An online survey with digital anteroposterior and lateral radiographs was sent to 5 arthroplasty surgeons and 5 adult reconstruction fellows. The survey included 62 cases with stemmed femoral and tibial components, considered failures and pending revision, and scored by each reviewer independently using the classification system. Each case was scored in 2 separate sessions. Interobserver and intraobserver reliability was assessed using the intraclass correlation coefficient (ICC). RESULTS: Interobserver grading for both the femur (0.69) and tibia (0.72) showed strong reliability among the attendings and fellows, with slightly stronger reliability in tibia cases. The intraclass correlation coefficient (ICC) for attendings and fellows was similar overall, demonstrating consistency of the grading regardless of training level. Intraobserver comparisons showed a strong ICC for attendings and fellows in femoral cases, while fellows had near-perfect ICC in tibia cases. Across all reviewers there was on average 93% agreement within 1 grade per case with the majority of the discrepancy occurring at the metaphyseal-diaphyseal junction. CONCLUSION: This classification demonstrated overall strong interobserver and intraobserver reliability, with 93% agreement within 1 grade of bone loss. With further education, this classification system can ultimately be used to standardize the degree of bone loss in failed stemmed components and help with preoperative planning.

Medial-Pivot Design Improved Knee Symptoms From Anteroposterior Instability in Early-Range Flexion and Resolved Anterior Knee Pain in Revision Total Knee Arthroplasty.

BACKGROUND: Instability can lead to poor functional results after tricompartmental total knee arthroplasty (TKA). We identified a group of patients who appeared to have anteroposterior (AP) instability in early-range flexion (ie, 20 to 30° range) associated with anterior knee pain and feelings of instability. The purpose of this study was to assess the clinical results in terms of stability and anterior knee pain after revision TKA with a medial-pivot implant and to assess the effect of the implant positioning used in the revision technique. METHODS: There were 45 patients (45 knees) evaluated retrospectively to assess standing lower extremity alignment and functional results by generating a knee stability score after revision TKA with medial pivot implant design. RESULTS: Revision TKA using the medial-pivot TKA lowered the joint line by 3.6 millimeters (mm) (P < .001) and positioned the tibia anteriorly by 3.5 mm (P < .001) on radiographic measurements as compared with results after primary TKA. Moreover, medial pivot revision TKA improved AP stability by a 56-point change in score (P < .001). CONCLUSION: Revision TKA using a medial pivot design improved AP stability and anterior knee pain after failed primary procedures.

Bone defect classifications in revision total knee arthroplasty, their reliability and utility: a systematic review.

BACKGROUND: There are various classification systems described in the literature for managing bone defects in revision knee arthroplasty (RTKA). We analysed the reliability and usefulness of these classification systems. QUESTIONS/PURPOSES: (1) To review and critique the various classification systems proposed for bone loss in RTKA. (2) Among all the proposed classifications which one is the most commonly used by surgeons to report their results. (3) What is the reliability of various bone defect classification systems for RTKA. In this review, we have assessed the studies validating those classifications with a detailed description of the limitations and the proposed modifications. METHODS: This systematic review was conducted following PRISMA guidelines. Pubmed/Medline, CINAHL, EMBASE, Scopus, Cochrane databases and Web of Science databases were searched using multiple search terms and MeSH terms where possible. Studies meeting inclusion criteria were assessed for statistical parameters of reliability of a classification system. RESULTS: We found 16 classification systems for bone defects in RTKA. Six studies were found evaluating a classification system with reporting their reliability parameters. Fifty-four studies were found which classified bone loss using AORI classification in their series. AORI classification is most commonly reported for classifying bone defects. Type T2B and F2B are the most common bone defects in RTKA. The average kappa value for AORI classification for femoral bone loss was 0.38 (0.27-0.50) and 0.76 (0.63-1) for tibial bone loss assessment. CONCLUSION: None of the available classification systems is reliably established in determining the bone loss and treatment plans in RTKA. Among all, AORI classification is the most widely used system in clinical practice. The reliability of AORI Classification is fair for femoral bone loss and substantial for tibial bone loss.

Is the Citak classification of distal femur morphology age and gender dependent?

INTRODUCTION: The purpose of this study was to compare the distal femur morphology in different age and gender groups using the Citak classification. MATERIALS AND METHODS: All patients who had standard knee anteroposterior radiographs between 2010 and 2020 were retrospectively reviewed using the electronic patient database. Patients were divided into three age groups as follows: young adults (Group I, younger than 50 years), middle-aged adults (Group II, ranging from age 51 to 73 years), and elderly (Group III, more than 74 years). From each age group, 80 patients were randomly selected with an equal number of gender (40 males/40 females). An age-stratified selection was applied to obtain the best sample that represents the selected age groups. Patients younger than 18 years of age, history of previous fracture or surgical procedure, those with fixation implants or prosthesis, and abnormalities of the lower limb, such as a congenital deformity, were excluded from the study. All measurements were performed by an experienced orthopedic surgeon familiar with the Citak classification. All measured variables were compared between age and gender groups. RESULTS: There were 240 patients (120 male and 120 female) with a mean age of 59.6 ± 20.4 (range 18-95). The distal femur morphology index was similar (p:0.811), and the morphological types were equally distributed among age groups (p:0.819). Furthermore, there was no significant difference between genders on the measured variables (p > 0.05 for all variables). Citak classification types were similarly distributed between the genders (p:0.153). No correlation was found between age and the Citak index in either gender (p:0.967 and p:0.633, respectively). CONCLUSIONS: Distal femoral morphology classified by the Citak index is not age and gender dependent. Type C, which has a wider diaphyseal diameter, and is supposed to be more common in elderly subjects, was equally distributed in all age groups. LEVEL OF EVIDENCE: Level IV. Retrospective case series.

Application of structural allogenous bone graft in two-stage exchange arthroplasty for knee periprosthetic joint infection: a case control study.

BACKGROUND: Knee prosthetic joint infection (PJI) is a common but devastating complication after knee arthroplasty. The revision surgeries for knee PJI may become more challenging when it is associated with large bone defects. The application of structural bone allograft in knee revision surgeries with large bone defects is not a new technique. However, there is a lack of literature reporting its efficacy in PJI cases. This study aimed to investigate the outcome of structural fresh frozen allogenous bone grafts in treating patients in knee PJI with large bone defects. METHODS: We performed a retrospective cohort analysis of knee PJI cases treated with two-stage exchange arthroplasty at our institution from 2010 to 2016. 12 patients with structural allogenous bone graft reconstructions were identified as the study group. 24 patients without structural allograft reconstructions matched with the study group by age, gender, and Charlson comorbidity index were enrolled as the control group. The functional outcome of the study group was evaluated with the Knee Society Score (KSS). Treatment success was assessed according to the Delphi-based consensus definition. The infection relapse rate and implant survivorship were compared between groups. RESULTS: Revision knees with structural allograft presented excellent improvement in the KSS (33.1 to 75.4). There was no significant difference between infection relapse-free survival rate and prosthesis survival rate in the two groups. The 8-year prosthesis survival rate was 90.9% in the study group and 91% in the control group (p = 0.913). The 8-year infection relapse-free survival rate was 80 and 83.3% in the study group and control group, respectively (p = 0.377). CONCLUSION: The structural fresh frozen allogenous bone graft provided an effective way for bone defect reconstruction in knee PJI with an accountable survival rate. Meanwhile, using structural allografts did not increase the relapse rate of infection.

Patient safety in distal femoral resection knee arthroplasty for non-tumor indications: a single-center consecutive cohort study of 45 patients.

BACKGROUND: Distal femoral resection knee arthroplasty may be a viable option for several indications other than bone tumors. Resection knee arthroplasty appears to be becoming more common, but patients requiring this type of surgery are often elderly and with high comorbidity. The aim of this study was to report in-hospital complications, readmissions, reoperations, and mortality after distal femoral resection knee arthroplasty for non-tumor indications. METHODS: We retrospectively identified a consecutive cohort of 45 knees (45 patients) treated with distal femoral resection knee arthroplasty in a single institution between 2012 and 2021. Indications for surgery were failure of osteosynthesis (8), primary fracture treatment (2), periprosthetic fracture (22), and revision arthroplasty with severe bone loss (13). A major reoperation was defined as a major component exchange procedure or amputation. Mean follow-up was 3.9 years. RESULTS: The mean age was 71.3 years (SD 12.3), and 64.4% were female; 8.9% were ASA I, 40% ASA II, and 51% ASA III. Median length of stay was 7 days (range 3-19) with no major in-hospital complications, but 55.6% (n = 25) required blood transfusion. The 90-day readmission rate was 17.8% (n = 8), of which 50% was prosthesis-related. Four patients (8.9%) underwent major reoperation due to infection (n = 2), mechanical failure (n = 1), or periprosthetic fracture (n = 1). The mortality rate was 0% ≤ 90 days and 2.2% ≤1 year. CONCLUSIONS: Distal femoral resection knee arthroplasty in this fragile patient population appears to be a viable and safe option considering that it is a limp salvage procedure most cases.

Readability and quality of online information for patients pertaining to revision knee arthroplasty: An objective analysis.

BACKGROUND: Modern patients use the internet more frequently for their health information. Our aim was to assess the quality and readability of online patient education materials relating to revision knee arthroplasty. We hypothesised that this information would be too difficult to read for the average patient and of a lesser quality than desired. METHOD: A search of the top 50 results on 3 search engines (Google, Bing, Yahoo) was completed (MeSH "revision knee arthroplasty", "revision knee replacement"). Readability of these websites was calculated using a specialised website, www.readable.com to produce 3 scores (Gunning-Fog (GF), Flesch Reading Ease (FRE), Flesch-Kincaid Grade (FKG). Quality was assessed using the Journal of American Medical Association (JAMA) benchmark criteria and the Health On the Net (HON) code toolbar extension. RESULTS: 89 unique websites were identified. Mean FRE was 44.01 ± 11.05. The mean GF was 12.01 ± 2.94. The mean FKG level was 10.06 ± 1.95. As per the FRE score, no webpage was pitched at or below a sixth grade reading level. The GF index identified only 3 websites (3.4%) at 6th grade reading level. As per FKG score, most webpages (n = 58, 65.2%) found themselves in the 10th grade reading level and above. Four websites (4.5%) displayed a HONcode certificate. However, all had expired. Most websites (n = 34, 38.2%) didn't meet any of the JAMA criteria. CONCLUSION: The reading level of these materials is too high for the average patient and of a low quality. Given what we know about levels of health literacy and their relationship with patient outcomes, it is vital that we address these deficiencies promptly.

Reduced Infection Rate After Aseptic Revision Total Knee Arthroplasty With Extended Oral Antibiotic Protocol.

BACKGROUND: The optimal postoperative antibiotic duration has not been determined for aseptic revision total knee arthroplasty (R-TKA) where the risk of periprosthetic joint infection (PJI) is 3%-7.5%. This study compared PJI rates in aseptic R-TKA performed with extended oral antibiotic prophylaxis (EOAP) to published rates. METHODS: Aseptic R-TKAs consecutively performed between 2013 and 2017 at a tertiary care referral center in the American Midwest were retrospectively reviewed. All patients were administered intravenous antibiotics while hospitalized and discharged on 7-day oral antibiotic prophylaxis. Infection rates and antibiotic-related complications were assessed. RESULTS: Sixty-seven percent of the 176 analysis patients were female, with an average age of 64 years and body mass index of 35 kg/m2. Instability and aseptic loosening comprised 86% of revision diagnoses. Overall, 87.5% of intraoperative cultures were negative, and the remainder were single positive cultures considered contaminants. PJI rates were 0% at 90 days, 1.8% (95% confidence interval 0.4%-5.3%) at 1 year, and 2.2% (95% confidence interval 0.6%-5.7%) at mean follow-up of approximately 3 years (range, 7-65 months). CONCLUSION: EOAP after aseptic R-TKA resulted in a PJI rate equivalent to primary TKA, representing a 2- to-4-fold decrease compared with published aseptic R-TKA infection rates. Further study on the benefits and costs of EOAP after aseptic R-TKA is encouraged.

Early Infection After Aseptic Revision Knee Arthroplasty: Prevalence and Predisposing Risk Factors.

BACKGROUND: Although patient factors have been associated with prosthetic joint infection (PJI) after primary total knee arthroplasty, there are insufficient data on the relationship of patient and technical factors with early PJI after aseptic revision. METHODS: This is a retrospective study of 157 aseptic revisions performed by 2 surgeons at 1 academic center. A negative intraoperative culture during revision surgery was required for inclusion. Mean follow-up time was 3.8 years (standard deviation 2.8). PJI was defined by positive aspiration or draining wound, and an additional operation within 1 year of aseptic revision. Patient demographics, medical comorbidities, and technical factors were reviewed. Data points were evaluated with univariate and adjusted multivariate regression analyses. RESULTS: The prevalence of PJI after aseptic revision was 9% (14/157). The most common organism was Staphylococcus aureus. Initial treatment included debridement and liner exchange (11) and antibiotic spacer (3). Two patients ultimately had an above-knee amputation. Univariate analysis showed a significant difference in preoperative anemia (P < .01), transfusion (P < .01), and diabetes (P = .05) between cohorts. There was no association among the length of surgery, use of a metaphyseal cone, or the number of components revised and PJI. Adjusted logistic regression demonstrated that preoperative anemia (P < .01) was a significant risk factor for PJI. CONCLUSION: The prevalence of early PJI was similar to other studies in the literature. Anemia was an independent predictor of PJI, while technical factors did not have an association. Medical optimization of patients should be considered prior to revision surgery.