Clinical outcomes and prognostic factors for esophageal cancer in patients aged 80 years or older who were treated with definitive radiotherapy and chemoradiotherapy.

OBJECTIVE: Aging of populations has been rapidly increasing worldwide. The aim of this study was to identify prognostic factors of overall survival (OS) and progression-free survival (PFS) in patients aged 80 years or older who had esophageal cancer and received radiotherapy. METHODS: Patients aged 80 years or older who received radiotherapy between 2004 and 2015 were retrospectively reviewed. Pretreatment age, gender, performance status, Charlson comorbidity index score, tumor location, histology, clinical stage, results of blood tests and treatment methods were obtained to determine prognostic factors of OS and PFS. Survival curves were drawn using the Kaplan-Meier method and prognostic factors were analyzed using Cox's hazards model. RESULTS: Ninety-two patients were included. Thirty-five patients were treated with chemo-radiotherapy. The median follow-up period was 19.0 months. The 3-year OS and PFS rates were 44.7% and 28.4%, respectively. In multivariate analysis, clinical stage (hazard ratio [HR] 2.28, 95% confidence interval [CI] 1.40-3.73, p = 0.001) and the geriatric nutritional risk index (GNRI, HR 0.95, 95% CI 0.92-0.97, p < 0.001) were significant prognostic factors of OS. Clinical stage (HR 2.06, 95% CI 1.34-3.18, p = 0.001), tumor location (HR 2.04, 95% CI 1.39-3.01, p < 0.001) and GNRI (HR 0.96, 95% CI 0.94-0.99, p = 0.003) were significant prognostic factors of PFS. CONCLUSION: Clinical stage and GNRI were significant prognostic factors of OS and PFS. Tumor location was a significant prognostic factor of PFS. These prognostic factors might be useful for decision-making for elderly patients with esophageal cancer.

The Completion of Postoperative Radiotherapy After Breast-Conserving Surgery in a Patient With Recurrent Erythema Multiforme: A Case Report.

Radiotherapy (RT) can induce dermatitis and exacerbate a patient's preexisting skin conditions. We present a case of RT in a 61-year-old Japanese woman with a history of erythema multiforme (EM). She was diagnosed with a nodule on her right breast during therapy for EM. EM was noticed on the anterior chest and upper and lower extremities. RT was initially postponed due to exacerbation of EM before postoperative RT for right breast cancer. However, considering that EM tends to recur every one to two months, RT was commenced during a period of less active dermatitis, and a total dose of 50 Gy of conventional irradiation was successfully administered. One year after RT, there was no EM recurrence, dermatitis development, obvious late effects, or radiation pneumonitis. Our experience suggests that RT can be administered relatively safely to patients with recurrent EM but should be administered with caution.

Malignant Hip Flexion Failure Syndrome: An Oncologic Disease Compared to Malignant Psoas Syndrome.

Malignant psoas syndrome (MPS) causes painful hip immobilization when a malignant tumor reaches the psoas muscle. However, there exists a different condition in which a malignant tumor invades the psoas muscle, leading to hip flexion failure without painful hip immobilization. This study aimed to define malignant hip flexion failure syndrome (MHFFS) as tumors located in the upper lumbar region or at the lesser trochanter of the femur, near the origin or termination of the psoas muscle, and to compare its prevalence, characteristics, and outcomes with those of classical MPS. We analyzed 291 patients who received palliative radiotherapy (RT) in the lumbar, pelvic, and lower leg regions from 2013 to 2023. The prevalence of MPS and MHFFS, pathological features, distinctive clinical presentations, treatment modalities, and treatment outcomes have been summarized. We also defined the 'Clinical sign reported by Ishikawa and Teramura (IT sign)' to describe the characteristic action of lifting the affected lower leg with both hands in MHFFS cases and assessed its clinical significance. Among the 291 patients, 6 (2.1%) had MHFFS and 11 (3.8%) had MPS. MHFFS resulted from metastatic tumors in the 11th and 12th thoracic vertebrae, as well as the 1st and 2nd lumbar vertebrae or the lesser trochanter of the femur, and it was characterized by hip and groin pain along with hip flexion dysfunction. All cases showed a positive IT sign. The response to RT varied, with symptomatic improvement observed in 50% of the patients. MPS is characterized by tumor invasion of the psoas muscle, causing severe lumbosacral nerve pain. Strong opioids were used for pain management in all patients, and epidural anesthesia was required in some patients. The median survival time of patients with MPS and MHFFS was 13.2 months. MPS required opioids more potently than MHFFS, but MHFFS responded relatively well to early RT.

Feasibility of the analytical dose calculation method for Au-198 brachytherapy.

PURPOSE: A dose calculation algorithm Computed Tomography (CT)-based analytical dose calculation method (CTanly), which can correct for subject inhomogeneity and size-dependent scatter doses, was applied to the 198Au seed. In this study, we evaluated the effectiveness of the CTanly method by comparing the gold standard Monte Carlo (MC) method and the conventional TG43 method on two virtual phantoms and patient CT images simulating oral cancer. METHODS: As virtual phantoms, a water phantom and a heterogeneous phantom with soft tissue inserted cubic fat, lung, and bone were used. A 2-mm-thick lead plate was also inserted into the heterogeneous phantom as a dose attenuator. Virtual 198Au seeds and a 2-mm-thick lead plate were placed on the patient CT images. Dose distributions obtained via the TG43 and CTanly methods were compared with those of the MC by gamma analysis with 2%/2-mm thresholds. The computation durations were also compared. RESULTS: In the water phantom, dose distributions comparable to those obtained via the MC method were obtained regardless of the algorithm. For the inhomogeneity phantom and patient case, the CTanly method showed an improvement in the gamma passing rate and dose distributions similar to those of the MC method were obtained. The computation time, which was days with the MC method, was reduced to minutes with the CTanly method. CONCLUSIONS: The CTanly method is effective for 198Au seed dose calculations and takes a shorter time to obtain the dose distributions than the MC method.

Thoracic Spinal Metastasis With Hip Flexion Failure and Psoas Muscle Atrophy Successfully Improved With Radiotherapy: A Case Report.

When a malignant tumor infiltrates the psoas muscle, it is termed malignant psoas syndrome (MPS). We are reporting this case because the malignancy led to atrophy of the psoas muscle, and the clinical course differed from the typical presentation of MPS. A 72-year-old Japanese female with advanced sigmoid colon cancer and multiple metastases had been undergoing systemic chemotherapy for four years. She complained of severe back pain on a numeric rating scale (NRS) of 4-5, left groin pain, and hip flexion weakness. Although she could stand up, she started experiencing difficulties while walking and became reliant on a wheelchair. At the time of referral to our department, her performance status was 2. On examination, she was capable of hip adduction and abduction, and flexion was impossible on the left side and possible on the right side. Imaging revealed metastases to the 11th and 12th thoracic vertebrae, extending to the upper portion of the first lumbar vertebra, leading to atrophy of the left psoas major muscle and impairment of hip flexion. She received palliative radiation therapy (RT) of 30 Gy in 10 fractions over a period of 2 weeks. Following RT, she had grade 1 skin inflammation but no severe complications. Two weeks after RT, her pain improved (NRS 0-1) and she regained hip flexion. When hip flexion failure occurs in patients with malignant tumors, it is important to recognize that it may be caused by a tumor located near the lower thoracic or upper lumbar spine, even if the psoas muscle itself is not directly infiltrated by the tumor.

Prognostic Factors and Impact of Therapeutic Intervention in Patients With Brain Metastases at the Initial Presentation.

Background Studies investigating the normative characteristics and prognosis of patients diagnosed with brain metastases (BMs) at the onset of cancer are scarce. Therefore, we analyzed real-world treatment options. Methodology This retrospective study enrolled 112 patients newly diagnosed with BM between May 2006 and October 2021. The variables examined included patients' age, sex, recurrence split analysis, Glasgow prognostic score (GPS), number of lesions, tumor size, peripheral brain tumor edema, targeted therapy, supportive care, chemotherapy, and date of onset. Prognostic factors were assessed using recursive partitioning analysis (RPA), graded prognostic assessment (GPA) scores, and GPS scoring, with magnetic resonance imaging (MRI) and computed tomography (CT) studies. Primary treatment comprised whole-brain radiotherapy (WBRT), with regular follow-up. Results Data from 112 survivors were analyzed, revealing a median overall survival time (MST) of 7.7 months, with some patients surviving beyond 24 months post-WBRT. Univariate analysis revealed associations between MST and RPA class, GPS, and treatment modalities (including targeted therapy and chemotherapy). RPA class 2, GPS of 0, and targeted therapy were identified as predictors of better prognosis in the multivariate analysis. In the subgroup not receiving chemotherapy, no significant difference in prognosis was seen between groups with or without WBRT. Conclusions Alongside RPA, scores indicating chronic inflammatory changes, including GPS, were confirmed as crucial prognostic factors. Moreover, treatment with molecularly targeted drugs correlated with favorable prognoses. The treatment-naïve group exhibited poorer prognoses, and WBRT was not deemed a significant prognostic factor in the chemotherapy group.

A Case of Hypofractionated Radiation Therapy for Early-Stage Breast Cancer in a Patient With Fabry Disease.

Fabry disease is a metabolic disorder caused by a deficiency in lysosomal enzymes and is inherited as an X-chromosomal disorder. Patients with Fabry disease have a low incidence of cancer, and reports of malignant tumors, especially in the thoracic region, are rare. In this case report, we describe our experience with radiation therapy following breast-conserving surgery in a patient with left breast cancer and Fabry disease, and we review the existing literature. The patient, a woman in her 40s, required postoperative irradiation for left breast cancer (pT1N0M0). There were several patients with Fabry disease in her family, and the diagnosis of Fabry disease was made five years ago. Cardiac function evaluation revealed no significant abnormalities, but a myocardial biopsy had suggested the presence of Fabry disease. Due to the relatively preserved distance between the heart and the chest wall, the patient received heart-shielded three-dimensional conformal radiation therapy at a dose of 53.2 Gy in 20 fractions, without the use of deep-inspiration breath-hold or intensity-modulated radiotherapy. After treatment was completed, only mild radiation dermatitis was observed. Six months have passed since treatment, and there have been no serious adverse events.

Glasgow prognostic score for assessing the efficacy of whole-brain radiation therapy in cases of recursive partitioning analysis class 2 and class 3 multiple brain metastases: a retrospective study.

PURPOSE: Whole-brain radiotherapy (WBRT) may not be beneficial for patients with brain metastases (BMs). The Glasgow Prognostic Score (GPS) is a suggested prognostic factor for malignancies. However, GPS has never been assessed in patients with BMs who have undergone WBRT. The purpose of this study was to determine whether GPS can be used to identify subgroups of patients with BMs who have a poor prognosis, such as recursive partitioning analysis (RPA) Class 2 and Class 3, and who will not receive clinical prognostic benefits from WBRT. MATERIALS AND METHODS: A total of 180 Japanese patients with BMs were treated with WBRT between May 2008 and October 2015. We examined GPS, age, Karnofsky Performance Status (KPS), RPA, graded prognostic assessment (GPA), number of lesions, tumor size, history of brain surgery, presence of clinical symptoms, and radiation doses. RESULTS: The overall median survival time (MST) was 6.1 months. seventeen patients (9.4%) were alive more than 2 years after WBRT. In univariate analysis, KPS ≤ 70 (p = 0.0066), GPA class 0-2 (p = 0.0008), > 3 BMs (p = 0.012), > 4 BMs (p = 0.02), patients who received ≥ 3 Gy per fraction (p = 0.0068), GPS ≥ 1 (p = 0.0003), and GPS ≥ 2 (p = 0.0009) were found to significantly decrease the MST. Patients who had brain surgery before WBRT (p = 0.036) had a longer survival. On multivariate analysis, GPS ≥ 1 (p = 0.008) was found to significantly decrease MST. CONCLUSION: Our results suggest that GPS ≥ 1 indicates a poor prognosis in patients undergoing WBRT for intermediate and poor prognosis BMs.

An Unusual Case of Hip Flexion Failure Caused by Bone Metastasis From Hepatocellular Carcinoma Infiltrating the Psoas Muscle.

When malignant tumors infiltrate the psoas muscle, they can result in what is referred to as malignant psoas syndrome (MPS). We are reporting this case as the malignant tumor had invaded the psoas muscle, and the clinical course of the patient differed from that of typical MPS. A 75-year-old male patient with liver cancer presented with pain around the right hip joint and difficulty in flexing the right hip joint, resulting in gait disturbance. There was no painful immobilization of the right hip, and the patient was able to extend the lower extremity. A CT scan revealed multiple liver tumors, multiple bone metastases, and swelling of the psoas muscle contiguous with the tumor at the lesser trochanter of the right femur. There were no apparent intracranial or spinal cord lesions, and no obvious abnormalities were detected around the psoas muscle in the abdominal cavity. Palliative radiation therapy was administered at a dose of 20 Gy in five fractions for pain relief. One month later, a follow-up CT scan presented no change in the shape of the tumor; however, the swelling of the right psoas muscle had improved. Unfortunately, the patient passed away 1 month after irradiation because of progressive liver and renal failure. When a patient with a malignant tumor presents with periprosthetic hip pain and hip flexion failure, one should consider the possibility of a malignant tumor in the lesser trochanter.

Optimal Bladder Condition in Volumetric Modulated Arc Therapy for Prostate Cancer: The Role of Superior-Inferior Lengths of the Bladder and Dose Constraints.

Background Optimal bladder conditions based on dose constraints in prostate cancer radiation therapy (RT) are important. In this study, the superior-inferior (SI) lengths of the bladder were assessed to define the ideal bladder state for RT. Materials and methods In this study, 50 prostate cancer cases treated with three-dimensional conformal radiation therapy between January and December 2021 were retrospectively analyzed. Using their CT data, a volumetric modulated arc therapy (VMAT) plan was simulated. Bladder dose constraints and dimensions, including SI, right-left (RL), and anterior-posterior (AP) lengths, were assessed. In total, 28 cases met the dose constraints and 22 cases did not meet the dose constraints.  Results Median bladder volumes (BVs) for compliant and non-compliant cases were 163.6 ml and 88.5 ml, respectively (p<0.0001). For compliant plans, median bladder dimensions were RL: 78 mm, AP: 89 mm, and SI: 51 mm. Non-compliant plans showed RL: 72 mm, AP: 84 mm, and SI: 42 mm, with significant differences (SI: p=0.0004, RL: p=0.0065, AP: p=0.037). Established thresholds were SI: 46 mm, RL: 92 mm, AP: 75 mm, and BV: 142.8 ml. SI showed the strongest correlation with BV (coefficient: 0.78). Conclusions This study analyzed the SI lengths of the bladder concerning dose constraints in VMAT for prostate cancer. It was concluded that smooth treatment planning could be achieved with proper consideration of the bladder's SI distance. Further case collection and prospective studies are warranted.

Pre-treatment Evaluation of Patients Eligible for Whole Brain Radiation Therapy: The Risk of Hippocampal Metastases in a Retrospective Study of 248 Cases at a Single Institution.

Whole brain radiation therapy (WBRT) is effective for multiple brain metastases (BMs) but may impair neurocognitive function (NCF). The incidence of hippocampal metastasis (HM) is low, and the factors associated with the occurrence of HM remain unclear. This study aimed to assess the occurrence of limbic system metastasis (LSM), including HM, and to analyze the risk of HM. We retrospectively analyzed 248 patients who underwent three-dimensional conformal radiation therapy for BMs between May 2008 and October 2015. Gadolinium-enhanced brain MRI or CT scans were used for diagnosis. Statistical analysis involved assessing clinical factors, including age, gender, primary tumor, number of BMs, and maximum metastasis diameter, in relation to the presence of HMs using logistic regression and receiver operating characteristic (ROC) curve analysis. The median age at treatment was 62 years (range: 11-83 years). Primary lesion sites included the lung (n = 150; 60.5%), breast (n = 45; 18.1%), gastrointestinal tract (n = 18; 7.3%), and bone and soft tissue (n = 2; 0.8%). Histological cancer types included adenocarcinoma (n = 113; 45.6%), squamous cell carcinoma (n = 26; 10.5%), small cell carcinoma (n = 28; 11.3%), invasive ductal carcinoma (n = 35; 14.1%), sarcoma (n = 3; 1.2%), and others (n = 43; 17.3%). MRI or CT scans of the 248 patients were analyzed, indicating a total count of 2,163 brain metastases (median: five metastases per patient). HMs were identified in 18 (7.3%) patients. The most common location for LSMs was the cingulum/cingulate gyrus in 26 (10.5%) patients. In univariate and multivariate analyses, patients with 15 or fewer BMs had a significantly lower incidence of HMs (odds ratio (OR), 0.018 (95% confidence interval (CI), 0.030-0.24)) (p < 0.0001). A maximal tumor size of less than 2 cm significantly increased the incidence of HMs (OR, 13.8 (95%CI, 1.80-105.3)) (p = 0.0003). The presence of cingulum/cingulate gyrus metastases also demonstrated a significant increase in the incidence of HMs (OR, 9.42 (95%CI, 3.30-26.84)) (p < 0.0001). The present study has uncovered a novel association between a high number of metastases in the cingulate gyrus and the development of HMs. Patients with BMs eligible for WBRT with metastases in the cingulate gyrus may be at risk of developing HM.

Tapia Syndrome and Severe Pain Induced by Occipital Bone Metastasis of Prostate Cancer.

Tapia syndrome is characterized by unilateral tongue paralysis, hoarseness, and dysphagia. It is often associated with issues in the lower cranial nerves and is rarely caused by malignant tumors. A 71-year-old Japanese male with prostate cancer and bone metastases experienced severe headaches, oral discomfort, dysphagia, and hoarseness for a month. Neurological examination revealed left-sided tongue atrophy and left vocal cord paralysis, suggesting problems with cranial nerves IX and XII. CT scans showed bone metastasis in the left occipital bone. Brain MRI showed no brain or meningeal metastasis, but neck MRI revealed a mass near the left hypoglossal canal. His prostate-specific antigen (PSA) level was 53.2 ng/mL. Based on these findings, we diagnosed him with occipital bone metastasis of prostate cancer with Tapia syndrome. We treated him with palliative radiation therapy (RT), delivering 30 Gy in 10 fractions over two weeks. We did not use drug treatment or chemotherapy due to side effects and the patient's preferences. After just one day of RT, his severe headache and oral discomfort significantly improved. By the end of the two-week treatment, his hoarseness had also improved, and he was able to eat. However, tongue atrophy had not improved three months after RT. We presented a unique case of palliative RT for occipital bone metastasis of prostate cancer with Tapia syndrome. Within two weeks, the patient's headache and dysphagia had greatly improved, although tongue atrophy remained partially unresolved after palliative RT.

Development of a collapsed cone convolution/superposition dose calculation algorithm with a mass density-specific water kernel for magnetic resonance-guided radiotherapy.

This study aimed to develop and validate a collapsed cone convolution for magnetic resonance-guided radiotherapy (CCCMR). The 3D energy deposition kernels (EDKs) were generated in water in a 1.5-T transverse magnetic field. The CCCMR corrects the inhomogeneity in simulation geometry by referring to the EDKs according to the mass density between the interaction and energy deposition points in addition to density scaling. Dose distributions in a water phantom and in slab phantoms with inserted inhomogeneities were calculated using the Monte Carlo (MC) and CCCMR. The percentage depth dose (PDD) and off-axis ratio (OAR) were compared, and the gamma passing rate (3%/2 mm) was evaluated. The CCCMR simulated asymmetric dose distributions in the simulation phantoms, especially the water phantom, and all PDD and OAR profiles were in good agreement with the findings of the MC. The gamma passing rates were >99% for each field size and for the entire region. In the inhomogeneity phantoms, although the CCCMR underestimated dose in the low mass density regions, it could reconstruct dose changes at mass density boundaries. The gamma passing rate for the entire region was >95% for the field size of 2 × 2 cm2, but it was 68.9-86.7% for the field sizes of ≥5 × 5 cm2. Conclusively, in water, the CCCMR can obtain dose distributions comparable to those with the MC. Although the dose differences between them were mainly in inhomogeneity regions, the possibility of the effective use of the CCCMR in small field sizes was demonstrated.

A case of COVID-19 vaccination during radiotherapy for breast cancer.

BACKGROUND: The coronavirus disease 19 (COVID-19) vaccination has been progressing. The safety of vaccination during radiotherapy is not clear. CASE PRESENTATION: We experienced a patient who received a COVID-19 vaccine during radiotherapy. A 60-year-old woman with breast cancer underwent postoperative radiotherapy. She received two vaccine doses and she suffered from severe vertigo. Her radiotherapy was suspended for several days and the radiotherapy schedule needed to be changed. CONCLUSIONS: The association between vertigo and vaccination during radiotherapy is not clear. However, if the general condition of patients worsens, suspension of treatment might be necessary. Therefore, attention should be given to COVID-19 vaccination during radiotherapy.

Ultrasonographically assessed carotid atherosclerosis in Japanese type 2 diabetic patients: Role of nonesterified fatty acids.

The aim of the present study was to evaluate the association of carotid atherosclerosis (intimal-medial thickness [IMT] in plaque-free segments and carotid stenosis in plaque segments) with serum nonesterified fatty acids (NEFA) in diabetic and nondiabetic patients. Fifty-one nonobese nonhypertensive Japanese type 2 diabetic patients aged 38 to 83 years (60.0 +/- 1.5 years, mean +/- SEM) and 23 age-matched (60.4 +/- 2.2 years, P =.439; range, 36 to 74 years) and sex-matched nondiabetic subjects were examined. The duration of diabetes was 9.6 +/- 1.0 years. Body mass index (BMI), blood pressure (systolic pressure, diastolic pressure), glycosylated hemoglobin (HbA(1c)), and fasting concentrations of plasma glucose, serum lipids (triglycerides, total, and high-density lipoprotein [HDL] cholesterol, low-density lipoprotein [LDL] cholesterol) and serum NEFA were measured. Using high-resolution B-mode ultrasound scan, we measured IMT in plaque-free segments of bilateral common carotid arteries, and the mean of IMT in 2 vessels was used for the analysis. Furthermore, we calculated the degree of stenosis in plaque segments of bilateral common carotid arteries. The degree of carotid stenosis was expressed as a percentage ratio between the area of plaque and that of the lumen using the formula (Lumen Area - Residual Lumen) x 100. Both the areas were automatically measured by the system on a frozen transverse scanning plane at the site of maximal narrowing. When 2 or more plaques were present in the vessel, only that causing the greatest degree of stenosis was considered for analysis. Univariate regression analyses showed that mean IMT in plaque-free segments was positively correlated with age (r =.498, P =.0004) and NEFA (r =.354, P =.0188) in type 2 diabetic patients. The degree of stenosis was positively correlated to age (r =.422, P =.0028), duration of diabetes (r =.313, P =.0268) and NEFA (r =.540, P =.0003) in diabetic patients. Other variables, including BMI and lipid profile, were not associated both with mean IMT in plaque-free segments and the degree of stenosis in plaque segments in our diabetic patients. Multiple regression analyses showed that mean IMT in plaque-free segments was independently associated with age (P =.0003, F = 15.2), which explained 26.1% of the variability of IMT in our diabetic patients. The degree of stenosis was independently predicted by NEFA (P =.0047, F = 8.9), which explained 17.2% of the variability of the carotid stenosis in our diabetic patients. In contrast, mean IMT in plaque-free segments was positively correlated to age in nondiabetic subjects (r =.450, P =.0347). There was, however, no relationship between the degree of stenosis and the variables, including age and NEFA, in nondiabetic subjects. These results indicate that the factors contributing to IMT in plaque-free segments and the degree of carotid stenosis in plaque segments are different in nonobese nonhypertensive Japanese type 2 diabetic patients. IMT in plaque-free segments was independently associated with age both in nondiabetic and diabetic subjects, whereas the serum NEFA level independently predicted the degree of stenosis in plaque segments in our diabetic patients, while not in nondiabetic subjects. Thus, NEFA is considered to be one of the new risk factors responsible for the progression of carotid atherosclerosis in nonobese nonhypertensive Japanese type 2 diabetic patients.

The antioxidant and non-antioxidant contributions of vitamin E in vitamin E blended ultra-high molecular weight polyethylene for total knee replacement.

Vitamin E (VE) blended ultra-high molecular weight polyethylene (UHMWPE) has been developed in Japan as a material for use in total knee replacement (TKR). Various results have demonstrated that VE blended UHMWPE reduces the incidence of delamination failure and lowers the amount of wear produced during knee simulator testing. It was also found that wear particles from VE blended UHMWPE elicited a reduced biological response compared to conventional UHMWPE. A great deal of research concerning vitamin E (VE) stabilized ultrahigh molecular weight polyethylene (UHMWPE) has focused on VE's effects as an antioxidant and its ability to prevent the oxidative degradation of UHMWPE chains. However, other chemical and mechanical changes have been observed in VE blended UHMWPE that are unrelated to the oxidative protection that VE provides. This paper provides a general review of VE blended UHMWPE, with a particular focus on the non-antioxidant effects of VE. The potential application of VE blended UHMWPE in total hip replacement (THR), along with the differences in loading conditions between the knee and the hip are also discussed.

Strain-induced crystallization and orientation of vitamin E-blended ultrahigh molecular weight polyethylene.

The effects of vitamin E addition on the strain-induced crystallization and molecular chain orientation of ultrahigh molecular weight polyethylene (UHMWPE) were examined in order to clarify the wear mechanism of vitamin E-blended UHMWPE in knee prostheses. The structure changes of vitamin E-blended UHMWPE before and after tensile strain were analyzed by X-ray diffraction, Raman spectroscopy and image correlation method. The vitamin E-blended UHMWPE exhibited lower strain-induced crystallization than virgin UHMWPE but a higher Ic value in Raman spectroscopic analysis. The vitamin E-blended UHMWPE also exhibited a larger percentage of negative areal dilatation under tensile strain. These results suggest that the addition of vitamin E to UHMWPE decreases the strain-induced crystallization and increases the strain-induced orientation of the molecular chains present in the amorphous phase.

Reduction of wear volume from ultrahigh molecular weight polyethylene knee components by the addition of vitamin E.

Wear performance and debris-size distribution of vitamin E (DL-alpha tocopherol, VE)-added ultrahigh molecular weight polyethylene (UHMWPE) was evaluated using a knee-simulator test. VE was mixed with GUR 1050 UHMWPE powder at 0.3 wt%, and the tibial components of the knee joint were made by direct compression molding. The VE-added UHMWPE showed consistently lower wear volume throughout the test.