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Rupture of the extensor pollicis longus (EPL) tendon is a known complication after undisplaced distal radius fracture (DRF). However, no report has revealed the relationship between EPL tendon rupture and the fracture pattern. Thus, this study aimed to investigate the characteristics of fractures at risk of EPL tendon rupture using fracture line mapping of undisplaced DRFs. This study used computed tomography imaging data of undisplaced DRFs with (n=18) and without EPL tendon rupture (n=52). Fracture lines obtained from 3D reconstruction data were drawn manually after matching with a 2D template wrist model. Fracture maps represented the fracture line distribution by superimposing the fracture lines of all 70 patients. Heat maps showed the relative frequency of the fracture lines as a gradual color change. Fracture lines of cases with EPL tendon rupture were concentrated in the proximal border of Lister’s tubercle. By contrast, fracture lines of cases without EPL tendon rupture were relatively dispersed.

The improved cemented cup technique has attained excellent long-term results in primary total hip arthroplasty. When cup revision surgery was performed, the cemented cup, which was loosened at the bone-cement interface, was easily removed. However, with a well-fixed bone-cement interface, it remains difficult to remove the cemented cup for a revision in the event of a recurring dislocation. In addition, protrusions in the cement can cause unpredictable bone defects. A new removal device was created and used successfully to remove a well-fixed cemented cup safely and efficiently. This report introduces the device and the technique used in cemented cup removal.

A 65-year-old man presented with a left medial meniscus (MM) posterior root tear (PRT). Unicompartmental knee arthroplasty was performed 12 months after transtibial pullout repair of the MMPRT. Repaired MM posterior root tissue was subjected to histological analysis. Immunostaining and picrosirius red staining showed sufficient deposition of type I collagen, and hematoxylin-eosin staining using a polarized microscope showed well-aligned fiber orientation in the repaired tissue. The repaired posterior root (post-transtibial pullout repair) showed mature and well-aligned ligament-like tissue. Preserving the MM posterior root remnant to mimic the original posterior root tissue might be useful when performing pullout repair.

One of the problems during surgery for intramedullary lipoma is the ambiguous boundary between the lipoma and the spinal cord, resulting in either incomplete resection or damage to the spinal cord. We report a case of intramedullary lipoma resection on a 61-year-old man in which the boundary between the tumor and spinal cord was repeatedly visualized with intraoperative ultrasonography. We focused on the distinctive features of fat as hyperechoic, in contrast to low-echo neural tissue. Subtotal resection of the tumor was achieved without any aggravation of neurological symptoms. Intraoperative ultrasonography may be useful for confirming tumor boundaries during intramedullary lipoma resection.

This is the second report of an atypical peri-implant femoral fracture occurring at the distal screw after intramedullary nail fixation of a pertrochanteric fracture. A 94-year-old Japanese female with a 5-year history of alendronate intake presented with prodromal pain in her right thigh after intramedullary nail fixation. Plain radiographs showed an incomplete noncomminuted transverse fracture at the distal screw, suggesting an atypical peri-implant femoral fracture. The pathogenesis of an atypical peri-implant femoral fracture could be a combined systemic bone metabolism disorder and repetitive overloading at the screw, similar to the pathogenesis of an atypical periprosthetic femoral fracture around stem implantation.

The intraoperative pathological diagnosis (IPD) plays an important role in determining the optimal surgical treatment for spinal cord tumors. The final pathological diagnosis (FPD) is sometimes different from the IPD. Here, we sought to identify the accuracy of the IPD of spinal cord tumors compared to the FPD. We retrospec-tively analyzed the cases of 108 patients with spinal cord tumors treated surgically in our institute; the IPD, FPD, mismatched cases, and concordance rate between the IPD and FPD were investigated. Five cases involved a mismatch between the IPD and FPD. The overall concordance rate was 95.4%, with 90.9% for extra-dural lesions, 98.5% for intradural extramedullary lesions, 84.2% for intramedullary lesions, and 100% for dumbbell-type tumors. The concordance rate of intramedullary lesions tended to be lower than that of other lesions (p = 0.096). A lower concordance rate was revealed for intramedullary lesions compared to the other lesions. Despite the IPD clearly remaining a valuable tool during operative procedures, surgeons should recog-nize the limitations of IPDs and make comprehensive decisions about surgical treatments.

Medial meniscus posterior root tears (MMPRTs) have recently attracted considerable interest in orthopedics. To date, no in vivo human study has investigated suture translation changes in repaired MMPRTs with different degrees of knee flexion. This study examined suture translation at various degrees of knee flexion in 30 patients undergoing medial meniscus posterior root repair using the modified Mason-Allen suture technique between August 2016 and September 2017. Intraoperatively, sutures were provisionally fixed to an isometric positioner at the tibial site of the desired meniscal attachment, and the suture translation was measured at 0°, 30°, 60°, and 90° of knee flexion. The results showed significant increases in mean suture translation at the knee flexion positions from 0° to 30°, 30° to 60°, and 60° to 90° (p

Intra-operative acetabular fracture is a total hip arthroplasty complication that can occur during cementless cup insertion, especially in osteoporotic patients. We conducted this biomechanical study to investigate the impact resistance of the acetabulum with simulated bones of different density by drop-weight impact testing. Low- and high-density polyurethane foam blocks were used as osteoporotic and healthy bone models, respectively. Polyurethane blocks were used as the acetabular cancellous bone. Composite sheets were used as the acetabu-lum’s medial cortex. The testing revealed that the osteoporotic bone model’s impact resistance was significantly lower than that the healthy bone model’. In the healthy bone model, even thin acetabular cancellous bone with ≥ 1 mm acetabulum medial cortex was less likely to fracture. In the osteoporotic bone model, fracture was pos-sible without ≥ 1 mm medial cortex of the acetabulum and thick acetabular cancellous bone. Although impac-tion resistance differs due to bone quality, the impaction resistance in this osteoporotic bone model was equiv-alent to that healthy bone model’s when a thick medial wall was present. To avoid intra-operative acetabulum fracture, surgeons should consider both the bone quality and the thicknesses of the medial cortex and acetabu-lar cancellous bone.

We investigated the relationship between the initial contact status and stress shielding in total hip arthroplasty (THA) using fit-and-fill type straight-stem implants. In addition we evaluated the clinical and radiographic outcomes. Subjects were 100 hips of 94 patients who underwent THA and were followed-up for ≥10 years. Contact areas with the femoral cortical bone were investigated according to the zonal distribution of Gruen using postoperative CT images. Depending on the number of contact areas, the patients were classified into high contact [HC], medium contact [MC], and low contact [LC] groups. Radiographic and clinical outcomes were evaluated. In the HC group (20 hips), severe stress shielding was observed in 12 hips, which was statistically significant (p=0.008). In the LC group (29 hips), mild stress shielding was observed in 27 hips which was statistically significant (p

We studied phrenic nerve conduction times in 90 phrenic nerves of 45 normal subjects. The phrenic nerve was stimulated at the posterior border of the sternomastoid muscle in the supraclavicular fossa, just above the clavicle, with bipolar surface electrodes. For recording, positive and negative electrodes were placed on the xiphoid process and at the eighth intercostal bone-cartilage transition, respectively. We studied both the right and left sides to determine whether there was any difference between the two sides. The mean onset latency (± SD) of the right compound muscle action potentials (CMAPs) (5.99±0.39 msec) was significantly shorter than that of the left CMAPs (6.45±0.50 msec). The mean peak latency was significantly shorter in the right CMAPs (10.22±1.33 msec) than the left CMAPs (12.48±2.02 msec). The mean (± SD) amplitude was significantly lower in the left CMAPs (0.42±0.11 mV) than the right CMAPs (0.49±0.10 mV). The difference between the length of the nerve on the right and left sides might have affected the difference in latency between the two sides.

Medial meniscus (MM) posterior root tear (PRT) results in joint overloading and degenerative changes in the knee. MM root repair is recommended to prevent subsequent cartilage degeneration following MMPRT. Favorable clinical outcomes have been reported after transtibial pullout repair of MMPRT. However, it is unclear whether pullout repair can cause compositional change in the MM posterior segment. We examined this question in 14 patients who underwent MMPRT pullout repair. Magnetic resonance imaging examinations were performed preoperatively and 3 months postoperatively at 10° knee flexion. The region-of-interest was marked along the MM posterior segment edge. Intra-meniscal signal intensity (IMSI) was expressed as the signal intensity ratio of the repaired MM to the intact lateral meniscus, which was used as a control. MMPRT pullout repair reduced IMSI from 1 to 0.915±0.096 (range, 0.760-1.074) 3 months postoperatively (p=0.006, power=0.90). Meniscal degeneration causes high proton density-weighted imaging signal intensity of the meniscal body. In our study, MMPRT pullout repair reduced IMSI contrary to other tears. This technique may decrease the MM posterior segment signal intensity by restoring the hoop tension mechanism. Measuring IMSI may be useful to assess the effect of MMPRT pullout repair on meniscal healing.

Venous thromboembolism (VTE) is a major complication in patients with acute spinal cord injury. There are few reports of VTE with acute thoracolumbar spinal cord injury (TLSCI). We assessed the incidence of VTE with acute TLSCI using color Doppler ultrasonography. We retrospectively assessed 75 patients with acute TLSCI (T1 to L1). All patients were surgically treated. VTE of the lower extremity and pelvis was assessed using color Doppler ultrasound regardless of whether symptoms were present. This retrospective study included patients who were assessed between 6 and 10 days (mean 8.1 days) after injury. VTE was detected in 27 of the 75 patients (35.7%) with or without paralysis. Of the 13 patients who had complete motor paralysis, 8 (62%) had VTE; of the 31 patients with incomplete motor paralysis, 10 (32%) had VTE, and of the 31 patients without motor paralysis, 9 (29%) had VTE. Among the patients with TLSCI, those with VTE had a significantly higher mean age than those without. The incidence of VTE in TLSCI patients is not related to the severity of paralysis in a Japanese population. The incidence appears to be related primarily to age.

This is the first report of extensive bilateral patellar tendon ossification occurring over a prolonged time after a unilateral knee injury. An 84-year-old Japanese man with a spinal cord injury caused by a burst fracture of the T12 vertebra presented with a bony hard prominence on the left knee, which was injured in a traffic accident when he was 77 years old. Radiography revealed extensive ossification of the bilateral patellar tendons. We review the English literature with a focus on the localization of bilateral heterotopic ossification of the knee in patients who had a central nervous system injury.

Extrusion of the medial meniscus (MM) is associated with knee joint pain in osteoarthritic knees. The relationships among MM radial/oblique tears, MM extrusion (MME), and the effect of arthroscopic meniscal repair are not established. Here we evaluated the effects of arthroscopic all-inside MM repair on MME and the clinical outcomes in patients with radially oriented MM tears and mildly osteoarthritic knees. Twenty patients with a symptomatic radial or oblique tear of the MM posterior segment, MME ≥2.5 mm, and mildly osteoarthritic knees were treated using FasT-Fix 360 All-inside Meniscal Suture devices. We used magnetic resonance imaging (MRI) to measure the patients’ MM body width (MMBW), absolute MME, and relative MME. The Japanese Knee Injury and Osteoarthritis Outcome Score, Lysholm, Tegner, IKDC Subjective Knee Evaluation, and Visual Analogue Scale scores were obtained. Arthroscopic all-inside MM repair prevented increases of absolute and relative MME. The preoperative and 3- and 12-month MRI-based MMBW values were similar. Over a 24-month follow-up after the MM repairs, the clinical scores showed significant improvements. Our results suggest that all-inside meniscal repairs would be useful in preventing the progression of MME in patients suffering from symptomatic MM radial/oblique tears associated with mildly osteoarthritic knees.

Total hip arthroplasty (THA) is the most effective treatment for advanced or end-stage hip osteoarthritis. However, venous thromboembolism (VTE) remains one of its unresolved complications. We reviewed the records of 322 patients undergoing primary THA and investigated the efficacy of anticoagulant prophylaxis for VTE. Our study cohort consisted of 60 patients who received no anticoagulants, 100 patients who received a factor Xa inhibitor (fondaparinux), 100 patients who received low molecular weight heparin (enoxaparin), and 62 patients who selectively received no anticoagulant prophylaxis due to perioperative bleeding, weight, and/or hemoglobin concentration. Enhanced 64-slice multidetector row computed tomography was performed postoperatively for 7 days in all cases. The incidence of VTE in the four groups was 15ｵ, 9.0ｵ, 6.0ｵ, and 6.4ｵ, respectively. The incidence of VTE was significantly lower in the groups receiving anticoagulant prophylaxis and the group selectively receiving no anticoagulant prophylaxis than in the group receiving no anticoagulants. Complications of fondaparinux therapy included hepatic dysfunction in 4 cases (4.0ｵ), minor bleeding in 2 cases (2.0ｵ), persistent wound drainage in 3 cases (3.0ｵ), and eruption in 1 case (1.0ｵ). The complications of enoxaparin therapy were persistent wound drainage in 1 case (1.0ｵ) and progression of anemia in 1 case (1.0ｵ). The incidence of VTE was low in patients who selectively received no anticoagulant prophylaxis, so we conclude that anticoagulant prophylaxis should be used selectively in THA cases.

Osteoradionecrosis (ORN), a well-known complication of radiotherapy in the mandibular bone, is very rare in the cervical spine. The authors report the result of a 3-year follow-up of a 63-year-old female patient with ORN of the cervical spine. The patient had a history of laryngeal carcinoma and was treated with chemotherapy and radiation therapy with a total of 120 Gy. Eight years later, she developed acute, severe neck pain due to cervical spine necrosis. The authors performed vascularized fibular bone graft and posterior pedicle screw fixation to reconstruct her cervical spine. The patient was successfully treated with surgery, and cervical alignment was preserved. She had neither neurological deficits nor severe neck pain at her final follow-up 3 years later. Delaying treatment of ORN may be life threatening, so the early diagnosis of this condition is important for patients who receive radiotherapy. Otolaryngologists and spine surgeons should understand this potential complication to speed diagnosis and treatment as early as possible.

Patients with cerebral palsy (CP) frequently present with scoliosis; however, the pattern of curve progression is difficult to predict. We aimed to clarify the natural course of the progression of scoliosis and to identify scoliosis predictors. This was a retrospective, single-center, observational study. Total of 92 CP patients from Asahikawasou Ryouiku Iryou Center in Okayama, Japan were retrospectively analyzed. Cobb angle, presence of hip dislocation and pelvic obliquity, and Gross Motor Function Classification System (GMFCS) were investigated. Severe CP was defined as GMFCS level IV or V. The mean observation period was 10.7 years. Thirtyfour severe CP patients presented with scoliosis and were divided into 3 groups based on their clinical courses: severe, moderate and mild. The mean Cobb angles at the final follow-up were 129°, 53°, and 13° in the severe, moderate, and mild groups, respectively. The average progressions from 18 to 25 years were 2.7°/year, 0.7°/year, and 0.1°/year in the severe, moderate, and mild curve groups, respectively. We observed the natural course of scoliosis and identified 3 courses based on the Cobb angle at 15 and 18 years of age. This method of classification may help clinicians predict the patients’ disease progression.

The present report describes the first known, case of a pseudoaneurysm of the perforating branch of the deep femoral artery following anterior cruciate ligament (ACL) reconstruction. A 19-year-old man underwent ACL reconstruction using the outside-in femoral tunnel-creation method. Seven days after the surgery, he complained of abnormal thigh pain and had swelling with local heat on the distal lateral thigh. Magnetic resonance imaging, computed tomography, and color Doppler ultrasonography showed the pseudoaneurysm in the thigh. Resection surgery was successfully performed by a vascular surgeon 12 days after ACL reconstruction. Careful examination and awareness of postoperative symptoms such as thigh pain and swelling after ACL reconstruction were critical for the early diagnosis of pseudoaneurysm.

Spinal deformity is an important clinical manifestation of Chiari I malformation (CM-I) and syringomyelia. Here we report the result of an 8-year follow-up of a 13-year-old girl with severe scoliosis associated with Chiari malformation and a large syringomyelia. The patient presented at our hospital at the age of 13 with a 68° scoliosis. Magnetic resonance imaging showed Chiari malformation and a large syringomyelia. Neurosurgical treatment involved foramen magnum decompression and partial C1 laminectomy, but the scoliosis still progressed. We present the first case report of a rare course of scoliosis in a patient with CM-I and a large syringomyelia.

We reviewed the treatment outcome in 14 hips of 7 patients who were diagnosed as having bilateral developmental dislocation of the hip (DDH) after walking age and could be followed up until they were at least 14 years of age. Based on the results of two-directional arthrography of the hip, closed reduction was performed in 2 hips, and open reduction was performed without osteotomy in 12 hips. The final radiographic evaluations were made according to the Kalamchi and MacEwen classification and Severin classification. The mean age at the initial visit was 1 year and 9 months (range, 1 year and 5 months to 3 years). The outcome was satisfactory for one hip in Group Ⅰ and 2 hips in Group Ⅱ according to the Kalamchi and MacEwen classification, and in 83% of the Severin Class Ⅰ and Ⅱ hips. Arthrography was useful for identifying asymmetry, demonstrating the usefulness of a treatment strategy based on arthrography of the hip.

Cervical spinal schwannoma is benign, and outcomes after surgical resection are generally excellent. A surgical dilemma sometimes arises as to whether to perform total tumor removal, which carries a risk of sacrificing the nerve root, or subtotal removal, where the risk can be tumor recurrence. The purpose of this study was to identify factors with the potential to predict clinical impairment after surgery for cervical spinal schwannomas. Thirty cases of cervical schwannomas treated surgically in our institute were retrospectively reviewed;initial symptoms, tumor location, Eden classification, surgical method, functional outcome, and tumor recurrence were investigated. All permanent motor deficits were the result of resecting functionally relevant nerve roots (i.e., C5-8). The rate of permanent sensory deficit was 11% after C1-4 nerve root resection, and 67% after C5-8 nerve root resection. Permanent neurological deficits occurred in 14% of patients younger than 40 years and 38% of those older than 40. Dumbbell tumors were associated with the need for total or ventral nerve root transection, as well as with a high incidence of tumor recurrence. The incidence of permanent neurological deficit was significantly higher in patients undergoing C5-8 nerve root resection, and tended to be higher in those over 40.

There are few reports on skeletal reconstruction using the bone transport technique to repair bone defects caused by resections of tumors associated with osteosarcoma. We attempted to reconstruct a 23 cm bone defect after resection of an osteosarcoma of the left femur, and succeeded in gaining 17 cm by bone transport. Five years after surgery, this patient remains alive without metastasis or local recurrence.

Cervical misalignment after upper cervical fusion including the occipital bone may cause trismus or dysphagia, because the occipito-atlanto joint is associated with most of the flex and extended motion of the cervical spine. There are no reports of dysphagia and trismus after C1-2 fusion. The purpose of this paper is to demonstrate the potential risk of dysphagia and trismus even after upper cervical short fusion without the occipital bone. The patient was a 69-year-old man with myelopathy caused by os odontoideum and Klippel-Feil syndrome, who developed dysphagia and trismus immediately after C1-2 fusion and C3-6 laminoplasty. Radiographs and CT revealed that his neck posture was extended, but his symptoms still existed a week after surgery. The fixation angle was hyperextended 12 days after the first surgery. His symptoms disappeared immediately after revision surgery. The fixation in the neck-flexed position is thought to be the main cause of the patientʼs post-operative dysphagia and trismus. Dysphagia and trismus may occur even after short upper cervical fusion without the occipital bone or cervical fusion in the neck-extended position. The pre-operative cervical alignment and range of motion of each segment should be thoroughly evaluated.

We report on 2 patients who experienced injury to one of their lumbar arteries related to pedicle screw misplacement. In this report, the lumbar pedicle screw holes were made laterally with resultant injury to the lumbar artery. During surgery, arterial bleeding was controlled with pressure and gauze; however, the patients experienced vital shock after surgery. Vital shock ensued and they were rescued by catheter embolization. If patients receiving lumbar instrumentation surgery experience severe anemia or vital shock postoperatively, the surgeon should assume lumbar artery injury as a differential diagnosis.

The purpose of this study was to quantitatively evaluate Akahori's preoperative classification of cubital tunnel syndrome. We analyzed the results for 57 elbows that were treated by a simple decompression procedure from 1997 to 2004. The relationship between each item of Akahori's preoperative classification and clinical stage was investigated based on the parameter distribution. We evaluated Akahori's classification system using multiple regression analysis, and investigated the association between the stage and treatment results. The usefulness of the regression equation was evaluated by analysis of variance of the expected and observed scores. In the parameter distribution, each item of Akahori's classification was mostly associated with the stage, but it was difficult to judge the severity of palsy. In the mathematical evaluation, the most effective item in determining the stage was sensory conduction velocity. It was demonstrated that the established regression equation was highly reliable (R = 0.922). Akahori's preoperative classification can also be used in postoperative classification, and this classification was correlated with postoperative prognosis. Our results indicate that Akahori's preoperative classification is a suitable system. It is reliable, reproducible and well-correlated with the postoperative prognosis. In addition, the established prediction formula is useful to reduce the diagnostic complexity of Akahori's classification.

In this study, we studied the relationship between fracture patterns and motor function recovery in 70 consecutive patients with cervical spinal cord injury. Fractures were categorized into 6 fracture types and subdivided into stages according to the Allen-Ferguson classification system:compressive flexion (CF), distractive flexion (DF), compressive extension (CE), distractive extension (DE), vertical compression (VC) and lateral flexion (LF). Paralysis was evaluated using the American Spinal Injury Association (ASIA) impairment scale at the time of injury and 3 months afterwards. The residual rate of complete motor palsy (ASIA grade A or B) at the final examination was higher in those patients with DE fractures than those with CF, DF or CE. The final outcomes were as follows. Of the 14 patients who were classified with CF fractures, residual palsy was frequently seen in patients who had stage 5 injury. Of the 27 patients with DF fractures, residual palsy occurred in about half of the patients who had stage 4 or 5 injury. Of the 18 patients with CE fractures, residual palsy occurred in half of the patients with stage 3 injury or higher. Finally, of the 7 patients with DE fractures, the rate of residual palsy was high even for the stage 1 and 2 cases;indeed, all DE patients who had complete motor palsy at the first examination had residual palsy at the final examination. Accordingly, we conclude that motor recovery may be related to fracture pattern.

An 11 year-old girl had 66 degrees of kyphosis in the thoracolumbar junction. For the purpose of planning for kyphosis correction, we created a 3-D, full-scale model of the spine and consulted spinal navigation. Three-dimensional models are generally used as tactile guides to verify the surgical approach and portray the anatomic relations specific to a given patient. We performed posterior fusion from Th10 to L3, and vertebral column resection of Th12 and L1. Screw entry points, directions, lengths and diameters were determined by reference to navigation. Both tools were useful in the bone resection. We could easily detect the posterior element to be resected using the 3D model. During the anterior bony resection, navigation helped us to check the disc level and anterior wall of the vertebrae, which were otherwise difficult to detect due to their depth in the surgical field. Thus, the combination of navigation and 3D models helped us to safely perform surgery for a patient with complex spinal deformity.

Total hip arthroplasty (THA) is the most effective treatment for advanced or end-stage hip osteoarthritis. However, venous thromboembolism (VTE) remains one of its unresolved complications. We reviewed the records of 322 patients undergoing primary THA and investigated the efficacy of anticoagulant prophylaxis for VTE. Our study cohort consisted of 60 patients who received no anticoagulants, 100 patients who received a factor Xa inhibitor (fondaparinux), 100 patients who received low molecular weight heparin (enoxaparin), and 62 patients who selectively received no anticoagulant prophylaxis due to perioperative bleeding, weight, and/or hemoglobin concentration. Enhanced 64-slice multidetector row computed tomography was performed postoperatively for 7 days in all cases. The incidence of VTE in the four groups was 15%, 9.0%, 6.0%, and 6.4%, respectively. The incidence of VTE was significantly lower in the groups receiving anticoagulant prophylaxis and the group selectively receiving no anticoagulant prophylaxis than in the group receiving no anticoagulants. Complications of fondaparinux therapy included hepatic dysfunction in 4 cases (4.0%), minor bleeding in 2 cases (2.0%), persistent wound drainage in 3 cases (3.0%), and eruption in 1 case (1.0%). The complications of enoxaparin therapy were persistent wound drainage in 1 case (1.0%) and progression of anemia in 1 case (1.0%). The incidence of VTE was low in patients who selectively received no anticoagulant prophylaxis, so we conclude that anticoagulant prophylaxis should be used selectively in THA cases.

Epigenetics is an essential mechanism to control gene expression and fundamental cellular processes. DNA methylation in CpG-rich promoters correlates with gene silencing. Histone modification including histone acetylation and deacetylation determines the stability of the chromatin structure. Condensed chromatin (heterochromatin), which has a higher-order histone-DNA structure, prevents the access of transcriptional activators to their target genes. The fundamental unit of eukaryotic chromatin consists of 146 bp of DNA wrapped around a histone octamer. Posttranslational modifications of the histone tail and the chromatin remodeling complex disrupt histone-DNA contacts and induce nucleosome mobilization. Histone acetylation of specific lysine residues in the histone tail plays a crucial role in epigenetic regulation. Histone acetylation is a dynamic process regulated by the antagonistic actions of 2 families of enzymes - the histone acetyltransferases (HATs) and the histone deacetylases (HDACs). The balance between histone acetylation and deacetylation serves as a key epigenetic mechanism for transcription factor-dependent gene expression and the developmental process. We review emerging evidence that DNA methylation, histone acetylation modified by HAT and/or HDAC, and transcription factor-associated molecules contribute to a mechanism that can alter chromatin structure, gene expression, and cellular differentiation during chondrogenesis.

Plain X-ray radiography is frequently used for the diagnosis of developmental dislocation of the hip (DDH). The aim of this study was to construct a diagnostic support system for DDH based on clinical findings obtained from the X-ray images of 154 female infants with confirmed diagnoses made by orthopedists. The data for these subjects were divided into 2 groups. The Min-Max method of nonlinear analysis was applied to the data from Group 1 to construct the diagnostic support system based on the measurement of 4 items in X-ray images:the outward displacement rate, upward displacement rate, OE angle, and alpha angle. This system was then applied to the data from Group 2, and the results were compared between the 2 groups to verify the reliability of the system. We obtained good results that matched the confirmed diagnoses of orthopedists with an accuracy of 85.9%.

Femoroacetabular impingement (FAI) is a condition characterized by the impingement of the femur and acetabulum. In Japan, this disorder has become recognized gradually. Here we report a rare case of surgically treated FAI, associated with an osseous protrusion on the acetabulum of a 30-year-old female. Plain computed tomography (CT) and reconstructive 3D-CT images clearly demonstrated an anterolateral bony protrusion. Hip arthroscopy showed no degeneration of the cartilage on either the femoral or acetabular side, but degeneration at the edge of labrum was observed in the region of the bony protrusion. The complete removal of the bony protrusion under hip arthroscopy was thus considered impracticable, and a small skin incision was therefore made anteriorly to approach the acetabulum. The Short-Form 36-Item Health Survey (SF-36) revealed improvement in all scores.

This retrospective study assessed the radiographic results of 16 patients with avascular necrosis following treatment for developmental dislocation of the hip (DDH) who were subsequently treated between 1991 and 2005 by rotation acetabular osteotomy (RAO) combined with femoral intertrochan-teric osteotomy (FIO). Initial treatment was by Pavlik harness, cast fixation, or overhead traction. The parameters that showed consistent improvement were the index of centralization, the index of acetabular coverage, adequate reduction of the greater trochanter, and abductor sufficiency. The combined procedure appears to be effective in cases in which preoperative planning shows a reasonable expectation of congruency and osteoarthritis is limited to the early stages.

In 1957, Pavlik introduced the Pavlik harness as a useful treatment for developmental dislocation of the hip (DDH), and subsequent studies have documented favorable outcomes among patients treated with this device. However, there are only a few articles reporting how early radiographic measurements can be used to determine the prognosis after treatment with the Pavlik harness. In this study, 217 hips from 192 patients whose DDH treatment with the Pavlik harness was initiated before they were 6 months old and whose follow-up lasted at least 14 years (rate, 63.8%) were analyzed using measurements from radiographs taken immediately before and after harness treatment, and at 1, 2, and 3 years of age. Severin's classification at the final follow-up was I or II in 71.9% and III or IV in 28.1% of the hips, respectively. Avascular necrosis of the femoral head (AVN) was seen in 10% of the hips. Stepwise multiple regression analysis was performed to retrospectively determine whether any radiographic factors were related to the final classification as Severin I/II or III/IV. Receiver opera-ting characteristic (ROC) curves were drawn for these factors, and a Wiberg OE angle (Point O was the middle point of the proximal metaphyseal border of the femur) of 2 degrees on the 3-year radiographs was found to be the most useful screening value for judging the acetabular development of DDH cases after treatment with a Pavlik harness, with a sensitivity of 71% a specificity of 93%, and a likelihood ratio of 10.1.

Surgical treatment of metastatic spinal cord compression is controversial. The purpose of this study was to investigate the effectiveness of our current surgical treatments and the use of spinal instrumentation. In this retrospective study covering the years between 1990 and 2006, 100 patients with spinal metastases which were secondary to various cancers underwent posterior and/or anterior decompression with spinal stabilization for the purposes of reduction of pain, and/or to help correct or improve neurological deficits. The group was made up of 60 men and 40 women whose ages ranged from 16 to 83 years (average of 60 years), and the average follow-up period was 14 months. The effect of treatment upon pain relief and neural deficits was assessed, and the cumulative survival rate was calculated by the Kaplan-Meier method. The average surgical time was 185min. This was calculated based on the following times, listed here with the surgery type:178min for posterior surgery;245min for anterior surgery;465 min for combined surgery;and 475min for total en bloc spondylectomy. Average blood loss during surgery was 1,630 ml for posterior surgery, 1,760 ml for anterior surgery, 1,930 ml for combined surgery, and 3,640 ml for total en bloc spondylectomy. Preoperative pain and paralysis were improved by 88% and 53%, respectively. In regards to surgical complications, postoperative epidural hematoma was observed in 2 patients, and instrumentation-related infection was observed in 1. Only 2 patients died within 2 months of surgery. In conclusion, posterior and/or anterior decompression with spinal stabilization is a safe and effective treatment for patients with spinal metastases, and can improve their quality of life.

A minimally invasive plate osteosynthesis technique using a locking compression plate (LCP) has been used widely in trauma cases. Its advantages are that the MIPO technique does not interfere with the fracture site and thus provides improved biological healing, and that the LCP has excellent angular stability. Its use in bone lengthening, however, has not been established. In such cases, it is desirable to shorten the external skeletal fixation period as much as possible. Here, the MIPO technique using an LCP was applied to femoral distraction osteogenesis in an attempt to shorten the external skeletal fixation period. For femoral lengthening, the MIPO technique was performed in 2 stages. Orthofix external fixators (Orthofix, England) were used to insert screws from the anterolateral side rather than from the lateral side of the femur for bone lengthening. When sufficient callus formation was detected postoperatively at the site of bone lengthening, and the absence of infection was ensured, limb draping was performed, including a whole external fixator, and then the MIPO technique was applied with an LCP. In 3 cases (5 limbs), the average duration of external skeletal fixation was 134days, the average external-fixation index was 24days/cm, and the average consolidation index was 22days/cm. The MIPO technique using an LCP made it possible to shorten the external skeletal fixation-wearing period in femoral lengthening.

The purpose of this study was to investigate the surgical outcomes and to determine indicators of the necessity of surgical intervention. Twelve consecutive patients harboring symptomatic sacral perineural cysts were treated between 1995 and 2003. All patients were assessed for neurological deficits and pain by neurological examination. Magnetic resonance of imaging, computerized tomography, and myelography were performed to detect signs of delayed filling of the cysts. We performed a release of the valve and imbrication of the sacral cysts with laminectomies in 8 cases or recapping laminectomies in 4 cases. After surgery, symptoms improved in 10 (83%) of 12 patients, with an average follow-up of 27 months. Ten patients had sacral perineural cysts with signs of positive filling defect. Two (17%) of 12 patients experienced no significant improvement. In one of these patients, the filling defect was negative. In conclusion, a positive filling defect may become an indicator of good treatment outcomes.

In this study, we reviewed the clinical features of 11 patients with malignant schwannoma who were treated in our institute. Five patients had coexistent von Recklinghausen's disease and one of them showed multifocal occurrence. Patients with the centrally located tumors had a poorer prognosis than those with the others. The overall 3-year survival rate was 36%; 40% in patients with von Recklinghausen's disease and 33% in the others. At the time of the last follow-up, 9 patients had died of the tumor, one continued to be tumor free, and one was alive with tumor. Postoperative local recurrence developed in 5 patients (45%); 4 out of 6 patients (67%) who underwent a marginal excision and one out of 3 (33%) who underwent primary amputation. There was no local recurrence in patients after a wide excision with at least 3cm of normal tissue removed surrounding the tumor in all directions. Nine patients (82%) developed pulmonary metastasis. The effect of adjuvant chemotherapy was not clear in this study. The high risk of pulmonary metastasis in this disease indicates the necessity of more effective adjuvant chemotherapy.

We report second malignant neoplasms which developed between 7 and 19 years after treatment in 3 pediatric patients with osteosarcoma. Two patients had been treated with only surgery, and another patient had been treated with a combination of surgery with chemotherapy and radiation therapy for primary lesions. Pediatric patients with osteosarcoma, in particular, require careful long-term follow-up to monitor not only metastases but also development of second malignant neoplasms.

We evaluated the surgical problems encountered during treatment of 14 patients with malignant tumors originating in the pelvic region at our department. The tumor involved the iliac bone in 6 patients, the ischial bone in 2, the pubic bone in 2, and the gluteal region in 4. Invasion to the sacrum was observed in 7 patients. Twelve patients underwent surgical procedures consisting of intralesional resection in 6, marginal resection in 3, and wide margin resection in 3. Six of the 7 patients with sacral invasion developed local recurrence. Two patients with chondrosarcoma and one with parosteal osteosarcoma survived for 4 or more years, but the mean survival period in those with high grade malignant tumors was 11 months. These findings indicate the difficulties encountered in the treatment of malignant pelvic tumors.