Four stem fractures in a 12-year follow-up study of 9,135 patients with Exeter hip stems at seven teaching facilities in Japan.

BACKGROUND: Although excellent long-term results have been reported for the Exeter stem, stem fracture is recognized as a rare complication. However, there have been no reports on the incidence and risk factors for stem fractures based on detailed population information. This study aimed to clarify the incidence of Exeter hip stem fracture based on detailed population information from seven Exeter stem teaching centers in Japan and to examine the risk factors for stem fracture. METHODS: A total of 8,499 primary total hip arthroplasties (THA) and 636 revision hip arthroplasties (revisions) performed at seven Exeter teaching hospitals between 1999 and 2021 were included and retrospectively investigated based on medical records. RESULTS: Stem fractures were identified in two primary THA (fracture rate: 0.02%) and two revision THA (fracture rate: 0.21%) cases. The stem length was ≤125 mm in three out of these four cases. Revision and 30 stem were the risk factors for stem fractures. Weight and body mass index (BMI) were not significantly associated with the occurrence of stem fractures. CONCLUSIONS: In Western countries, the incidence of Exeter stem fractures is reportedly 0.017-0.15% for primary THA and 0.99-1.21% for revision THA. In this study, the incidence of primary THA was 0.02%, which is similar to the lowest reported rate, whereas the incidence of revision THA was 0.21%, which is lower than that reported in previous studies. Revision surgery had the same risk factors as those reported in the West-namely, stem length ≤125 mm (except for the 30 stem) and BMI, which were not risk factors in Japanese patients.

Multi-center study of use of the Exeter stem in Japan: a 10-year follow-up report.

PURPOSE: Since the introduction of the Exeter stem for clinical use in Japan in 1996, the number of stems used has continued to rise owing to its favorable results. We investigated the outcomes of patients who had previously undergone total hip arthroplasty with the Exeter stem in Japan with a 10-year + follow-up period. METHODS: This retrospective cohort study used clinical and radiographic data of 682 cases of primary total hip arthroplasty performed using the Exeter stem. RESULTS: The mean postoperative follow-up period was 13.3 years. Femoral-side revision was required in 14 hips, with no cases of aseptic stem loosening-associated revision observed. Kaplan-Meier survival analysis predicted 97.3% 15-year survival when revision for any reason was used as the endpoint. CONCLUSION: The obtained findings suggested the excellent long-term stability of the Exeter stem for primary total hip arthroplasty in Japan.

Impaction bone grafting for femoral revision hip arthroplasty with Exeter stem in Japan: An extended 10- to 15-year stem survival analysis of the previously reported series.

BACKGROUND: Femoral impaction bone grafting (IBG) was introduced in the late 1990s in Japan and has gradually become recognized as a useful option for femoral revision. The aim of the present study was to retrospectively analyze 10 to 15 years of clinical results of femoral revision arthroplasties of IBG using Exeter stem performed by experienced Japanese surgeons. METHODS: We investigated radiographic and clinical records more than 2 years after surgery in 99 hips of 93 patients. The average age was 66.3 years (36-84 years) and the average follow-up period was 11 years (2-23 years and 8 months). Merle d'Aubigné and Postel hip score was used for clinical assessment, and re-operations for any reason were recorded. The survival curve was estimated using Kaplan-Meier method. RESULTS: The mean Merle d'Aubigné and Postel hip score improved from 9.0 points to 14.5 points at the final follow-up. Re-operations were undertaken in 15 hips of 14 patients for aseptic acetabular component loosening (n = 1 hip), recurrent dislocation (n = 2 hips), infection (n = 4 hips), and periprosthetic femoral fracture (n = 8 hips). The survival rates at 10 and 15 years after operation were 87.1% and 81.1% with any type of re-operation as the endpoint, 92.2% and 92.2% with stem removal or exchange as the endpoint, 94.9% and 88.1% with re-operation for periprosthetic femoral fracture as the endpoint, and 99.0% and 99.0% with re-operation for aseptic stem loosening as the endpoint, respectively. CONCLUSIONS: The present study showed encouraging results of femoral IBG over 10 years by experienced surgeons in Japan. Although femoral IBG is recognized as a technically complex procedure, survivorship of the stem is excellent, with a 15-year stem survival rate of 99.0% at the end point of aseptic loosening.

Multi-centre study of cement-in-cement and in-cement femoral revision total hip arthroplasty using polished, stainless steel stems.

BACKGROUND: Exposure of the acetabular component during revision total hip arthroplasty is often difficult and stems are often difficult to remove. Polished and tapered cemented stems are easily removed and can be easily reconstructed by either cement-in-cement or in-cement technique. This study was a retrospective review of the medium-term outcomes of revision total hip arthroplasty conducted with the Exeter stem fixed by cement-in-cement or in-cement method in four institutions. METHODS: This study included hips (n = 103) reconstructed by cement-in-cement or in-cement technique on the femoral side during revision total hip arthroplasty in four institutions between 2003 and 2015. The mean age at surgery was 71.1 years (range, 43-86 years), and the mean follow-up period was 5.6 years (range, 0-13 years). RESULTS: Revision arthroplasty was required for acetabular component complications in 69 hips, for dislocation in 25, for infection in eight, and for stem fracture in one hip. Re-revision was required in 10 hips for: infection (n = 6), acetabular component complications (n = 3), and dislocation (n = 1). No radiographic loosening, cement fractures, or osteolysis of the femoral components were observed. Ten-year survival rate was 99% with the endpoint of femoral revision surgery, and 100% with the endpoint of femoral aseptic loosening. CONCLUSIONS: The medium-term outcomes of revision total hip arthroplasty on the femoral side conducted using the cement-in-cement or in-cement technique were favourable, with no cases of aseptic loosening. As long as the bone-cement interface remains robust, there is no need to remove all the cement, and the cement-in-cement or in-cement technique should be used for reconstruction.

Th Balance-Related Host Genetic Background Affects the Therapeutic Effects of Combining Carbon-Ion Radiation Therapy With Dendritic Cell Immunotherapy.

PURPOSE: The goal of this study is to clarify the underlying mechanisms of metastasis suppression by carbon-ion radiotherapy combined with immature dendritic cell immunotherapy (CiDC), which was shown previously to suppress pulmonary metastasis in an NR-S1-bearing C3H/He mouse model. METHODS AND MATERIALS: Mouse carcinoma cell lines (LLC, LM8, Colon-26, and Colon-26MGS) were grafted into the right hind paw of syngeneic mice (C57BL/6J, C3H/He, and BALB/c). Seven days later, the tumors on the mice were locally irradiated with carbon ions (290 MeV/n, 6 cm spread-out Bragg peak, 1 or 2 Gy). At 1.5 days after irradiation, bone marrow-derived immature dendritic cells (iDCs) were administrated intravenously into a subset of the mice. The number of lung metastases was evaluated within 3 weeks after irradiation. In vitro-cultured cancer cells were irradiated with carbon ions (290 MeV/n, mono-energy, LET approximately 70-80 keV/µm), and then cocultured with iDCs for 3 days to determine the DC maturation. RESULTS: CiDC effectively repressed distant lung metastases in cancer cell (LLC and LM8)-bearing C57BL/6J and C3H/He mouse models. However, Colon-26- and Colon-26MGS-bearing BALB/c models did not show enhancement of metastasis suppression by combination treatment. This result was evaluated further by comparing LM8-bearing C3H/He and LLC-bearing C57BL/6J models with a Colon-26-bearing BALB/c model. In vitro coculture assays demonstrated that all irradiated cell lines were able to activate C3H/He- or C57BL/6J-derived iDCs into mature DCs, but not BALB/c-derived iDCs. CONCLUSIONS: The genetic background of the host could have a strong effect on the potency of combination therapy. Future animal and clinical testing should evaluate host genetic factors when evaluating treatment efficacy.

Characterization of a Novel Murine Colon Carcinoma Subline with High-Metastatic Activity Established by In Vivo Selection Method.

The establishment of cancer cell lines, which have different metastatic abilities compared with the parental cell, is considered as an effective approach to investigate mechanisms of metastasis. A highly metastatic potential mouse colon cancer cell subline, Colon-26MGS, was derived from the parental cell line Colon-26 by in vivo selection using continuous subcutaneous implanting to immunocompetent mice. To clarify the mechanisms involved in the enhancement of metastasis, morphological characteristics, cell proliferation, and gene expression profiles were compared between Colon-26MGS and the parental cell. Colon-26MGS showed over 10 times higher metastatic ability compared with the parental cell, but there were no differences in morphological characteristics and in vitro proliferation rates. In addition, the Colon-26MGS-bearing mice exhibited no marked change of splenocyte population and lung pre-metastatic niche with tumor-free mice, but there were significant differences compared to Colon-26-bearing mice. RNA-seq analyses indicated that immune costimulatory molecules were significantly up-regulated in Colon-26MGS. These results suggest that Colon-26MGS showed not only higher metastatic activity, but also less induction property of host immune response compared to parental Colon-26. Colon-26MGS has proven to be a novel useful tool for studying multiple mechanisms involving metastasis enhancement.

Peri-prosthetic bone remodeling and change in bone mineral density in the femur after cemented polished tapered stem implantation.

OBJECTIVE: We examined longitudinal changes in bone mineral density (BMD) around the femur for 5 years after total hip arthroplasty (THA) using cemented collarless polished double-tapered stem implantation and investigated the influence of BMD changes on radiological remodeling of the femur. MATERIALS AND METHODS: Sixty hips from 56 patients who underwent cemented THA with a collarless polished double-tapered stem were included. BMD was measured 2 weeks postoperatively (baseline), 3 months, 6 months, 1 year and annually thereafter until 5 years after surgery using dual-energy X-ray absorptiometry on the lumbar spine and proximal femur of the operated side according to the Gruen's zone classification. We analyzed predictable factors for BMD preservation in the proximal femur and compared radiological remodeling of the femur and changes in BMD. RESULTS: BMD at 5 years in zone 7 decreased less than 10%, whereas BMD in zone 1 increased to over the baseline (+ 1.9%). Multiple linear regression analyses revealed that body weight was a predictor for positive BMD change in the proximal femur. The frequency of radiolucency of the femur was significantly lower in patients who exhibited an increase in BMD at 5 years compared with BMD at 2 weeks in zone 7. CONCLUSION: BMD preservation of the proximal femur after cemented collarless polished double-tapered stem implantation was more effective in heavier patients. Furthermore, the frequency of radiolucency around the stem was significantly lower in patients who exceeded 100% of the baseline BMD in zone 7 at 5 years.

Effect of inoculum size on single-cell oil production from glucose and xylose using oleaginous yeast Lipomyces starkeyi.

Oleaginous microbes can convert substrates such as carbon dioxide, sugars, and organic acids to single-cell oils (SCOs). Among the oleaginous microorganisms, Lipomyces starkeyi is a particularly well-suited host given its impressive native abilities, including the capability to utilize a wide variety of carbon sources. In this work, the potential of L. starkeyi NBRC10381 to produce SCOs in a synthetically nitrogen-limited mineral medium (-NMM) was investigated by differing the inoculum size using glucose and/or xylose as a carbon source. Fermentation using glucose and xylose as mixed carbon sources generated the highest production of biomass at 40.8 g/L, and achieved a lipid content of 84.9% (w/w). When either glucose or xylose was used separately, the totals for achieved lipid content were 79.6% (w/w) and 85.1% (w/w), respectively. However, biomass production was higher for glucose than for xylose (30.3 vs. 28.7 g/L, respectively). This study describes the first simultaneous achievement of higher levels of cell mass and lipid production using glucose and/or xylose as the carbon sources in different inoculum sizes.

Biochemical Gas Sensors (Biosniffers) Using Forward and Reverse Reactions of Secondary Alcohol Dehydrogenase for Breath Isopropanol and Acetone as Potential Volatile Biomarkers of Diabetes Mellitus.

This study describes two biosniffers to determine breath acetone and isopropanol (IPA) levels and applies them for breath measurement in healthy subjects and diabetic patients. Secondary alcohol dehydrogenase (S-ADH) can reduce acetone and oxidize nicotinamide adenine dinucleotide (NADH to NAD+) in a weak acid environment. NADH can be excited by 340 nm excitation lights and subsequently emit 490 nm fluorescence. Therefore, acetone can be measured by the decrease in NADH fluorescence intensity. S-ADH can also oxidize IPA and reduce NAD+ to NADH when it is in an alkaline environment. Thus, IPA can be detected by the increase of fluorescence. The developed biosniffers show rapid response, high sensitivity and high selectivity. The breath acetone and IPA analysis in healthy subjects shows that the mean values were 750.0 ± 434.4 ppb and 15.4 ± 11.3 ppb. Both acetone and IPA did not show a statistical difference among different genders and ages. The breath acetone analysis for diabetic patients shows a mean value of 1207.7 ± 689.5 ppb, which was higher than that of healthy subjects (p < 1 × 10-6). In particularly, type-1 diabetic (T1D) patients exhaled a much higher concentration of acetone than type-2 diabetic (T2D) patients (p < 0.01). The breath IPA also had a higher concentration in diabetic patients (23.1 ± 20.1 ppb, p < 0.01), but only T2D patients presented a statistical difference (23.9 ± 21.3 ppb, p < 0.01). These findings are worthwhile in the study of breath biomarkers for diabetes mellitus diagnosis. Additionally, the developed biosniffers provide a new technique for volatolomics research.

Proximal femoral reconstruction with impaction bone grafting and circumferential metal mesh.

INTRODUCTION: Impaction bone grafting (IBG) using a circumferential metal mesh is one of the options that allow restoration of the femoral bone stock and stability of the implant in revision hip arthroplasty. Here we examine the clinical and radiographic outcome of this procedure using a cemented stem, including experimental analysis of the initial stability of mesh-grafted bone-cemented stem complexes. METHODS: We retrospectively reviewed six hips (six patients) that had undergone femoral revisions with a circumferential metal mesh, impacted bone allografts, and a cemented stem. The mean follow-up period was 3.9 years (range 2.4-4.8 years). Hip joint function was evaluated using the Japanese Orthopaedic Association hip score, and radiographic changes were determined from radiographs. The initial resistance of mesh-grafted bone-cemented stem complexes to axial and rotational force was measured in a composite bone model with various segmental losses of the proximal femur. RESULTS: The hip score improved from 50 (range 10-84) preoperatively to a mean of 74 (range 67-88) at the final follow-up. The overall implant survival rate was 100 % at five years when radiological loosening or revision for any reason was used as the endpoint. No stem subsided more than 3 mm vertically within one year after implantation. Computed tomography showed reconstitution of the femoral canal in a metal mesh. In mechanical analyses, there was no relationship between IBG reconstruction rates under axial compression and stem subsidence or failure load. In contrast, under rotational load, the rotation angles of the stem to the stainless steel mesh were strongly affected by the IBG reconstruction rate. CONCLUSIONS: The short-term results show good outcomes for reconstruction of proximal bone loss with IBG and a circumferential mesh. The procedure should be applied in cases where the circumferential proximal bone loss is less than half the length of the implanted stem.

Impaction bone grafting for femoral revision hip arthroplasty with Exeter Universal stem in Japan.

OBJECTIVES: The purpose of the present study was to analyze the retrospective clinical and radiographic results of femoral revision arthroplasties with impaction bone grafting performed by experienced Japanese surgeons. PATIENTS AND METHODS: We investigated the radiographic and clinical records more than 2 years after the surgery in 99 hips of 93 patients. The average age was 66.3 years (36-84 years) and the average follow-up period was 5.2 years (2-13 years). The Merle d'Aubigné and Postel hip score was used for clinical assessment, and peri-operative fractures were recorded. The survival curve was estimated using Kaplan-Meier method. RESULTS: The mean Merle d'Aubigné and Postel hip score improved from 9.0 points to 15.2 points at the final follow-up. Augmentations for segmental defect of femoral cortices were undertaken in 55 hips. Metal or strut allograft plates were applied to 9 hips and 21 hips, respectively. Intra-operative fractures or perforations occurred in 20 hips. Re-operations of the femur were undertaken in nine hips including five post-operative femoral fractures. More than 5 mm of subsidence was observed in only 2 hips. The survival rates at 8 years after the operation were 94.8 % with femoral fractures as the end point, 93.1 % with any stem removal or exchange as the end point, and 99.0 % with aseptic stem loosening as the end point, respectively. CONCLUSION: The present study showed encouraging mid-term results of impaction bone grafting for femoral revision arthroplasty by experienced surgeons in Japan. Aggressive augmentation of segmental defects and attenuated femoral shafts prevents massive stem subsidence and periprosthetic fracture.

Multi-center study of use of the Exeter stem in Japan: evaluation of 1000 primary THA.

BACKGROUND: The Exeter stem was introduced to the Japanese market in 1996. Since then, owing to excellent clinical results, the number of stems used has increased year by year and more than 2000 stems were implanted in 2009. The objective of this study was to prove the efficacy of the Exeter stem for Japanese patients by evaluating the short-term results of four major dedicated hip centers. METHODS: We performed a retrospective study of clinical and radiographic results of 1000 primary total hip arthroplasties (THA) performed using the Exeter stem on 881 patients who were followed-up for at least 2 years after surgery. The average age of the patients at operation was 62.3 years (range 23-89 years). Mean postoperative follow-up period was 4.0 (range 2-9) years. RESULTS: Thirty postoperative complications were observed, including 9 infections, 14 dislocations, 5 cases of deep vein thrombosis, and 2 cases of sciatic nerve palsy. No symptomatic pulmonary embolization or femoral fractures were observed. Re-operations for infection and dislocation were performed in 8 and 6 hips, respectively. According to Barrack's classification, the postoperative cementing grade was judged as A for 735 hips, B for 246 hips, and C for 4 hips. At final follow-up, no radiolucent line was observed at the bone-cement interface. Cortical hypertrophy was observed in 9.5 % of cases in Gruen zones 2-6. Kaplan-Meier survival analysis predicted 100 % survival at 5 years when a radiolucent line at the bone-cement interface of the femur was used as the endpoint, 98.8 % when re-operation was required for any reason. CONCLUSIONS: This study revealed that excellent short-term results were achieved by fixing the Exeter stem with modern cementing techniques for primary THA in Japanese patients.

Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ): a patient-based evaluation tool for hip-joint disease. The Subcommittee on Hip Disease Evaluation of the Clinical Outcome Committee of the Japanese Orthopaedic Association.

BACKGROUND: The Japanese Orthopaedic Association Hip Score is widely used in Japan, but this tool is designed to reflect the viewpoint of health-care providers rather than that of patients. In gauging the effect of medical therapies in addition to clinical results, it is necessary to assess quality of life (QOL) from the viewpoint of patients. However, there is no tool evaluating QOL for Japanese patients with hip-joint disease. METHODS: With the aim of more accurately classifying QOL for Japanese patients with hip-joint disease, we prepared a questionnaire with 58 items for the survey derived from 464 opinions obtained from approximately 100 Japanese patients with hip-joint disease and previously devised evaluation criteria. In the survey, we collected information on 501 cases, and 402 were subjected to factor analysis. From this, we formulated three categories-movement, mental, and pain-each comprising 7 items, for a total of 21 items to be used as evaluation criteria for hip-joint function. RESULTS: The Cronbach's α coefficients for the three categories were 0.93, 0.93, and 0.95, respectively, indicating the high reliability of the evaluation criteria. The 21 items included some related to the Asian lifestyle, such as use of a Japanese-style toilet and rising from the floor, which are not included in other evaluation tools. CONCLUSIONS: This self-administered questionnaire may become a useful tool in the evaluation of not only Japanese patients, but also of members of other ethnic groups who engage in deep flexion of the hip joint during daily activities.

Long-term outcomes of shelf acetabuloplasty for developmental dysplasia of the hip in adults: a minimum 20-year follow-up study.

BACKGROUND: Shelf acetabuloplasty has been applied to secondary osteoarthritis of the hip due to congenital dislocation or acetabular dysplasia; however, there are few reports on the long-term outcomes of this operation. Here, we aimed to investigate the long-term effects of our shelf acetabuloplasty for developmental dysplasia of the hip in adults. METHODS: Outcomes for 28 hips (7 with pre-arthrosis, 21 with initial stage of arthrosis) were retrospectively reviewed clinically and radiologically at a minimum of 20 years after operation. Mean age of the patients at operation was 34 years (range 17-54 years), and the mean follow-up period was 25 years (range 20-32 years). RESULTS: Mean Japanese Orthopaedic Association hip score improved from 76 points preoperatively to 82 points, and mean pain score improved from 24 points preoperatively to 33 points at 20 years. Mean Sharp angle improved from 51° preoperatively to 37° immediately after the operation. Similarly, the mean center-edge angle improved from -4° to 38°, and the mean acetabulum head index improved from 52 to 99%. More than 50% of the hips showed no change in joint space width at 20 years. Survival rates were 100% at 10 years, 93% at 20 years and 71% at 32 years, with conversion to total hip replacement as the endpoint. CONCLUSION: Long-term outcomes of our shelf acetabuloplasty were comparable to other reports, and the clinical outcomes and survivorship revealed positive long-term effects of our procedure over approximately 20 years.

A novel technique for impaction bone grafting in acetabular reconstruction of revision total hip arthroplasty using an ex vivo compaction device.

BACKGROUND: Impaction bone grafting allows restoration of the acetabular bone stock in revision hip arthroplasty. The success of this technique depends largely on achieving adequate initial stability of the component. To obtain well-compacted, well-graded allograft aggregates, we developed an ex vivo compaction device to apply it in revision total hip arthroplasty on the acetabular side, and characterized mechanical properties and putative osteoconductivity of allograft aggregates. METHODS: Morselized allograft bone chips were compacted ex vivo using the creep technique and subsequent impaction technique to form the bone aggregates. Impaction allograft reconstruction of the acetabulum using an ex vivo compaction device was performed on eight hips. The mechanical properties and three-dimensional micro-CT-based structural characteristics of the bone aggregates were investigated. RESULTS: In clinical practice, this technique offered good reproducibility in reconstructing the cavity and the segmental defects of the acetabulum, with no migration and no loosening of the component. In vitro analysis showed that the aggregates generated from 25 g fresh-frozen bone chips gained compression stiffness of 13.5-15.4 MPa under uniaxial consolidation strain. The recoil of the aggregates after compaction was 2.6-3.9%. The compression stiffness and the recoil did not differ significantly from those measured using a variety of proportions of large- and small-sized bone chips. Micro-CT-based structural analysis revealed average pore sizes of 268-299 µm and average throat diameter of pores in the bone aggregates of more than 100 µm. These sizes are desirable for osteoconduction, although large interconnected pores of more than 500 µm were detectable in association with the proportion of large-sized bone chips. Cement penetration into the aggregates was related to the proportion of large-sized bone chips. CONCLUSION: This study introduces the value of an ex vivo compaction device in bone graft compaction in clinical applications. In vitro analysis provided evidence that compaction of sequential layers of well-compacted, well-graded bone aggregates, i.e., the aggregates comprising smaller sized chips at the host bone side and larger sized chips at the component side, may have the advantages of initial stability of the acetabular component and biological response of the grafted aggregates.