Asymmetric Pericentrosomal CD133 Endosomes Induce the Unequal Autophagic Activity During Cytokinesis in CD133-Positive Human Neuroblastoma Cells.

CD133 is a transmembrane protein that mainly localizes to the plasma membrane in hematopoietic/neural stem cells and cancer stem cells. Although CD133 also localizes to the cytoplasm and is degraded through autophagy, the precise mechanisms responsible for the autophagic degradation of endosomal CD133 currently remain unknown. We demonstrated that endosomal CD133 has unique properties for cell homeostasis. Endosomal CD133 is degraded through p62/SQSTM1-mediated selective autophagy. However, in low basal autophagic cells, such as SK-N-DZ and SH-SY5Y cells, endosomal CD133 accumulates at the pericentrosomal region and conversely suppresses autophagy. Endosomal CD133 also asymmetrically distributes to the pericentrosomal region and induces unequal autophagic activity between 2 daughter cells during cytokinesis in SK-N-DZ and TGW cells. In addition, the asymmetric distribution of pericentrosomal CD133 endosomes and nuclear ß-catenin cooperatively suppresses autophagic activity against p62 in SK-N-DZ cells. Thus, the present study suggests that the asymmetric distribution of pericentrosomal CD133 endosomes induces the symmetry breaking of autophagic activity during cytokinesis in cooperation with nuclear ß-catenin.

Refracture of pediatric both-bone diaphyseal forearm fracture following intramedullary fixation with Kirschner wires is likely to occur in the presence of immature radiographic healing.

PURPOSE: Refracture of pediatric both-bone diaphyseal forearm fractures (PBDFFs) may occur, even if the fractures are treated with intramedullary nailing. The purpose of this study was to investigate the risk of refracture of PBDFFs treated with intramedullary Kirschner wires (K-wires), which are commonly used in our clinic. METHODS: The present multicenter retrospective study included 60 consecutive patients with 60 PBDFFs who were treated with intramedullary K-wires at 5 hospitals between 2007 and 2016. The age of the patients at the time of the primary fracture ranged from 2 to 15 years. The characteristics of the primary fractures and treatment course were evaluated. RESULTS: Refracture occurred in 6 patients (10.0%). Three of the patients were young girls; the other 3 were adolescent boys. Refractures were caused by falling or during sports activity. The duration from primary fracture to refracture ranged from 46 to 277 days, and in 5 of the 6 patients refractures occurred within 6 months. Although we were unable to identify factors significantly contributing to refracture (e.g. fracture type or treatment procedures), radiographs at the latest visit before refracture demonstrated findings of immature healing in five of six patients. Both K-wires and external immobilization had been removed before complete fracture healing in a large proportion of patients with refracture (80.0%). CONCLUSIONS: Refracture of PBDFF may occur several months after treatment with intramedullary K-wires if the primary fracture shows immature healing. Physicians should pay special attention when judging radiographic fracture healing, even when the fracture is deemed to have clinically healed.

PPP3CB contributes to poor prognosis through activating nuclear factor of activated T-cells signaling in neuroblastoma.

We previously identified a gain-of-function mutation in PPP3CB in a neuroblastoma (NB) with MYCN amplification. Here we investigated the functional and clinical role of PPP3CB in NB. High PPP3CB expression was an independent indicator predicting poor prognosis of NB. Overexpression of wildtype or mutated PPP3CB (PPP3CBmut) promoted cell growth, but PPP3CB knockdown decreased cell growth in NB cells. Forced expressions of PPP3CB and PPP3CBmut activated NFAT2 and NFAT4 transcription factors and inhibited GSK3ß activity, resulting in the increase in the expressions of c-Myc, MYCN, and ß-catenin, which were downregulated in response to PPP3CB knockdown. Treatment with calcineurin inhibitor cyclosporin A (CsA) or FK506 suppressed cell proliferation and induced apoptotic cell death in both MYCN-amplified and MYCN-non-amplified NB cell lines. Expression of PPP3CB protein was decreased in response to two calcineurin inhibitors. c-Myc, MYCN, and ß-catenin were downregulated at the mRNA and protein levels in CsA or FK506-treated NB cells. Our data indicate that elevated expression of PPP3CB and the expression of its constitutively active mutant contribute to the aggressive behavior of NB tumors and therefore suggest that inhibition of calcineurin activity might have therapeutic potential for high-risk NB.

Characteristics of patients with fragility hip fractures in the northern Kyushu district in Japan: a multicenter prospective registry based on an electronic data capture system.

Osteoporosis has become a worldwide public health problem, in part due to the fact that it increases the risk of fragility hip fractures (FHFs). The epidemiological assessment of FHFs is critical for their prevention; however, datasets for FHFs in Japan remain scarce. This was a multicenter, prospective, observational study in the northern district of Kyushu Island. Inclusion criteria were age > 60 years with a diagnosis of FHF and acquisition of clinical data by an electronic data capture system. Of 1294 registered patients, 1146 enrolled in the study. Nearly one third of patients (31.8%) had a history of previous fragility fractures. The percentage of patients receiving osteoporosis treatment on admission was 21.5%. Almost all patients underwent surgical treatment (99.1%), though fewer than 30% had surgery within 48 h after hospitalization. Bone mineral density (BMD) was evaluated during hospitalization in only 50.4% of patients. The rate of osteoporosis treatment increased from 21.5% on admission to 39.3% during hospitalization. The main reasons that prescribers did not administer osteoporosis treatment during hospitalization were forgetfulness (28.4%) and clinical judgment (13.6%). Age and female ratio were significantly higher in patients with previous FHFs than in those without. There was a significant difference in the rate of osteoporosis treatment or L-spine BMD values in patients with or without previous FHFs on admission. In conclusion, this study confirmed that the evaluation and treatment of osteoporosis and FHFs is still suboptimal in Japan, even in urban districts.

Management of Intra-Articular Calcaneal Fractures: Clinical Results of Reduction Technique Using a Bone Spreader.

The purpose of the present study was to examine the clinical results of surgery for intra-articular calcaneal fractures using a calcaneal locking plate and a bone spreader as a reduction tool. Ten patients with intra-articular calcaneal fractures were treated. An extended lateral approach was used. The reduction of the intra-articular fragments of the posterior facet was temporarily held using a bone spreader and Kirschner wires. Internal fixation was achieved with a locking calcaneal plate. Böhler's angle and Preiss' angle were assessed on the day of injury and the day of the final follow-up examination. The step off and gap of the posterior facet were assessed on the day of injury and the first week after surgery. The functional outcome was evaluated using the American Orthopaedic Foot and Ankle Society ankle hindfoot scale score. The mean Böhler's angle ranged from 2.1° ± 11.0° to 30.4° ± 5.0° (p < .0001), the mean Preiss' angle ranged from 23.5° ± 4.5° to 15.5° ± 2.9° (p < .0001), the mean step off ranged from 4.0 ± 1.9 mm to 0.1 ± 0.2 mm (p = .0002), and the mean gap ranged from 2.6 ± 1.0 mm to 1.2 ± 0.6 mm (p = .0035). The mean American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale score was 89.2 (range 85 to 100) at a mean of 14.3 months after surgery. Our results suggest that a locking calcaneal plate can be used to restore and reduce an intra-articular calcaneal fracture and achieve good clinical results.

Avulsion Fracture of the Tibial Tuberosity Requiring Meniscal Repair: A Case Report.

Avulsion fractures of the tibial tuberosity are uncommon injuries. A 16-year-old male sustained injuries to his right knee joint after jumping from stairs and landed on his feet with his right knee forced into flexion. X-ray photographs showed a type III avulsion fracture of the tibial tuberosity. On the next day of the injury, open reduction and internal fixation, followed by arthroscopy was performed. The fracture fragment was fixed with three 5.0mm cannulated cancellous screws. The torn anterior portion of medial meniscus was repaired with 3-0 Polydioxanone (PDS) using outside-in sutures and the torn midportion of medial meniscus was repaired using the FasT-Fix meniscal repair system. Eight months after the injury, removal of the screws and arthroscopy were undertaken. The medial meniscus was completely healed. The range of motion was full at the knee joint. Meniscal suture should be strongly considered for type III avulsion fractures of the tibial tuberosity in adolescents.

Open pelvic ring fracture and multiple fractures of the lower extremities: a case report.

A 73-year-old female was hit by a car, and transferred to our hospital. On examination, her consciousness was alert, but her vital signs were unstable. There are three 10-cm open wounds on her right buttock. X-rays showed an unstable pelvic ring fracture, a right femoral shaft, a right proximal tibia and a right tibial plafond fractures. One hour after the injury, transarterial embolization (TAE) followed by external fixation (EF), and retroperitoneal pelvic packing (RPP) was performed. Two days and five days after the injury, thorough debridement of the open wounds was performed. The skin defect on the right buttock and the lower abdomen had enlarged to 40 x 35 cm, therefore, negative pressure wound therapy was applied. On the same day, right femur was fixed using a retrograde intramedullary nailing. 12 days after the injury, the proximal tibial fracture was fixed using a plate, and the tibial plafond fracture was fixed using screws and external fixators. 28 days after the injury, the split-thickness skin graft was performed on the right buttock and the lower abdomen. Seven months after the injury, the open wounds were completely healed without infection. She was able to walk smoothly with a T-cane. For the management of open pelvic ring fractures, it is essential to perform TAE, EF and RPP as soon as possible. Providing aggressive management, including thorough debridement, is mandatory to prevent severe infection and sepsis. We achieved a good clinical outcome by using a combination of TAE, EF, RPP and staged surgery, including thorough debridement.

Isolated trochlea osteochondral fracture of the distal humerus in a 6-year-old patient surgically fixed using biodegradable pins: A case study with over 3 years of follow-up.

Isolated humeral trochlea fracture, particularly in skeletally immature children, is extremely rare. The exact mechanism of this injury remains unknown because the humeral trochlea is embraced within the olecranon fossa without any muscular or ligamentous attachment. We report the treatment of a 6-year-old boy who sustained an isolated trochlea osteochondral fracture when he fell with his elbow in a flexed position while skateboarding. The patient had a history of lateral condyle fracture of the ipsilateral humerus one year previously. At the diagnosis, computed tomography (CT) revealed a small bony fragment displaced anteromedially from the superior border of the trochlea with lifting of its lateral border. Ultrasonography confirmed instability of the fractured segment. At the time of surgery, the anterior trochlea surface fracture formed a hinged fracture line on its proximal and medial border. The fracture was anatomically reduced and fixed using biodegradable pins. Postoperatively, the involved elbow showed a sufficient functional recovery to a normal level without complications during 3 years of observation, although the biodegradable pins remained radiographically in place with partial degradation. The laterally opened avulsed fragment on primary CT clearly depicted the mechanism of injury: the impact entered from the lateral side of the elbow and progressed from the longitudinal ridge of the coronoid process onto the sulcus of the trochlea to shear off the anteromedial portion of the trochlea in a medial direction. The use of biodegradable pins for fixing a trochlea fracture in a skeletally immature patient provided favorable fracture healing; however, close observation is necessary until the completion of skeletal growth because of the lack of sufficient information on the long-term prognosis of trochlea fracture, especially when treated using biodegradable implants.

Perpendicular probing and screwing technique: A simple method for accurate pedicle screw placement based on the human internal reference frame for angle estimation.

The pedicle screw (PS) is widely used for spinal fixation surgery. However, PS malpositioning can cause critical complications; thus, the accuracy of ascertaining PS trajectory is paramount. This study aimed to demonstrate the accuracy and safety of a simple and cost-effective PS placement technique using a human internal reference frame for angle estimation. Ex vivo lumbar porcine spine samples were fixed to a wooden board with rostrocaudal and mediolateral rotational angles adjusted by two angle vises. PS entry points (EPs) were identified using clear anatomical vertebral landmarks. PS placement was performed on one side using the perpendicular probing and screwing technique (PPST), wherein the attitude angle of the sample was adjusted such that the longitudinal axis of the target pedicle was perpendicular to the ground. The pedicle probe and PS driver were manually maintained perpendicular to the ground during probing and PS placement. PS placement on the contralateral side was performed freehand as a control. Offsets between the preoperatively planned and implanted PS rotational angles measured using computed tomography for PPST and freehand method were analyzed. Pedicle wall penetration was also evaluated. The mean ± standard error of the medial rotational offsets was 5.83° ± 0.57° in the freehand group versus 2.89° ± 0.31° in the PPST group (p <0.001), and the rostrocaudal rotational offsets were 4.81° ± 0.65° in the freehand group versus 2.92° ± 0.45° in the PPST group (p = 0.01). The mean pedicle wall penetration distance was significantly reduced by PPST (0.28 ± 0.12 mm vs 0.80 ± 0.17 mm in the freehand group, p = 0.0071). Thus, PPST improved PS positioning accuracy, resulting in reduced pedicle wall penetration and increased PS placement safety. This simple technique is also potentially cost-effective for institutions without computer-assisted surgical systems.

A Gustilo type IIIB open forearm fracture treated by negative pressure wound therapy and locking compression plates: a case report.

A 91-year-old female sustained injuries to her left forearm while walking across a crosswalk. X-rays showed left radial shaft and ulna shaft fractures, and the injury was a type IIIB open fracture. On the day of admission, irrigation and debridement of the open wound, and temporary fixation of the radius and ulna using an external fixator and a Kirschner wire were peformed. Six days after the surgery, we used negative pressure wound therapy (NPWT) using the V.A.C.ATS system for the open wound. Thirteen days after the first surgery, definitive fixation was performed by using locking compression plates, and full thickness skin grafting was undertaken for the open wound. NPWT is a treatment that accelerates the wound healing process through the delivery of continuous subatmospheric pressure within a closed environment. In our case, we could reduce the healing period of the soft tissue and could convert to the definitive fixation in a timely fashion. NPWT is thought to be a useful adjunct in the management of the soft tissues of open fractures.

Risk factors for excessive postoperative sliding of femoral trochanteric fracture in elderly patients: A retrospective multicenter study.

INTRODUCTION: The application of a load on the internal fixation of a trochanteric fracture exerts a moment along the lag screw, causing the proximal bone fragment to slide along the lag screw, allowing contact between the proximal and distal bone fragments, which promotes healing. However, excessive sliding is related to poor postoperative outcomes. We aimed to identify the risk factors for excessive sliding. MATERIALS AND METHODS: We conducted a multicenter retrospective study including 115 trochanteric fractures sustained through low-energy trauma in 19 male and 96 female patients aged 60 years or older (mean age: 82.9 years) between September 2013 and December 2014. We measured the postoperative sliding distance after osteosynthesis using a sliding hip screw or intramedullary nailing, and classified participants with ≥8 mm of sliding into the excessive sliding group (ESG) and with <8 mm into non-ESG. Finally, we investigated the risk factors of excessive postoperative sliding. RESULTS: Fifty participants were classified into the ESG and 65 participants into the non-ESG. Female sex (p = 0.0264), an A3 fracture type (p = 0.0003), greater tip-apex distance (p = 0.0250), and poor reduction in either the anteroposterior or lateral radiographic views (p = 0.0156) were identified as risk factors for excessive sliding by multivariate regression analysis. CONCLUSIONS: Female sex, an unstable fracture type, a greater tip-apex distance, and a poor reduction, in either the anteroposterior or lateral views, are associated with excessive postoperative sliding. Therefore, surgery should aim to achieve good reduction and stabilization from both radiographic views.

Predictive factors of non-treatment and non-persistence to osteoporosis medication after fragility hip fractures at 3 years after discharge: a multicentre, prospective cohort study in the northern Kyushu district of Japan.

We examined osteoporosis medication use and factors affecting persistence in 497 patients with fragility hip fractures. Only 25.5% of patients received continuous medication for 3 years, and 44.1% of patients received no treatment. Low Barthel index at discharge was a risk factor for both non-treatment and non-persistence to osteoporosis medication. PURPOSE: Fragility hip fractures (FHF) caused by osteoporosis decrease the quality of life and worsen life expectancy. Use of osteoporosis medication may be an efficient method in the prevention of secondary FHF. However, previous studies have reported low rates of osteoporosis medication and persistence after FHF. This study aimed to evaluate osteoporosis medication use and factors affecting persistence in patients with FHF in the northern Kyushu area of Japan. METHODS: A total of 497 FHF patients aged ≥ 60 years with a 3-year follow-up were included. We prospectively collected data from questionnaires sent every 6 months regarding compliance with osteoporosis medication. We compared baseline characteristics among three groups: no treatment (NT), no persistence (NP), and persistence (P), and conducted multivariable regression models to determine covariates associated with non-treatment (NT vs. NP/P) and non-persistence (NP vs. P). RESULTS: There were 219 (44.1%), 151 (30.4%), and 127 (25.5%) patients in the NT, NP, and P groups, respectively. Factors associated with non-treatment were male sex, chronic kidney disease, no previous osteoporosis treatment, and low Barthel index (BI) at discharge. The only factor associated with non-persistence was a low BI at discharge. Factors associated with a low BI at discharge were male sex, older age, trochanteric fracture, and surgical delay. CONCLUSION: Low BI at discharge is a risk factor for both non-treatment and non-persistence to osteoporosis medication. Therefore, appropriate interventions to improve BI may result in persistence to osteoporosis medication.

Use of an inertial measurement unit sensor in pedicle screw placement improves trajectory accuracy.

Ascertaining the accuracy of the pedicle screw (PS) trajectories is important as PS malpositioning can cause critical complications. We aimed to determine the angle range over which estimation is unreliable; build a low-cost PS placement support system that uses an inertial measurement unit (IMU) to enable the monitoring of surgical tools and PS trajectories, and determine the situations where IMU support would be most beneficial. In PS insertion experiments, we used cadaver samples that included lumbar porcine spines. Computed tomography images obtained before and after PS insertion were viewed. Offsets between the planned and implanted PS trajectories in the freehand and IMU-assisted groups were analyzed. The PS cortical bone breaches were classified according to the Gertzbein and Robbins criteria (GRC). Added head-down tilted sample experiments were repeated wherein we expected a decreased rostro-caudal rotational accuracy of the PS according to the angle estimation ability results. Evaluation of the PS trajectory accuracy revealed no significant advantage of IMU-assisted rostro-caudal rotational accuracy versus freehand accuracy. According to the GRC, IMU assistance significantly increased the rate of clinically acceptable PS positions (RoCA) than the freehand technique. In the head-down tilted sample experiments, IMU assist provided increased accuracies with both rostro-caudal and medial rotational techniques when compared with the freehand technique. In the freehand group, RoCA was significantly decreased in samples with rostral tilting relative to that in the samples without. However, In the IMU-assisted group, no significant difference in RoCA between the samples with and without head-down tilting was observed. Even when the planned PS medial and/or rostro-caudal rotational angle was relatively large and difficult to reproduce manually, IMU-support helped maintain the PS trajectory accuracy and positioning safety. IMU assist in PS placement was more beneficial, especially for larger rostro-caudal and/or medial rotational pedicle angles.

Recycling endosomal CD133 functions as an inhibitor of autophagy at the pericentrosomal region.

CD133 is a transmembranous protein that mainly localises to the plasma membrane in haematopoietic and neural stem cells as well as cancer stem cells. Although CD133 also localises to the cytoplasm, the mechanism of action and function of cytoplasmic CD133 currently remain unknown. We herein demonstrated that when Src family kinase activity is weak, CD133 interacts with HDAC6 and is transported to the pericentrosomal region after internalization and endosome formation via the dynein-based traffic system. Pericentrosomal CD133 is then recycled to the plasma membrane via recycling endosomes. At the pericentrosomal region, endosomal CD133 captures GABARAP, an initiator of autophagy, and inhibits GABARAP-mediated ULK1 activation and the subsequent initiation of autophagy. Furthermore, pericentrosomal CD133 suppresses cell differentiation, such as primary cilium formation and neurite outgrowth, by inhibiting autophagy. Thus, the present results provide evidence to suggest that pericentrosomal CD133 has the unique property of maintaining the undifferentiated status of cells by inhibiting autophagy.

Predictive factors of mortality of patients with fragility hip fractures at 1 year after discharge: A multicenter, retrospective study in the northern Kyushu district of Japan.

PURPOSE: Fragility hip fractures (FHFs) are associated with a high risk of mortality, but the relative contribution of various factors remains controversial. This study aimed to evaluate predictive factors of mortality at 1 year after discharge in Japan. METHODS: A total of 497 patients aged 60 years or older who sustained FHFs during follow-up were included in this study. Expected variables were finally assessed using multivariable Cox proportional hazards models. RESULTS: The 1-year mortality rate was 9.1% (95% confidence interval: 6.8-12.0%, n = 45). Log-rank test revealed that previous fractures (p = 0.003), Barthel index (BI) at discharge (p = 0.011), and place-to-discharge (p = 0.004) were significantly associated with mortality for male patients. Meanwhile, body mass index (BMI; p = 0.023), total Charlson comorbidity index (TCCI; p = 0.005), smoking (p = 0.007), length of hospital stay (LOS; p = 0.009), and BI (p = 0.004) were the counterparts for females. By multivariate analyses, previous vertebral fractures (hazard ratio (HR) 3.33; p = 0.044), and BI <30 (HR 5.42, p = 0.013) were the predictive variables of mortality for male patients. BMI <18.5 kg/m2 (HR 2.70, p = 0.023), TCCI ≥5 (HR 2.61, p = 0.032), smoking history (HR 3.59, p = 0.018), LOS <14 days (HR 13.9; p = 0.007), and BI <30 (HR 2.76; p = 0.049) were the counterparts for females. CONCLUSIONS: Previous vertebral fractures and BI <30 were the predictive variables of mortality for male patients, and BMI <18.5 kg/m2, TCCI ≥5, smoking history, LOS <14 days, and BI <30 were those for females. Decreased BI is one of the independent and preventable risk factors. A comprehensive therapeutic approach should be considered to prevent deterioration of activities of daily living and a higher risk of mortality.

Recovery of Wrist Function after Volar Locking Plate Fixation for Distal Radius Fractures.

BACKGROUND: The purpose of our present study was to examine the recovery of the postoperative wrist function, and to compare the range of motion among each direction ofthe wrist joint during the same time periods after surgery for distal radius fractures. METHODS: Twenty patients treated with a volar locking plate were evaluated. The active range of motion and grip strength were assessed at four weeks, six weeks, three months, six months and one year after surgery. RESULTS: The ratio of the range of motion in pronation and supination recovered significantly earlier than for any other directions within six months after surgery (p = 0.0205), however, the ratio of the range of motion among the six directions was not significantly different at one year after surgery (p = 0.0823). The recovery of the range of motion in flexion was 96.8% compared with the contralateral wrist at one year after surgery, and it was not significantly lower than that in extension, radial deviation or ulnar deviation (97.8%, 93.5%, 94.4%, respectively). The grip strength of dominant hand recovered from 50% after four weeks to 66% after six weeks, 83% after three months, 91% after six months and 106% at the examination performed after one year compared with the uninjured non-dominant hand. The grip strength of non-dominant hand recovered from 52% after four weeks to 59% after six weeks, 79% after three months, 84% after six months and 94% at the examination performed after one year compared with the uninjured dominant hand. The mean DASH score was 5.3. CONCLUSIONS: The range of motion in flexion can achieve similar improvement to that in the other directions by obtaining the appropriate postoperative parameters. The optimal postoperative radiographic parameters were thus identified to be essential for successfully obtaining a recovery of the wrist function for unstable distal radius fractures.

Recurrent dislocations of the atlantooccipital and atlantoaxial joints in a halo vest fixator are resolved by backrest elevation in an elevation angle-dependent manner.

BACKGROUND CONTEXT: Halo fixation is now universally performed in the initial reduction and fixation of unstable upper cervical spine injuries; however, persistent high instability and recurrent dislocations of the atlantooccipital and atlantoaxial joints after fixation are not well recognized. PURPOSE: The aim was to describe persistent instability of traumatic dislocations of the atlantooccipital and atlantoaxial joints after halo fixation and a useful method for preventing instability. STUDY DESIGN: This was a case report of a patient who survived traumatic dislocations of the atlantooccipital and atlantoaxial joints. PATIENT SAMPLE: A 73-year-old woman diagnosed with dislocations of the atlantooccipital and atlantoaxial joints along with multiple other injuries sustained in a traffic accident was included. METHODS: After initial closed reduction and halo fixation, congruity of the atlantooccipital and atlantoaxial joints was evaluated using, condylar gap, atlantodental interval, and flexion angulation of C1-C2 after the initial examination and before surgery. RESULTS: Changes in parameters 12 hours after halo fixation revealed re-dislocations and instability of the joints. Backrest elevation with halo fixation tended to reduce re-dislocations. Therefore, we carefully increased the backrest angle and measured the parameters at several angles of elevation within a range that did not affect vital signs to observe the effectiveness of elevation against re-dislocations. Elevation changed the parameters in an elevation angle-dependent manner, and these changes suggested that elevation was effective for reducing re-dislocation of both the atlantooccipital and atlantoaxial joints during halo fixation. With no major complications, this method enabled us to maintain good congruity of the joints for approximately 2 weeks until posterior spinal fusion with internal fixation. CONCLUSIONS: Backrest elevation with halo fixation appears safe to be performed without any other devices and is beneficial for blocking re-dislocation of both the atlantooccipital and atlantoaxial joints as well as possible secondary damage to the upper cervical spinal cord during the external fixation period.

An external snapping hip caused by osteochondroma of the proximal femur.

We herein report the findings of a 17-year-old boy who suffered from a right external snapping hip, which was caused by an osteochondroma of the proximal femur. He has been asymptomatic since the excision of the tumor. This case shows a rare etiology in which an external snapping hip occurred between the iliotibal band and the osteochondroma.