Non-metastatic hip fractures surgery in patients with active cancer: benefit and risk

PURPOSE

Although rare, non-metastatic proximal femoral fracture (PFF) can develop in patients with active cancer. However, little data are available regarding the risks and benefits of surgical treatment in such patients. The purpose of his study was to investigate the risks and benefits of surgical treatment of PFF in patients with and without cancer.

METHODS

We retrospectively examined the medical records of all patients treated for PFF, excluding those with pathological fracture, at our hospital from July 2013 to December 2020. The patients were divided into two groups; The active cancer group and the standard group. We investigated in both groups about surgical and medical complications during the perioperative period, walking ability two weeks postoperatively, and one-year postoperative mortality rate.

RESULT

After the inclusion and exclusion criteria, 39 patients in the active cancer group and 331 patients in the standard group were finally investigated. There were no statistically significant differences between the two groups. The complication rate did not appear statistical significance between two groups (16.7% in active cancer group vs 10.7% in standard group: p = 0.272). Walking ability was also similar in two groups. Mortality rate at one year was significantly higher in the active cancer group. (41.2% in active cancer group vs 6.0% in standard group: p < 0.05).

CONCLUSION

Although the active cancer group had a higher mortality rate at one year, which was influenced by the prognosis of the cancer, the benefits of surgical intervention, such as regaining walking ability, were the same in patients with and without active cancer.

Differences in acoustic parameters of hammering sounds between successful and unsuccessful initial cementless cup press-fit fixation in total hip arthroplasty

Aims

It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA.

Methods

In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound.

Results

The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation.

Conclusion

The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation.

Conventional versus lateral fasciotomy for prevention of lateral femoral cutaneous nerve injury in the non-fan-type nerve in total hip arthroplasty with direct anterior approach

Aims

Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury.

Methods

In this trial, 134 patients were randomized into a lateral fasciotomy (n = 67) or a conventional fasciotomy (n = 67) group. This study was a dual-centre, double-blind, prospective randomized controlled two-arm trial with parallel group design and a 1:1 allocation ratio. The primary endpoint was the presence of LFCN injury, which was determined by the presence of numbness, decreased sensation, tingling, jolt-like sensation, or pain over the lateral aspect of the thigh, excluding the surgical scar, using a patient-based questionnaire. The secondary endpoints were patient-reported outcome measures (PROMs) using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS-12). Assessments were obtained three months after surgery.

Results

The incidence of LFCN injury tended to be lower in the lateral fasciotomy group (p = 0.089). In the lateral fasciotomy group, there were no significant differences in the mean PROM scores between patients with and without LFCN injury (FJS-12: 54.42 (SD 15.77) vs 65.06 (SD 26.14); p = 0.074; JHEQ: 55.21 (SD 12.10) vs 59.72 (SD 16.50); p = 0.288; WOMAC: 82.45 (SD 6.84) vs 84.40 (SD 17.91); p = 0.728). In the conventional fasciotomy group, there were significant differences in FJS-12 and JHEQ between patients with and without LFCN injury (FJS-12: 43.21 (SD 23.08) vs 67.28 (SD 20.47); p < 0.001; JHEQ: 49.52 (SD 13.97) vs 59.59 (SD 15.18); p = 0.012); however, there was no significant difference in WOMAC (76.63 (SD 16.81) vs 84.16 (SD 15.94); p = 0.107).

Conclusion

The incidence of LFCN injury at three months after THA was comparable between the lateral and conventional fasciotomy groups. Further studies are needed to assess the long-term effects of these approaches.

Recent advances in the direct anterior approach to total hip arthroplasty: a surgeon's perspective

INTRODUCTION

The direct anterior approach (DAA) has its origins in the first and oldest approach for hip replacement in the literature, but at the same time it would not be fanciful to suggest its increasing popularity as the latest approach for hip replacement procedures, especially among younger surgeons. However, in a geographical context, the DAA is not considered the major approach in most countries. Moreover, the term DAA encompasses numerous variations in terms of technique.

AREAS COVERED

In this narrative review, we describe our recent experience of advances in the DAA in terms of improved techniques and devices, along with some of its disadvantages. Also, we express our perspective on its future application.

EXPERT OPINIONS

The DAA is established as one of exemplary approaches to THA. The use of fluoroscopy, the traction table, and appropriate soft tissue management has become essential in the DAA for a safe and trouble-free procedure with adequate patient comfort. With the combination of recent technologies such as robotics, three-dimensional preoperative planning, and artificial intelligence (AI)-based surgeon assist systems, we can look forward to the DAA being performed more efficiently in the future.

Patients With Shorter Stature Exhibit Minimal Hammering Sound Changes During Cementless Stem Insertion in Total Hip Arthroplasty

Background

Listening to the change in the hammering sound is 1 of the elements used to assess the cementless stem stability. This study aimed to quantitatively investigate the change in the acoustic characteristics between the early and late phases of cementless stem insertion in total hip arthroplasty and to identify which patient characteristics contribute to the change in the hammering sound.

Methods

The acoustic parameters of the hammering sounds in the early and late phases of cementless taper-wedged stem insertion for 51 hips in 45 patients who underwent total hip arthroplasty (mean age = 68 years, height = 1.56 m, weight = 55.0 kg) were analyzed. Parameters including patient's basic characteristics, radiographical femoral morphology, and canal fill ratio were assessed as potential contributors to the change in the hammering sound.

Results

The low-frequency bands (0.5-1.0 kHz and 1.0-1.5 kHz) showed the largest changes during stem insertion and were therefore considered key bands for the analysis of sound alterations. Multivariate linear regression analysis showed that height (β = 8.312, P = .013) and proximal canal fill ratio (β = -3.8568, P = .038) were independently associated with the sound alterations. The decision tree analysis identified height (≥1.66 m or <1.66 m) as the best single discriminator for the sound alteration.

Conclusions

Patients with smaller stature showed the least change in the hammering sound during stem insertion. Understanding the acoustic characteristics of hammering sound alteration during cementless stem insertion may aid in the achievement of optimal stem insertion.

Validation of a preoperative formula to estimate postoperative pelvic sagittal alignment and mobility before performing total hip arthroplasty for patients with hip osteoarthritis

BACKGROUND

Although it is important to consider pelvic alignment and mobility in the standing and sitting positions before THA, it is not known how to preoperatively predict individual postoperative pelvic alignment and mobility. The purpose of this study was to investigate the pelvic alignment and mobility before and after THA, and to develop a predictive formula using preoperative factors to calculate postoperative sagittal alignment and mobility.

METHODS

One hundred seventy patients were assessed. The 170 patients were randomly divided into a prediction model analysis group (n = 85) and an external validation group (n = 85). In the prediction model analysis group, preoperative spinopelvic parameters were used to develop the predictive formulas to predict the postoperative sacral slope (SS) in standing and sitting positions and ΔSS. These were applied to the external validation group and assessed.

RESULTS

R² in multiple linear regression models for postoperative SS in standing, SS in sitting and ΔSS were 0.810, 0.672, and 0.423, respectively. The values of predicted and postoperative parameters were very close with no significant difference: SS in standing (33.87 vs. 34.23, P = 0.834), SS in sitting (18.86 vs. 19.51, P = 0.228), and ΔSS (15.38 vs. 14.72, P = 0.619).

CONCLUSION

The present study showed that the pelvic alignment and mobility after THA can be predicted using preoperative factors. Although a model with higher accuracy is needed, it is important to use a predictive formula to estimate the postoperative condition before performing THA.

Highly accurate acoustical prediction using support vector machine algorithm for post-operative subsidence after cementless total hip arthroplasty

PURPOSE

Acoustic analysis has recently been applied to cementless total hip arthroplasty (THA). The aim of this study was to develop a machine learning algorithm to predict post-operative subsidence with high accuracy.

METHODS

The acoustic parameters of the hammering sounds during a broaching procedure for 62 hips in 55 patients who underwent THAs with cementless taper-wedged stem were analysed. The patient's basic background such as age, sex, height, weight and body mass index, the femoral morphological parameters and the hammering sound characteristics of 24 features of normalised sound pressure (nSP) in 24 frequency ranges were applied to binary classification using a support vector machine using the following models with different features: model A, nSP only; model B, nSP + patients' basic background features; model C, nSP + patients' basic background features + femoral morphological parameters.

RESULTS

In 62 hips with 310 hammering sounds, 12 hips (19.4%) showed ≥ 3 mm of post-operative subsidence; hence, 60 hammering sounds were set as positive examples and 250 hammering sounds were set as negative examples. The AUC was very high in all models. The accuracy (AUC/sensitivity/specificity/positive predictive value/negative predictive value/accuracy rate) of each model was as follows: model A, 0.963/0.656/0.996/0.980/0.925/0.934; model B, 0.9866/0.675/1.000/1.000/0.928/0.937 and model C, 0.998/0.750/1.000/1.000/0.950/0.957.

CONCLUSION

In this study, we developed a high-accuracy machine learning algorithm for post-operative subsidence using acoustic parameters and additional pre-operative features. Our results represent a step toward the realisation of acoustic monitoring to avoid the complication in cementless THA.

Relationship between labral length and symptoms in patients with acetabular dysplasia before rotational acetabular osteotomy

The aim of this study was to investigate the relationship between acetabular labral length and symptoms in patients with acetabular dysplasia. In a retrospective medical record review, 218 patients with acetabular dysplasia who had undergone rotational acetabular osteotomy were identified. After implementing the inclusion and exclusion criteria, 53 patients were analyzed for preoperative symptoms measured by the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), acetabular bone morphology parameters by anteroposterior pelvic radiographs and labral parameters by radial magnetic resonance imaging. Spearman's correlation coefficients were calculated among JHEQ scores, bone morphologic parameters and labral parameters. Multiple linear regression models to determine the predictive variables of JHEQ score and labral length were obtained. There was no correlation between bone morphologic parameters and JHEQ scores. Labral length measured anteriorly correlated with JHEQ pain {r [95% confidence interval (CI)] = -0.335 (-0.555, -0.071), P = 0.014}, movement subscale [r (95% CI) = -0.398 (-0.603, -0.143), P = 0.003], mental subscale [r (95% CI) = -0.436 (-0.632, -0.188), P = 0.001] and total JHEQ score [r (95% CI) = -0.451 (-0.642, -0.204), P = 0.001]. The multiple linear regression results showed that anterior labral length was independently associated with JHEQ subscales in some models. Meanwhile, age, acetabular head index and total JHEQ score were independently associated with anterior labral length in all models. Labral length, notably in anterosuperior area, in patients with symptomatic acetabular dysplasia was related to patient's symptom. Labral length may be an important objective image finding that can be used to assess the severity of cumulative hip instability.

Blood cobalt ion level in patients with different sizes of cobalt/chrome femoral head with the Accolade TMZF stem

BACKGROUND

Corrosion of stem-cobalt/chromium (Co/Cr) head interface and subsequent systemic Co ion complication have been a clinical concern after total hip arthroplasty (THA). The aim of this study is to investigate correlation between type of femoral head and blood Co ion level.

METHODS

One hundred four patients with THA using accolade TMZF and Co/Cr femoral head (32-mm; 55 cases, 36-mm; 20 cases, dual mobility system (DM) with 22.2 or 28-mm inner head; 29 cases) participated in this study, and blood Co ion concentration test was performed in patients a minimum of four years after THA.

RESULTS

DM group was significantly older than 32-mm and 36-mm group (DM: 73.9 ± 4.6, 32-mm: 63.3 ± 8.5, 36-mm: 66.8 ± 10.5). The median (interquartile range) blood Co concentration of each group was 32-mm group 0.26 µg/L (0.69), 36-mm group; 0.21 µg/L (0.30); and DM group 0.21 µg/L (0.13). There was a significant difference of Co concentration between DM and 32-mm group (p = 0.023). Abnormal values of the blood Co concentration (> 1 µg/L) were observed in the 32-mm group; 12 cases (21.8%), 36-mm group; 2 cases (10.0%); and DM group; 0 case (0%) (p = 0.018).

CONCLUSIONS

Co blood concentration differed among the different sizes of Co/Cr femoral head. THA using DM is a safe option with low risk of complication from cobalt ion if it is used for elderly patients.

Acetabular morphological variation in Asian patients with femoral neck fracture: A three-dimensional CT-based study

AIMS

The acetabular morphology varies greatly among individuals, and hypoplasia is more common in Asia than in Europe. Dislocation after bipolar hip arthroplasty (BHA) for femoral neck fracture occurs at a constant rate, and is affected by the acetabular morphology. This study aimed to clarify individual differences in the acetabula of Asian patients with displaced femoral neck fractures.

PATIENTS AND METHODS

Fifty patients with displaced femoral neck fractures were assessed (50 fractured hips, 50 non-fractured hips). On CT corrected by the anterior pelvic plane, the 100 hips were assessed regarding acetabular coverage (six parameters), acetabular depth (two parameters), and acetabular opening angle (four parameters). Additional parameters related to the fracture and sex were examined. The percentile of each parameter was shown for all hips.

RESULTS

There was no patient with hip dysplasia defined as superior acetabular sector angle (SASA) less than 110° Compared with men, women had a significantly smaller anterior acetabular sector angle (AASA) (p = 0.016), and significantly larger acetabular inclination angle (p = 0.006) and acetabular index angle (p = 0.034). In the group with a normal SASA, seven hips (7.3%) had an anterior wall defect (AASA<50°) and five hips (5.2%) had a posterior wall defect (posterior acetabular sector angle<90°).

CONCLUSION

Older adults with femoral neck fractures can have anterior wall and posterior wall defects, even if their SASA is normal. Hidden acetabular dysplasia may be related to post-BHA dislocation. So, our results suggest that is important to accurately evaluate the acetabulum of patients with femoral neck fracture before surgery.

Lateral versus conventional fasciotomy for prevention of lateral femoral cutaneous nerve injury in total hip arthroplasty with direct anterior approach: a study protocol for a dual-center, double-blind, randomized controlled trial

BACKGROUND

An incision for total hip arthroplasty (THA) via the direct anterior approach (DAA) is generally made outside of the space between the sartorius and tensor fasciae latae muscles to prevent lateral femoral cutaneous nerve (LFCN) injury. Anatomical studies have revealed that the LFCN courses between the sartorius and tensor fasciae latae muscles. When the LFCN branches radially while distributing in the transverse direction from the sartorius muscle to the tensor fasciae latae muscle, it is called the fan type. Studies suggest that damage to the fan type LFCN is unavoidable during conventional fasciotomy. We previously demonstrated that injury to non-fan variation LFCN occurred in 28.6% of patients who underwent THA by fasciotomy performed 2 cm away from the intermuscular space. This suggests that the conventional approach also poses a risk of LFCN injury to non-fan variation LFCN. LFCN injury is rarely reported in the anterolateral approach, which involves incision of fascia further away than the DAA. The purpose of this study is to investigate how the position of fasciotomy in DAA affects the risk of LFCN injury.

METHODS

We will conduct a prospective, randomized, controlled study. All patients will be divided into a fan variation and a non-fan variation group using ultrasonography before surgery. Patients with non-fan variation LFCN will receive conventional fasciotomy and lateral fasciotomy in the order specified in the allocation table created in advance by our clinical trial center. The primary endpoint will be the presence of LFCN injury during an outpatient visit using a patient-based questionnaire. The secondary endpoints will be assessed based on patient-reported outcomes at 3 months after surgery in an outpatient setting using the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip-disease Evaluation Questionnaire, and the Forgotten-Joint Score-12.

DISCUSSION

We hypothesize that the incidence of LFCN injury due to DAA-THA is reduced by making the incision further away from where it is typically made in conventional fasciotomy. If our hypothesis is confirmed, it will reduce the disadvantages of DAA and improve patient satisfaction.

TRIAL REGISTRATION

UMIN Clinical Trials Registry, UMIN000035945 . Registered on 20 February, 2019.

Acetabular cartilage abnormalities in elderly patients with femoral neck fractures

INTRODUCTION

Both hemiarthroplasty (HA) and total hip arthroplasty (THA) are widely accepted surgical procedures for hip replacement following displaced femoral neck fractures. However, in cases involving an intact joint line before surgery, the choice between HA and THA remains debatable. This study investigated the prevalence of acetabular cartilage and labral abnormalities in elderly patients with femoral neck fractures.

METHODS

Thirty-seven patients underwent hip arthroplasty for femoral neck fractures between April 2020 and February 2021. After excluding 4 patients, 33 patients (6 men and 27 women; mean age = 82.2 [range = 67-98] years) with fractures in 12 left and 21 right hips were included. After femoral head removal during arthroplasty, the acetabulum was macroscopically examined for the presence of cartilage and labral lesions. Acetabular cartilage abnormalities were classified as either overall degeneration or partial damage according to the cartilage damage classification system.

RESULTS

Acetabular cartilage abnormalities, including overall degeneration or partial damage, were found in all hips (100%). Out of the 33 hips, overall degeneration, partial damage, and labral abnormalities were detected in 32 (96.9%), 16 (48.4%), and 9 (27.2%) hips, respectively.

DISCUSSION

In this study, most elderly patients with femoral neck fractures exhibited acetabular cartilage and labral abnormalities, which were already present at the time of surgery. Therefore, surgeons should carefully examine these abnormalities as they may impact postoperative outcomes such as pain and function.

Grafting of autologous concentrated bone marrow processed using a point-of-care device for patients with osteonecrosis of the femoral head: A phase 1 feasibility and safety study

Introduction

Materials and methods

Results

Conclusion

•

There are accumulated evidence of concentrated bone marrow grafting for hip osteonecrosis.

•

A “point-of-care device” for concentrated bone marrow (CBM) grafting has been developed.

•

This study has confirmed the feasibility and safety of CBM grafting using BioCUE system.

•

A further study aiming for the authorization of this procedure should be conducted in the future.

Horror of three synergistic factors in THA: high mechanical stress, dissimilar metals, low elasticity stem: a case report

Background

A large-diameter femoral head is effective in preventing dislocation after total hip arthroplasty. However, although rare, catastrophic stem tribocorrosion may occur at the head-stem junction.

Case presentation

A 70-year-old woman underwent revision surgery 7.5 years after total hip arthroplasty because of catastrophic stem corrosion with dissociation of the metal head (cobalt/chromium) and stem (TiMo12Zr6Fe2). Abnormal levels of cobalt were found in the intra-articular fluid, capsule, hip muscle, and blood. Revision surgery was performed via the direct anterior approach. The well-fixed femoral stem was explanted, and a cemented stainless stem with stainless head was implanted. Three months after the revision surgery, the cobalt concentration in the blood had decreased to normal.

Conclusions

Stem dissociation in the present case might have been caused by synergistic combination of a 36-mm-diameter femoral head and long neck length offset with high frictional torque, a cobalt-chromium head with a high risk of galvanic corrosion, and a TMZF (TiMo12Zr6Fe2) alloy stem with a low Young’s modulus of elasticity. The combination of these factors must be avoided.

Use of Dual Mobility Acetabular Component and Anterior Approach in Patients With Displaced Femoral Neck Fracture

BACKGROUND

Although the antidislocation effect of total hip arthroplasty (THA) via the direct anterior approach (DAA) with dual mobility cup (DMC) for displaced femoral neck fracture (FNF) has already been reported, the clinical result of DMC-DAA-THA for displaced FNF in terms of mortality, complications, and walking ability are still unclear.

METHODS

106 cases with DMC-DAA-THA for displaced FNF were investigated of dislocation; perioperative complications; 3-, 6-, and12-month mortality rate; and pre/early postoperative walking ability. The walking ability was stratified into the following four categories: (1) use of a wheelchair (no walking), (2) walking alongside a support (including walkers designed for the elderly), (3) walking using one stick, and (4) unaided walking.

RESULTS

There was no dislocation withing one-year postoperative. The 3-, 6-, and 12-month mortality rate was 2.8%, 4.7%, and 5.7%. Total complications occurred in 14 cases (14.7%). Although there was no revision surgery, two cases (1.9%) of intraoperative fracture treated without additional fixation, and one case of postoperative fracture was occurred. Among patients with preinjury walking category 2, 3, and 4 (total 94 cases), the number of patients who recovered same walking category at two-week postoperation was 56 cases (59.6%).

CONCLUSIONS

Our study demonstrated that DMC-DAA-THA for displaced FNF offered quick recovery of walking ability with no dislocation and low one-year mortality rate. We believe that the combination of early postoperative recovery due to the minimal invasiveness of the DAA and decreased dislocation rate due to increased range of motion by DMC and adequate soft tissue tension by DAA contributed to null dislocation.

Total hip arthroplasty with reconstruction of acetabulum through direct anterior approach for metastatic bone disease of acetabulum combined with pathological proximal femoral neck fracture: A case report

Most surgical treatment options for metastatic acetabular lesions involve variants of total hip arthroplasty (THA). However, these are technically complex reconstructions performed in very frail patients, and previous reports indicate complications such as dislocation, deep infection, aseptic loosening, and intraoperative death. A 73-year-old man presented to the emergency department at our hospital with right hip pain following a fall. He had undergone nephrectomy for the treatment of right kidney cancer at the age of 68 years. Four years after the nephrectomy, multiple lung metastases, pelvic bone metastases, and right femoral head and neck bone metastases were found. A radiograph of the hip joint showed a pathological proximal femoral fracture with a radiolucent lesion of the acetabulum. THA with acetabular reconstruction using a Kerboull-type (KT) plate through the direct anterior approach (DAA) was performed. After removal of the femoral head, curettage of the metastatic acetabular dome lesion was carefully performed under fluoroscopic guidance. After the KT plate was placed, cementation of the metastatic acetabular dome lesion was performed, and an optimally sized polyethylene liner was fixed with cement. A cemented stem was inserted after confirming the hip joint stability. At the 14-month follow-up, he could walk steadily without any complications and his modified Harris hip score was 100. The DAA conserves soft tissue because it is an intermuscular approach. Accordingly, postoperative recovery is fast and thus associated with a low dislocation rate and effective pain reduction. The acetabulum with metastatic disease was reconstructed using a KT plate for hip joint stability. Bone with metastatic disease that appears adequate at the time of THA may become incompetent after a few years. THA with acetabular reconstruction using a KT plate through the DAA was an effective treatment for metastatic bone disease of the acetabulum combined with pathological proximal femoral neck fracture.

Use of traction table did not increase complications in total hip arthroplasty through direct anterior approach performed by novice surgeon

PURPOSE

The purpose of this study was to investigate the surgical outcomes of total hip arthroplasty (THA) through direct anterior approach (DAA) performed by beginners by comparing the outcomes after the introduction of DAA-THA between using a normal operating table and a traction table.

METHODS

The total subjects were 200 patients, there were 120 cases from the introduction of three surgeons using a normal table and 80 cases from two surgeons using a traction table. The surgical procedure was standardized, and a surgeon skilled in DAA entered the operating room and instructed the novice surgeons of DAA in all cases.

RESULTS

The mean operative time was no significant difference between the two groups (p = 0.093). The difference in slope of the operative time was no significant difference between the two groups (p value = 0.089). The mean fluoroscopy time and the mean blood loss were significant difference between the two groups (p < 0.05). The difference in slope of the fluoroscopy time and blood loss were significant difference between the two groups (p < 0.05). There were no intraoperative complications and no reoperations for any reason.

CONCLUSIONS

At the facility with a surgeon skilled in DAA, the use of a traction table in DAA did not increase the complication rate compared with the use of a normal operating table when the exclusion criteria for DAA were set and surgery was performed using intraoperative fluoroscopy under supervision by a skilled surgeon.

Does increased diameter of metal femoral head associated with highly cross-linked polyethylene augment stress on the femoral stem and cortical hypertrophy?

PURPOSE

Cortical hypertrophy (CH) after total hip arthroplasty (THA) is thought as a process of femoral cortical functional adaptation against the stem. However, no study has been performed to investigate the association between CH and femoral head size. The purpose of this study is to investigate the factors related to femoral CH around the cementless stem after THA.

METHODS

THAs in 31 patients using 36-mm metal head and as a control, age-matched 62 THAs with 32-mm metal head have been analyzed. Radiographs were reviewed at four years to determine cortical thickness change from immediate post-operative one. Pre-operative and immediate post-operative radiographs were used to calculate the femoral morphology, canal fill ratio, stem alignment, and femoral and acetabular offset. Univariate and multivariate logistic regression analyses were performed to identify the risk factors for CH.

RESULTS

Patients with a 36-mm metal head had a significantly higher rate of severe CH (P = 0.001) than those with a 32-mm metal head. The multivariate logistic regression analysis with dependent variables of CH showed that the use of a 36-mm metal head had a significantly positive effect on CH. The odds ratio of a 36-mm metal head in mild CH was 2.517 (95% confidence interval, 1.032-6.143; P = 0.043), and that in severe CH was 8.273 (95% confidence interval, 2.679-25.551; P = 0.000). Age and the canal flare index were weakly and negatively influenced by mild CH.

CONCLUSIONS

The use of a 36-mm metal head was the dominant risk factor for CH.

Does total hip arthroplasty via the direct anterior approach using dual mobility increase leg length discrepancy compared with single mobility?

Background

Total hip arthroplasty (THA) via the direct anterior approach (DAA) using dual mobility cup (DMC) is considered to effectively prevent postoperative dislocation. However, the dislocation and reduction procedure using a trial implant during the surgery is difficult because of high soft tissue tension. Thereby, leg length discrepancy (LLD) is difficult to assess when using DM via the DAA.

Purpose

To compare the LLD between cases using conventional SM and those using DMC in THA via the DAA with fluoroscopy.

Patients and methods

We retrospectively investigated 34 hips treated with DMC (DMC-DAA group) and 31 hips treated with SM (SM-DAA group). The LLD was defined as the difference in the distance from the teardrop to the medial-most point of the lesser trochanter between the operative and nonoperative sides at immediate postoperative X-ray.

Results

The mean LLD in the DMC-DAA group and SM-DAA group was 0.68 ± 7.7 mm and 0.80 ± 5.5, respectively, with no significant difference. The absolute value of the LLD in the DMC-DAA group and SM-DAA group was 6.3 ± 4.4 mm and 5.9 ± 5.5, respectively, with no significant difference.

Conclusion

Despite the difficulty in assessment of the LLD during THA via the DAA using DMC, this technique does not increase the LLD compared with the use of SM.

Level of evidence

III, matched case-control study.

Bowing-head sign: rare but detectable in pre-catastrophic hip implant failure

Recently, catastrophic failure (i.e., dissociation between the metal femoral head and stem due to stem neck deformation) after total hip arthroplasty (THA) has been reported. Early detection of this complication is very important, because it is accompanied by an increased cobalt concentration in the body, which might influence systemic conditions such as heart failure and immune system diseases. However, early detection of stem neck deformation is considered as difficult. In most cases in the literatures, the diagnosis was made at the time of acute dissociation. We report a case of early detection of stem neck deformation with the 'Bowing-head sign' before acute dissociation. The patient is a 71-year old woman complained of a clicking sensation in the right hip during regular follow-up after THA with a 32-mm cobalt/chromium head with polyethylene insert for osteoarthritis performed 7 years previously. The plain radiograph showed that the angle between the metal femoral head and the axis of the stem neck was not perpendicular ('Bowing-head sign'). Dynamic evaluation under fluoroscopy showed movement of the stem neck in the metal femoral head with hip abduction and adduction. Laboratory data showed abnormal serum cobalt (6.3 μg/L, normal < 1 μg/L) and chromium (3.8 μg/L, normal < 5 μg/L) levels. Considering those radiographic findings, deformation of the stem neck due to trunnionosis was diagnosed, and elective revision surgery was performed without any complications. Plain radiographs after THA should be assessed with attention to this complication, 'Bowing-head sign' must not be overlooked.

Diagnosis of and Early Revision Surgery for Biological Fixation Failure Due to Proximal-Distal Mismatch of Proximally Coated Tapered Cementless Stem

The diagnosis of and decision-making for early revision surgery to treat failure of biological fixation with a proximally coated cementless stem are challenging. A 73-year-old woman was referred to our hospital with thigh pain 2 years after the initial total hip arthroplasty. Although a plain radiograph showed no signs indicating biological fixation failure, digital tomosynthesis showed a highly radiodense line along the proximal part, and bone scintigraphy showed uptake at the distal part. With the diagnosis of biological fixation failure due to the proximal-distal mismatch, the cementless stem was revised to a cemented stem, and the thigh pain was improved after the revision surgery. Digital tomosynthesis and bone scintigraphy can be helpful for the diagnosis of biological fixation failure due to proximal-distal mismatch.

A bolus of saline injection leads to increase in coronary flow based on the viscosity reduction effect: the mechanism of saline induced Pd/Pa ratio

Background

In conjunction with fractional flow reserve (FFR), our previous study has shown the accuracy and utility of saline induced Pd/Pa ratio (SPR) for the assessment of myocardial ischemia. However, the potential mechanism how saline injection leads to increase in coronary flow remains speculative.

Purpose

This study aimed to clarify the underlying mechanism of SPR by using swine models.

Methods

The study was conducted in four swine models, and bolus of 25°C saline, 40°C saline, and 25°C dextran was injected at rates of 40mL/5sec through a catheter inserted into the superior mesenteric artery. Its peripheral arterioles were observed and recorded by a digital microscope, and transit time of each fluid and a luminal diameter of arterioles before and after injection were measured.

Results

The result from arterioles diameters of pre- and post-injection (0.049±0.016mm vs. 0.050±0.016mm; P=0.636) indicated that luminal diameters remained unchanged regardless of fluid administration. The transit time of 25°C saline was significantly shorter than 25°C dextran (3.19±0.68sec vs. 6.15±1.19sec; P&lt;0.0001). Although the result showed no significance, the transit time of 40°C saline with lower viscosity was shorten compared to 25°C saline (3.1±0.43sec vs. 3.65±0.46sec; P=0.088).

Conclusions

Compared to 25°C dextran (viscosity of 4.991mPa·s) having the same viscosity as 37°C whole blood, 25°C saline (viscosity of 1.012mPa·s) caused increasing to double the intravascular flow volume without dilating arterioles. The results strongly suggested that the potential mechanism of SPR was viscosity reduction effect. Combined with FFR which is based on vasodilation-mediated hyperemia, these findings may contribute to clarifying the pathophysiology and especially the microcirculation in coronary artery diseases.

Funding Acknowledgement

Type of funding source: None

The developing mechanism of atherosclerotic lesion in coronary side branch on the ventricular free wall differs by the location of lesion

Background

The effective treating method of coronary side branch lesions such as ostial stenosis or thin arteries has not been established. On the other hand, tortuous side branch rarely has stenotic lesions.

Purpose

We focused on coronary side branches on the ventricular free wall, and examined coronary risk factors and bending and stretching motion of branch which can contribute to the development of atherosclerotic lesion.

Methods

In elective and first-time coronary angiograms, we included side branches on the ventricular free wall (&gt;2mm in diameter) and excluded previously treated ones. Study A; we divided arteries into proximal, middle, and distal segment, and examined the presence of tortuosity and stenotic lesions exceeding 50% diameter stenosis (DS) for each segment. A score of 1 was assigned to tortuous segment, and 0 to non-tortuous one. Study B; we included stenotic lesion (&gt;50% DS) in side branch ostium and excluded those extended across main coronary arteries. Relation between lesions and patients' characteristics was examined.

Results

Study A; in 1,828 side branches from 472 patients, middle and distal segments had significantly higher tortuosity score than proximal (0.68, 0.78 vs. 0.34; p&lt;0.0001). On the contrary, proximal segments had more stenotic lesions except ostial stenosis (230 vs. 69, 5; p&lt;0.0001). Study B; in 1,740 side branches from 465 patients, 122 ostial stenotic lesions were found (7.0%). Multivariate logistic regression analysis revealed diabetes mellitus and age as independent contributors to development of ostial stenosis (Table).

Conclusions

Side branch stenosis developed less frequently in middle and distal segments, where stronger ventricular wall motion reinforces bending and stretching motion and tortuosity of arteries. This fact indicates that those characteristics may prevent developing atherosclerosis through increasing shear stress. On the other hand, diabetes mellitus strongly contributes to the development of ostial stenosis. Thus, the developing mechanism of atherosclerotic lesion in side branch on the ventricular free wall differs by the location of lesion.

Funding Acknowledgement

Type of funding source: None

Radiation-induced segregation in a ceramic

Radiation-induced segregation is well known in metals, but has been rarely studied in ceramics. We discover that radiation can induce notable segregation of one of the constituent elements to grain boundaries in a ceramic, despite the fact that the ceramic forms a line compound and therefore has a strong thermodynamic driving force to resist off-stoichiometry. Specifically, irradiation of silicon carbide at 300 °C leads to carbon enrichment near grain boundaries, whereas the enrichment diminishes for irradiation at 600 °C. The temperature dependence of this radiation-induced segregation is different from that shown in metallic systems. Using an ab initio informed rate theory model, we demonstrate that this difference is introduced by the unique defect energy landscapes present in the covalent system. Additionally, we discover that grain boundaries in unirradiated silicon carbide grown by chemical vapour deposition are intrinsically carbon-depleted. The inherent grain boundary chemistry and its evolution under radiation are both critical for understanding the many properties of ceramics associated with grain boundaries.

Plate coverage predicts failure for volarly unstable distal radius fractures with volar lunate facet fragments

INTRODUCTION

Loss of reduction after operative fixation of volarly unstable distal radius fractures with a volar lunate facet fragment (VLF) is considered problematic because it results in carpal subluxation or dislocation and subsequent impaired function. We hypothesized that the indicator of loss of reduction of the VLF after fixation is plate coverage of the bony fragment. We investigated the relationship between the plate coverage of the VLF and loss of reduction after fixation, and calculated the plate coverage that was associated with failure of fixation of the VLF.

MATERIALS AND METHODS

We conducted a retrospective review. We included patients with surgically treated volarly unstable distal radius fractures with VLF with a volar locking plate who had a minimum follow-up of 6 months. A total of 33 patients (35 wrists) met criteria for inclusion into the study. The patients were divided into a displacement group and a non-displacement group. We calculated and compared longitudinal dimension and plate coverage of the VLF between the two groups to reveal the risk factors for loss of reduction.

RESULTS

At final follow-up, 25 fractures maintained radiographic alignment and 10 (28.6%) lost reduction. Univariate analysis between the two groups showed that plate coverage against the transverse and longitudinal dimension of the VLF was correlated with loss of reduction after operative fixation. In multivariate logistic regression analysis, only plate coverage against the longitudinal dimension of the VLF remained a significant predictor of failure. With 64.7% as the cut-off point for plate coverage against the longitudinal dimension of the VLF, the sensitivity and specificity of the prediction were 96% and 80%, respectively.

CONCLUSION

The predictor of loss of reduction after fixation of volarly unstable distal radius fractures with a VLF was plate coverage against the longitudinal dimension of the VLF.

Pelvic mobility before and after total hip arthroplasty

BACKGROUND

Pre-operative evaluation of pelvic motion using the sacral slope (SS) has been proposed for risk assessment of dislocation after total hip arthroplasty (THA). The purposes of this study were to elucidate the statistical characteristics of pre-operative and post-operative pelvic mobility and investigate the relationship between pre-operative spinopelvic factors and post-operative pelvic mobility.

METHODS

Eighty-six patients with osteoarthritis were assessed. The parameters evaluated were lumbar lordosis angle and the SS in the standing and sitting preo-peratively and post-operatively. The pelvic mobility was defined as the difference in the SS between standing and sitting. The presence of osteoarthritis in the contralateral hip, spondylolisthesis, vertebral compression fracture and lumbar scoliosis was investigated.

RESULTS

The median (interquartile range) pre-operative and post-operative pelvic mobility was 19.0 (13.75-27.0) and 16.0 (10.0-25.25), respectively, with significant difference. The pre-operative SS while standing and pre-operative pelvic mobility were associated with post-operative pelvic mobility (r = 0.409, P < 0.05 and r = 0.533, P < 0.05). The multivariate linear regression analysis showed that the following factors contributed to post-operative pelvic mobility: incidence of osteoarthritis in the contralateral hip, lumbar scoliosis, pre-operative SS while standing and pre-operative SS while sitting.

CONCLUSION

The pre-operative and post-operative pelvic mobility is not equal and ranges widely among patients. In addition to assessment of pre-operative pelvic mobility, other pre-operative spinopelvic factors may also influence post-operative pelvic mobility, such as the SS while standing and sitting, the condition of the contralateral hip and the presence of scoliosis. Risk assessment for dislocation using these pre-operative factors may be useful before THA.

Positive-Parity Linear-Chain Molecular Band in ^{16}C

An inelastic excitation and cluster-decay experiment ^{2}H(^{16}C,^{4}He+^{12}Be or ^{6}He+^{10}Be)^{2}H was carried out to investigate the linear-chain clustering structure in neutron-rich ^{16}C. For the first time, decay paths from the ^{16}C resonances to various states of the final nuclei were determined, thanks to the well-resolved Q-value spectra obtained from the threefold coincident measurement. The close-threshold resonance at 16.5 MeV is assigned as the J^{π}=0^{+} band head of the predicted positive-parity linear-chain molecular band with (3/2_{π}^{-})^{2}(1/2_{σ}^{-})^{2} configuration, according to the associated angular correlation and decay analysis. Other members of this band were found at 17.3, 19.4, and 21.6 MeV based on their selective decay properties, being consistent with the theoretical predictions. Another intriguing high-lying state was observed at 27.2 MeV which decays almost exclusively to ^{6}He+^{10}Be(∼6  MeV) final channel, corresponding well to another predicted linear-chain structure with the pure σ-bond configuration.

Does a fluoro-assisted direct anterior approach for total hip arthroplasty pose an excessive risk of radiation exposure to the surgeon?

Introduction: Intraoperative fluoroscopy can be easily used because patients are placed in the supine position during total hip arthroplasty via direct anterior approach (DAA-THA) to reduce complications. However, the cumulative level of radiation exposure by intraoperative fluoroscopy increases as the annual number of cases increases, increasing the risk of influencing the health of both the patients and medical workers. The objective of the study was to compare the radiation exposure time of DAA-THA with osteosynthesis and to determine if the level of radiation exposure exceeded safety limits. Material and methods: DAA-THA was performed in 313 patients between January 2016 and July 2018 and 60 patients with proximal femoral fracture were treated with osteosynthesis. The intraoperative fluoroscopy time was retrospectively surveyed and compared between these two groups. A total of eight surgeons operated DAA-THA employing the same procedure using a traction table. A total of nine surgeons operated osteosynthesis and fluoroscopy was appropriately used during reduction and implant insertion. Results: The mean operative time of DAA-THA was 103.3 min and that of osteosynthesis was 83.3 min, showing a significant difference (p < 0.05). The mean intraoperative fluoroscopy time was 0.83 min (SD ± 0.68) in DAA-THA and 8.91 min (SD ± 8.34) in osteosynthesis showing a significant difference (p < 0.05). Conclusions: The intraoperative exposure level was significantly lower and the fluoroscopy time was significantly shorter in DAA-THA than in osteosynthesis for proximal femoral fracture. It was clarified that the annual cumulative radiation exposure level in DAA-THA does not exceed the tissue dose limit.

Posterior versus direct anterior approach in revision hip arthroplasty using Kerboull-type plate

Introduction: The purpose of this study was to investigate revision with a Kerboull-type plate through the posterior approach (PA) and direct anterior approach (DAA) and compare the clinical outcome.

Subjects and methods: Fifty-four patients (56 hip joints) underwent revision surgery in which acetabular reconstruction was performed concomitantly using the Kerboull-type plate and allogeneic bone. Revision surgery through DAA was performed in 21 hip joints and these were compared with 34 hip joints treated through PA. There was no significant difference in the patient demographics between the DAA and PA.

Results: There was no significant difference between the operative times in the DAA and PA groups (203.2 ± 43.5 and 211.7 ± 41.8 min). There was a significant difference between the intraoperative blood loss in the DAA and PA groups (503.9 ± 223.7 mL and 703.8 ± 329.6 mL, respectively, p < 0.05). There was no significant difference between the modified Harris Hip Score in the DAA and the PA groups. The loosening of the acetabular component was observed in four cases (11.8%) in the PA group. In the DAA and PA groups, the 5-year survival rates were 100 and 85.7%, respectively. Recurrent dislocation of the hip was observed in six cases (one case in the DAA group (4.8%) and five cases in the PA group (14.7%)).

Conclusions: It was verified that the difference in the surgical approach of acetabular reconstruction concomitantly using the Kerboull-type plate and allogeneic bone graft influenced the postoperative outcome.

Is actual surgical experience reflected in virtual reality simulation surgery for a femoral neck fracture?

INTRODUCTION

A virtual reality simulator developed for orthopaedic and trauma surgical training has been introduced. However, it is unclear whether the experiences of actual surgery are reflected in virtual reality simulation surgery (VRSS) using a simulator. The aim of this study is to investigate whether the results in VRSS differ between a trauma expert and a trauma novice.

METHODS

In Group A (expert), there are ten orthopaedic trauma surgeons and in Group B (novice) ten residents within 2 years after medical school graduation. VRSS for a femoral neck fracture using Hansson hook-pins (Test 1) and Hansson twin hook plate (Test 2) was performed. The parameters evaluated were total procedure time (s), fluoroscopy time (s), number of times X-ray was used (defined by the number of times the foot pedal was used), number of retries in guide placement, and final implant position.

RESULTS

In Test 1, the averages of four parameters (distance to posterior cortex (p = 0.009), distal pin distance above lesser trochanter (p = 0.015), distal pin hook angular error (p = 0.004), and distal pin tip distance to centre (lateral) (p = 0.015)) were significantly different between Groups A and B. In Test 2, no parameters in a mean were significantly different between groups, but seven parameters in a variance (guide wire distance to joint surface (p = 0.0191), twin hook length outside barrel (p = 0.011), twin hook tip distance to centre (lateral) (p = 0.042), twin hook distance to centre of lateral cortex (lateral) (p = 0.016), plate end alignment error (lateral) (p = 0.027), guide wire angle with lateral cortex (front) (p = 0.024), and 3.2-mm drill outside cortex (p = 0.000)) were significantly different between groups. In Test 1, Group B showed significantly longer fluoroscopy time than Group A (p = 0.044). In Test 2, Group B showed significantly fewer instances of X-ray use than Group A (p = 0.046).

CONCLUSIONS

Our study showed that the experiences of actual surgery are reflected in the result of VRSS using the simulator.

Longitudinal changes in 18 F-THK5351 positron emission tomography in corticobasal syndrome

BACKGROUND AND PURPOSE

Corticobasal syndrome (CBS) is pathologically characterized by tau deposits in neuronal and glial cells and by reactive astrogliosis. In several neurodegenerative disorders, ¹⁸ F-THK5351 has been observed to bind to reactive astrocytes expressing monoamine oxidase B. In this study, the aim was to investigate the progression of disease-related pathology in the brains of patients with CBS using positron emission tomography with ¹⁸ F-THK5351.

METHODS

Baseline and 1-year follow-up imaging were acquired using magnetic resonance imaging and positron emission tomography with ¹⁸ F-THK5351 in 10 subjects: five patients with CBS and five age-matched normal controls (NCs).

RESULTS

The 1-year follow-up scan images revealed that ¹⁸ F-THK5351 retention had significantly increased in the superior parietal gyrus of the patients with CBS compared with the NCs. The median increases in ¹⁸ F-THK5351 accumulation in the patients with CBS were 6.53% in the superior parietal gyrus, 4.34% in the precentral gyrus and 4.33% in the postcentral gyrus. In contrast, there was no significant increase in the regional ¹⁸ F-THK5351 retention in the NCs.

CONCLUSIONS

Longitudinal increases in ¹⁸ F-THK5351 binding can be detected over a short interval in the cortical sites of patients with CBS. A monoamine oxidase B binding radiotracer could be useful in monitoring the progression of astrogliosis in CBS.

Abstract P6-17-06: Characterization, monitoring and management of interstitial lung disease in patients with metastatic breast cancer: Analysis of data available from multiple studies of DS-8201a, a HER2-targeted antibody drug conjugate with a topoisomerase I inhibitor payload

Background: Several classes of anti-cancer agents including certain immunotherapies, systemic chemotherapies, and targeted therapies including trastuzumab and T-DM1 increase the risk of interstitial lung disease (ILD) and fatal cases have been reported. For DS-8201a, interim efficacy and safety analyses of available data established a final recommended dose of 5.4 mg/kg IV q3wk in advanced HER2-positive breast cancer (BC). Based on preliminary clinical results, ILD was identified as an important risk for DS-8201a. A robust monitoring and management plan was established across all studies and an international, independent ILD adjudication committee (AC) reviews the cases reported as ILD on an ongoing basis.

Methods: All subjects (sbj) who received ≥1 dose of DS-8201a across 7 ongoing studies were included in this analysis. Reported ILD (standardized MedDRA Query terms) included the terms ILD, pneumonitis, and organizing pneumonia. ILD frequencies were calculated based on investigator's assessment and after adjudication. The analysis of potential risk factors associated with ILD is ongoing.

Results: As of 21 June 2018, 448 sbj received ≥1 dose of DS-8201a across multiple tumor types, including BC. Of the 321 sbj with BC, 173 (53.9%) were from Japan, 103 (32.1%) from the US, and 45 (14.0%) from 6 other countries (Spain, South Korea, Taiwan, Belgium, France, and Italy). These sbj received 1 of 7 doses of DS-8201a (0.8 mg/kg: 3 sbjs, 1.6 mg/kg: 1 sbj, 3.2 mg/kg: 3 sbjs, 5.4 mg/kg: 111 sbjs, 6.4 mg/kg: 178 sbj, 7.4 mg/kg: 20 sbj, 8.0 mg/kg: 5 sbj). Overall, 44 cases of potential ILD were reported by the investigators across all tumor types (44/448, 9.8%; Grade ≥3 10/448, 2.2%). In sbj with BC who received 5.4 mg/kg, any grade and Grade ≥3 investigator-reported ILD were 7.2% (8/111) and 0.9% (1/111), respectively. The ILD AC assessed 30 of 44 cases; 22 were considered drug-related ILD, 4 were ILD but not drug-related, and 4 were found not to be ILD. For adjudicated drug-related ILD cases, the median time to onset was 159 (range; 46-591) days from the time of first dose.

  Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 All Grades All tumors, All doses (N=448)      Investigator-reported20 (4.5)14 (3.1)4 (0.9)1 (0.2)5 (1.1)44 (9.8)Cases adjudicated13840530Adjudicated as drug-related ILD9 (2.0)6 (1.3)3 (0.7)04 (0.9)22 (4.9) BC, All doses (N=321)      Investigator-reported17 (5.3)11 (3.4)3 (0.9)1 (0.3)4 (1.2)36 (11.2)Cases adjudicated11830426Adjudicated as drug-related ILD8 (2.5)6 (1.9)3 (0.9)04 (1.2)21 (6.5) BC, 5.4 mg/kg (N=111)      Investigator-reported4 (3.6)3 (2.7)001 (0.9)8 (7.2)Cases adjudicated120014Adjudicated as drug-related ILD00001 (0.9)1 (0.9)n (%), except where noted

Conclusions: These analyses confirm that ILD is an important identified risk for DS-8201a. Further analyses are ongoing to better understand the potential risk factors associated with the incidence of on-treatment ILD. When ILD is suspected, early diagnosis through appropriate imaging, laboratory tests, and pulmonary consultation as well as prompt management with steroids are recommended.

Citation Format: Powell CA, Camidge DR, Gemma A, Kusumoto M, Baba T, Kuwano K, Bankier A, Kiura K, Tamura K, Modi S, Tsurutani J, Doi T, Iwata H, Krop IE, Zhang L, Jasmeet S, Saito K, Shahidi J, Yver A, Takahashi S. Characterization, monitoring and management of interstitial lung disease in patients with metastatic breast cancer: Analysis of data available from multiple studies of DS-8201a, a HER2-targeted antibody drug conjugate with a topoisomerase I inhibitor payload [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-06.

Direct actions of androgen, estrogen and anti-Müllerian hormone on primate secondary follicle development in the absence of FSH in vitro

STUDY QUESTION

What are effects of androgen, estrogen and anti-Müllerian hormone (AMH), independent of FSH action, on the development and function of primate follicles from the preantral to small antral stage in vitro?

SUMMARY ANSWER

Androgen and estrogen, but not AMH, promote follicle survival and growth in vitro, in the absence of FSH. However, their growth-promoting effects are limited to the preantral to early antral stage.

WHAT IS KNOWN ALREADY

FSH supports primate preantral follicle development in vitro. Androgen and estrogen augment follicle survival and growth in the presence of FSH during culture.

STUDY DESIGN SIZE, DURATION

Nonhuman primate model; randomized, control versus treatment groups. Rhesus macaque (n = 6) secondary follicles (n = 24 per animal per treatment group) were cultured for 5 weeks.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Follicles were encapsulated in 0.25% (w/v) alginate and cultured individually in modified alpha minimum essential media with (i) FSH (1 ng/ml; control), (ii) no FSH, (iii) no FSH + estradiol (E2; 100 pg/ml)/dihydrotestosterone (DHT; 50 ng/ml) and (iv) no FSH + AMH (50 ng/ml). In a second experiment, follicles were cultured with (i) FSH (1 ng/ml), (ii) no FSH, (iii) no FSH + E2 (1 ng/ml), (iv) no FSH + DHT (50 ng/ml) and (v) no FSH + E2/DHT. Follicle survival, antrum formation and growth pattern were evaluated. Progesterone (P4), E2 and AMH concentrations in culture media were measured.

MAIN RESULTS AND THE ROLE OF CHANCE

In the first experiment, FSH deprivation significantly decreased (P < 0.05) follicle survival rates in the no FSH group (16 ± 5%), compared to CTRL (66 ± 9%). E2/DHT (49 ± 5%), but not AMH (27 ± 8%), restored follicle survival rate to the CTRL level. Similarly, antrum formation rates were higher (P < 0.05) in CTRL (56 ± 6%) and E2/DHT groups (54 ± 14%), compared to no FSH (0 ± 0%) and AMH (11 ± 11%) groups. However, follicle growth rate after antrum formation and follicle diameter at week 5 was reduced (P < 0.05) in the E2/DHT group (405 ± 25 μm), compared to CTRL (522 ± 29 μm). Indeed, the proportion of fast-grow follicles at week 5 was higher in CTRL (29% ± 5), compared to E2/DHT group (10 ± 3%). No fast-grow follicles were observed in no FSH and AMH groups. AMH levels at week 3 remained similar in all groups. However, media concentrations of P4 and E2 at week 5 were lower (P < 0.05, undetectable) in no FSH, E2/DHT and AMH groups, compared to CTRL (P4 = 93 ± 10 ng/ml; E2 = 4 ± 1 ng/ml). In the second experiment, FSH depletion diminished follicle survival rate (66 ± 8% in control versus 45 ± 9% in no FSH, P = 0.034). E2 plus DHT (31.5 ± 11%) or DHT alone (69 ± 9%) restored follicle survival rate to the control (FSH) level as expected. Also, E2 plus DHT or DHT alone improved antrum formation rate. However, in the absence of FSH, E2 plus DHT or DHT alone did not support growth, in terms of follicle diameter, or steroid (P4 or E2) production after the antral stage.

LIMITATIONS REASONS FOR CAUTION

This study is limited to in vitro effects of E2, DHT and AMH during the interval from the secondary to small antral stage of macaque follicular development. In addition, the primate follicle pool is heterogeneous and differs between animals; therefore, even though only secondary follicles were selected, follicle growth and developmental outcomes might differ from one animal to another.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides novel information on the possible actions of estrogen and androgen during early follicular development in primates. Our results suggest that sequential exposure of preantral follicles to local factors, e.g. E2 and DHT, followed by gonadotropin once the follicle reaches the antral stage, may better mimic primate folliculogenesis in vivo.

STUDY FUNDING/COMPETING INTEREST(S)

Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Center for Translational Research on Reproduction and Infertility 5P50HD071836, and the NIH Primate Centers Program 8P510D011092. There are no conflicts of interest.

Preoperative ultrasound to identify distribution of the lateral femoral cutaneous nerve in total hip arthroplasty using the direct anterior approach

Introduction: Recently, the branching pattern of the lateral femoral cutaneous nerve (LFCN) named Fan type has been reported that LFCN injury cannot be avoided in surgical dissections that use the direct anterior approach to the hip joint in the cadaveric study. We hypothesized that the Fan type can be identified by ultrasound The aim of this study was to investigate whether LFCN injury occurs in DAA-THA in cases identified as the Fan type based on preoperative ultrasound of the proximal femur.

Methods: Ultrasonography of the proximal femur on the surgical side was performed before surgery and the LFCN distribution was judged as the Fan type or Non-Fan type. A self-reported questionnaire was sent to the patients at two months after surgery, and the presence or absence of LFCN injury was prospectively surveyed.

Results: After application of exclusion criteria, 45 hips were included. LFCN injury was observed after surgery in 9 of the 10 patients judged as the Fan type based on the ultrasound of the proximal femur (positive predictive value: 90%), and no LFCN disorder was actually observed in 25 of the 26 patients judged as Non-Fan type (specificity: 96.2%).

Conclusions: To prevent injury of the LFCN in patients judged as the Fan type on the ultrasound test before surgery, the risk of direct injury of the LFCN may be reduced through the approach in which an incision is made in the fascia which is opposite to the radial spreading, i.e., between the sartorius and tensor fasciae latae muscles or slightly medial from it.

Total hip arthroplasty via the direct anterior approach with a dual mobility cup for displaced femoral neck fracture in patients with a high risk of dislocation

Introduction: Although total hip arthroplasty (THA) is superior to bipolar hemiarthroplasty (BHA) for displaced femoral neck fracture in terms of hip pain, function and reoperation rate, THA has a higher rate of dislocation. The direct anterior approach (DAA) and a dual mobility cup (DMC) are associated with lower rates of dislocation. The aim of this study was to investigate the outcomes of THA compared with BHA, and in those patients who had a THA we investigated those with a DMC (DMC-THA) and compared them with those had a single conventional cup (Single cup-THA).

Materials: A total of 89 patients living independently were included between 2009 and 2015. We assessed patient characteristics, peri- and post-operative outcomes, walking ability and one-year mortality. Adjusted odds ratios (Adjusted ORs) were estimated for decrease of walking ability and one-year mortality using a logistic regression model with adjustment for potential confounders such as age, neuromuscular diseases with weakness, duration of surgery, perioperative blood loss and preoperative walking ability.

Results: BHA (20 patients) versus THA (69 patients): There was no significant difference in the walking ability in either group. Multivariable logistic regression analysis demonstrated a significant association with one-year mortality in both groups [THA Adjusted ORs 0.088 (95% CI 0.0007–0.69); p = 0.020]. Single cup-THA (36 patients) versus DMC-THA (33 patients): The DMC-THA group had significantly greater age and more patients with neuromuscular diseases with weakness compared with the Single cup-THA group. Multivariable logistic regression analysis demonstrated no significant difference in the decrease of walking ability and in the one-year mortality between the groups. There were no post operative dislocations in any group.

Discussion: THA via the DAA is one of the best treatments for displaced femoral neck fracture with a low risk of dislocation. THA via the DAA with a DMC is a safe and effective treatment for the patients with a high risk of dislocation.