Concerns with alumina bipolar hemiarthroplasties compared to metal bipolar hemiarthroplasties when performed for nontraumatic osteonecrosis of the femoral head.

PURPOSE: A nationwide multicenter follow-up cohort study of hip replacement arthroplasties performed for nontraumatic osteonecrosis of the femoral head (ONFH) aimed to answer the following questions: What factors were associated with need for reoperation? Although many modifications were made in bipolar hemiarthroplasties (BPs) to improve their durability, could we find any evidence of their efficacy? METHODS: Excluding 58 infected hips and 43 ABS THAs with very poor survivorship, we analyzed 7393 arthroplasties; 6284 total hip arthroplasties (THAs), 886 BPs, 188 total resurfacing arthroplasties, and 35 hemi-resurfacing arthroplasties (hRSs). In the 886 BPs, 440 hips had a smooth small-diameter prosthetic neck (nBPs), 667 hips had a smooth neck (sBPs), 116 hips had highly cross-linked polyethylene in the outer head (hBPs), and 238 hips had an outer head whose outer surface was alumina ceramic (aBPs) (648 hips had an outer head whose outer surface was metal [mBPs]). Multivariate analyses using a Cox proportional-hazard model analyzed risk factors. RESULTS: Follow-up ranged from 0.1 to 27 (average, 6.9) years, during which 265 hips (3.6%) needed reoperation. Combined systemic steroid use and excessive alcohol consumption and lateral approach were associated with higher risks, aBPs were less durable than THAs or mBPs, and hRSs were inferior to the others. Regarding BPs, the following divisions did not influence their survivorship; nBP or not, sBP or not, and hBP or not. CONCLUSIONS: Factors associated with reoperation risk were identified as described above. The modifications made in BPs did not improve their durability, but aBPs made it worse. LEVEL OF CLINICAL EVIDENCE: Level III, therapeutic cohort study.

Patient-specific mechanical analysis of pedicle screw insertion in simulated osteoporotic spinal bone models derived from medical images.

Study Design: Biomechanical study. Purpose: To investigate the mechanical characteristics of bone models created from medical images. Overview of Literature: Recent advancements in three-dimensional (3D) printing technology have affected its application in surgery. However, a notable gap exists in the analyses of how patient's dimorphism and variations in vertebral body anatomy influence the maximum insertional torque (MIT) and pullout strength (POS) of pedicle screws (PS) in osteoporotic vertebral bone models derived from medical images. Methods: Male and female patients with computed tomography data were selected. Dimensions of the first thoracic (T1), fourth lumbar (L4), and fifth lumbar (L5) vertebrae were measured, and bone models consisting of the cancellous and cortical bones made from polyurethane foam were created. PS with diameters of 4.5 mm, 5.5 mm, and 6.5 mm were used. T1 PS were 25 mm long, and L4 and L5 PS were 40 mm long. The bone models were secured with cement, and the MIT was measured using a calibrated torque wrench. After MIT testing, the PS head was attached to the machine's crosshead. POS was then calculated at a crosshead speed of 5 mm/min until failure. Results: The L4 and L5 were notably larger in female bone models, whereas the T1 vertebra was larger in male bone models. Consequently, the MIT and POS for L4 and L5 were higher in female bone models across all PS diameters than in male bone models. Conversely, the MIT for T1 was higher in male bone models across all PS; however, no significant differences were observed in the POS values for T1 between sexes. Conclusions: The mechanical properties of the proposed bone models can vary based on the vertebral structure and size. For accurate 3D surgical and mechanical simulations in the creation of custom-made medical devices, bone models must be constructed from patientspecific medical images.

Using the combined C-reactive protein and controlling nutritional status index for elderly non-small cell lung cancer.

Background: We found that conventional controlling nutritional status (CONUT) score can serve as a sensitive prognostic marker. Some prognostic indicators do include C-reactive protein (CRP), such as the CRP-lymphocyte ratio (CLR), CRP-albumin-lymphocyte index (CALLY), and CRP-albumin ratio (CAR). However, CRP has not been combined with the CONUT score, which we believe could result in a more sensitive marker. This study evaluated the combined use of the CONUT score and CRP to predict prognostic outcomes in elderly non-small cell lung cancer (NSCLC) patients undergoing surgical resection. Methods: This study involved the retrospective analysis of 114 NSCLC patients who were over 80 years old and underwent curative resection. The summation of the CRP score and CONUT score was defined as the combined CRP and controlling nutritional status (C-CONUT) score. The capacity of CRP, CONUT score, and C-CONUT score to predict overall survival (OS) was evaluated via receiver operating characteristics (ROC) curves. Prognostic markers for OS were then identified using the Cox proportional hazards regression model. Results: The ROC curves identified the C-CONUT score as the most reliable marker of prognosis (area under the curve =0.745). Forty-seven patients were included in the high C-CONUT (≥3) group, while 67 patients were included in the low C-CONUT (0 to 2) group. Worse prognosis rates were observed in the high C-CONUT group in comparison to the low C-CONUT group in terms of OS (five-year OS: 39.8% versus 87.4%, P<0.001). Lymphatic invasion (P<0.001), histological findings (P=0.02), and C-CONUT score [hazard ratio (HR): 5.07, 95% confidence interval (CI): 2.39-10.8, P<0.001] were identified as exclusive markers for OS prognosis in the multivariate analysis. Conclusions: Our current findings indicate that C-CONUT score may serve as an innovative prognostic marker in the elderly NSCLC population.

Radial Nerve Palsy Caused by Desmoid-Type Fibromatosis: A Case Report and Review of the Literature.

Radial nerve palsy (RNP) is classified as traumatic, non-traumatic, or iatrogenic. The most frequent etiologic agent is the fracture of the humerus of the shaftand distal. We experienced a case of RNP caused by desmoid-type fibromatosis around the radial nerve. The RNP caused by desmoid-type fibromatosis has not been reported in the literature. We present this case here with a review of the RNP literature. The patient is a 16-year-old female, right-hand dominant, who became aware of the difficulty in extending her right little finger without any triggers five months ago. She was also aware of the difficulty in extending the ring finger, and her symptoms gradually worsened. She was referred to our hospital after consulting a home doctor. MRI of the elbow showed a high-intensity occupying lesion on T2-weighted images (T2WI) slightly proximal to the elbow joint. Ultrasonography (US) showed a partial nerve constriction and radial nerve enlargement on the distal side of the constriction. The approach was made from the posterior lateral side of the distal upper arm, and the radial nerve was exposed. There was a 1 cm white tissue strongly adherent on the radial nerve, which was compressing the radial nerve, and it was resected piece by piece. After the resection, the radial nerve was indented. The pathological diagnosis of the resected tissue was fibromatosis. Gradually, she was able to extend her fingers after the surgery and recovered completely in six months.

An effective plication technique for diaphragmatic eventration under thoracoscopy with laparoscopic image display.

Diaphragmatic eventration causes respiratory distress with the development of severe diaphragmatic compression of lung volume. While non-surgical treatment, such as physical therapy and pulmonary rehabilitation, is adequate for mild cases, surgical intervention is critical for severe diaphragmatic eventration. A 45-year-old man with respiratory fatigue was diagnosed with left diaphragmatic eventration and underwent surgery with diaphragmatic plication with double-row stapling under a video-assisted approach. Thoracoscopy with laparoscopic image display avoided visceral tissue involvement, and the double-stapling technique prevented diaphragmatic rupture and lowered the diaphragmatic level. The procedure improved the patient's respiratory function by reducing respiratory fatigue. This procedure is safe and effective for the thin and vulnerable diaphragmatic muscle.

[Verification of Response Uncertainty in Electrometers through Cross-Comparison with a Novel Current Source: A Comparative Study with Guidelines for Electrometers Used in Radiation Therapy Dosimeters].

BACKGROUND: A new quality assurance and control method for electrometers using a new current source, different from the method published in the guidelines for electrometers, has been reported. This current source uses dry batteries and exhibits excellent performance in terms of voltage, temperature, and time characteristics. The electrometer sensitivity coefficient can be calculated by comparing the sensitivity of one electrometer with that of another on the electrometer calibration coefficient that has been calibrated by a calibration laboratory in advance in both methods. The guideline method requires two or more sets of ionization chambers and electrometers in the facility. In contrast, our method does not use ionization chambers; therefore, the sensitivity ratio of the electrometer can be measured in any facility. This study compared the uncertainty of the electrometer sensitivity factor calculated using the new current source method (current method) with that calculated using a linear accelerator (LINAC) and ionization chambers (LINAC method) described in the electrometer guidelines. METHOD: In this study, we used a current source that we invented previously by Kawaguchi Electric Works in Japan. The sensitivity ratios of the electrometers were measured with three manufacture's electrometers. The electrometer sensitivity factor was calculated by multiplying the electrometer calibration coefficient. The ionization chamber was 30013 (PTW), and the current source was the current obtained from 10 MV TrueBeam X-rays under calibration conditions. The mean value, standard deviation, and coefficient of variation were calculated. The time required to set up the ionization chamber for calculating the sensitivity ratio of the electrometer was also measured. The accuracy was confirmed by calculating the expanded uncertainty of the electrometer sensitivity coefficients. RESULTS: The LINAC method had a maximum coefficient of variation of 0.072%. The gross time of the LINAC method was approximately 110 min. The current method had a maximum coefficient of variation of 0.0055% and took less than half the time taken by the LINAC method (35 min) because there was no waiting time for the ionization chamber to be set up and the applied voltage to stabilize under calibration conditions. The expanded uncertainties of the electrometer calibration coefficients were 0.36% and 0.36%, respectively. CONCLUSION: The new cross-comparison method for electrometer sensitivity factors using a current source is more efficient and useful than the linear accelerator method described in the guidelines; furthermore, this method ensured accuracy for quality assurance and control of electrometers.

Xanthogranulomatous appendicitis presenting asymptomatically 3 years after surgery for hilar cholangiocarcinoma: A case report.

INTRODUCTION: Xanthogranulomatous appendicitis (XGA) is a rare condition involving chronic inflammation of the appendix that is often difficult to distinguish from malignancy using imaging because of the formation of a heterogeneous mass with indistinct borders. Herein, we present a case of XGA with unusual clinical manifestations. PRESENTATION OF CASE: A 78-year-old female patient underwent radical resection of hilar cholangiocarcinoma with extended right hepatic lobectomy and biliary reconstruction. Three years postoperatively, she presented with an irregular mass in the right lateral pelvis, which was observed on computed tomography. The patient had not experienced recent clinical symptoms and did not present with abdominal tenderness. Routine blood tests did not indicate an increased inflammatory response; however, carcinoembryonic antigen levels continued to increase. Although disseminated recurrence of hilar cholangiocarcinoma and appendiceal carcinoma were suspected, XGA was diagnosed via laparoscopic appendectomy. DISCUSSION: XGA generally presents with symptoms of acute or chronic appendicitis, and is diagnosed incidentally during surgery. Hilar cholangiocarcinoma has a high recurrence rate, even after radical resection, and disseminated recurrence usually requires chemotherapy. In the present case, XGA was not suspected preoperatively because of the lack of physical symptoms and increased levels of tumor markers during follow-up for hilar cholangiocarcinoma. There have been no reports of XGA with such a confusing clinical course, thus confirming the difficulty in preoperatively diagnosing XGA. CONCLUSION: The preoperative diagnosis of XGA is difficult to differentiate from malignancy because of its clinical and imaging findings. We diagnosed the patient with XGA using laparoscopic surgery.

Minimally Invasive Conversion Surgery for Unresectable Gastric Cancer with Splenic Metastasis and Splenic Vein Tumor Thrombus: A Case Report.

While the importance of conversion surgery has increased with the development of systemic chemotherapy for gastric cancer (GC), reports of conversion surgery for patients with GC with distant metastasis and tumor thrombus are extremely scarce, and a definitive surgical strategy has yet to be established. Herein, we report a 67-year-old man with left abdominal pain referred to our hospital following a diagnosis of unresectable GC. Esophagogastroduodenoscopy and contrast-enhanced abdominal computed tomography (CT) revealed advanced GC with splenic metastasis. A splenic vein tumor thrombus (SVTT) and a continuous thrombus to the main trunk of the portal vein were detected. The patient was treated with anticoagulation therapy and systemic chemotherapy comprising S-1 and oxaliplatin. One year following chemotherapy initiation, a CT scan revealed progressive disease (PD); therefore, the chemotherapy regimen was switched to ramucirumab with paclitaxel. After 10 courses of chemotherapy resulting in primary tumor and SVTT shrinkage, the patient underwent laparoscopic total gastrectomy (LTG) and distal pancreaticosplenectomy (DPS). He was discharged without complications and remained alive 6 months postoperatively without recurrence. In summary, the wait-and-see approach was effective in a patient with GC with splenic metastasis and SVTT, ultimately leading to an R0 resection performed via LTG and DPS.

Assessing the utility of osteoporosis self-assessment tool for Asians in patients undergoing hip surgery.

Objectives: Diagnosis and treatment of osteoporosis are instrumental in obtaining good outcomes of hip surgery. Measuring bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA) is the gold standard for diagnosing osteoporosis. However, due to limited access to DXA, there is a need for a screening tool to identify patients at a higher risk of osteoporosis. We analyzed the potential utility of the Osteoporosis Self-assessment Tool for Asians (OSTA) as a screening tool for osteoporosis. Methods: A total of 1378 female patients who underwent hip surgery at 8 institutions were analyzed. For each patient, the BMD of the proximal femoral region was measured by DXA (DXA-BMD), and the correlation with OSTA score (as a continuous variable) was assessed. Receiver operating characteristic (ROC) curve analysis was performed to assess the ability of OSTA score to predict osteoporosis. Lastly, the OSTA score was truncated to yield an integer (OSTA index) to clarify the percentage of patients with osteoporosis for each index. Results: DXA-BMD showed a strong correlation with OSTA (r = 0.683; P < 0.001). On ROC curve analysis, the optimal OSTA score cut-off value of -5.4 was associated with 73.8% sensitivity and 80.9% specificity for diagnosis of osteoporosis (area under the curve: 0.842). A decrease in the OSTA index by 1 unit was associated with a 7.3% increase in the probability of osteoporosis. Conclusions: OSTA is a potentially useful tool for screening osteoporosis in patients undergoing hip surgery. Our findings may help identify high-risk patients who require further investigation using DXA.

Prognostic Significance of CONUT Score in Elderly NSCLC.

PURPOSE: This study evaluated the Controlling Nutritional Status (CONUT) score as a prognostic predictor in elderly non-small cell lung cancer (NSCLC) patients with surgical resection. METHODS: Overall, 114 patients over 80 years old undergoing curative resection for NSCLC were retrospectively analyzed. Receiver operating characteristic (ROC) analysis was conducted to evaluate the capacity of immune-inflammatory markers to predict overall survival (OS). Cox-proportional hazards regression analysis was implemented to investigate prognostic markers for OS. RESULTS: Based on ROC curves, the CONUT score was found to be the most valuable prognostic marker (area under the curve = 0.716). The high CONUT (≥2) group included 54 patients, and the low CONUT (0 or 1) group included 60 patients. The high CONUT group had poorer prognosis rates compared to the low CONUT group with regard to OS (5-year OS: 46.3% vs. 86.0%, p = 0.0006). In the multivariate data analysis, histology, lymphatic invasion, and CONUT score (hazard ratio: 4.23, p = 0.0003) were found to be exclusive and independent prognostic markers for OS. CONCLUSION: Preoperatively, the CONUT score can be used as a novel prognostic marker in elderly NSCLC patients. CONUT evaluations can also be used to design nutritional interventions to improve patient outcomes.

Current Concepts of Cervical Spine Alignment, Sagittal Deformity, and Cervical Spine Surgery.

There are not many reports on cervical spine alignment, and only a few analyze ideal surgical approaches and optimal amounts of correction needed for the various types of deformity. We comprehensively reviewed the present literature on cervical spinal deformities (with or without myelopathy) and their surgical management to provide a framework for surgical planning. A general assessment of the parameters actually in use and correlations between cervical and thoracolumbar spine alignment are provided. We also analyzed posterior, anterior, and combined cervical surgical approaches and indications for the associated techniques of laminoplasty, laminectomy and fusion, and anterior cervical discectomy and fusion. Finally, on the basis of the NDI, SF-36, VAS, and mJOA questionnaires, we fully evaluated the outcomes and measures of postoperative health-related quality of life. We found the need for additional prospective studies to further enhance our understanding of the importance of cervical alignment when assessing and treating cervical deformities with or without myelopathy. Future studies need to focus on correlations between cervical alignment parameters, disability scores, and myelopathy outcomes. Through this comprehensive literature review, we offer guidance on practical and important points of surgical technique, cervical alignment, and goals surgeons can meet to improve symptoms in all patients.

Pelvic Ring Fractures: A Biomechanical Comparison of Sacral and Lumbopelvic Fixation Techniques.

BACKGROUND CONTEXT: Pelvic ring fractures are becoming more common in the aging population and can prove to be fatal, having mortality rates between 10% and 16%. Stabilization of these fractures is challenging and often require immediate internal fixation. Therefore, it is necessary to have a biomechanical understanding of the different fixation techniques for pelvic ring fractures. METHODS: A previously validated three-dimensional finite element model of the lumbar spine, pelvis, and femur was used for this study. A unilateral pelvic ring fracture was simulated by resecting the left side of the sacrum and pelvis. Five different fixation techniques were used to stabilize the fracture. A compressive follower load and pure moment was applied to compare different biomechanical parameters including range of motion (contralateral sacroiliac joint, L1-S1 segment, L5-S1 segment), and stresses (L5-S1 nucleus stresses, instrument stresses) between different fixation techniques. RESULTS: Trans-iliac-trans-sacral screw fixation at S1 and S2 showed the highest stabilization for horizontal and vertical displacement at the sacral fracture site and reduction of contralateral sacroiliac joint for bending and flexion range of motion by 165% and 121%, respectively. DTSF (Double transiliac rod and screw fixation) model showed highest stabilization in horizontal displacement at the pubic rami fracture site, while the L5_PF_W_CC (L5-Ilium posterior screw fixation with cross connectors) and L5_PF_WO_CC (L5-Ilium posterior screw fixation without cross connectors) showed higher rod stresses, reduced L1-S1 (approximately 28%), and L5-S1 (approximately 90%) range of motion. CONCLUSIONS: Longer sacral screw fixations were superior in stabilizing sacral and contralateral sacroiliac joint range of motion. Lumbopelvic fixations displayed a higher degree of stabilization in the horizontal displacement compared to vertical displacement of pubic rami fracture, while also indicating the highest rod stresses. When determining the surgical approach for pelvic ring fractures, patient-specific factors should be accounted for to weigh the advantages and disadvantages for each technique.

Central sensitivity syndrome affects the disease activity index and treatment satisfaction in patients with rheumatoid arthritis.

AIM: Many rheumatoid arthritis (RA) patients prioritize pain improvement in treatment. As pain can result from various causes, including noninflammatory factors such as central sensitivity syndrome (CSS), we hypothesized that CSS might impact treatment satisfaction. In this cross-sectional study, we assessed the CSS effects on clinical disease activity and treatment satisfaction in RA patients. METHODS: In total, 220 consecutive RA patients receiving long-term follow-up were evaluated for clinical disease activity and treatment satisfaction. CSS was evaluated using the Central Sensitization Inventory (CSI). An overall score of ≥40 indicates the presence of CSS. We queried "How satisfied are you with your treatment?"; answers included (a) very satisfied, (b) satisfied, (c) not satisfied, or (d) very dissatisfied. For univariate analysis, we condensed these answers into "dissatisfied" or "satisfied." We also evaluated treatment satisfaction using the visual analog scale (VAS), with scores ranging from 0 mm (very dissatisfied) to 100 mm (very satisfied). RESULTS: Of the 220 patients, 17 (7.7%) were classified as having CSS. CSI score was significantly correlated with the clinical disease activity index (CDAI; r = .322, p < .01) and treatment satisfaction (r = -.336, p < .01). Regarding treatment satisfaction, univariate analysis revealed that patient global assessment (PtGA), pain VAS, Health Assessment Questionnaire-Disability Index (HAQ-DI), Disease Activity Score in 28 joints with C-reactive protein, CDAI, and CSI scores of patients who were satisfied with treatment differed significantly from those of dissatisfied patients. Multivariate analysis revealed that CSI, PtGA, and HAQ-DI scores were associated with treatment satisfaction. CONCLUSION: In RA patients, CSS may affect the disease activity index and reduce treatment satisfaction.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan.

OBJECTIVES: This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity. DESIGN: Retrospective observational study of a nationwide database. SETTING: The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint. PARTICIPANTS: This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018. MAIN OUTCOME MEASURE: The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis. RESULTS: The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years. CONCLUSION: ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact. TRIAL REGISTRATION NUMBER: Chiba University ID1049.

Fracture risk assessment of vascularized medial femoral condylar bone graft: A finite element analysis.

BACKGROUND: Vascularized medial femoral condyle (MFC) bone graft is useful for pseudarthrosis and osteonecrosis, but has the risk of fracture as a complication. This study aimed to create multiple three-dimensional (3D) finite element (FE) femur models to biomechanically evaluate the fracture risk in the donor site of a vascularized MFC bone graft. METHODS: Computer tomography scans of the femurs of nine patients (four males and five females) with no left femur disease were enrolled in the study. A 3D FE model of the left femur was generated based on the CT images taken from the patients. The descending genicular artery (DGA), the main nutrient vessel in vascularized MFC bone grafts, divides into the proximal transversal branch (TB) and the distal longitudinal branch (LB) before entering the periosteum. Thirty-six different bone defect models with different sizes and locations of the harvested bone were created. RESULTS: The highest stress was observed in the proximal medial and metaphyseal portions under axial and external rotation, respectively. In the bone defect model, the stress was most elevated in the extracted region's anterior or posterior superior part. Stress increased depending on proximal location and harvested bone size. CONCLUSION: Increasing the size of the bone graft proximally raises the stress at the site of bone extraction. For bone grafting to non-load-bearing areas, bone grafting distally using LB can reduce fracture risk. If TB necessitates a larger proximal bone extraction, it is advisable to avoid postoperative rotational loads.

Compensation Method for Missing and Misidentified Skeletons in Nursing Care Action Assessment by Improving Spatial Temporal Graph Convolutional Networks.

With the increasing aging population, nursing care providers have been facing a substantial risk of work-related musculoskeletal disorders (WMSDs). Visual-based pose estimation methods, like OpenPose, are commonly used for ergonomic posture risk assessment. However, these methods face difficulty when identifying overlapping and interactive nursing tasks, resulting in missing and misidentified skeletons. To address this, we propose a skeleton compensation method using improved spatial temporal graph convolutional networks (ST-GCN), which integrates kinematic chain and action features to assess skeleton integrity and compensate for it. The results verified the effectiveness of our approach in optimizing skeletal loss and misidentification in nursing care tasks, leading to improved accuracy in calculating both skeleton joint angles and REBA scores. Moreover, comparative analysis against other skeleton compensation methods demonstrated the superior performance of our approach, achieving an 87.34% REBA accuracy score. Collectively, our method might hold promising potential for optimizing the skeleton loss and misidentification in nursing care tasks.

Novel subtype of coxitis knee associated with acetabular dysplasia of the hip: a case series.

BACKGROUND: Multiple joint arthritis patterns require a comprehensive understanding to optimize patient management. This study aimed to present a patient cohort that deviated from known definitions of coxitis knee (CK), identifying and characterizing this atypical group. METHODS: Patients undergoing both total hip arthroplasty and total knee arthroplasty between January 2008 and December 2018 were retrospectively reviewed. The patients were classified into a typical coxitis knee group (classic, long leg arthropathy, and windswept deformity) and an atypical coxitis knee group. Leg-length discrepancy, body mass index (BMI), and radiographic parameters of the groups were compared and analyzed. RESULTS: A total of 31 patients were allocated to the typical coxitis knee group (n = 10), and atypical coxitis knee group (n = 21). In the atypical group, 27 hips were involved, of which 21 had acetabular dysplasia, 5 exhibited subchondral insufficiency fracture-like changes, and only 1 had classic osteoarthritis. Among the 27 knees undergoing total knee arthroplasty, 26 showed varus alignment, 1 was within the normal range, and none was valgus. Acetabular dysplasia involved ipsilateral (n = 1), contralateral (n = 14), and bilateral (n = 6) hips, showing atypical coxitis knee. Patients with acetabular dysplasia were more likely to exhibit atypical CK. CONCLUSION: Most patients in the cohort displayed acetabular dysplasia and contralateral varus knees, constituting a pattern referred to as acetabular dysplasia-associated gonarthritis. Identifying this novel subtype may have important clinical implications for regions with high risk factors, where acetabular dysplasia and constitutional genu varum are prevalent.

Lipid index to quantify the absorbed lipids in retrieved UHMWPE components of joint arthroplasty.

BACKGROUND: The ultra-high molecular weight polyethylene (UHMWPE) component of artificial joints is one of the most important factors affecting the clinical outcomes of joint arthroplasty. Although the possibility of in vivo UHMWPE degradation caused by absorbed lipids has been reported, a quantitative evaluation of this phenomenon has not yet been performed. OBJECTIVE: This study aimed to establish the lipid index (LI) as a quantitative indicator of the amount of absorbed lipids and the first step to quantify their effects on UHMWPE. METHODS: The LI was defined using the infrared spectrum obtained with a Fourier-transform infrared spectrophotometer and verified using the retrieved UHMWPE components. RESULTS: The LI was consistent with the amount of extract recovered in reflux extraction with hexane. In addition, the LI could replace lipid extraction for calculating the oxidation index (OI) because the value obtained by subtracting the LI from the OI showed good agreement with the OI obtained after lipid extraction. CONCLUSION: The LI represents the amount of lipids absorbed by UHMWPE and is useful for quantitatively evaluating the effects of lipids on UHMWPE. In addition, the LI enables OI measurements that are unaffected by absorbed lipids without requiring troublesome lipid-extraction procedures.