Incidence and outcomes of intraoperative periprosthetic acetabular fractures during cementless total hip arthroplasty: a prospective three-dimensional computer tomography-based study.

PURPOSE: Unlike periprosthetic femoral fractures, periprosthetic acetabular fractures during total hip arthroplasty (THA) have not been evaluated in detail. We prospectively evaluated the incidence, patterns, risk factors, and clinical outcomes of intraoperative periprosthetic acetabular fractures using pre- and postoperative computer tomography (CT). METHODS: In this prospective single-centre study, we evaluated 234 consecutive patients (250 hips) who underwent THA and three-dimensional CT before and after the surgery. We assessed the incidence, pattern of fractures, outcomes for each fracture pattern, reoperation and revision rates, Harris hip score, and visual analog scale (VAS) for pain. Multivariate regression models were used to identify risk factors for periprosthetic acetabular fractures. RESULTS: In total, 43 periprosthetic acetabular fractures (17.2%) were identified via CT. Fractures occurred most frequently at the superolateral wall. Early cup migration occurred in three hips. None of the patients underwent revision surgery for acetabular loosening. Regression modeling showed that rheumatoid arthritis was a significant predictor of periprosthetic acetabular fractures. CONCLUSIONS: Periprosthetic acetabular fractures are not infrequent during cementless THA and are more common in patients with rheumatoid arthritis.

Outcomes of total hip arthroplasty after failed free vascularized fibular grafting for osteonecrosis of the femoral head.

PURPOSE: Total hip arthroplasty (THA) after vascularized fibular grafting (VFG) is technically demanding with poorer outcomes compared to primary THA in patients with osteonecrosis of the femoral head (ONFH). The purpose of this study was to compare the outcomes of THA after VFG after removal of the graft with that of primary THA. METHODS: ONFH patients treated by VFG at a single institution were studied retrospectively. THAs after VFG performed by single arthroplasty surgeon with a single type of THA prosthesis were enrolled in the study. A control cohort of patients was created by 1:1 matching with the THA after VFG cohort according to age, gender, and American Society of Anesthesiology (ASA) score from ONFH patients treated by primary THA. Early and long-term outcomes were compared between the two groups. RESULTS: A total of 24 hips were included in the THA after VFG group and compared with 24 primary THA hips. No significant difference was noted in stem position. The THA after VFG group had increased blood loss and longer duration of operation time. There were two cases of intraoperative femur fractures in the THA after VFG group. The femoral stem of both groups were stable, with no cases of revision, and similar HHS scores at the last follow-up. CONCLUSION: THA after VFG may have similar short to midterm outcomes with primary THA after removal of the residual abutting bone graft and correct positioning of the femoral stem.

Usefulness of intraoperative C-arm image intensifier in reducing errors of acetabular component during primary total hip arthroplasty: an application of Widmer's method.

BACKGROUND: Acetabular prosthesis positioning in total hip arthroplasty (THA) is crucial in reducing the risk of dislocation. There has been minimal research on the proper way to put the acetabular components into the safe zone intraoperatively. Assessment of version by intraoperative imaging intensifier is very valuable. The value of Widmer's method, using the intraoperative C-arm available to determine cup anteversion was assessed. METHODS: One hundred one hips in 91 patients who underwent primary THA were eligible for inclusion. Utilizing intraoperative C-arm images, measurement was performed using the technique described by Widmer. The values obtained using 3D computed tomography postoperatively, which determined the anteversion of the acetabular component, were regarded as the reference standard. RESULTS: The method of Widmer obtained values similar to those obtained using 3D computed tomography and was considered accurate (n.s.). All 101 hips were positioned in the set target zone. Among the 101 hips, the cup position in nine hips (8.9%) was changed. The dislocation rate in our study was 1.0% with all dislocations occurring in hips placed in the target zone. The mean Harris hip score after THA in 1 year was 94.2 (82-98). CONCLUSIONS: The method of Widmer was accurate using intraoperative imaging intensifier for the measurement of the anteversion of the acetabular component during THA, with reference to the anteversion obtained from the 3D computed tomography. Also, utilizing intraoperative C-arm imaging was very useful because it allowed for correction of the position of the acetabular cup.

Long-Term Results of Total Hip Arthroplasty in Young Patients With Osteonecrosis After Allogeneic Bone Marrow Transplantation for Hematological Disease: A Multicenter, Propensity-Matched Cohort Study With a Mean 11-Year Follow-Up.

BACKGROUND: The number of young patients with hematological disease requiring total hip arthroplasty (THA) is expected to increase. We aimed to investigate the long-term THA outcomes in patients with osteonecrosis of the femoral head (ONFH) following allogeneic bone marrow transplantation (BMT) for hematological disease. METHODS: All patients who underwent THA for osteonecrosis after BMT from 1997 to 2012 were identified at 2 institutions. Using propensity scores, 75 THAs in 45 patients were matched for age, gender, body mass index, American Society of Anesthesiologists score, and year of surgery with 75 THAs in 58 patients with idiopathic ONFH without a history of hematological disease (1:1 ratio). The mean age at surgery was 36.7 years and 52% were men. Clinical and radiographic evaluations were performed and clinical scores were obtained at last follow-up. Kaplan-Meier analyses were used to compare survivorship. RESULTS: At a mean follow-up of 10.6 ± 3.5 years, clinical, radiographic, and survivorship outcomes, and the Harris hip scores were similar between both groups. The 13-year survivorship for all-cause revision was 93.4% for the BMT group and 95% for the control group (P = .928). No significant differences were observed between groups in the rates of reoperation (4% vs 5.3%, P = 1.000), 90-day readmission (all 5.3%), or overall mortality (4.4% vs 1.7%, P = .681). No hips had periprosthetic joint infection or septic loosening in either group. Osteolysis occurred in none of the BMT patients and in 2 hips (2.7%) of the control patients (P = .497). CONCLUSION: This large cohort multicenter survey at 11-year follow-up shows that contemporary cementless THA in young hematological disease patients after allogeneic BMT is not associated with a higher risk for surgical complications, revision, reoperation, readmission, and mortality compared to a matched cohort of idiopathic ONFH.

Fourth-generation ceramic-on-ceramic THA results in improvements in midterm outcomes compared to third-generation THA but does not resolve noise problems: a cohort study of a single-hip system.

BACKGROUND: Using data from the Korean Hip Registry, we aimed to investigate mid-term clinical and radiographic outcomes, including the prevalence of periprosthetic joint infection (PJI), osteolysis, and component loosening or dislocation, and to analyze the incidence of bearing-related complications following modern ceramic-on-ceramic (COC) total hip arthroplasty (THA) using a single cementless hip system. METHODS: Four hundred eighty-two patients (602 hips) who underwent Forte or Delta COC THAs with a single hip system and had a minimum 5-year follow-up were identified. The sample included 243 (50.4%) women and 239 (49.6%) men with a mean age of 50.6 years (range: 18-83 years). The Forte group comprised 310 hips, and the Delta group comprised 292 hips. The mean follow-up was 6.1 years (range: 5-10.2 years). RESULTS: Cup orientation did not differ between groups. No hip had a PJI or osteolysis in either group. All acetabular components and all but two femoral components (in the Delta group) were well fixed. Dislocations occurred in six (1.9%) hips in the Forte group and one (0.3%) hip in the Delta group (p = 0.124). A total of nine (1.5%) revisions were performed. The 5-year survival rates for all-cause revisions were 98.4 and 98.6%, respectively. One (0.3%) ceramic head fracture occurred in the Forte group. Sixteen (5%) hips exhibited clicking and 6 (2%) hips had squeaking in the Forte group; 16 (6%) hips exhibited clicking and 5 (2%) hips had squeaking in the Delta group. Multiple regression analysis revealed that noise generation was unassociated with any factor. CONCLUSIONS: From the Korean Hip Registry data, THA with modern ceramic bearings showed encouraging results, with lower risks of PJI, osteolysis, and component loosening. In particular, Delta COC THA resulted in no PJI or ceramic fracture and had a reduced dislocation risk. However, associated noise remains a concern.

Proximal Femoral Shape Changes the Risk of a Leg Length Discrepancy After Primary Total Hip Arthroplasty.

BACKGROUND: To evaluate how canal morphology affects the technical aspects of total hip arthroplasty, we investigated the effects of femoral cortical index (FCI) on the re-establishment of leg length at the conclusion of surgery. METHODS: We retrospectively reviewed age, gender, body mass index, and radiographs of 516 patients with osteoarthritis or osteonecrosis who underwent unilateral cementless primary total hip arthroplasty between 2008 and 2015. Patients were divided into level of FCI and leg length discrepancy (LLD). Each cohort was compared in terms of demographics and LLD. One-way analysis of variance and Kruskal-Wallis test were used. RESULTS: The mean FCI and LLD were 0.6 ± 0.1 and 3.5 ± 6.3 mm, respectively. Utilization of an extended offset stem was highest with Dorr type A and B hips (P = .001). High FCI increased the risk of lengthening (P = .017) and low FCI increased the risk of shortening (P = .005). CONCLUSION: A high FCI increases the probability of a leg length increase and a low FCI increases the probability of a leg length decrease. Surgeons might consider informing patients in advance of possible variation in leg length depending on the patients' proximal femoral shape and bony quality.

Surgical accuracy, function, and quality of life of simultaneous versus staged bilateral Total hip Arthroplasty in patients with Osteonecrosis of the femoral head.

BACKGROUND: The optimal surgical option for patients requiring bilateral hip replacement remains controversial. The purpose of this study was to compare surgical accuracy; functional outcome and health-related quality of life; and prosthetic-related complications and revision surgery of a simultaneous bilateral total hip arthroplasty (THA) with those of a staged bilateral THA with an interval between procedures <12 months. METHODS: A total of 123 unselected consecutive patients (mean age, 43.3 years) who underwent bilateral THAs for osteonecrosis of the femoral head (ONFH) with a minimum follow-up of two years (mean, 60.2 months) were studied retrospectively; 63 simultaneous procedures served as a test group and 60 staged procedures served as a control group. RESULTS: The mean postoperative leg-length discrepancy (LLD) and the percentage of patients who had an LLD >3 mm were significantly lower in the simultaneous group (P < 0.001 and P = 0.001, respectively). A higher number of cups within the safe zones, a higher correction rate, and a lower failure rate for the cup placement in the second-operated hip were also identified in the simultaneous group. The mean Harris hip score, EuroQol-5D index, and EuroQol-visual analogue scale score were all better in the simultaneous group at the latest follow-up (P < 0.001, in all comparisons). We found that the simultaneous procedure was associated with a lower incidence of postoperative prosthetic-related complications and revision surgery. CONCLUSIONS: We suggest that bilateral ONFH could be treated with a simultaneous THA rather than a staged THA to achieve a better surgical outcome.

Decreased blood pressure associated with in-vehicle exposure to carbon monoxide in Korean volunteers.

BACKGROUND: Carbon monoxide (CO) is one of the primary components of emissions from light-duty vehicles, and reportedly comprises 77% of all pollutants emitted in terms of concentration. Exposure to CO aggravates cardiovascular disease and causes other health disorders. The study was aimed to assess the negative effects by injecting different amounts of CO concentration directly to human volunteers boarding in the car. METHODS: Human volunteers were exposed to CO concentrations of 0, 33.2, and 72.4 ppm, respectively during the first test and 0, 30.3, and 48.8 ppm respectively during the second test while seated in the car. The volunteers were exposed to each concentration for approximately 45 min. After exposure, blood pressure measurement, blood collection (carboxyhemoglobin [COHb] analysis), medical interview, echocardiography test, and cognitive reaction test were performed. RESULT: In patients who were exposed to a mean concentration of CO for 72.4 ± 1.4 ppm during the first exposure test and 48.8 ± 3.7 ppm during the second exposure test, the COHb level exceeded 2%. Moreover, the diastolic blood pressure was decreased while increasing in CO concentration after exposure. The medical interview findings showed that the degree of fatigue was increased and the degree of concentration was reduced when the exposed concentration of CO was increased. CONCLUSION: Although the study had a limited sample size, we found that even a low concentration of CO flowing into a car could have a negative influence on human health, such as change of blood pressure and degree of fatigue.

Comparative Analysis of Radiographic Hip Joint Geometry Using Measurement Tools on Picture Archiving and Communication System: A Prospective Study of 100 Pelvic Radiographs of Koreans.

BACKGROUND: A contralateral normal hip joint has been often used as a reference standard in preoperative planning and intraoperative assessment of hip arthroplasty, with the assumption that bilateral hip joint geometries have no significant differences. However, one previous study using analog measurements on hardcopy films reported significant bilateral variation in hip joint geometry. We therefore investigated the level of agreement between the right and left hips for each measurement and determined index values and the range of normal bilateral variations. METHODS: We assessed 100 standard anteroposterior radiographs of the pelvis in this study. Two independent observers measured the actual value of femoral head diameter, location of the femoral head center, acetabular offset, femoral offset, hip offset, greater trochanteric height, neck-shaft angle, medullary canal diameter, and proximal femoral diameter. Intraclass correlation coefficients (ICCs) and values of mean difference were calculated for each measurement. RESULTS: The results demonstrated perfect agreement (ICC >0.8) between the right and left hips for most parameters and substantial agreement for greater trochanteric height (ICC = 0.735) and femoral offset (ICC = 0.773). The mean difference and standard deviation in the measurement between the right and left hips for the location of the femoral head center and the acetabular offset were 0.60 ± 0.48 mm and 0.42 ± 0.30 mm, respectively. CONCLUSION: Hip joint geometry is not influenced by side. In hip arthroplasty, a contralateral normal hip can be reliably used as a guide for preoperative planning using measurement tools on a picture archiving and communication system.

Human exposure and risk assessment of cadmium for residents of abandoned metal mine areas in Korea.

The objective of this study is to find the Cd levels in agricultural crops compared to soil, to evaluate the relationship between daily intake dose through the multimedia/multi-pathway of human exposure and biomarker levels of the residents in mine vicinity area. We collected and cited the data of four out of ten health impact assessments for the residents of abandoned mine areas undertaken by the Korea Ministry of Environment in 2008. The Cd levels in soil were significantly decreased by the separation distance from the mines. The Cd levels in blood were significantly different between residents in mine areas and in comparative areas, but urinary Cd levels did not differ. The Cd levels in blood were related to the age; the separation distance from mine to residence; the daily intake dose via ingestion of drinking water, crops, and surface soil; and inhalation of ambient air of Cd, but urinary Cd levels were not relevant with various sociodemographic characteristics and exposure factors. The average hazard quotient (HQ) value of Cd in the mining site was below 1.0, but the maximum HQ was closed to 1.0. The results indicated that the ingestion of Cd-contaminated soil and agricultural crops by local inhabitants could pose potential adverse health effects to long-term residents consuming rice grown near to the mining areas.

A Very Rare Form of Ceramic Head Fracture in Bipolar Hemiarthroplasty and Total Hip Arthroplasty: Unique Experience and Literature Review.

Introduction: A fracture of the ceramic head in bipolar hemiarthroplasty using an inner polyliner has not been reported yet, and there seems to be no report of simultaneous breakage of the fourth-generation BIOLOX Delta ceramic head and liner in total hip arthroplasty. Method: A 44-year-old male patient underwent bipolar hemiarthroplasty using a third-generation BIOLOX Forte ceramic head 3 years and 9 months earlier for osteonecrosis of femoral head (ONFH) and visited our hospital due to a ceramic head fracture. Conversion total hip arthroplasty was performed. A 64-year-old female patient underwent total hip arthroplasty using a fourth-generation BIOLOX Delta ceramic head and liner articulation for osteoarthritis of the hip. The ceramic head and liner were fractured during the third dislocation. Ceramic head and liner exchange revision surgery was performed. Conclusion: When using ceramic bearings, fractures or delamination following trauma can occur, confirming the need to carefully evaluate the condition of the ceramic components in symptomatic patients.

Prevalence of Venous Thromboembolism after Immediate Screening in Hip Fracture Patients.

Purpose: Venous thromboembolism (VTE) is a major complication for hip fracture patients, and may exist preoperatively. This study aimed to examine the prevalence of VTE after immediate screening in hip fracture patients. Materials and Methods: Hip fracture patients with an elevated level of D-dimer underwent screening for VTE using computed tomography (CT) angiography. Anticoagulation treatments were administered preoperatively to patients diagnosed with VTE, followed by administration of additional anticoagulation postoperatively. Medical records were reviewed to identify risk factors for preoperative VTE and determine the prognosis of the patients. Results: Among 524 hip fracture patients, 66 patients (12.6%) were diagnosed with VTE, including 42 patients with deep vein thrombosis (DVT), 17 patients with pulmonary thromboembolism (PTE), and 7 patients with both DVT and PTE. Of the patients with VTE, 68.2% were diagnosed within 24 hours of injury, and 33.3% of these patients had PTE. VTE patients showed a tendency toward being overweight (P<0.01) and not on anticoagulant medication (P=0.02) compared to patients without VTE. The risk of VTE was higher for femur shaft fractures (odds ratio [OR] 4.83, 95% confidence interval [CI] 2.18-10.69) and overweight patients (OR 2.12, 95% CI 1.17-3.85), and lower for patients who were previously on anticoagulants (OR 0.36, 95% CI 0.18-0.74). Patients with preoperatively diagnosed VTE were asymptomatic before and after surgery. Conclusion: Clinicians should be aware that VTE may be present within 24 hours of injury, and screening for VTE or prophylactic measures should be considered for high-risk patients.

A simple method using a PACS to minimize leg length discrepancy in primary THA: a method to minimize leg length discrepancy.

We determined whether a PACS-based method (head-lesser trochanter distance [HLD]) better equalized leg length discrepancy (LLD) after primary THA than a conventional method. We retrospectively reviewed 312 patients (379 hips) with osteonecrosis or primary osteoarthritis who underwent primary cementless THA: 198 patients (240 hips) underwent THA using the HLD method, while the conventional group consisted of 114 patients (139 hips) in whom we measured with the method of McGee and Scott. We then compared the LLDs in the two groups. We observed no difference in the mean postoperative LLD. A higher percentage of patients in the HLD group had an LLD less than 6 mm: 81% vs 68% hips, respectively. HLD method decreases the possibility of an LLD over 6mm after THA.

Weight-Based Bisphosphonate Administration for Multiple Myeloma Patients and the Risks of Skeletal Complications.

High-dose bisphosphonate for multiple myeloma patients might elevate risks of skeletal complications earlier than general expectations. This study aims to find incidences of atypical femoral fracture (AFF) and medication-related osteonecrosis of the jaw (MRONJ), elucidate their risk factors, and suggest cut-off values for the safer dosing of high-dose bisphosphonate treatment. By using the clinical data warehouse of a single institute, retrospective cohort data of multiple myeloma-diagnosed patients with high-dose bisphosphonate (pamidronate or zoledronate) treatment from 2009 to 2019 was extracted. Among 644 patients, the incidence of prominent AFF requiring surgery was 0.93% (6/644) and MRONJ was diagnosed in 11.8% (76/644) of the study population. For both AFF and MRONJ, the total potency-weighted sum of total dose per body weight (OR = 1.010, p = 0.005) were significant on logistic regression. Cutoffs of the potency-weighted total dose (mg) per body weight (kg) for AFF and MRONJ were 77.00 and 57.70 mg/kg, respectively. After roughly one year of treatment with high-dose zoledronate (about four years for pamidronate), an earlier thorough re-evaluation of skeletal complications should be taken. Body weight adjustments for accumulative dose calculation in terms of permissible dosing should be taken into consideration.

The incidence of focal osteonecrosis of the femoral head and its impact on conversion hip arthroplasty after screw fixation of femoral neck fractures: a multicenter retrospective study based on postoperative magnetic resonance imaging.

PURPOSE: Osteonecrosis of the femoral head (ONFH) and subsequent head collapse is a major concern after internal fixation of femoral neck fracture (FNF). Previous studies focused on ONFH incidence using plain radiography; postoperative magnetic resonance imaging (MRI) was rarely performed. We performed a multicenter retrospective study to investigate the incidence of ONFH and the need for conversion hip arthroplasty after FNF screw fixation. METHODS: We reviewed 195 patients who underwent screw fixation during closed FNF reduction between 2012 and 2017 at three institutions. Except for patients who did not consent to MRI, all patients underwent postoperative MRI either 1-3 years after screw fixation. The occurrence of ONFH was investigated through plain radiography and MRI. RESULTS: Thirty patients were diagnosed with ONFH through plain radiography, and an additional 33 patients were diagnosed with MRI, resulting in a total of 63 patients (32.3%) diagnosed with ONFH. The mean time to ONFH diagnosis was 18.9 months and the conversion rate to hip arthroplasty was 10.2%. Of the 33 patients who were normal on hip radiography but exhibited ONFH on MRI, all had small focal lesions not associated with head collapse at the last follow-up. The ONFH group diagnosed through plain radiography had more unstable FNFs than the group diagnosed through MRI. CONCLUSION: Although postoperative MRI revealed a higher incidence of ONFH after FNF screw fixation than reported previously, the small focal MRI lesions were not associated with increased risks of femoral head collapse or conversion to arthroplasty.

Non-thermal atmospheric pressure plasma treatment increases hydrophilicity and promotes cell growth on titanium alloys in vitro.

Most medical implants are made of titanium. When titanium is exposed to air for a long time, hydrocarbons are deposited and the surface becomes hydrophobic. Cell attachment is important for bone ingrowth to occur on the implant surface, and hydrophilicity can enhance this. We examined whether non-thermal atmospheric pressure plasma treatment could increase the hydrophilicity of the titanium surface. Samples coated with four widely used coating types [grit blasting, micro arc oxidation (MAO), titanium plasma spray (TPS), and direct metal fabrication (DMF)] were treated with plasma. Each of the four surface-treated samples was divided into groups with and without plasma treatment. We analysed wettability by surface analysis and evaluation of contact angles, cell proliferation, and adhesion using scanning electron microscopy (SEM), confocal laser scanning microscopy, absorbance tests, and alkaline phosphatase (ALP) activity assay; four different Ti6Al4V surface types were compared. After plasma treatment, the contact angle was reduced on all surfaces, and the carbon content was reduced on all surfaces based on X-ray photoelectron spectroscopy (XPS) surface analysis. Under confocal laser scanning, the cell layer was thicker on the plasma-treated samples, especially in groups TPS and DMF. Cell proliferation was 41.8%, 17.7%, 54.9%, and 83.8% greater for the plasma- than non-plasma-treated grit blasting, MAO, TPS, and DMF samples, respectively. Hydrophilicity increased significantly under plasma treatment, and biological responsivity was also improved.

Simple Minimally Invasive Method to Reduce Valgus-Impacted and Tilted Femoral Neck Fractures without Soft Tissue or Cartilage Injury: Radiological and Clinical Results.

OBJECTIVE: This is a rare study comparing the radiological and functional outcomes of fixation after reduction with in situ fixation group using Femoral Neck System (FNS). The aim of this study was to introduce a simple, innovative, minimally invasive method to reduce valgus-impacted and tilted femoral neck fractures without soft tissue or cartilage injury. METHODS: A retrospective comparative analysis of 46 patients between May 2020 and February 2022 was performed. In the control group, 23 patients underwent in situ fixation without reduction. In the study group, another 23 patients were managed by fixation after reduction using a percutaneous pull-out technique with a full threaded Steinmann pin. Caput-collum-diaphysis (CCD) angle, tilt, and femoral neck shortenings were compared between the two groups. In addition, Harris Hip Score (HHS) was evaluated and compared at 1 year after surgery. Basically, independent samples t-test was used to compare radiological and functional results. RESULTS: Patients' initial valgus and tilt angles were not significantly different between the groups (n.s.). However, the CCD and tilt angles measured immediately and at one year postoperatively were significantly different between the groups (p < 0.05). Regarding femoral neck shortening, shortening in the three directions, the x, y, and z vectors, was significantly less in the reduction group immediately postoperatively and at 1 year post-surgery (p < 0.05). The mean HHS at 1 year postoperatively was 79.7 ± 8.4 in the in situ fixation group and 87.9 ± 6.6 in the reduction groups, and there was a significant difference (p < 0.05). CONCLUSION: The pull-out method with a threaded Steinmann pin to reduce valgus-impacted and tilted femoral neck fracture is safe and effective for accomplishing anatomical restoration. This may achieve successful bone union and maintain the femoral neck length and original tilt without nearby soft tissue or cartilage injury.

Is the construct stability of the acetabular cup affected by the acetabular screw configuration in bone defect models?

BACKGROUND: In revision surgery with significant segmental acetabular defects, adequate implant selection and fixation methods are critical in determining successful bony ingrowth. Commercially available total hip prosthesis manufacturers generally offer additional multi-hole options of acetabular shells with identical designs for use in revision THAs where screw holes configurations vary from product to product. This study aims to compare the mechanical stability of the two types of acetabular screw constructs for the fixation of acetabular components: spread-out and pelvic brim-focused configurations. METHODS: We prepared 40 synthetic bone models of the male pelvis. In half of the samples with acetabular defects, identical curvilinear bone defects were manually created using an oscillating electrical saw. On the right side, multi-hole-cups in which the direction of the screw holes are centered on the pelvic brim (brim-focused) and, on the left side, multi-hole-cups with the direction of the screw hole spread throughout the acetabulum (spread-out) were implanted into the pelvic synthetic bones. Coronal lever-out and axial torsion tests were performed with a testing machine, measuring load versus displacement. RESULTS: The average torsional strengths were significantly higher in the spread-out group over the brim-focused group regardless of the presence of the segmental defect of the acetabulum (p < 0.001). But for the lever-out strength, the spread-out group exhibited significantly higher average strength over the brim-focused group for the intact acetabulum (p = 0.004), whereas the results were reversed in the brim-focused group when the defects were generated (p < 0.001). The presence of acetabular defects reduced the average torsional strengths of the two groups by 68.66% versus 70.86%. In comparison, the decrease in the average lever-out strength was less significant for the brim-focused group than the spread-out group (19.87% vs. 34.25%) (p < 0.001). CONCLUSION: Constructs of multi-hole acetabular cups with the spread-out screw holes configuration exhibited statistically better axial torsional strength and coronal lever-out strength. With the presence of posterior segmental bone defects, the spread-out constructs demonstrated significantly better tolerance to axial torsional strength. Still, they exhibited inverted results of higher lever-out strength in the pelvic brim-focused constructs.

Evaluation of transdermal exposure of phthalates in children's products.

In this study, 16 children's products with the highest detection potential of phthalates were selected, and a phthalate assay and transdermal delivery analysis (NIER, US EPA Wipe [stress condition], US EPA Wipe [physiological condition], and US EPA Hand Wipe) were conducted with these products. The content of 6 controlled phthalates (DBP, BBP, DEHP, DNOP, DINP, and DIDP) was measured and most products contained more phthalates than the regulated guidelines (a total content of 6 phthalates to be ≤0.1%). For transdermal delivery, all items were found to be lower in the NIER transdermal delivery test method compared to the US EPA Hand Wipe (stress condition and physiological condition) transdermal delivery test method. For the US EPA Hand Wipe (stress condition and physiological condition) transdermal delivery test method, a similar result was observed, except for DINP. The average daily dose (ADD) estimated by determining the exposure algorithm for each transdermal delivery test method was highest in mats with a large contacting surface area and a long exposure time in the respective test methods. Conclusively, there was a difference between the NIER transdermal delivery test method and the US EPA Wipe transdermal delivery test method.

Utilizing Three-Dimensional Head-Lesser Trochanter Distance Could Further Reduce Leg Length Inequality in Primary Bipolar Hemiarthroplasty.

Background: The aim of this study was to investigate whether the use of three-dimensional (3-D) computed tomography (CT)-based head-lesser trochanter distance (HLD) could reduce leg length discrepancy (LLD) more than the use of a two-dimensional (2-D) plain film method in primary bipolar hemiarthroplasty. Methods: Propensity score matching (PSM) analysis was used to adjust the confounding factors. A retrospective comparative analysis of 128 patients was performed. In the control group, the leg length was equalized using the 2-D, plain film-based HLD. In the study group, primary bipolar hemiarthroplasty was performed using the 3-D CT-based HLD method. Postoperative LLDs were compared between the two groups using the method of Ranawat. In addition, the Harris hip score (HHS) was evaluated and compared at one year after surgery. Results: A significant difference was observed in mean postoperative LLD between the 2-D HLD group and the 3-D CT HLD group: 1.6 ± 1.2 mm (range, 0.1−6.0 mm) and 1.1 ± 1.2 mm (range, 0.1−5.1 mm), respectively (p < 0.05). Additionally, a higher percentage of patients in the 3-D CT HLD group had an LLD of less than 2 mm. The mean HHS at one year after surgery showed no significant difference between the two groups. Conclusions: To minimize the occurrence of LLD, HLD measurement from a CT scanner may be more accurate than an X-ray. The 2-D and 3-D HLD differences in the 3-D CT HLD group were statistically significant. Using a 3-D, CT-based HLD method might decrease the possibility of an LLD over 2 mm.