Inferior Healing Rate in Isolated Meniscal Repair than that in Meniscal Repair with Concomitant ACL Reconstruction Evaluated with MRI.

Introduction: Isolated meniscal repair has been suggested as one of the contributing factors in unhealed meniscal repair. The purpose of this study was to compare the healing rate between isolated meniscal repair and meniscal repair with concomitant anterior cruciate ligament reconstruction (ACLR) using a standardised assessment method after propensity score matching. Materials and methods: Accuracy of the Crues' grading system for meniscal healing was validated using second-look arthroscopy as the reference standard in 17 patients. Propensity score matching (one-to-one) was performed between 26 patients who underwent isolated meniscal repair and 98 patients who underwent meniscal repair with concomitant ACLR. Patients were matched for sex, age, side and zone of the meniscal repair, and number of sutures. Healing rates at one year which were evaluated with magnetic resonance imaging (MRI) were compared between the two groups. Results: The sensitivity and specificity of the Crues' grading system on multiple plane MRI for meniscal healing were 100% and 83.3%, respectively. Both the isolated meniscal repair group and the meniscal repair with concomitant ACLR group included 21 patients after propensity score matching. Baseline characteristics did not differ significantly between the two groups. The healing rate was significantly lower in the isolated meniscal repairs group (14.3%) than in the meniscal repair concomitant with ACLR group (47.6%, P=0.04). Conclusion: The healing rate for isolated meniscal repair using a standardised MRI assessment method was inferior to that of meniscal repair with concomitant ACLR after propensity score matching.

Temporal pattern of Fos and Jun families expression after mitogenic stimulation with FGF-2 in rat neural stem cells and fibroblasts

Intense stimulation of most living cells triggers the activation of immediate early genes, such as Fos and Jun families. These genes are important in cellular and biochemical processes, such as mitosis and cell death. The present study focused on determining the temporal expression pattern of Fos and Jun families in fibroblasts and neural stem cells of cerebellum, hippocampus, and subventricular zone (SVZ) of rats of different ages at 0, 0.5, 1, 3, and 6 h after stimulation with fibroblast growth factor (FGF)-2. In neonates, a similar expression pattern was observed in all cells analyzed, with lower expression in basal condition, peak expression at 0.5 h after stimulation, returning to baseline values between 1 and 3 h after stimulation. On the other hand, cells from adult animals only showed Fra1 and JunD expression after stimulation. In fibroblasts and hippocampus, Fra1 reached peak expression at 0.5 h after stimulation, while in the SVZ, peak level was observed at 6 h after stimulation. JunD in fibroblasts presented two peak expressions, at 0.5 and 6 h after stimulation. Between these periods, the expression observed was at a basal level. Nevertheless, JunD expression in SVZ and hippocampus was low and without significant changes after stimulation. Differences in mRNA expression in neonate and adult animals characterize the significant differences in neurogenesis and cell response to stimulation at different stages of development. Characterizing these differences might be important for the development of cell cultures, replacement therapy, and the understanding of the physiological response profile of different cell types.

Evaluation of large airway specimens obtained by transbronchial lung cryobiopsy in diffuse parenchymal lung diseases.

BACKGROUND: The difference in diagnostic yield between surgical lung biopsy and transbronchial lung cryobiopsy (TBLC) in diffuse parenchymal lung diseases (DPLD) has been reported to be due to differences in the rate of interpathologist agreement, specimen size, and specimen adequacy. In TBLC, the specimens containing large airway components are generally believed as inadequate specimens for histological evaluation, but the detailed characteristics of TBLC specimens including the large airway and the impact on histological diagnostic rates of DPLD have not been investigated. METHODS: We retrospectively reviewed the specimen characteristics of patients with DPLD who underwent TBLC. RESULTS: Between February 2018 and January 2020, 74 patients and 177 specimens were included. There were 85 (48.0%) large airway specimens (LAS) that contained bronchial gland or bronchial cartilage. The ideal specimen ratio was significantly lower in the LAS-positive group than that in the LAS-negative group (5.8% vs. 45.6%), and the proportion of bronchioles, alveoli, and perilobular area were similarly lower in the LAS-positive group. The presence of traction bronchiectasis and diaphragm overlap sign on high-resolution computed tomography (HRCT) were also significantly higher in the LAS-positive group than those in the LAS-negative group. We observed a statistically significant trend in histological diagnostic yield (40.7% in LAS positive group; 60.8% in LAS positive and negative group; 91.6% in LAS negative group) (Cochran-Armitage trend test). CONCLUSION: LAS is a specimen often collected in TBLC and contains a low percentage of bronchioles, alveoli, and perilobular area. Since the histological diagnostic yield tends to be higher in cases that do not contain LAS, it may be important to determine the biopsy site that reduces the frequency of LAS collection by referring to the HRCT findings in TBLC.

Influence of double layer filter on mean glandular dose (MGD) and image quality in low energy image of contrast enhanced spectral mammography (LE-CESM).

INTRODUCTION: The aim of this study was to evaluate mean glandular dose (MGD) and image quality in low energy imaging from contrast-enhanced spectral mammography (CESM) when using double-layer filtration. METHODOLOGY: A dedicated phantom was used to quantitatively estimate the MGD and image quality. The target slab of the phantom consisted of three iodine coins having a concentration of 1.0 mgI/cm3, 2.0 mgI/cm3, 4.0 mgI/cm3, a 100% adipose equivalent coin and a 100% glandular equivalent coin. The phantom was exposed using a semiautomated function at 28 k, 30 kV and 32 kV. MGD. Contrast to noise ratio (CNR) and figure of merit (FOM) were estimated for Mo/Rh, Mo/Rh + Cu, Mo/Rh + Al and Mo/Rh + Cd combinations using three breast equivalent compositions. RESULTS: MGD was reduced up to a maximum of 1.03 mGy from 1.17 mGy for 100% adipose tissue. 1.18 mGy from 1.34 mGy for 50% glandular tissue and 1.39 mGy from 1.72 mGy for the 100% glandular phantom when using double-layer filtration. All of the above-mentioned results were obtained for the 50 mm phantom using 32 kV. CNR and FOM values were not significantly reduced with a double-layer filter when compared to a single-layer filter. CONCLUSION: The present study concluded that Mo/Rh + Cu is the best combination to reduce the MGD significantly when compared to Mo/Rh + Al or Mo/Rh + Cd. Mo/Rh + Cu also achieved optimal image quality when compared to the Mo/Rh single filter combination. IMPLICATIONS OF PRACTICE: The use of a double-layer filter in low energy imaging of CESM results in a significant reduction in MGD without degrading the quality of the image.

Drug repositioning of antipsychotic drugs for cisplatin-induced pica behavior in mice.

We aimed to clarify whether various antipsychotics ameliorate cisplatin-induced pica behavior in mice using a drug repositioning approach. Mice were administered cisplatin (12.5 mg/kg, i.p.) with or without olanzapine (1 mg/kg, i.p.), asenapine (4 mg/kg, i.p.), mirtazapine (5 mg/kg, i.p.) or standard three-drug antiemetics (granisetron [0.5 mg/kg, i.p.], fosaprepitant [25 mg/kg, i.p.], and dexamethasone [3 mg/kg, i.p.]). Kaolin, food, and water intake, and spontaneous motor activity on the day before and seven consecutive days after the cisplatin administration were measured using a telemetry system. At the primary endpoint, kaolin intake was significantly higher at day three in the cisplatin group than in the pre-treatment and saline groups ( p < 0.05). Additionally, kaolin intake was not significantly higher in cisplatin with olanzapine, asenapine, and mirtazapine groups for seven days than in the pre-treatment group. At the secondary endpoint, cisplatin decreased the food and water intake, and spontaneous motor activity in a time-dependent manner. Three antipsychotics failed to improve the cisplatin-induced decrease in food and water intake, and spontaneous motor activity. The findings suggest that prophylactic administration of antipsychotics besides olanzapine may improve cisplatin-induced nausea and vomiting in a delayed phase and de-escalate standard 3-drug antiemetics.

Reflections on low-dose radiation, the misconceptions, reality and moving forward.

Low dose radiation has been widely accepted by the radiation protection community as presenting a very low risk to human health, if any. Over-conservatism in optimisation principles and regulations have resulted in a disproportionate fear of radiation amongst the general public and government authorities alike, overlooking the great benefits nuclear science and techniques have brought to society as a whole. As such, the World Nuclear Association advocates for a recontextualisation of the radiation hazards with regards to low dose radiation, and a greater awareness as to the absence of any discernible effects associated with it.

Preventive effects of self-administered cryotherapy on paclitaxel-induced peripheral neuropathy in patients with early-stage breast cancer: a propensity score analysis.

We hypothesized that suppression of peripheral circulation via cryotherapy may be effective in preventing paclitaxel-induced peripheral neuropathy (PIPN). Therefore, this study aimed to clarify whether self-administered cryotherapy could prevent PIPN in patients with early-stage breast cancer, using real-world data. A single-center, retrospective, observational study was conducted. Data from the electronic medical records of consecutive patients aged ≥ 20 years with early-stage breast cancer who received a regimen containing paclitaxel for 12 cycles with or without self-administered cryotherapy at the National Cancer Center Hospital from March 2018 to May 2019 were evaluated. The primary endpoint was the cumulative dose of paclitaxel until the onset of grade ≥ 2 PIPN. To compare the difference between the two groups, multivariable Cox proportional hazards models adjusted for prognostically important variables were used. Ninety Japanese patients were included in this study. The estimated incidence of grade ≥ 2 PIPN was 26.9% and 37.7% in the self-administered cryotherapy group and control group, respectively (P = 0.314). The multivariable Cox proportional hazards model showed that the self-administered cryotherapy group had a decreased risk of onset of grade ≥ 2 PIPN (hazard ratio: 0.63, 95% confidence interval: 0.25 to 1.39; P = 0.281). Sensitivity analyses using multivariable Cox proportional hazards models along with two propensity score-adjusted methods demonstrated consistent results. The findings suggest that the methods of self-administered cryotherapy may prevent PIPN and should be reinforced appropriately in clinical practice. A randomized controlled multicenter trial of self-administered cryotherapy is warranted.

Effect of renin-angiotensin system inhibitors on pemetrexed plus platinum-induced hematological toxicities: a multicenter retrospective study using three propensity score analyses.

Hematological toxicities induced by pemetrexed plus platinum therapy remain a critical issue in clinical practice. We hypothesized that inhibition of the renin-angiotensin system (RAS) can ameliorate pemetrexed-induced hematological toxicities through drug-drug interactions involving organic anion transporters. Thus, this study aimed to clarify whether RAS inhibitors (RASIs) could prevent pemetrexed plus platinum-induced hematological toxicities. We retrospectively analyzed data from 305 consecutive patients with non-small cell lung cancer or malignant pleural mesothelioma who received their first cycle of a pemetrexed plus platinum regimen and were treated with or without RASIs. The primary endpoint was the incidence of severe myelosuppression after the first cycle. Propensity score (PS)-matched, PS-adjusted, and inverse probability of treatment weighting (IPTW) analyses were used. The number of patients with grade ≥3 hematological toxicities was 27 (8.9%). PS-matched analyses revealed that the concomitant use of RASIs was slightly associated with a lower risk of grade ≥3 hematological toxicities (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.20-2.32; p = 0.536). Additionally, sensitivity analyses using PS-adjusted and IPTW methods demonstrated similar results (OR, 0.63; 95% CI, 0.19-2.15; p = 0.463 and OR, 0.37; 95% CI, 0.11-1.29; p = 0.117, respectively). These findings suggest that RASIs might prevent pemetrexed plus platinum-induced hematological toxicities.

Safety and feasibility of minimally invasive esophagectomy for elderly esophageal cancer patients.

The number of elderly patients with esophageal cancer has increased in recent years. The use of thoracoscopic esophagectomy has also increased, and its minimal invasiveness is believed to contribute to postoperative outcomes. However, the short- and long-term outcomes in elderly patients remain unclear. This study aimed to elucidate the safety and feasibility of minimally invasive esophagectomy in elderly patients. This retrospective study included 207 patients who underwent radical thoracoscopic esophagectomy for thoracic esophageal squamous cell carcinoma at Kobe University Hospital between 2005 and 2014. Patients were divided into non-elderly (<75 years) and elderly (≥75 years) groups. A propensity score matching analysis was performed for sex and clinical T and N stage, with a total of 29 matched pairs. General preoperative data, surgical procedures, intraoperative data, postoperative complications, in-hospital death, cancer-specific survival, and overall survival were compared between groups. The elderly group was characterized by lower preoperative serum albumin levels and higher American Society of Anesthesiologists grade. Intraoperative data and postoperative complications did not differ between the groups. The in-hospital death rate was 4% in the elderly group, which did not significantly differ from the non-elderly group. Cancer-specific survival was similar between the two groups. Although overall survival tended to be poor in the elderly group, it was not significantly worse than that of the non-elderly group. In conclusion, the short- and long-term outcomes of minimally invasive esophagectomy in elderly versus non-elderly patients were acceptable. Minimally invasive esophagectomy is a safe and feasible modality for elderly patients with appropriate indications.

Time-dependent changes in serum magnesium levels in patients receiving cetuximab with low baseline serum sodium levels.

Cetuximab causes electrolyte abnormalities, such as hypomagnesemia, hypokalemia, and hypocalcemia. However, little is known about the relationships between the onset of hypomagnesemia, patient background before administration, and time-dependent changes in serum magnesium levels. Therefore, we examined the patient backgrounds that influenced the onset of hypomagnesemia and the time-dependent changes in serum magnesium levels in patients receiving cetuximab. A retrospective study was performed to investigate patients with advanced or recurrent colorectal cancer or head and neck cancer, treated with a cetuximab regimen from 2012 to 2020 at Kindai University Nara Hospital. In total, 52 patients who met the inclusion criteria were enrolled in this study. The serum magnesium level was significantly lower in the hyponatremia before the administration group than in the non-hyponatremia group (p < 0.001). Univariate logistic regression analysis revealed that the baseline serum sodium levels (odds ratio [OR]: 0.741, 95% confidence interval [CI]: 0.588-0.934) and the combination of magnesium oxide tablet (OR: 0.997, 95% CI: 0.995-0.999) were one of the independent factors for hypomagnesemia. These results indicated that hyponatremia before administration may be an indicator of serum magnesium levels after administration of cetuximab. Cetuximab-induced hypomagnesemia may be predicted using baseline serum sodium levels, and hypomagnesemia may be prevented by administration of magnesium oxide tablets. Our findings provided new evidence for the management of serum magnesium levels in patients receiving cetuximab.

Association between dexamethasone treatment and alterations in serum concentrations of trace metals.

Previously, a significant elevation in the serum levels of iron (Fe) was observed within a few days after the initiation of cisplatin (CDDP)-based chemotherapy. To clarify the underlying mechanisms, the serum concentration of hepcidin, a negative regulator of Fe release, was determined in the clinical samples obtained from six patients with cancer. The result showed that the serum concentration of hepcidin in patients receiving CDDP-based chemotherapy was significantly increased after 4-6 days of treatment, in comparison to the baseline level, suggesting that aforementioned excessive systemic Fe was not explained by the change of serum hepcidin level. All these patients received antiemetic premedication. We next evaluated of the effects of Pt-containing drugs and prophylactic antiemetic dexamethasone medication on the serum concentration of trace metals in mice, and on the hepatic and renal concentration of trace metals. The serum concentrations of Fe, Cu, and Zn in the CDDP-treated and oxaliplatin-treated mice were not significantly altered in comparison to those of the vehicle-treated control group. The serum concentrations of Fe, Cu, and Zn were increased after 24 h of dexamethasone treatment, compared to those of the control group (P < 0.05). The hepatic concentration of Mn was significantly reduced, whereas those of Fe and Cu inclined to diminish. The present findings suggest that dexamethasone can partly contribute to the changes in the serum concentrations of trace metals during anticancer chemotherapy.

Preparation, characterization and antidermatophytic activity of free- and microencapsulated cinnamon essential oil.

Essential oils (EO) are effective natural antimicrobials but are susceptible to oxidation. Microencapsulation improves EO stability, reduces toxicity, and controls release. The aim of this study was preparation, characterization and antidermatophytic activity of free and microencapsulated cinnamon essential oil (MP). MP were prepared by the spray drying method and the success of MP encapsulation was confirmed by UV-vis spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The antifungal effect of EO and MP was evaluated by the broth microdilution method against Microsporum gypseum and Trichophyton mentagrophytes. The checkerboard method was used to assess synergistic interactions. Fluorescence microscopy and scanning electron microscopy were used to investigate the inhibition of hyphal growth by EO and MP. A cytotoxic assay was performed using the VERO cell line. Microencapsulated cinnamon essential oil was found to be micrometric, with a round, regular structure. The minimum inhibitory concentration of EO was found to be between 125-250µg/mL, while that of MP was 220.5-440.5µg/mL. EO was synergistic with fluconazole while microencapsulated oil was less cytotoxic than EO.

Intratumoural immune cell landscape in germinoma reveals multipotent lineages and exhibits prognostic significance.

AIMS: Alterations in microenvironments are a hallmark of cancer, and these alterations in germinomas are of particular significance. Germinoma, the most common subtype of central nervous system germ cell tumours, often exhibits massive immune cell infiltration intermingled with tumour cells. The role of these immune cells in germinoma, however, remains unknown. METHODS: We investigated the cellular constituents of immune microenvironments and their clinical impacts on prognosis in 100 germinoma cases. RESULTS: Patients with germinomas lower in tumour cell content (i.e. higher immune cell infiltration) had a significantly longer progression-free survival time than those with higher tumour cell contents (P = 0.03). Transcriptome analyses and RNA in-situ hybridization indicated that infiltrating immune cells comprised a wide variety of cell types, including lymphocytes and myelocyte-lineage cells. High expression of CD4 was significantly associated with good prognosis, whereas elevated nitric oxide synthase 2 was associated with poor prognosis. PD1 (PDCD1) was expressed by immune cells present in most germinomas (93.8%), and PD-L1 (CD274) expression was found in tumour cells in the majority of germinomas examined (73.5%). CONCLUSIONS: The collective data strongly suggest that infiltrating immune cells play an important role in predicting treatment response. Further investigation should lead to additional categorization of germinoma to safely reduce treatment intensity depending on tumour/immune cell balance and to develop possible future immunotherapies.

Weight of salivary gland ultrasonography compared to other items of the 2016 ACR/EULAR classification criteria for Primary Sjögren's syndrome.

OBJECTIVE: Major salivary gland ultrasonography (SGUS) is widely used for the diagnosis of primary Sjögren's syndrome (pSS). Our objective was to assess the contribution of SGUS compared to other items of the 2016 ACR/EULAR pSS classification criteria, based on expert opinion. METHODS: A secure web-based relational database was used by 24 experts from 14 countries to assess 512 realistic vignettes developed from data of patients with suspected pSS. Each vignette provided classification criteria items and information on history, clinical symptoms and SGUS findings. Each expert assessed 64 vignettes, and each vignette was assessed by 3 experts. A diagnosis of pSS was defined according to at least 2 of 3 experts. Validation was performed in the independent French DiapSS cohort of patients with suspected pSS. RESULTS: A criteria-based pSS diagnosis and SGUS findings were independently associated with an expert diagnosis of pSS (P < 0.001). The derived diagnostic weights of individual items in the 2016 ACR/EULAR criteria including SGUS were as follows: anti-SSA, 3; focus score ≥ 1, 3; SGUS score ≥ 2, 1; positive Schirmer's test, 1; dry mouth, 1; and salivary flow rate < 0.1 mL/min, 1. The corrected C statistic area under the curve for the new weighted score was 0.96. Adding SGUS improves the sensitivity from 90.2 % to 95.6% with a quite similar specificity 84.1% versus 82.6%. Results were similar in the DiapSS cohort: adding SGUS improves the sensitivity from 87% to 93%. CONCLUSION: SGUS had similar weight compared to minor items, and its addition improves the performance of the 2016 ACR/EULAR classification criteria.

Insulin secretion and sensitivity before and after surgical treatment for aldosterone-producing adenoma.

AIM: Primary aldosteronism, which is usually caused by an aldosterone-producing tumour, affects glucose metabolism. The effects of this condition on insulin secretion and insulin sensitivity have remained unclear, however. To gain insight into the influence of primary aldosteronism on glucose tolerance, various parameters related to insulin secretion or insulin sensitivity in patients with an aldosterone-producing tumour were comprehensively analyzed. METHODS: To assess 14 patients with an aldosterone-producing tumour, hyperglycaemic and hyperinsulinaemic-euglycaemic clamp tests as well as oral glucose tolerance tests (OGTTs) were performed before and after tumour excision. Time between presurgical analysis and surgery was 27-559 (194±132) days, and 14-142 (51±38) days between surgery and postsurgical analysis. Various parameters related to insulin secretion or sensitivity as determined by OGTT as well as hyperglycaemic and hyperinsulinaemic-euglycaemic clamp analyses were evaluated. RESULTS: Surgical treatment of tumours ameliorated hypokalaemia and reduced plasma aldosterone levels. First and second phases of insulin secretion during the hyperglycaemic clamp, as well as the insulinogenic index and total insulin secretion measured during OGTT, were also improved after surgery. In addition, the insulin sensitivity index determined during the hyperinsulinaemic-euglycaemic clamp was reduced after surgery. CONCLUSION: Primary aldosteronism impairs insulin secretion.

Retraction Note: Enhanced suppression of tumor growth using a combination of NK4 plasmid DNA-PEG engrafted cationized dextran complex and ultrasound irradiation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Usefulness of medication instruction sheets for sharing information on cancer chemotherapy within the health care team.

Patients receiving cancer chemotherapy may experience a number of potentially severe adverse drug reactions. It is crucial for all members of the health care team to monitor the effect of medicines on the patient to ensure the safety and efficacy of the chemotherapy. The present study prepared medication instruction sheets (MISs) on hematological malignancy and conducted a questionnaire survey to verify their usefulness among physicians, dentists, and nurses. MISs were prepared for 103 chemotherapy and 44 pretreatment regimens for hematopoietic stem cell transplantation in the Department of Hematology at Kyushu University Hospital. Eight questions were prepared to investigate whether MISs could help physicians, dentists, and nurses manage cancer chemotherapy more safely, effectively, and efficiently, as well as in the sharing of information. A total of 35 medical staff working in inpatient wards, including 8 physicians, 3 dentists, and 24 nurses, participated in the questionnaire survey. All of the staff responded to the questionnaire survey, which showed that the MISs were favorably accepted by the participants. There was no negative opinion on the management of chemotherapy using the MISs. The MIS was a useful tool for sharing information on cancer chemotherapy between patients and medical staff and for enabling efficient management, thereby improving the safety and efficacy of treatment.

Evaluation of the compliance with antiemetic guidelines for prevention of chemotherapy-induced nausea and vomiting in patients with hematologic malignancy.

To assess compliance with the Japanese antiemetic guidelines for chemotherapy-induced nausea and vomiting (CINV), the frequencies of CINV occurrence and use of antiemetic rescue medications were examined in patients with hematological malignancy. A total of 40 patients with hematologic malignancy were eligible in this study. This study was performed in the Department of Hematology, Kyushu University Hospital, as a subgroup analysis from a nationwide, multicenter prospective cohort study conducted by the CINV Study Group of Japan. In the patients with hematological malignancy, the guideline compliance rate was 45 %. Five patients (22.7 %) experienced vomiting during the observation period after receiving non-guideline-consistent antiemetic prophylaxis, whereas no patient experienced vomiting after receiving guideline-consistent antiemetic prophylaxis. The study was not sufficiently powered to reach a statistical significance in its frequency of occurrence between the compliance and non-compliance groups. In the entire study period, 8 out of 40 patients required rescue medication, but there was no association between the status of compliance and the antiemetic guidelines. A total of 22 (55.0 %) patients achieved complete response, which was defined as no vomiting and no use of antiemetic rescue medication, during the study period. The rate of compliance with the prophylactic antiemetic treatment guidelines seemed to be low in patients with hematological malignancy, although the status of the guideline compliance did not always influence the antiemetic effects.

Morphometric geometrical analysis to determine the centre of the acetabular component placement in Crowe type IV hips undergoing total hip arthroplasty.

AIMS: We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component, as assessed by morphometric geometrical analysis, and its reliability. PATIENTS AND METHODS: A total of 52 Crowe IV hips (42 patients; seven male, 35 female; mean age 68.5 years (32 to 82)) and 50 normal hips (50 patients; eight male, 42 female; mean age 60.7 years (34 to 86)) undergoing total hip arthroplasty were retrospectively identified. In this CT-based simulation study, the acetabular component was positioned at the true acetabulum with a radiological inclination of 40° and anteversion of 20°. Acetabular shape and the position of the centre of the acetabular component were analyzed by morphometric geometrical analysis using the generalized Procrustes analysis. RESULTS: The acetabular shapes of Crowe IV hips were distinctively triangular; the ideal position of the centre of the acetabular component was superior on the posterior bony wall. The first and second relative warps explained 34.2% and 18.4% of the variance, respectively, compared with that of 28.6% and 18.0% in normal hips. We defined the landmark as one-third the distance from top on the posterior bony wall in Crowe IV hips. The average distance from the centre of the acetabular component was 5.6 mm. CONCLUSION: Crowe IV hips are distinctively triangular; the point one-third from the top on the posterior bony wall was a useful landmark for placing the acetabular component.