Oncological and functional outcomes of pathological fractures of lower extremities in patients with malignant bone tumors.

As managing pathological fractures of the extremities can be difficult, the present study aimed to present a treatment algorithm for lower extremity bone malignancies. A total of 38 patients with impending and pathological fractures were treated at the Department of Orthopedic Surgery in Kindai University Hospital. Age, sex, fracture site, type of primary malignancy, number of metastases, pre-fracture Eastern Cooperative Oncology Group performance status (ECOG-PS) score, adjuvant therapy, treatment modality, operative time, blood loss, postoperative complications, Musculoskeletal Tumor Society (MSTS) score, outcomes, follow-up period and the MSTS scores and ECOG-PS were compared in cases of primary malignant tumors and those cases of metastatic malignant tumors were retrospectively surveyed. Post-treatment MSTS scores in cases of impending and pathological fractures were compared between intramedullary nail fixation and non-intramedullary nail fixation procedures. Disease sites included the sub-trochanteric femur in 10 patients, trochanteric femur in 8, femoral diaphysis in 7, femoral neck in 5, bilateral trochanteric femur in 3, proximal tibia in 3 and distal femur in 2 patients. A total of 10 patients had metastases between 3-20 sites. The median pre-fracture ECOG-PS score was 1. Adjuvant radiotherapy was administered to 5, chemotherapy to 8 and radiotherapy with chemotherapy to 10 patients. Surgical procedures included intramedullary nails in 18 patients, tumor arthroplasty in 4, plate fixation in 3, artificial head replacement in three, compression hip screw (CHS) in 3, conservative treatment in 2, bilateral intramedullary nail fixation in 2 and artificial bone stem with combined intramedullary nail and plate fixation, right-sided artificial head replacement and left-sided CHS in 1 patient each. The MSTS score was 19.9±8.95 for intramedullary nail fixation and 24.3±7.45 for other procedures, with a negative association between the MSTS score and pre-fracture ECOG-PS. The median follow-up period was 8 months. The outcomes were as follows: Alive with disease, 23 patients; continued disease-free, 1 patient; and dead due to disease, 14 patients. The 1-year postoperative overall survival rate was 60.5%. Moreover, the group with metastatic malignant tumors, which had significantly worse ECOG-PS, had significantly lower MSTS scores than the group with primary malignant tumors. The authors' treatment algorithm for malignant bone tumors of the lower extremity was shown to be useful.

Morphological Changes and Concentricity of the Hip Joint During Gradual Reduction in Infants with Late-Detected Developmental Dysplasia of the Hip: A Retrospective Study.

Background: The relationship between hip morphological changes and joint concentricity in infants with late-detected developmental dysplasia of the hip (DDH) treated with gradual reduction remains unclear. Therefore, we investigated hip morphological changes and concentricity in infants with late-detected unilateral DDH using magnetic resonance imaging (MRI) during gradual reduction. Methods: We enrolled 20 infants aged ≥ 12 months with unilateral DDH. Treatment comprised continuous traction, a hip-spica cast, and an abduction brace. MRI was performed before treatment, immediately after hip-spica cast placement, after cast removal, and at the end of the brace. We evaluated the acetabulum and femoral head morphology and joint concentricity. Results: The mean age was 25 months, and female sex and the left side were predominant. Before treatment, the acetabulum was small and shallow and the femoral head was spherically flat on the affected side. Immediately after the continuous traction, the affected acetabulum and femoral head were still smaller than the healthy/contralateral one. However, they improved to a deeper acetabulum and round femoral head. Intra-articular soft tissue (IAST) and femoral-acetabular distance (FAD) continuously decreased, indicating gradual improvement in joint concentricity. Deeper formation of the acetabulum and round shaping of the femoral head had occurred even in non-concentric reduction. Conclusion: The shape and concentricity of the hip joint improved after treatment; however, the acetabulum and femoral head remained small. The deeper acetabulum and round femoral head were observed the non-concentric reduction before the concentric reduction was achieved. The continuous decrease in IAST and FAD indicates effective post-traction therapy.

Total management of hemangiopericytoma/solitary fibrous tumor of the buttock: A case report.

BACKGROUND: Solitary fibrous tumors can manifest at various anatomical sites, predominantly occurring at extrapleural sites with a peak incidence between 40 and 70 years. SFT necessitates long-term follow-up owing to its tumor characteristics. However, comprehensive reports covering the period from initial diagnosis to the patient's demise are lacking. Herein, we present a case of a malignant SFT of the buttocks that was treated at our hospital from the time of initial diagnosis to the end of life, with a literature review. METHODS: A 54-year-old woman had a T1 low-to-isobaric and T2 isobaric-to-hyperintense mass in the psoas muscle on magnetic resonance imaging, diagnosed as an SFT. Wide excision was performed, followed by postoperative radiotherapy and chemotherapy. Multiple lung metastases were treated, while bone metastases appeared in the left femur. Multiple spinal metastases developed, causing respiratory distress due to pleural effusion. Best support care was initiated; however, a thrombus appeared in the inferior vena cava. Despite anticoagulant therapy, the patient died 11 years and 6 months after the initial surgery. Herein, marginal resection resulted in a relatively short operative time and average blood loss. The radiotherapy dose was 66 Gy; no complications occurred, and local recurrence was prevented. Tumor arthroplasty was performed to stabilize the affected limbs, and the patient required careful follow-up. RESULTS: Despite the poor prognosis, the patient survived >11 years after surgery and had a favorable outcome. CONCLUSION: Long-term monitoring for potential complications remains necessary.

Grisel's Syndrome After COVID-19 in a Pediatric Patient: A Case Report.

An eight-year-old female presenting with posterior neck pain and torticollis who had been diagnosed with coronavirus disease 2019 (COVID-19) three weeks earlier was radiographed and diagnosed with atlantoaxial rotatory fixation (AARF). Following treatment with non-steroidal anti-inflammatory drugs (NSAIDs), the posterior neck pain improved, and the torticollis was cured. Symptoms returned after two weeks, and computed tomography showed a 3.94 mm atlantodental interval and axis rotation. The patient was diagnosed with AARF relapse; symptoms resolved spontaneously prior to subsequent examination, and no further relapses were observed. This case highlights the need for clinicians to be aware that AARF may develop after COVID-19. Treatment options should be carefully considered.

Catheter Ablation Approach Targeting Epicardial Connections to the Right Pulmonary Vein Antrum Detected before Pulmonary Vein Isolation.

BACKGROUND: Epicardial connections from surrounding structures to the right pulmonary vein (PV) antrum impede PV isolation. OBJECTIVE: This study aimed to evaluate the efficacy of an ablation approach targeting epicardial connections for right PV isolation. METHODS: We prospectively enrolled 124 patients with atrial fibrillation undergoing initial PV isolation. We identified the activation breakthrough into the right PV antrum (BT-RPV) on the activation map created during high right atrial pacing before PV isolation. BT-RPV sites were targeted when right PV isolation was not achieved by wide antral circumferential ablation (WACA). RESULTS: BT-RPV was observed in 83 cases (67%). PV isolation was achieved by WACA in all 41 cases without BT-RPV. Among cases with BT-RPV, PV isolation was achieved by WACA in 48 cases when all BT-RPV sites were covered by the PV isolation line. Conversely, PV isolation was completed by WACA in only 5 out of 35 cases when not all BT-RPV sites were covered. In cases where WACA failed, 35 sites were targeted for BT-RPV ablation. Initial BT-RPV ablation led to PV isolation at 20 sites, while the remaining 15 BT-RPV sites required repeat BT-RPV ablation. The ablated area of successful BT-RPV ablation was 0.9 [0.6-1.2] cm2, corresponding to the area activated within 15 [14-16] ms after BT-RPV emergence. Ablating the area activated within 14 ms after BT-RPV emergence was associated with successful PV isolation (sensitivity 91% and specificity 100%). CONCLUSION: Ablation targeting BT-RPV sites is effective for right PV isolation. Extensive ablation is required to eliminate BT-RPV.

Characteristics of radiofrequency lesions in patients with symptomatic periesophageal vagal nerve injury after pulmonary vein isolation.

Background: Periesophageal vagal nerve injury (PNI) is an unpredictable and serious complication of atrial fibrillation (AF) ablation. We aimed to identify the factors associated with symptomatic PNI. Methods: This study included 1391 patients who underwent ablation index-guided pulmonary vein isolation (PVI) using the CARTO system. The target ablation index was set at 550, except for the left atrial (LA) posterior wall near the esophagus, where radiofrequency (RF) power and duration were limited. Ten patients (0.72%) were diagnosed with symptomatic PNI. We randomly selected 40 patients without PNI (1:4 ratio) matched based on age, sex, body mass index, LA diameter, type of AF, and esophageal location. We measured the shortest distance from the RF lesions to the esophagus (LED) and classified the RF lesions according to the LED into four groups: 0-5, 5-10, 10-15, and 15-20 mm. We conducted a comparative analysis of classified RF lesions between patients with PNI (n = 10) and those without (n = 40). Results: The contact force at LED 0-5 mm was significantly higher in patients with PNI than in those without (14.6 ± 1.7 vs. 12.0 ± 2.9 g; p = .01). Multivariate logistic analysis revealed that the independent factor for PNI was contact force at an LED of 0-5 mm (odds ratio: 1.506; 95% confidence interval: 1.053-2.153; p = .025). Conclusions: The symptomatic PNI was significantly associated with a higher contact force near the esophagus. Strategies for regulating contact force near the esophagus may aid in the prevention of PNI.

Tmem119 deficiency delays bone repair in mice.

Tmem119 was identified as a bone anabolic factor in osteoblasts, however the roles of Tmem119 on bone repair have remained unknown. Therefore, we herein investigated the roles of Tmem119 on bone repair by examining the bone repair process after a femoral bone defect using Tmem119-deficient mice. In Tmem119-deficient mice, bone repair after a femoral bone defect was significantly delayed 10 and 14 days after bone injury in female and male mice with 3-dimensional micro-computed tomography analyses, respectively. The number of alkaline phosphatase-positive cells at the damaged sites was significantly decreased 7 days after bone injury in Tmem119-deficient mice, although the number of Osterix-positive cells was not significantly different 4 days after bone injury. The number of tartrate-resistant acid phosphatase-positive multinucleated cells as well as the number and luminal area of CD31-positive vessels at the damaged sites were not significantly different between Tmem119-deficient and wild-type mice. The present study first showed that Tmem119 deficiency delayed bone repair partly through a decrease in the osteoblastic bone formation of differentiated osteoblasts.

Treatment algorithm for metastatic malignancies in the lower extremities.

A high prevalence of proximal femoral metastases persists in patients with cancer, particularly regarding lower extremity fractures. This study offers a detailed analysis of clinical characteristics of patients undergoing surgical treatment for pathological or impending fractures, enhancing treatment strategies for metastatic malignancies. A total of thirty patients who underwent treatment of impending and pathological fractures at Kindai University Hospital (Osakasayama, Japan) were included. The retrospective study comprised parameters including age, sex, fracture site, type of primary malignancy, number of metastases, pre-fracture Eastern Cooperative Oncology Group performance status (ECOG-PS) score, adjuvant therapy, treatment modality, operative time, blood loss, postoperative complications, Musculoskeletal Tumor Society (MSTS) score, outcome and follow-up period. Post-treatment MSTS scores were compared in cases of impending and pathological fractures, and between intramedullary nailing and other surgical procedures. In addition, one-year postoperative survival rates were calculated. Furthermore, operative time, blood loss and survival rates were compared between impending and pathological fractures. The participants' median age was 70.5 years, with disease sites primarily in the subtrochanteric femur, trochanteric femur, femoral diaphysis, femoral neck and other locations. Pathologies included multiple myeloma and unknown primary, lung, breast, kidney, liver, gastric, esophageal and uterine cancers. The median ECOG-PS score pre-fracture was 2. Treatment approaches involved radiotherapy, chemotherapy and a combination of both. Surgical interventions included intramedullary nailing (16 cases), endoprosthesis (1 case), bipolar head replacement (3 cases) and compression hip screw (3 cases), among others. A negative correlation (R=-0.63) existed between MSTS and pre-fracture ECOG-PS scores. The operative time was significantly shorter in impending than in pathological fractures, with impending fractures showing significantly lower blood loss. The treatment algorithm for malignant bone tumors of the lower extremity provided in the present study was efficient, potentially optimizing treatment strategies for such cases, and contributing to improved patient care and outcomes in oncology and orthopedic surgery.

Measurement of the Acetabular Cup Orientation After Total Hip Arthroplasty Based on 3-Dimensional Reconstruction From a Single X-Ray Image Using Generative Adversarial Networks.

BACKGROUND: The purpose of this study was to reconstruct 3-dimensional (3D) computed tomography (CT) images from single anteroposterior (AP) postoperative total hip arthroplasty (THA) X-ray images using a deep learning algorithm known as generative adversarial networks (GANs) and to validate the accuracy of cup angle measurement on GAN-generated CT. METHODS: We used 2 GAN-based models, CycleGAN and X2CT-GAN, to generate 3D CT images from X-ray images of 386 patients who underwent primary THAs using a cementless cup. The training dataset consisted of 522 CT images and 2,282 X-ray images. The image quality was validated using the peak signal-to-noise ratio and the structural similarity index measure. The cup anteversion and inclination measurements on the GAN-generated CT images were compared with the actual CT measurements. Statistical analyses of absolute measurement errors were performed using Mann-Whitney U tests and nonlinear regression analyses. RESULTS: The study successfully achieved 3D reconstruction from single AP postoperative THA X-ray images using GANs, exhibiting excellent peak signal-to-noise ratio (37.40) and structural similarity index measure (0.74). The median absolute difference in radiographic anteversion was 3.45° and the median absolute difference in radiographic inclination was 3.25°, respectively. Absolute measurement errors tended to be larger in cases with cup malposition than in those with optimal cup orientation. CONCLUSIONS: This study demonstrates the potential of GANs for 3D reconstruction from single AP postoperative THA X-ray images to evaluate cup orientation. Further investigation and refinement of this model are required to improve its performance.

Life Course Epidemiology of Hip Osteoarthritis in Japan: A Multicenter, Cross-Sectional Study.

BACKGROUND: The incidence of developmental dysplasia of the hip (DDH) in Japanese newborns has reduced drastically following a primary prevention campaign initiated around 1972 to 1973; this perinatal education campaign promoted maintaining the hips of newborns in the naturally flexed-leg position. The purpose of the present study was to describe the life course epidemiology of hip osteoarthritis (OA) in adolescent and adult patients and to assess its association with exposure to the primary prevention campaign for DDH. METHODS: We included new patients with hip OA diagnosed from January 1, 2022, to December 31, 2022, at 12 core hospitals (8 special-function hospitals and 4 regional medical care support hospitals). The trend in the percentage of hips with a history of DDH treatment in childhood was estimated with use of a centered moving average using the birth year of the patient. We compared the prevalence of severe subluxation (Crowe type II, III, or IV) between patients with secondary hip OA due to hip dysplasia who were born in or before 1972 and those who were born in or after 1973. RESULTS: Overall, 1,095 patients (1,381 hips) were included. The mean age at the time of the survey was 63.5 years (range, 15 to 95 years). A total of 795 patients (1,019 hips; 73.8% of hips) were diagnosed with secondary OA due to hip dysplasia. Approximately 13% to 15% of hips among patients born from 1963 to 1972 had a history of DDH treatment in childhood; however, the percentage decreased among patients born in or after 1973. The prevalence of severe subluxation (Crowe type II, III, or IV) among patients born in or after 1973 was 2.4%, which was significantly less than that among patients born in or before 1972 (11.1%; odds ratio, 0.20; p < 0.001). CONCLUSIONS: As of 2022, secondary hip OA due to hip dysplasia is still responsible for most new cases of adolescent and adult hip OA seen in core hospitals in Japan. However, the perinatal education campaign initiated 50 years ago, which utilized a population approach and advocated for maintaining the hips of newborns in the naturally flexed-leg position, may have improved the environmental factors of DDH, as indicated by the apparently reduced need for treatment of DDH in childhood and the associated severe subluxation. This may result in a reduced need for challenging hip surgery later in life. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Fabrication of Artificial Nerve Conduits Used in a Long Nerve Gap: Current Reviews and Future Studies.

There are many commercially available artificial nerve conduits, used mostly to repair short gaps in sensory nerves. The stages of nerve regeneration in a nerve conduit are fibrin matrix formation between the nerve stumps joined to the conduit, capillary extension and Schwann cell migration from both nerve stumps, and, finally, axon extension from the proximal nerve stump. Artificial nerves connecting transected nerve stumps with a long interstump gap should be biodegradable, soft and pliable; have the ability to maintain an intrachamber fibrin matrix structure that allows capillary invasion of the tubular lumen, inhibition of scar tissue invasion and leakage of intratubular neurochemical factors from the chamber; and be able to accommodate cells that produce neurochemical factors that promote nerve regeneration. Here, we describe current progress in the development of artificial nerve conduits and the future studies needed to create nerve conduits, the nerve regeneration of which is compatible with that of an autologous nerve graft transplanted over a long nerve gap.

The optimal slow pathway ablation site in atrioventricular nodal reentrant tachycardia cases with an inferiorly located His bundle.

INTRODUCTION: The optimal slow pathway (SP) ablation site in cases with an inferiorly located His bundle (HIS) remains unclear. METHODS AND RESULTS: In 45 patients with atrioventricular nodal reentrant tachycardia, the relationship between the HIS location and successful SP ablation site was assessed in electroanatomical maps. We assessed the location of the SP ablation site relative to the bottom of the coronary sinus ostium in the superior-to-inferior (SPSI), anterior-to-posterior (SPAP), and right-to-left (SPRL) directions. The HIS location was assessed in the same manner. The HIS location in the superior-to-inferior direction (HISSI), SPSI, SPAP, and SPRL were 17.7 ± 6.4, 1.7 ± 6.4, 13.6 ± 12.3, and -1.0 ± 13.0 mm, respectively. The HISSI was positively correlated with SPSI (R2 = 0.62; P < .01) and SPAP (R2 = 0.22; P < .01), whereas it was not correlated with SPRL (R2 = 0.01; P = .65). The distance between the HIS and SP ablation site was 17.7 ± 6.4 mm and was not affected by the location of HIS. The ratio of the amplitudes of atrial and ventricular potential recorded at the SP ablation site did not differ between the high HIS group (HISSI ≥ 13 mm) and low HIS group (HISSI < 13 mm) (0.10 ± 0.06 vs. 0.10 ± 0.06; P = .38). CONCLUSION: In cases with an inferiorly located HIS, SP ablation should be performed at a lower and more posterior site than in typical cases.

Bone ingrowth into a porous structure is achieved by preceding fibrogenesis and vascularization.

Porous structures are frequently used in surgical implants to strengthen the interlocking power produced by bone ingrowth. Therefore, we aimed to elucidate the mechanism underlying bone ingrowth into a porous structure accompanied by vascularization. A nonbioactive polyetheretherketone implant with a 3D-printed porous structure was prepared and implanted in a bone hole created in the tibias of rabbits. We observed bone ingrowth in the same individual specimens immediately and at 2, 4, 8, and 12 weeks post-implantation using in-vivo computed tomography (CT). Furthermore, a detailed evaluation with blood vessels of each specimen at 2, 4, and 12 weeks was performed with ex-vivo CT and histological specimen. Additional histological evaluation was performed using thin sections of an implant made with thermoplastic polyurethane having the same structure. As a result, the bone invasion began after four weeks, when the construction of fibrous tissue and the spread of new blood vessels within the voids matured. As the bone matured in the load-bearing area, new blood vessels outside the bone matrix regressed. This longitudinal evaluation study suggests that preceding fibrogenesis and vascularization may be key in developing bone ingrowth. STATEMENT OF SIGNIFICANCE: A porous structure is an essential structure for dental and orthopedic implants because it provides strong fixation through bone invasion. Although it was known that vascularization was involved in this, the details were not known. This in vivo study revealed that in order for bone ingrowth to begin, a preparatory period of approximately 4 weeks was required to establish blood flow inside and outside the implant. Furthermore, it was confirmed that by spreading the fibrous structure in advance, it has an advantageous effect on the migration of cells involved in the formation of bones and blood vessels. We pointed out that it is necessary to consider fibrogenesis and vascularization when creating future implants.

Strontium-loaded 3D intramedullary nail titanium implant for critical-sized femoral defect in rabbits.

The treatment of critical-sized bone defects has long been a major problem for surgeons. In this study, an intramedullary nail shaped three-dimensional (3D)-printed porous titanium implant that is capable of releasing strontium ions was developed through a simple and cost-effective surface modification technique. The feasibility of this implant as a stand-alone solution was evaluated using a rabbit's segmental diaphyseal as a defect model. The strontium-loaded implant exhibited a favorable environment for cell adhesion, and mechanical properties that were commensurate with those of a rabbit's cortical bone. Radiographic, biomechanical, and histological analyses revealed a significantly higher amount of bone ingrowth and superior bone-bonding strength in the strontium-loaded implant when compared to an untreated porous titanium implant. Furthermore, one-year histological observations revealed that the strontium-loaded implant preserved the native-like diaphyseal bone structure without failure. These findings suggest that strontium-releasing 3D-printed titanium implants have the clinical potential to induce the early and efficient repair of critical-sized, load-bearing bone defects.

How Do Spinal Parameters Change in Patients Who Have Improvement of Low Back Pain After Total Hip Arthroplasty? A Propensity Score-Matched Cohort Study.

BACKGROUND: Many studies have demonstrated that low back pain (LBP) improves after total hip arthroplasty (THA). However, the mechanism underlying this improvement remains unclear. We aimed to investigate changes in the spinal parameters of patients who had LBP improvement after THA to elucidate the mechanism of LBP improvement. METHODS: We included 261 patients who underwent primary THA between December 2015 and June 2021 and had a preoperative visual analog scale score of ≥ 2 for LBP. The patients were classified into the LBP-improved or LBP-continued groups based on the visual analog scale for LBP at 1 year after THA. Preoperative and postoperative changes in the coronal and sagittal spinal parameters were compared between the 2 groups after propensity score matching for age, sex, body mass index, and preoperative spinal parameters. RESULTS: A total of 161 patients (61.7%) were classified into the LBP-improved group. After 85 patients in both groups were matched, the LBP-improved group showed significant differences in spinal parameter changes, which were a higher lumbar lordosis (LL) (P = .04) and lower sagittal vertical axis (SVA) (P = .02) and pelvic incidence (PI) minus LL (PI-LL) (P = .01) postoperatively, whereas the LBP-continued group showed worsened changes in LL and SVA and PI-LL mismatch. CONCLUSION: Patients who had LBP improvement after THA had significant differences in spinal parameter changes in LL, SVA, and PI-LL. These spinal parameters may be the key factors in the mechanism of LBP improvement after THA.