Utility score is a preference-based measure of general health state – where 0 is equal to death, and 1 is equal to perfect health. To understand a patient's smallest A tertiary institutional registry (SMART) was used as the study cohort. Patients who underwent unilateral TKA for osteoarthritis from January 2012 to January 2020 were included. Utility score was calculated from VR12 responses using the standardised Brazier's method. Distribution and anchor methods were used for the MCID calculation. For distribution methods, 0.5 standard deviations of the baseline and change scores were used. For anchor methods, the physical and emotional anchor questions in the VR12 survey were used to benchmark utility score outcomes. Anchor methods included mean difference in change score, mean difference in 12 month score, and receiver operating characteristics (ROC) analysis with the Youden index. Complete case analysis of 1735 out of 1809 eligible patients was performed. Significant variation in the MCID estimates for VR12 utility score were reported dependent on the calculation method used. The MCID estimate from 0.5 standard deviations of the change score was 0.083. The MCID estimate from the ROC analysis method using physical or emotional anchor question improvement was 0.115 (CI95 0.08-0.14; AUC 0.656). Different MCID calculation methods yielded different MCID values. Our results suggest that MCID is not an umbrella concept but rather many distinct concepts. A general consensus is required to standardise how MCID is defined, calculated, and applied in clinical practice.
Approximately 20% of patients feel unsatisfied 12 months after primary total knee arthroplasty (TKA). Current predictive tools for TKA focus on the clinician as the intended user rather than the patient. The aim of this study is to develop a tool that can be used by patients without clinician assistance, to predict health-related quality of life (HRQoL) outcomes 12 months after total knee arthroplasty (TKA). All patients with primary TKAs for osteoarthritis between 2012 and 2019 at a tertiary institutional registry were analysed. The predictive outcome was improvement in Veterans-RAND 12 utility score at 12 months after surgery. Potential predictors included patient demographics, co-morbidities, and patient reported outcome scores at baseline. Logistic regression and three machine learning algorithms were used. Models were evaluated using both discrimination and calibration metrics. Predictive outcomes were categorised into deciles from 1 being the least likely to improve to 10 being the most likely to improve. 3703 eligible patients were included in the analysis. The logistic regression model performed the best in out-of-sample evaluation for both discrimination (AUC = 0.712) and calibration (gradient = 1.176, intercept = −0.116, Brier score = 0.201) metrics. Machine learning algorithms were not superior to logistic regression in any performance metric. Patients in the lowest decile (1) had a 29% probability for improvement and patients in the highest decile (10) had an 86% probability for improvement. Logistic regression outperformed machine learning algorithms in this study. The final model performed well enough with calibration metrics to accurately predict improvement after TKA using deciles. An ongoing randomised controlled trial (ACTRN12622000072718) is evaluating the effect of this tool on patient willingness for surgery. Full results of this trial are expected to be available by April 2023. A free-to-use online version of the tool is available at smartchoice.org.au.
Surgical site infections (SSIs) after spinal fusion surgery increase healthcare costs, morbidity and mortality. Routine measures of obesity fail to consider site specific fat distribution. We aimed to assess the association between the spine adipose index and deep surgical site infection and determine a threshold value for spine adipose index that can assist in preoperative risk stratification in patients undergoing posterior instrumented lumbar fusion (PILF). A multicentre retrospective case-control study was completed. We reviewed patients who underwent PILF from January 1, 2010 to December 31, 2018. All patients developing a deep primary incisional or organ-space SSI within 90 days of surgery as per US Centre for Disease Control and Prevention criteria were identified. We gathered potential pre-operative and intra-operative deep infection risk factors for each patient. Spine adipose index was measured on pre-operative mid-sagittal cuts of T2 weighted MRI scans. Each measurement was repeated twice by three authors in a blinded fashion, with each series of measurement separated by a period of at least six weeks. Forty-two patients were included in final analysis, with twenty-one cases and twenty-one matched controls. The spine adipose index was significantly greater in patients developing deep SSI (p =0.029), and this relationship was maintained after adjusting for confounders (p=0.046). Risk of developing deep SSI following PILF surgery was increased 2.0-fold when the spine adipose index was ≥0.51. The spine adipose index had excellent (ICC >0.9; p <0.001) inter- and intra-observer reliabilities. The spine adipose index is a novel radiographic measure and an independent risk factor for developing deep SSI, with 0.51 being the ideal threshold value for pre-operative risk stratification in patients undergoing PILF surgery.
Most previous studies investigating autograft options (quadriceps, hamstring, bone-patella-tendon-bone) in primary anterior cruciate ligament (ACL) reconstruction are confounded by concomitant knee injuries. This study aims to investigate the differences in patient reported outcome measures and revision rates for quadriceps tendon in comparison with hamstring tendon and bone-patella-tendon-bone autografts. We use a cohort of patients who have had primary ACL reconstruction without concomitant knee injuries. All patients from the New Zealand ACL Registry who underwent a primary arthroscopic ACL reconstruction with minimum 2 year follow-up were considered for the study. Patients who had associated ipsilateral knee injuries, previous knee surgery, or open procedures were excluded. The primary outcome was Knee Injury and Osteoarthritis Outcome Score (KOOS) and MARX scores at 2 years post-surgery. Secondary outcomes were all-cause revision and time to revision with a total follow-up period of 8 years (time since inception of the registry). 2581 patients were included in the study; 1917 hamstring tendon, 557 bone-patella-tendon-bone, and 107 quadriceps tendon. At 2 years, no significant difference in MARX scores were found between the three groups (2y mean score; 7.36 hamstring, 7.85 bone-patella-tendon-bone, 8.05 quadriceps, P = 0.195). Further, no significant difference in KOOS scores were found between the three groups; with the exception of hamstring performing better than bone-patella-tendon-bone in the KOOS sports and recreation sub-score (2y mean score; 79.2 hamstring, 73.9 bone-patella-tendon-bone, P < 0.001). Similar revision rates were reported between all autograft groups (mean revision rate per 100 component years; 1.05 hamstring, 0.80 bone-patella-tendon-bone, 1.68 quadriceps, P = 0.083). Autograft revision rates were independent of age and gender variables. Quadriceps tendon is a comparable autograft choice to the status quo for primary ACL reconstruction without concomitant knee injury. Further research is required to quantify the long-term outcomes for quadriceps tendon use.
The purpose of this study is to report the overall infection control rate and prognostic factors associated with acute, hematogenous and chronic PJIs treated with DAIR. All DAIR procedures performed at 2 institutions from 2009 to 2018 (n=104) were reviewed and numerous data were recorded, including demographics, preoperative laboratory tests, Charleston Comorbidity Index, surgical information and organism culture results. Treatment success was defined according to the criteria reported by Diaz-Ledezma. A multivariable analysis was utilized to identify prognostic factors associated with treatment and a Kaplan-Meier survival analysis was used to depict infection control rate as a function of time.Aim
Methods
The functional ante-inclination (AI) of the cup after total hip arthroplasty (THA) is a key component in the combined sagittal index (CSI) to predict joint stability after THA. To accurately predict AI, we deducted a mathematic algorithm between the radiographic anteversion (RA), radiographic inclincation (RI), pelvic tilting (PT), and AI. The current study aims (1) to validate the mathematic algorithm; (2) to convert the AI limits in the CSI index (standing AI ≤ 45°, sitting AI ≥ 41°) into coronal functional safe zone (CFSZ) and explore the influences of the stand-to-sit pelvic motion (PM) and pelvic incidence (PI) on CFSZ; (3) to locate a universal cup orientation that always fulfill the AI criteria of CSI safe zone for all patients or subgroups of PM(PM ≤ 10°, 10° < PM ≤ 30°, and PM > 30°) and PI (PI≤ 41°, 41°< PI ≤ 62°, and PI >62°), respectively. A 3D printed phantom pelvic model was designed to simulate changing PT values. An acetabular cup was implanted with different RA, RI, and PT settings using robot assisted technique. We enrolled 100 consecutive patients who underwent robot assisted THA from April, 2019 to June, 2019 in our hospital. EOS images before THA and at 6-month follow-up were collected. AI angles were measured on the lateral view radiographs as the reference method. Mean absolute error (MAE), Bland-Altman analysis and linear regression were conducted to assess the accuracy of the AI algorithm for both the phantom and patient radiographic studies. The 100 patients were classified into three subgroups by PM and PI, respectively. Linear regression and ANOVA analysis were conducted to explore the relationship between the size of CFSZ, and PM and PI, respectively. Intersection of the CFSZ was conducted to identify if any universal cup orientation (RA, RI) existed for the CSI index.Introduction
Methods
Only a small number of studies exist that report the results of EBM-produced porous coated trabecular titanium cups in primary total hip arthroplasty (THA). This study aims to investigate the patient satisfaction level, clinical function and radiographic outcomes of the patients who underwent THA using an EBM-produced porous coated titanium cup. A total of 32 patients who underwent primary THA with using an EBM-produced porous coated titanium cup from five hospitals between May and December, 2012 were retrospectively reviewed. Five patients were lost prior to the minimum 6-year follow-up. Clinical and radiographic outcomes were analyzed with an average follow-up of 81.48 (range: 77.00–87.00) months.Aims
Patients and Methods
Core decompression (CD) is effective to relieve pain and delay the advent of total hip arthroplasty (THA) for osteonecrosis of the femoral head (ONFH). However, the influence of CD on the subsequent THA has not been determined yet. Literatures published up to and including November 2018 were searched in PubMed, Embase and the Cochrane library databases with predetermined terms. Comparative studies of the clinical outcomes between conversion to THA with prior CD (the Prior CD group) and primary THA (the Control group) for ONFH were included. Data was extracted systematically and a meta- analysis was performed.Background
Methods
The incidence of thigh pain with the short stem varies widely across different studies. We aimed to evaluate the incidence and characteristics of post-operative thigh pain after using a particular bladed short stem and its potential risk factors. We respectively reviewed 199 consecutive patients who underwent unilateral total hip replacement using the Tri-lock stem from 2013–2016, of which 168 patients were successfully followed up with minimum two year clinical follow-up. All information about thigh pain and pre- and postoperative HHS score were gathered and all preoperative and immediate postoperative radiographs were available for review. Any complications were recorded.Aims
Patients and Methods
Failed ingrowth and subsequent separation of revision acetabular components from the inferior hemi-pelvis constitutes a primary mode of failure in revision total hip arthroplasty (THA). Few studies have highlighted other techniques than multiple screws and an ischial flange or hook of cages to reinforce the ischiopubic fixation of the acetabular components, nor did any authors report the use of porous metal augments in the ischium and/or pubis to reinforce ischiopubic fixation of the acetabular cup. The aims of this study were to introduce the concept of extended ischiopubic fixation into the ischium and/or pubis during revision total hip arthroplasty [Fig. 2], and to determine the early clinical outcomes and the radiographic outcomes of hips revised with inferior extended fixation. Patients who underwent revision THA utilizing the surgical technique of extended ischiopubic fixation with porous metal augments secured in the ischium and/or pubis in a single institution from 2014 to 2016 were reviewed. 16 patients were included based on the criteria of minimum 24 months clinical and radiographic follow-up. No patients were lost to follow-up. The median duration of follow-up for the overall population was 37.43 months. The patients' clinical results were assessed using the Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and Short form (SF)-12 score and satisfaction level based on a scale with five levels at each office visit. All inpatient and outpatient records were examined for complications, including infection, intraoperative fracture, dislocation, postoperative nerve palsy, hematoma, wound complication and/or any subsequent reoperation(s). The vertical and horizontal distances of the center of rotation to the anatomic femoral head and the inclination and anteversion angle of the cup were measured on the preoperative and postoperative radiographs. All the postoperative plain radiographs were reviewed to assess the stability of the components.Background
Methods
Severe, superior acetabular bone defects are one of the most challenging aspects to revision total hip arthroplasty (THA). We propose a new concept of “superior extended fixation” as fixation extending superiorly 2 cm beyond the original acetabulum rim with porous metal augments, which is further classified into intracavitary and extracavitary fixation. We hypothesized that this new concept would improve the radiographic and clinical outcomes in patients with massive superior acetabular bone defects. Twenty eight revision THA patients were retrospectively reviewed who underwent reconstruction with the concept of superior extended fixation from 2014 to 2016 in our hospital. Patients were assessed using the Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC). In addition, radiographs were assessed and patient reported satisfaction was collected.Aims
Patients and Methods
Self tapping bone screw has been widely used in the fixation of Arthroplasty implants and bone graft. But the unwanted screw or driver breakage can be a direct result of excessive driving torque due to the thread cutting resistance. Previous studies showed that bone drill bit cutting rake angle was a critical factor and was inversely related to the bone cutting efficiency.1, 2, 3, 4 (Figure 1) However to date there was no data for how the rake angle could influence the performance of self tapping bone screw. The purpose of this study was to investigate the torque generated by the self tapping cortical screw in simulated bone insertion as a function of the screw tip cutting flute rake angle. Two 5 mm thick BM5166 polyurethane block were stacked together and drilled through with 2.5mm diameter holes. Five 30mm long 3.5 mm diameter Ti6AL4V alloy self tapping cortical screws with 0°rake angle cutting flutes (Figure 2) were inserted in the holes and driven by the spanner attached to the test machine (Z5.0TN/TC-A-10) with a displacement control of 3 revolutions/min and 30N constant axial loading. The screws were driven into the stacked polyurethane block for 8mm depth. The maximum driving torque was recorded. Procedure was repeated for five same screws but with 7° rake angle cutting flutes. (Figure 2) The driving torqueses were compared. Student t test was performed with confidence level of 95% was assumed.Introduction
Methods
The purpose of this study was to investigate how rim poly locking scallop cutting depth could affect the rigidity of acetabular cup. (11) generic FEA models including (5) 50mm OD Ti6Al4VELI hemispherical acetabular shells with thicknesses of 3.0, 3.5, 4.0, 4.5 and 5.0mm, and (6) 4mm thick hemispherical shells with standard rim poly indexing scallops varied in cutting depths from inner diameter of the cup in 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5mm. All cups were analyzed in ANSYS® Workbench™ FEA software with a loading condition of 2000N applied to the cup rim per V15 ISO/TC 150/SC 4 N. Verification was carried out by the physical test of a same generic Ti6Al4VELI 50mmOD and 5mm thick solid hemispherical shell under 2000N rim directed load. The cup deformation was compared with FEA results. The maximum deformation of FEA scalloped cups were compared with that of solid hemispherical cups with different shell thickness.Objective
Materials and Methods
Mechanical properties of irradiated Ultra High Molecular Weight Polyethylene (UHMWPE) after aging have been well documented. However there was no sufficient data for the dimensional change due to irradiation and aging. This change may have adverse effects to the implant modular locking mechanism. The purpose of this study was to characterize the dimensional change of UHMWPE after irradiation and aging. Total (30) ø15mm × 50mm virgin GUR 1050 UHMWPE rods were cleaned, dried, inspected, vacuum packaged and stored in 20°C environment for 2 days. Among them, (20) samples were measured along the 50mm length at 20°C +/-2°C before and after two conditions: 1, (10) were submerged in 40°C DI water for 2 hours and dried in 40°C to simulate the cleaning process and 2, (10) were soaked in 37°C saline for 14 days to simulate initial in-vivo environment. Remaining (10) samples were measured in the same way after irradiation of 30KGy dosage and then measured again after soaking in 37°C saline for 14 days to simulate the actual radiation sterilization and in-vivo soaking conditions. Same samples were measured once more after accelerated aging per ASTM-1980-07 for 80 days to simulate the 3 year in vivo life. The differences in measurements between virgin and end conditions were documented as the percentage dimensional change. After the measurements, in the groups of DI water, saline soaking and radiation + aging, (3) samples were randomly selected for DSC measurements. The results were compared with dimensional measurements. Statistical analysis was performed by the student t test to compare virgin condition and the conditions after each treatment. 95% significance level was assumed.Introduction
Materials and Method
The purpose of this study was to compare the proximal femoral morphology between normal Chinese and Caucasian populations by 3D analysis derived from CT data. 141 anonymous Chinese femoral CT scans (71 male and 70 female) with mean age of 60.1years (range 20–93) and 508 anonymous Caucasian left femoral CT scans (with mean age of 64.8years (range 20–93). The CT scans were segmented and converted to virtual bones using custom CT analytical software. (SOMA™ V.4.0) Femoral Head Offset (FHO) and Femoral Head Position (FHP) were measured from head center to proximal canal central axis and to calcar or 20mm above Lesser Trochanter (LT) respectively. The Femoral neck Anteversion (FA) and Caput-Collum-Diaphyseal (CCD) angles were also measured. The Medial Lateral Widths(MLWn) of femoral canal were measured at 0, -10, LT, -30, -40, -60, -70 and -100mm levels from calcar. Anterior Posterior Widths (APWn) were measured at 0, -60 and -100mm levels. The Flare Index (FI) was derived from the ratio of widths at 0 and -60mmor FI=W0/W−60. All measurements were performed in the same settings for both populations. The comparison was analyzed by Student T test. P<0.05 was considered significant.Objective
Materials and Methods
Soft tissue tension and intra-articular pressure distribution plays a crucial role in postoperative function and survivorship of TKA prosthesis. Although posterior stabilized (PS) and cruciate retaining (CR) knees have both been successful in relieving pain and restore function, it is reported that the joint gaps were significantly distinct between the two designs during flexion. The aim of this study is to find out what is the difference in intra-articular pressure distribution between PS and CR knees. We prospectively included 45 consecutive patients (50 knees) scheduled for total knee arthroplasty between August, 2013 and April, 2014 in our hospital. 23 patients (25 osteoarthritic knees) received a Genesis II CR TKA (Smith & Nephew, Memphis, USA), and the other 22 patients (25 osteoarthritic knees) received Genesis II PS TKA (Smith & Nephew, Memphis, USA). During operation, after the bone osteotomy and soft tissue balance were completed, we measured and compared the intra-articular pressure distribution at 0°, 30°, 45°, 60°, 90°, and 120° flexion with a previously validated “Wireless Force Measurement System (WFMS)”. Joint gaps were measured at extension and 90° flexion. The soft tissue was not considered balanced until the medial and lateral joint gap difference ≤ 2mm at extension and 90° flexion. There are no significant differences in age, gender, BMI, varus angle and flexion deformity, and preoperative range of motion between the two groups. The medial-lateral pressure distribution and total pressure were compared at different angles between CR and PS knees.Background
Methods
The development of T-smart tomosynthesis has greatly improved the imaging quality of THA by reducing the peri-implant artifacts. In order to find out whether these improvements could lead to diagnostic advantages on stability of cementless THA arthroplasty components, we conducted a diagnostic research by comparing T-smart tomosynthesis, X-ray, and computed tomography. We retrospectively included 48 patients who undergone THA revisions in our center between Aug, 2013 and Mar, 2014. For patients with hybrid fixation as their primary prosthesis, the femoral or acetabular components with cement fixation were excluded. There were 41 cementless femoral stems and 35 cementless acetabular cups remained for evaluation. All patients took anterior-posterior and lateral view x-ray examination, anterior-posterior T-smart tomosynthesis scan, and computed tomography before revision surgery. As the gold standard, intraoperative pull-out tests and twisting tests were done for every patient to examine the stability of all implants. 7 orthopedic surgeons evaluated the preoperative images independently, who were divided into the senior group (3 doctors with 6∼13 years’ clinical experience) and the junior group (4 doctors with 2∼4 years’ clinical experience). The x-rays were evaluated first, followed by computed tomography 4 weeks later, and after another 4 weeks’ interval the T-smart tomosynthesis were assessed. All doctors used the same criteria for diagnosis. Diagnostic accuracy for each imaging examination was calculated by comparing with the results of intraoperative tests. The diagnostic accuracy, kappa values between 3 imaging techniques were calculated, and chi-square tests were conducted to examine the difference between the senior and junior groups for each technique.Background
Methods
By retrospective analysis of clinical data, to find new risk factors for postoperative dislocation after total hip replacement and the dose-effect relationship when multiple factors work simultaneously. A nested case-control study was used to collect the dislocated hips from 5513 primary hip replacement case from 2000 to 2012. Apart from the patients with given cause of dislocation, 39 dislocated hips from 38 cases were compared with 78 hip from 78 cases free from dislocation postoperatively, which matched by the admission time. The factors that may affect the prosthetic unstable was found by the univariate analysis, and then they were performed multivariate logistic regression analysis and evaluation of a dose-effect factors.Objective
Methods
Implant-related infection (IRI) is closely related to the local immunity of peri-implant tissues. The generation of reactive oxygen species (ROS) in activated macrophages plays a prominent role in the innate immune response. In previous studies, we indicated that implant wear particles promote endotoxin tolerance by decreasing the release of proinflammatory cytokines. However, it is unclear whether ROS are involved in the damage of the local immunity of peri-implant tissues. In the present study, we assessed the mechanism of local immunosuppression using titanium (Ti) particles and/or lipopolysaccharide (LPS) to stimulate RAW 264.7 cells. The results indicate that the Ti particles induced the generation of a moderate amount of ROS through nicotinamide adenine dinucleotide phosphate oxidase-1 (NOX-1), but not through catalase. Pre-exposure to Ti particles inhibited ROS generation and extracellular regulated protein kinase (ERK) activation in LPS-stimulated macrophages. These findings indicate that chronic stimulation by Ti particles may lead to a state of oxidative stress and persistent inflammation, which may result in the attenuation of the immune response of macrophages to bacterial components such as LPS. Eventually, immunosuppression develops in peri-implant tissues, which may be a risk factor for IRI.
Periacetabular spherical osteotomy for the treatment of dysplastic hip is effective but technically demanding. To help surgeons perform this difficult procedure reliably and safely, a computer assisted navigation technique has been developed and evaluated. Computed tomographic scans of 5 cadaveric pelvises were obtained and three-dimensional models were generated. The osteotomy was planned preoperatively. The pelvises were registered using an optimized algorithm. Periacetabular spherical osteotomy was performed at one side of each pelvis with navigation and at another side without navigation. The deviation of the real osteotomized surface from the planned surface was measured.Objective:
Methods:
