Transient osteoporosis of the hip with a femoral neck fracture during follow-up: a case report.

We report a case of transient osteoporosis of the hip with a femoral neck fracture found during follow-up. A 53-year-old man presented with left hip pain without trauma. The pain did not improve after 2 weeks and he was brought to our hospital by ambulance. Magnetic resonance imaging (MRI) of the left hip joint showed diffuse edema in the bone marrow, which was identified by low signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and increased signal intensity on short tau inversion recovery. This edema extended from the femoral head and neck to the intertrochanteric area. He was diagnosed with transient osteoporosis of the left hip. Rest gradually improved his pain; however, 3 weeks later, his left hip pain worsened without trauma. X-ray, computed tomography, and MRI results of the hip joint demonstrated a left femoral neck fracture, and osteosynthesis was performed. Differential diagnoses included avascular necrosis of the femoral head, infection, complex regional pain syndrome, rheumatoid arthritis, leukemia, and other cancers. Transient osteoporosis of the hip generally has a good prognosis with spontaneous remission within a few months to 1 year. However, a sufficient length of follow-up from condition onset to full recovery is necessary to avoid all probable complications such as fractures.

Calcitonin gene-related peptide is not involved in neuropathic pain induced by partial sciatic nerve ligation in mice.

BACKGROUND: Optimal neuropathic pain (NeP) therapy has still not been established despite great efforts to develop new strategies for NeP analgesia. One possible target might be calcitonin gene-related peptide (CGRP). This is because the expression of CGRP and its receptors in the dorsal horn of the spinal cord might be associated with the persistence of pain symptoms including symptoms of NeP. We previously developed αCGRP knockout mice, and we aimed in this study to clarify the roles of CGRP in NeP by partial sciatic nerve ligation (PSNL) using the knockout mice. METHODS: PSNL was performed in αCGRP knockout mice and wild-type (WT) mice, and spontaneous pain behavior and mechanical and thermal hyperalgesia were evaluated after PSNL. CGRP immunoreactivity (IR) was also observed in the superficial dorsal horn and deep dorsal horn of L4 to L5 segments of the spinal cord in WT mice after PSNL. RESULTS: Spontaneous pain behavior and mechanical and thermal hyperalgesia after PSNL were not different between αCGRP knockout mice and WT mice throughout the observation period. The expression of CGRP-IR was not different between the PSNL model and the sham operation model at 1 day and 7 days after surgery. CONCLUSION: The results suggest that the involvement of αCGRP may differ depending on the type and site of nerve injury, and clinical indications for anti-CGRP treatment of NeP should be carefully based on various pathophysiological conditions of NeP.

The Relationship between Perivertebral Venous Cement Embolism and Balloon Expansion Pressure in Balloon Kyphoplasty.

INTRODUCTION: Osteoporotic vertebral compression fractures (OVCFs) are common fractures in the elderly suffering osteoporosis. Most patients have bone fusion with deformity of vertebral collapse; however, some patients suffer nonunion and persistent pain at the fracture site. Due to the limitations of conservative treatment, balloon kyphoplasty (BKP) has been recently performed for OVCFs. This study aimed to investigate the relationship between cement embolization and balloon expansion pressure (BEP) in patients who underwent BKP. METHODS: We investigated 62 patients who underwent BKP for cement embolization into the perivertebral veins among the 155 patients admitted to our hospital due to thoracolumbar vertebral compression fractures between April 1, 2019, and March 31, 2020. Surgery was indicated for patients who had severe back or low back pain and whose daily life was severely impaired, and in whom the shape of the vertebral body was clearly changed on functional X-ray. RESULTS: Intraoperative X-ray and postoperative CT revealed cement embolization into the perivertebral veins in three cases (4.83%). The BEP was significantly higher in the group with cement embolism than in the group without cement embolism (P < 0.001). Pulmonary cement embolism (PCE) and infection were not observed. One case of cement leakage into the spinal canal was observed (1.61%). CONCLUSIONS: While the surgical intervention of BKP can contribute to the treatment of OVCFs, careful attention should be paid to the prevention of complications, including cement embolization into the perivertebral veins, and such complications should be appropriately managed.

Reverse Z-effect phenomenon in a basicervical femoral fracture using cephalomedullary nail with two superior antirotation screws: A case report and procedure evaluation.

We present a case of reverse Z-effect phenomenon in a basicervical femoral fracture using a cephalomedullary nail together with two superior antirotation screws and evaluate the procedure. An 86-year-old woman fell in her home and could not stand due to right hip joint pain. X-ray and CT imaging showed a right basicervical femoral fracture (AO/OTA classification; 31B3), and open reduction and internal fixation (OR/IF) was performed with a cephalomedullary nail and two superior antirotation screws (TES Nail, HOMS, Tokyo, Japan). Two months later, X-ray showed penetration of the femoral head by the inferior lag screw with lateral migration of the two superior antirotation screws; the so-called "reverse Z-effect"; without any trauma. We performed the exchange of a shorter inferior lag screw for the longer one, and replaced the sliding type end cap with one of rocking type. The reverse Z-effect has been reported in cases with two lag screws, i.e. one inferior and one superior, in the past; however, to our knowledge, there has been no case reported in the literature using two superior antirotation screws together with one inferior lag screw.

Deficiency of the adrenomedullin-RAMP3 system suppresses metastasis through the modification of cancer-associated fibroblasts.

Tumor metastasis is a primary source of morbidity and mortality in cancer. Adrenomedullin (AM) is a multifunctional peptide regulated by receptor activity-modifying proteins (RAMPs). We previously reported that the AM-RAMP2 system is involved in tumor angiogenesis, but the function of the AM-RAMP3 system remains largely unknown. Here, we investigated the actions of the AM-RAMP2 and 3 systems in the tumor microenvironment and their impact on metastasis. PAN02 pancreatic cancer cells were injected into the spleens of mice, leading to spontaneous liver metastasis. Tumor metastasis was enhanced in vascular endothelial cell-specific RAMP2 knockout mice (DI-E-RAMP2-/-). By contrast, metastasis was suppressed in RAMP3-/- mice, where the number of podoplanin (PDPN)-positive cancer-associated fibroblasts (CAFs) was reduced in the periphery of tumors at metastatic sites. Because PDPN-positive CAFs are a hallmark of tumor malignancy, we assessed the regulation of PDPN and found that Src/Cas/PDPN signaling is mediated by RAMP3. In fact, RAMP3 deficiency CAFs suppressed migration, proliferation, and metastasis in co-cultures with tumor cells in vitro and in vivo. Moreover, the activation of RAMP2 in RAMP3-/- mice suppressed both tumor growth and metastasis. Based on these results, we suggest that the upregulation of PDPN in DI-E-RAMP2-/- mice increases malignancy, while the downregulation of PDPN in RAMP3-/- mice reduces it. Selective activation of RAMP2 and inhibition of RAMP3 would therefore be expected to suppress tumor metastasis. This study provides the first evidence that understanding and targeting to AM-RAMP systems could contribute to the development of novel therapeutics against metastasis.

Endogenous Calcitonin Gene-Related Peptide Deficiency Exacerbates Postoperative Lymphedema by Suppressing Lymphatic Capillary Formation and M2 Macrophage Accumulation.

Lymphedema is a chronic condition caused by disruption of lymphatic vessels, which often occurs after invasive surgery. Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide produced by alternative splicing of the primary transcript of the calcitonin/CGRP gene (Calca). CGRP was initially identified as a neuropeptide released primarily from sensory nerves and involved in regulating pathophysiological nociceptive pain. However, recent studies have shown CGRP is also released from a variety of other cells and possesses multiple functions. In this study, CGRP knockout (-/-) mice were used to show the actions of endogenous CGRP in postoperative lymphedema. After generating a mouse postoperative tail lymphedema model, the edema was observed to be more severe in CGRP-/- mice than in wild-type mice. Numbers of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1)-positive lymphatic capillaries were decreased and lymphatic capillary formation-related factors were down-regulated in CGRP-/- mice. In addition, accumulation of M2 but not M1 macrophages was selectively reduced in the edematous tissue of CGRP-/- mice. Selective depletion of M2 macrophages decreased lymphatic capillary formation and worsened lymphedema in wild-type mice but not CGRP-/- mice, where numbers of M2 macrophages were already diminished. These findings suggest that endogenous CGRP acts to ameliorate postoperative lymphedema by enhancing lymphatic capillary formation and that M2 macrophages play critical roles. CGRP may be a useful therapeutic target for the treatment of postoperative lymphedema.

Development of a Novel Model of Central Retinal Vascular Occlusion and the Therapeutic Potential of the Adrenomedullin-Receptor Activity-Modifying Protein 2 System.

Central retinal vein occlusion (CRVO) is an intractable disease that causes visual acuity loss with retinal ischemia, hemorrhage, and edema. In this study, we developed an experimental CRVO model in mice and evaluated the therapeutic potential of the pleiotropic peptide adrenomedullin (ADM) and its receptor activity-modifying protein 2 (RAMP2). The CRVO model, which had phenotypes resembling those seen in the clinic, was produced by combining i.p. injection of Rose bengal, a photoactivator dye enhancing thrombus formation, with laser photocoagulation. Retinal vascular area, analyzed using fluorescein angiography and fluorescein isothiocyanate-perfused retinal flat mounts, was decreased after induction of CRVO but gradually recovered from day 1 to 7. Measurements of retinal thickness using optical coherence tomography and histology revealed prominent edema early after CRVO, followed by gradual atrophy. Reperfusion after CRVO was diminished in Adm and Ramp2 knockout (KO) mice but was increased by exogenous ADM administration. CRVO also increased expression of a coagulation factor, oxidative stress markers, and a leukocyte adhesion molecule in both wild-type and Adm KO mice, and the effect was more pronounced in Adm KO mice. Using retinal capillary endothelial cells, ADM was found to directly suppress retinal endothelial injury. The retinoprotective effects of the Adm-Ramp2 system make it a novel therapeutic target for the treatment of CRVO.

Effects of Endoprosthesis Head Material on Acetabular Cartilage Metabolism: An Animal Study Using Crossbred Pigs.

BACKGROUND: Hip endoprosthesis is one option for the treatment of displaced femoral neck fractures and avascular necrosis of the femoral head. Few reports are available describing acetabular cartilage metabolism after endoprosthesis surgery of the hip. The purpose of this study was to compare the biological effects on cartilage between cobalt-chrome (Co-Cr) and alumina ceramic heads wherein the cartilage articulates directly. METHODS: We used the acetabular cartilage from six hips of three immature crossbred pigs to examine the effects on cytokines, the amount of hyaluronic acid (HA), and cartilage mRNA expression of ceramic head and Co-Cr head endoprosthesis. Mechanical loading of materials of Co-Cr and ceramic heads was performed on the acetabular cartilage in culture media as an organ culture model. Thereafter, protein levels of cytokines (MMP-1, 3, TNF-alpha (α), Interleukin (IL)-1 alpha (α), and IL-1 beta (ß)) and the amount of HA were measured from the culture media. Cartilage RNA extraction was performed, and quantitative reverse transcriptase-polymerase chain reaction was performed with primer sets for type I, II, and III collagens; aggrecan; MMP-1, 3, 13; TNF-α; and IL-1 α, IL-1 ß. RESULTS: Protein level of IL-1 ß and amount of HA in the Co-Cr group were significantly higher than those of the Ceramic group. Type II collagen mRNA expression in the Ceramic group was significantly higher than in the Co-Cr group. IL-1 ß mRNA expression was significantly higher in the Co-Cr group than in the Ceramic group. CONCLUSIONS: The present study showed that ceramic bipolar produces smaller adverse effects on cartilage cells compared to Co-Cr bipolar. These results could have significant implications for implant usage not only in hip joints, but also in other joints, including the shoulder, talus and radial head.

RAMP3 deficiency enhances postmenopausal obesity and metabolic disorders.

There is a marked increase in the incidence of visceral adiposity and insulin resistance among women following menopause. Adrenomedullin (AM) is an endogenous peptide first identified as a vasodilator, but now known to exert a variety of physiological effects. RAMP3 is a receptor activity-modifying protein that binds to the AM receptor (calcitonin receptor-like receptor). As expression of both AM and RAMP3 is reportedly activated by estrogen, we hypothesized that RAMP3 is crucially involved in the pathophysiology of postmenopausal obesity. To test this idea, we compared the effects of ovariectomy (OVX) and a high-fat diet for 10 weeks (a model of postmenopausal obesity) between RAMP3 knockout (RAMP3-/-) and wild-type mice. RAMP3-/- OVX mice exhibited greater obesity and adipose tissue weight gain as compared to wild-type OVX mice. RAMP3-/- OVX mice also exhibited higher serum insulin levels. In periuterine WAT from RAMP3-/- OVX mice, expression of lipolysis-related factors was lower and expression of inflammation-related factors was higher than in wild-type OVX mice. Hepatic steatosis was also exacerbated in RAMP3-/- OVX. Notably, expression of the membrane-type estrogen receptor GPR30 was downregulated in periuterine WAT from RAMP3-/- OVX mice. These findings raise the possibility that a GPR30-RAMP3 interaction is involved in the pathophysiology of postmenopausal obesity and suggest RAMP3 plays a key role in the regulation of energy metabolism and exerts a hepatoprotective effect in this model of postmenopausal obesity. RAMP3 may thus be a useful therapeutic target for treatment of postmenopausal obesity and metabolic disorders.

Influence of the Medial Knee Structures on Valgus and Rotatory Stability in Total Knee Arthroplasty.

BACKGROUND: Precise biomechanical knowledge of individual components of the MCL is critical for proper MCL release during TKA. This study was to define the influences of the deep MCL and the POL on valgus and rotatory stability in TKA using cadaveric knees. METHODS: This study used six fresh-frozen cadaveric knees. All TKA procedures were performed using a cruciate-retaining TKA with a CT-free navigation system. We did a sequential sectioning on each knee, S1; femoral arthroplasty only, S2; medial half tibial resection with spacer, S3; anterior cruciate ligament cut, S4; tibial arthroplasty, S5; release of the dMCL, S6; release of the POL. The navigation system monitored motion after application of 10 N-m valgus loads and 5 N-m internal and external rotation torques to the tibia at 0°, 20°, 30°, 60°, and 90° of knee flexion for each sequence. RESULTS: There were no significant differences in medial gaps. Internal rotation angles significantly increased after S2 at 0°, 20°, and 30°, and after S6 at 90° compared with those after S1. External rotation angles significantly increased after S3 at 0°, S4 at 60°, S5 at 0°, 30° and 90°, and after S6 at 30°, 60° compared with those after S1. CONCLUSION: Significant increases of rotatory instability were seen on release of the dMCL, and then further increased after release of the POL. Surgical approach of retaining the dMCL and POL has a possibility to improve the outcome after primary TKA.

[Anesthetic Management of a Patient with Facioscapulohumeral Muscular Dystrophy: Importance of Monitoring Neuromuscular Function at Multiple Sites].

A 39-year-old female with facioscapulohumeral muscular dystrophy (FSHD) was scheduled for thoracoscopic resection of an anterior mediastinal tumor. She had slowly progressive weakness and atrophy in the fascial and shoulder girdle muscles. General anesthesia was induced and maintained with propofol, remifentanil, and fentanyl combined with thoracic paravertebral block. Rocuronium-induced neuromuscular blockade was evaluated with acceleromyography at the corrugator supercilii, masseter, and adductor pollicis muscles. There was no reaction at the atrophic corrugator supercilii muscle in response to train-of-four (TOF) stimulation even before rocuronium administration. In contrast twitch responses at the masseter and adductor pollicis muscles to TOF stimulation could be evoked and the duration of action of rocuronium was found to be similar to that of the normal population. The perioperative course was uneventful. Neuromuscular monitoring sites should be carefully selected in FSHD patients because of possible inability to monitor neuromuscular function at the atrophic muscles.