RESUMEN

Background: Aseptic loosening is one of the leading causes of stem revision. Einzel Bild Röntgen Analyse-Femoral Component Analysis allows for the detection of distal stem migration, which is used as a predictive factor for implant longevity. This study aims to demonstrate the migration behavior of a cemented collared anatomical stem. Methods: This study retrospectively examined all patients who received a cemented Lubinus SP II stem (Waldemar Link, Hamburg, Germany) between 2003 and 2019. We used the EBRA-FCA software (University of Innsbruck, Austria) to determine the migration patterns and thoroughly examined the patients' medical histories. In addition, the potential influence of femoral configuration and BMI on the migration behavior was assessed. Results: This study included 61 patients (48 females and 13 males) with a total of 61 stems that met our inclusion criteria. The mean age at surgery was 76 years (ranging from 30 to 93 years). According to EBRA-FCA migration analysis, a median subsidence of 0.7 mm was observed at 24 months and at the final follow-up (median 78 months). Distal stem migration was significantly higher at the 6-month time point in patients with Dorr type A femurs compared to Dorr type B femurs (p = 0.016). Body mass index (BMI) had no significant effect on stem migration. Conclusions: The measured subsidence of the Lubinus SP 2 stem using EBRA-FCA was below established thresholds, indicating excellent long-term outcomes. Although there was significantly increased subsidence in Dorr type A femurs during the initial 6 months, thereafter, no statistically significant difference was observed compared to Dorr type B femurs.

RESUMEN

High-entropy alloys (HEA) as a kind of new binder for cemented carbide have garnered significant attention. In this work, WC/(17~25 wt.%)Al0.5CoCrFeNiTi0.5 cemented carbides were prepared by hot pressing sintering (HPS), and the reactions between WC powder and Al0.5CoCrFeNiTi0.5 powder during hot pressing sintering were elucidated. It found that different from traditional Co binder, the Al0.5CoCrFeNiTi0.5 binder effectively inhibited WC grain growth. During HPS, the decomposed W and C atoms from WC diffused into the Al0.5CoCrFeNiTi0.5 binder, reacted with the elements in the binder, and then formed the M(Co, Fe, Ni)3W3C phase. The back-diffusion of W and C atoms to WC grains was restricted by the Al0.5CoCrFeNiTi0.5 alloy and inhibited them from re-precipitating onto the large undissolved WC grains. As a result, the average size of WC grains in the cemented carbides was less than 200 nm. This work bright new insight into the grain refinement mechanisms of WC cemented carbide with HEA binder and provide a guidance for designing performance-stable WC/HEA cemented carbide and promoting their application.

RESUMEN

The plastic flow behavior of soft rock exhibits non-coaxial features under complex stress paths, while traditional plasticity theories are ill-equipped to adequately represent this, which leads to the mechanism of soft rock failure still unclear. To investigate the evolution law of strain increments and non-coaxial characteristics of weakly cemented soft rock, the directional shear tests are conducted using the hollow cylinder apparatus (HCA). The results show that non-coaxiality does not occur when α is distinct from 0° or 90°. The oscillation of the non-coaxial angle is significantly more variable in soft rock experiencing combined tension-torsion (45° < α < 90°), as opposed to those under the influence of combined compression-torsion (0° < α < 45°). The non-coaxiality swiftly dissipates when the sample is approaching the failure state. The stress rate is decomposed into stress magnitude and direction to describe non-coaxial features of plastic strain. And a new method for non-coaxial stress rate is proposed which can express the plastic strain increment directions. The spherical interpolation coefficient method is utilized to describe the continuous change in non-coaxial plastic flow direction between tangential and normal directions of the yield surface. The non-coaxial parameter (Δ) is introduced to quantify the non-coaxial characteristics of soft rock and its validity is confirmed through test results. This method effectively captures the principal stress direction influence on non-coaxial behavior of soft rock and have significance for rock mechanics.

RESUMEN

Background: Early postoperative functional recovery is important in older patients with lower-extremity fractures to prevent disuse, and periprosthetic femoral fractures (PFFs) are no exception. This study aimed to compare the postoperative functional recovery in the early phase after revision for PFF with loose stems between cemented and cementless stems. Methods: Eighteen patients with Unified Classification System type B2 PFF were included in this retrospective cohort study with a follow-up period of about 2 years. All patients underwent stem revision and were divided into 2 groups: the cemented stem group (n = 9) and the cementless stem group (n = 9). In postrevision, functional independence measure score, independent walk rate, activities of daily living recovery rate to the original level at 2 weeks postoperatively, the Beals and Tower classification for radiological status, and survival rate for readmission as endpoints were compared between the 2 groups. Results: Patients in the cemented group recovered functional mobility earlier than in the cementless group, with higher postoperative functional independence measure functional subscale values (73 vs 50 points, P = .02), higher independent walk rate (89 vs 11%, P < .01), and more postoperative activities of daily living recovery (100% vs 44%, P = .03) at 2 weeks postoperatively. The Beals and Tower classification and survival rates were similar in both groups. Conclusions: Revision using a cemented stem for PFF in older patients was a useful surgical procedure in terms of early postoperative functional recovery. Cemented stem revision was comparable with cementless in bone union and safety at 2 years postoperatively.

RESUMEN

OBJECTIVE: Previous cementless total knee arthroplasty (TKA) designs faced challenges with insufficient initial fixation on tibial side, resulting in inferior functional outcomes and survival rates. The Zoned Trabecular Bone Cementless Knee is a novel implant designed for cementless TKA which aims to achieve excellent initial fixation, promoting effective osseointegration. The aim of this research was to compare the early clinical and radiographic results of this cementless TKA with cemented TKA. METHODS: Between September 2021 and April 2022, 64 patients (64 knees) were recruited in this prospective randomized controlled trial to receive either cementless 3D-printed trabecular metal TKA or a cemented posterior stabilized TKA. Preoperative and postoperative clinical evaluations, including the range of motion (ROM), Knee Society Score (KSS), and the Reduced Western Ontario and MacMaster Universities Score (WOMAC), were conducted and analyzed for comparison. Radiographs and computed tomography scans were utilized to assess the initial fixation. The complications between the two groups were also recorded and compared. Continuous data were analyzed for significance using independent-samples t-test or the Mann-Whitney U test and categorical data were analyzed using chi-squared or Fisher's exact test. RESULTS: Both groups demonstrated significant enhancement at 12 months follow-up in the ROM compared with baseline (ROM: 94.7 ± 23.4 vs. 113.1 ± 12.3 in cementless group and 96.5 ± 14.7 vs. 111.0 ± 12.8 in cemented group, p < 0.05). However, no statistical differences were observed between the two groups in postoperative ROM, KSS, or WOMAC score. The radiographs and computed tomography scans showed similar results, including radiolucent lines and osteolysis in either femoral or tibial. Additionally, there was no statistical difference in the overall complication rate between the two groups. Notably, one patient in the cementless TKA group required revision for periprosthetic infection as the end point. CONCLUSIONS: This novel 3D-printed trabecular metal cementless TKA achieved comparable clinical outcomes and initial fixation to cemented TKA in early stage. Longer-term examination is necessary to validate these results.

RESUMEN

OBJECTIVES: To compare marginal bone levels, biological, and technical outcomes of screw-retained versus cemented all-ceramic implant-supported zirconia-based single crowns after an observation period of 7.5 years. METHODS: Forty-four single implants in the esthetic zone in 44 patients (22 females, 22 males) were randomly assigned to two types of restorations: SR (screw-retained); veneered one-piece zirconia abutment and CR (cement-retained); veneered lithium disilicate crown intraorally cemented on a one-piece zirconia abutment. Patients were recalled annually up to 7.5 years and survival rates, biological, and technical parameters assessed. RESULTS: A total of 31 patients attended the 7.5-year follow-up visit (17 SR group, 14 CR group). The survival rate on the restorative level was 77.5% (74.0% CR, 81.0% SR, p = .6399). Median marginal bone loss (MBL) values yielded -0.073 mm (-0.305; 0.238) in the CR and -0.215 mm (-0.500; 0.555) in the SR group (intergroup p = .6194). Mean bleeding on probing (BoP) values were significantly in favor of group SR with 20 ± 17% compared to 40 ± 22% in group CR (p = .011). The overall biological complication rate amounted to 27.5% (42.1% CR, 14.3% SR, p = .0775), whereas the technical complication rate was 32.5% (42.1% CR, 23.8% SR, p = .314). In total, CR restorations showed significantly more complications (84.2% for CR, 38.1% for SR, p = .0041). CONCLUSION: One-piece zirconia-based single crowns on two-piece dental implants exhibited a high rate of technical and biological complications at 7.5 years of follow-up. Cemented restorations revealed significant higher rates of bleeding on probing and total complications compared to screw-retained restorations.

RESUMEN

INTRODUCTION: The integrity of the femoral bone is crucial when considering reconstructive options for the first-time revision of a total hip arthroplasty (THA). Aseptic loosening of primary stems, whether cemented or uncemented, significantly affects the volume and quality of resultant femoral bone loss. This study evaluates the impact of the initial fixation method on femoral bone defect patterns by comparing the extent of bone loss. MATERIALS AND METHODS: A retrospective cohort of 215 patients with either cemented or uncemented stems, indicated for aseptic stem loosening, and undergoing first-time stem revision from 2010 to 2022 at our institution was analyzed. Femoral bone loss extent at first-time revision was preoperatively gauged using radiographs and categorized by the Paprosky classification. Survival probabilities pre-first-time revision for both stem types were calculated using Kaplan-Meier methods. Hazard ratios were applied to compare the risk of initial revision for uncemented versus cemented stems within the first and subsequent 2nd to 10th years post-primary implantation. RESULTS: Cemented stems were associated with a higher occurrence of significant bone defects of type 3a (23.53% vs. 14.02%, p = .108), 3b (39.22% vs. 1.22%, p < .001), and 4 (3.92% vs. 0.00%) compared to uncemented stems. Conversely, smaller defects of type 1 and 2 were more prevalent in uncemented stem loosening (84.76% vs. 33.33%, p < .001). Notably, cemented stems exhibited a significantly prolonged revision-free period over the complete decade following primary insertion (p < .001). The unadjusted risk of first-time revision due to stem loosening showed a tendency to an increase in uncemented stems within the initial postoperative year (HR 5.55, 95% CI 0.74; 41.67, p = .096), and an adjusted risk of 2.1 (95% CI 0.26; 16.53, p = .488). However, these differences did not reach statistical significance. In the subsequent 2nd-10th years, the risk was lower compared to cemented stems (HR 2.35, 95% CI 1.39; 3.99, p = .002). CONCLUSIONS: Uncemented primary stems necessitating first-time revision due to aseptic loosening demonstrated notably smaller femoral bone defects in comparison to primary cemented stems.

RESUMEN

Background: Posterior glenoid bone loss in glenohumeral osteoarthritis poses significant challenges in shoulder arthroplasty. Anatomic total shoulder arthroplasty (TSA) with a humeral head autograft to address the glenoid bone deficiency is an option for these difficult cases. Variable results with this procedure are reported in the literature. This article describes the surgical technique of posterior glenoid bone grafting in TSA using a glenoid implant with hybrid fixation and a series of reported patient functional and radiographic outcomes. Methods: A retrospective chart review of cases from 2015 to 2020 by a single surgeon revealed 10 patients who underwent primary TSA with hybrid glenoid component and posterior glenoid bone grafting. Preoperative and postoperative radiographs were assessed for glenoid inclination, glenoid version, acromiohumeral distance, humeral stem status, and glenoid implant status. Functional outcomes were evaluated by range of motion, strength, and patient-reported clinical outcomes (pain and function on a visual analog scale, Disabilities of the Arm, Shoulder, and Hand score, Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons score). Complications and reoperations were also evaluated. Results: Average follow-up was 31.4 months, active forward flexion and external rotation improved on average from 105° to 150° and 20° to 60°, respectively (P < .001) and average abduction improved from 100° to 140° (P < .002). At an average of 26.7 months, patients reported assessments (visual analog scale pain and function, Disabilities of the Arm, Shoulder, and Hand score, Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons scores) reveal significant (P < .05) improvement in pain and functional outcomes. Radiographically, at 23.0 ± 20.1 months, all patients demonstrated a well-fixed humeral and glenoid component without evidence of lucent lines. The bone graft used in each patient was well unionized and no radiographic complications were reported. No patients underwent revision surgery, and there was one clinical complication reported, which consisted of a suspected rotator cuff injury at follow-up. Conclusion: Hybrid fixation with structural glenoid bone grafting in TSA resulted in excellent outcomes with no evidence of graft or component failure on follow-up radiographs and significantly reduced pain, improved functional scores, and improved active range of motion.

RESUMEN

Phosphogypsum (PG) cemented paste backfill (CPB) is a primary non-hazardous method for treating PG. However, using traditional binders like cement increases global carbon emissions and mining operational costs while complicating the reduction of fluoride leaching risks. This study introduces a novel PG-based CPB treatment method using steel slag (SS) and ground granulated blast furnace slag (GGBFS) as binders, calcium oxide as an exciter, with biochar serving as a fluoride-fixing agent. We investigated the effect of biochar addition on the hydration and solidification/stabilization (S/S) of fluoride in SS and GGBFS-PG-based materials (SSPC). The results indicated that the optimal strength and performance for fluoride S/S were achieved with a biochar addition of 0.2 wt%. Compared to the control group without biochar, the strength increased by 54.3%, and F leaching decreased by 39.4% after 28 days of curing for SSPC. The addition of 0.2 wt% biochar facilitated heterogeneous nucleation and acted as a microfiller, enhancing SSPC's properties. However, excessive biochar reduced the compactness of SSPC. Additionally, the distribution of fluoride was strongly correlated with P, Ca, Fe, and Al, suggesting that fluoride S/S is linked to the formation of stable hydration products like fluorapatite, fluorite, and complexes such as [AlF6]3- and [FeF6]3-. These findings offer a promising approach for the safe treatment of PG and the beneficial reuse of solid waste from SS and GGBFS.

Asunto(s)

RESUMEN

This study investigates the post-liquefaction monotonic undrained shearing behavior of cemented sand at the macro- and microscales, using the discrete element method. A series of cyclic undrained triaxial tests with different stress amplitudes and post-liquefaction monotonic undrained triaxial tests were simulated on cemented sand with diverse cement contents (CCs). For comparison, a series of monotonic undrained triaxial tests on cemented sand without liquefaction (virgin cemented sand) were also modeled. The macroscopic behavior was analyzed in conjunction with the microscopic characteristics of the assembly, such as the deviator fabric of contact normal orientation, mechanical coordination number, energy components, and bond breakage. The results show that the DEM model can capture the effect of CC and cyclic stress ratio (CSR) on the undrained shear strength, stiffness, and pore pressure observed in laboratory experiments. Referring to the virgin specimen, with an increase in CC, the mechanical coordination number and the input work increment increase, while the deviator fabric for total contacts changes irregularly, leading to a greater initial stiffness and shear strength. In the case of the liquefied specimen, the smaller initial mechanical coordination number results in a very low initial stiffness regardless of CC. Contrary to the uncemented sand, both the mechanical coordination number and the input work increment decrease with an increasing CSR for the cemented sand. The microstructure evolution governs the effect of cementation level and liquefaction history on the macroscopic post-liquefaction behavior.

RESUMEN

BACKGROUND: There have been several studies on intraoperative femoral fractures (IFFs) during primary total hip arthroplasty, but it is not well understood how this complication affects the patient population undergoing cemented hemiarthroplasty. This study aimed to analyze the impact of IFFs sustained during cemented hemiarthroplasty for the treatment of femoral neck fractures. METHODS: A retrospective review was conducted of all patients who were treated for Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association 31B fractures with cemented hemiarthroplasty between January 1, 2000 and December 31, 2021, at a single academic level 1 trauma center. An initial cohort was constructed of all patients who sustained an IFF during their surgery, yielding 31 patients after excluding those who sustained a pathologic fracture or had incomplete data. These patients were matched 1:2 on age, sex, and body mass index to patients in a control cohort. The primary outcome measure was implant failure. Secondary outcome measures included complications, all-cause mortality, and radiographic outcomes (subsidence, femoral component loosening, acetabular wear, and heterotopic ossification) postoperatively. RESULTS: Subsequent implant revision was required in 3.2% (n = 1) of patients who sustained an IFF and 1.6% (n = 1) of patients who did not. After adjusting for comorbidities, there was no observed excess risk of implant failure in the fracture cohort when compared to the control cohort (hazard ratio [HR] = 0.30, P = 0.740). There was no observed excess risk of morbidity (HR = 0.69, P = 0.621) or all-cause mortality (HR = 0.23, P = 0.330). Radiographic outcomes also did not significantly differ between the 2 cohorts (P > 0.05). CONCLUSIONS: Intraoperative fractures during cemented hemiarthroplasty do not contribute to an increased risk of secondary surgery, morbidity, or mortality after surgery. They also do not adversely affect radiographic outcomes postoperatively. LEVEL OF EVIDENCE: Level III, Retrospective Comparative Study.

RESUMEN

Metastatic lesions in the proximal femur are well-known in the literature and are important since they can progress to pathological fractures and impair the patient's mobility. We present the case of a middle-aged female with a history of breast carcinoma 20 years ago, who experienced diffuse chronic hip pain for the past two months. Radiographs, MRI, and PET scans revealed a metastatic lesion in her proximal femur. After consulting with an oncologist, it was determined that adjuvant chemoradiotherapy was unnecessary. The treatment strategy was dependent on the preoperative general health condition, the life expectancy, amount of metastasis, bone quality, pathological fractures and factors affecting the union and capacity to ambulate the patient postoperatively. The patient underwent a cemented bipolar hemiarthroplasty to excise all metastatic tissue and provide a painless, functional, and mobile joint. Bipolar hemiarthroplasties articulate at two levels, and this dual-bearing design is believed to reduce acetabular wear. The bipolar hemiarthroplasty also eliminated the risk of complications associated with the acetabular component, which would necessitate early revision surgery. Modular bipolar hemiarthroplasty is a good modality of replacement associated with fewer complications and improves quality of life.

RESUMEN

The utilization of industrial solid waste in mines is an important approach to resource utilization. The backfill material in mines is mainly composed of solid waste, which plays a supporting role. The excitation effect of lime on phosphogypsum and fly ash in backfill was studied in this paper. The macroscopic and microscopic characteristics of the backfill material were tested using uniaxial compression, nuclear magnetic resonance, scanning electron microscopy, and electrochemical techniques, and a relationship model was established between them. Furthermore, the influence of industrial solid waste on the properties of the backfill material under the action of lime and the hydration mechanism between different industrial solid wastes were studied. The results show that (1) under the action of lime, fly ash reacts with lime to produce C-S-H and C-A-H, and then C-A-H reacts with phosphogypsum to produce AFt. (2) The excess phosphogypsum also fills the pores. Therefore, 1.8% lime reduces the porosity of the backfill by 17.88% and increases the strength by 21.57%. (3) The cross-scale relationship shows that strength is inversely proportional to each type of pore content and fractal dimension, and it logarithmically increases with impedance at different frequencies. The lower the frequency, the stronger the relationship is. (4) This study indicates that industrial solid waste is a suitable cement replacement.

RESUMEN

In bone-milling surgical procedures, the intense friction between the tool and bone material often results in high cutting temperatures, leading to the thermal necrosis of bone cells. This paper aims to investigate the effect of micro-texture on the tribological properties of YG8 cemented carbide in contact with bone. The main objective is to guide the design of tool surface microstructures to reduce frictional heat generation. To minimize experimental consumables and save time, numerical simulations are first conducted to determine the optimal machining depth for the texture. Subsequently, micro-textures with different shapes and pitches are prepared on the surface of YG8 cemented carbide. These textured samples are paired with bovine cortical bone pins featuring various bone unit arrangements, and friction and wear tests are conducted under physiological saline lubrication. The experimental results indicate that the appropriate shape and pitch of the micro-texture can minimize the coefficient of friction. The parallel arrangement of bone units exhibits a lower coefficient of friction compared to the vertical arrangement. This study holds significant implications for the design and fabrication of future micro-texture milling cutters.

RESUMEN

OBJECTIVE: To investigate the pull-off forces on implant-supported restorations caused by sticky food, to understand how much retention force cemented restorations must have to withstand chewing forces without unintentional retention loss. The influence of food type, restoration design, and surface treatment were investigated. MATERIAL AND METHODS: Monolithic implant-supported CAD/CAM zirconia crowns were fabricated and divided into groups according to their design: no (NC), flat (FC) and high cusps (HC) and subdivided according to surface roughness: rough (r) and smooth (s) (n = 10/group). NC represented the control group. The crowns were fixed in a universal testing machine opposite to each other. Four sticky foods (caramel, fruit jelly, candy strips and licorice) and a resin crown remover were tested. These were heated (36.4°C), placed between the crowns and compressed, then tensile strength tests were performed. The maximum pull-off force was recorded (Newton [N]). Statistical analysis was performed using 3-way ANOVA. RESULTS: The highest mean pull-off force among food samples was with caramel_HC_r (12.09 ± 1.26 N), whereas the lowest was with licorice_FC_s (3.21 ± 0.15 N). For the resin crown remover, a mean pull-off force of 55.41 ± 3.87 N was measured in the HC_r group. Both food type and crown design showed a significant influence on pull-off force (p < 0.001), whereas no significant effect was reported with different surface roughnesses (p = 0.344). CONCLUSION: This study reported pull-off forces of up to 20 N between all-ceramic restorations caused by sticky food. The clinical implication of these findings is that a cemented implant-restoration must have a minimum retention force of 20 N to withstand unintentional displacement during function.

RESUMEN

BACKGROUND: Cementless total knee arthroplasty (TKA) is rising in popularity. The literature supporting its use over cemented TKA remains sparse. Using the Canadian Joint Replacement Registry (CJRR), we sought to investigate cementless versus cemented fixation in modern primary TKA and (1) determine whether there is an overall difference in revision by fixation, (2) perform a subanalysis of the most-commonly used cementless TKA brand in Canada, and (3) identify the reasons for revision. METHODS: The CJRR data was used to analyze TKA designs with cemented and cementless versions. Revision risk is reported as all-cause cumulative percent revision (CPR). Reasons for revision were analyzed. Cox proportional hazards models were used to report adjusted hazard ratios (HR) controlling for age, sex, patella resurfacing, and bearing constraints. We included 202,880 primary TKAs performed between 2012 and 2021. Of those, 9,163 (4.5%) were cementless. RESULTS: The CPR at 8 years was 4.49% for cementless and 3.14% for cemented implants. After adjusting for confounders, we did not detect a difference in revision risk overall (HR 0.87 [95% CI (confidence interval) 0.73 to 1.04], P = 0.128). However, the most commonly used cementless TKA brand demonstrated a CPR of 1.95% compared to 2.19% for its cemented version at 4 years. Furthermore, we detected a significantly lower revision risk compared to its cemented version after adjusting for confounders (HR 0.66 [95% CI 0.51 to 0.85], P = 0.001). The 4 most common reasons for revision in both groups were the following: (1) infection, (2) instability, (3) aseptic loosening, and (4) pain of unknown origin. CONCLUSIONS: Using CJRR data adjusted for confounding factors, no difference in revision risk was detected between cemented and cementless implants overall. However, for the most common brand of cementless TKA used in Canada, there was a lower risk of revision than its corresponding cemented version. The reasons for revision were similar.

RESUMEN

Both cementless and cemented stems have exhibited favorable long-term outcomes in total hip arthroplasty. Nonetheless, in elderly patients, cemented hips offer an advantage due to their reduced risk of periprosthetic fractures. This study aimed to assess the initial outcomes of 28 patients who underwent unilateral cemented total hip arthroplasty utilizing a calcar-guided A2 stem (ARTIQO GmbH, Lüdinghausen, Germany). Various types of antibiotic-loaded bone cement were employed. During follow-up, we recorded demographic data and comorbidities and employed standardized clinical assessment tools, including the Harris Hip Score. Radiographic assessments included preoperative, postoperative, and follow-up imaging to evaluate subsidence, osteolysis, and bone resorption. The results indicated that among the 28 patients, 5 withdrew consent and 2 patients passed away from unrelated causes. Additionally, one prosthesis was explanted due to the undersizing of the cement stopper, which resulted in an inadequate cement mantle. As a result, 20 patients underwent a 1-year follow-up, revealing noteworthy enhancements in clinical scores, with no instances of radiolucent lines or osteolysis. No infections were detected. In summary, our short-term experience with this particular cemented short-stem design yielded promising results, exhibiting excellent functional outcomes, no aseptic loosening attributable to the stem, and no infections. Further clinical studies and registry data are essential to corroborate these findings.

RESUMEN

Purpose: Aseptic loosening is the most common cause for revisions after total knee arthroplasty (TKA). Despite many studies exploring various risk factors associated with aseptic loosening, findings often present inconsistencies. To address this, we conducted a thorough review of the literature to identify and analyse these risk factors in cemented TKA. Additionally, we performed a meta-analysis to reconcile the divergent conclusions observed across studies. Methods: We searched PubMed, Web of Science and Embase from 1996 up to 2024 and evaluated the quality of the included literature. Seventy-four studies were included to assess the association of BMI, diabetes, high physical activity (HPA), osteoporosis, rheumatoid arthritis (RA), cement material and implant design. Twenty-nine studies were used to calculate relative risk and CIs (using the random effects theory) and study heterogeneity for six different risk factors (BMI, diabetes, HPA level, cement material, polyethylene and implant design). Results: Patients with diabetes are eight times more likely to experience aseptic loosening compared to those without diabetes (RR = 9.18, 95% CI: 1.80-46.77, p < 0.01). The use of tibial stem extension or highly crosslinked polyethylene can help reduce the incidence of aseptic loosening. However, we did not identify BMI, HPA, osteoporosis, RA, the use of high-viscosity cement and the utilization of mobile-bearing designs as risk factors for aseptic loosening post-cemented TKA. Conclusions: Patients with diabetes undergoing TKA should be counselled regarding their potential increased risk of aseptic loosening. The use of tibial stem extensions and HXLPE can mitigate the incidence of aseptic loosening in cemented TKA. However, given a limited number of studies were included in the meta-analysis, we believe that higher-level studies are necessary to clearly identify other risk factors. Level of Evidence: Level III.

RESUMEN

Purpose: Obesity is prevalent, with nearly one-third of the world's population being classified as obese. In patients with high body mass index (BMI)/body mass undergoing total knee arthroplasty (TKA), there is an increase in strain placed on the implant fixation interfaces. As such, component fixation is a potential concern when performing TKA in the obese patient. To address the growing concerns around the longevity of implant fixation, some have advocated cementless over cemented fixation. However, there is no clear consensus on whether a cementless fixation has more favourable outcomes. The aim of this paper was to present a systematic review and meta-analysis of the existing evidence to establish if cementless TKA has a lower rate of aseptic loosening in high BMI patients when compared to cemented TKA procedures. Methods: A systematic review was performed, and the following databases Medical Literature Analysis and Retrieval System Online (1946 to date), PubMed (1966 to date) and Excerpta Medica Database (1974 to date) were searched. All studies comparing cementless to cemented TKA in patients with BMI > 30 were considered. Meta-analysis compared aseptic loosening and all-cause revision between cemented and uncemented implant use in BMI > 30 patients. Results: The search returned 91 articles in total; after duplicates were removed, the yield was 44 studies. Of the remaining studies that were assessed, three studies met the inclusion criteria for meta-analysis. The pooled odds ratio for all-cause revisions was 0.17 (95%, 0.08-0.36) in favour of uncemented implants (p < 0.01). The pooled odds ratio for aseptic loosening was 0.15 (95% confidence interval, 0.02-0.90) in favour of uncemented implants (p = 0.04). Conclusions: Meta-analysis demonstrated a significant decrease in all-cause revisions and revisions for aseptic loosening when using uncemented fixation in high BMI patients when compared to the use of cemented implants. Level of Evidence: The level of evidence is 1 for our systematic review.

RESUMEN

With the gradual shift of coal mining to the western coal mining region of China, floor heave in weakly cemented mudstone roadways has become an issue affecting the safety and efficiency of coal mine production. Additionally, different mining rates can lead to fluctuating support stresses on the roof and floor of weakly cemented mudstone roadways. Therefore, obtaining a comprehensive understanding of the mechanical properties of weakly cemented mudstone at different loading rates is conducive to improving the issue of floor heave in such roadways and provides a theoretical basis for further study. In this context, a series of uniaxial mechanical tests with concurrent acoustic emission monitoring were conducted on specimens of weakly cemented mudstone under various loading rates (0.005, 0.01, 0.05, and 0.1 mm/s). The stress‒strain and acoustic emission response curves were obtained to effectively characterize the strength, deformation, damage, macroscale instability, and crack propagation characteristics of the mudstone under the influence of loading rate effects. The research results support the following findings: (1) With increasing loading rate, the peak strength and elastic modulus of weakly cemented mudstone significantly increase, while the peak axial strain and peak radial deformation significantly decrease. (2) With increasing loading rate, the stress required to trigger the expansion of weakly cemented mudstone gradually increases, and a significant power-law relationship arises between the strain of the mudstone at the start of expansion and the loading rate. (3) With increasing loading rate, the acoustic emission ringing count of weakly cemented mudstone increases: The failure of weakly cemented mudstone changes from small-range progressive failure to sudden failure, and the failure mode transitions from shear failure to tensile‒shear composite failure. (4) The studied mudstone damage variables increase with increasing loading rate, following an approximate exponential function. The conclusions obtained in this work can provide a theoretical basis for the evolution mechanism and control of floor heave in deep roadway mining.