Factors Influence on the Broaching Hammering Sound during Cementless Total Hip Arthroplasty

Background: The aim of this study is to identify the factors influence on the broaching hammering sound character during cementless total hip arthroplasty. Methods: We analyzed frequency spectrum of the hammering sound for 49 cases of uncomplicated cementless THAs using two types of proximal-coated stem performed by experienced surgeons. Normalized sound pressure (NSP) of each 0.5 kHz frequency band in final stage of broach procedure was determined by the fast Fourier transform analysis. The relationships between those sound characteristics and femoral morphology such as canal calcar ratio (CCR), Canal flare index (CFI), morphological cortical index (MCI) and femoral shaft length (FSL) in different cementless stem were investigated. Results: In Accolade 2, CCR was positively related to NSP in several bands [Frequency band (kHz);r: 2.0 - 2.5;0.37, 4.5 - 5.0;0.37, 9.5 - 10.0;0.44], and negatively related to 7.5 - 8.0 kHz (r = -0.39). Negative correlations were observed among CFI and MCI in specific frequency bands (4.5 - 5.0, 5.0 - 5.5, and 7.5 - 8.0 kHz). In Taperloc Microplasty, strong correlations were found between FSL and the NSP of 7.5. - 8.0 kHz (r = 0.78) and CCR and the 7.5 - 8.0 kHz bands. There was significant difference of NSPs between high and low group divided by morphological parameters. Acoustic characteristics of NSPs between Accolade 2 and Microplasty were significantly different in 9 frequency bands. Conclusions: The hammering sound correlated with four parameters of the femoral morphology and differed in different types of proximal-coated stem. Those novel five factors are important to consider when to predict complications using acoustic analysis.

Bipolar hemiarthroplasty for femoral neck fracture using the direct anterior approach

AIM: To evaluate whether walking ability recovers early after bipolar hemiarthroplasty(BHA) using a direct anterior approach.METHODS: Between 2008 and 2010, 81 patients with femoral neck fracture underwent BHA using the direct anterior approach(DAA) or the posterior approach(PA). The mean observation period was 36 mo. The age, sex, body mass index(BMI), time from admission to surgery, length of hospitalization, outcome after discharge, walking ability, duration of surgery, blood loss and complications were compared. RESULTS: There was no significant difference in the age, sex, BMI, time from admission to surgery, length of hospitalization, outcome after discharge, duration of surgery and blood loss between the two groups. Two weeks after the operation, assistance was not necessary for walking in the hospital in 65.0% of the patients in the DAA group and in 33.3% in the PA group(P < 0.05). As for complications, fracture of the femoral greater trochanter developed in 1 patient in the DAA group and calcar crack and dislocation in 1 patient each in the PA group.CONCLUSION: DAA is an approach more useful for BHA for femoral neck fracture in elderly patients than total hip arthroplasty in terms of the early acquisition of walking ability.

Biomechanical Study of Vertebral Compression Fracture Using Finite Element Analysis

This research aimed to mechanically analyze vertebral stress concentration in one healthy subject and one subject with osteoporotic first lumbar (L1) vertebral compression fracture by using finite element analysis (FEA). We constructed three-dimensional image-based finite element (FE) models (Th12L2) by using computed tomographic (CT) digital imaging and communications in medicine (DICOM) for each patient and then conducted exercise stress simulations on the spine models. The loadings on the 12th thoracic vertebra (Th12) due to compression, flexion, extension, lateral bending, and axial rotation were examined within the virtual space for both spine models. The healthy and vertebral compression fracture models were then compared based on the application of equivalent vertebral stress. The comparison showed that vertebral stress concentration increased with all stresses in the vertebral compression fracture models. In particular, compression and axial rotation caused remarkable increases in stress concentration in the vertebral compression fracture models. These results suggest that secondary vertebral compression fractures are caused not only by bone fragility but possibly also by the increase in vertebral stress concentration around the site of the initial

Biomechanical Effects of Implant Materials on Posterior Lumbar Interbody Fusion: Comparison of Polyetheretherketone and Titanium Spacers Using Finite Element Analysis and Considering Bone Density

Few biomechanical data exist regarding whether the polyetheretherketone (PEEK) spacer or titanium spacer is better for posterior lumbar interbody fusion (PLIF). This study evaluated the biomechanical influence that these types of spacers with different levels of hardness exert on the vertebra by using finite element analysis including bone strength distribution. To evaluate the risk of spacer subsidence for PLIF, we built a finite element model of the lumbar spine using computed tomography data of osteoporosis patients. Then, we simulated PLIF in L3/4 and built models with the hardness of the interbody spacer set as PEEK and titanium. Bones around the spacer were subjected to different load conditions. Then, fracture elements and some stress states of the two modalities were compared. In both models of PLIF simulation, fracture elements and stress were concentrated in the bones around the spacer. Fracture elements and stress values of the model simulating the PEEK spacer were significantly smaller compared to those of the titanium simulation model. For PLIF of osteoporotic vertebrae, this suggested that the PEEK spacer is in a mechanical environment less susceptible to subsidence caused by microfractures of bone tissue and bone remodeling-related fusion aspects. Therefore, PEEK spacers are bio-mechanically more useful.

The surgical Treatment and Outcome of Pathological Fracture in Patients with Giant Cell Tumor of Bone

Between 1992 and 2008, we treated 35 patients with giant cell tumor (GCT) of bone, seven of the 35 pre-sented with a pathological fracture. The fractures were located in the femur in five, and in the humerus and radius in one patient each. The surgical treatments were curettage in six cases and wide resection in the distal radius case. Two of the seven patients developed local recurrence, giving a local recurrence rate of 29%. The local recurrence rate in GCT patients without a pathological fracture was 21%. There was a tendency for there to be a higher recurrence rate associated with fractured GCT, but no statistically significant difference was observed between the two groups. Therefore, it was considered that a pathological fracture was not a risk factor for local recurrence in GCT.

Biomechanical Study of the Effects of Balloon Kyphoplasty on the Adjacent Vertebrae

We used the finite element method (FEM) to investigate the stress profiles of vertebrae in patients who underwent balloon kyphoplasty (BKP) for vertebral fracture. BKP is often performed for persistent pain after vertebral fractures. However, fractures are frequently reported in the adjacent vertebrae after BKP. The purpose was to clarify the mechanism of fractures that occur in the adjacent vertebrae after BKP. The subjects were two patients (first case: 74-year-old woman;second case: 88-year-old woman) who had BKP for osteoporotic vertebral fractures (L1). A bone analysis software program, Mechanical Finder, was used to construct three-dimensional finite element models (T11-L3) from computed tomographic (CT) digital imaging and communications in medicine (DICOM) data. Moment loadings were examined to evaluate stress concentrations on the vertebrae. Young’s moduli were lower in the second case than in the first case at all vertebral levels. Maximum Drucker-Prager stresses after BKP were larger in the second case than in the first case for compression, flexion, extension, and axial rotation. Strain energy density decreased in L1 and increased in the adjacent ver-tebrae. Our results suggest that post-BKP fractures of the adjacent vertebrae not only are due to bone fragility, but also can be caused by increased rigidity in the vertebrae filled with bone cement, which increases stress concentration on the adjacent verte-brae and raises the likelihood of fracture.

Effect of enpishin (press tack acupuncture needles) on autonomic function, WBC count and oxidative stress

Acupuncture as a vital component of traditional medical systems of the Far East has been used to restore and maintain health for over three millennia. However, the neurobiological correlates of this therapy remain largely unknown. The purpose of this study was therefore to determine the effect of enpishin acupuncture (press tack needles (PTN)) on autonomic function, WBC count, and oxidative stress between subjects that received either verum or placebo PTN treatment. Twenty men (mean(SD) age: 36.7(5.1) years) who provided oral consent were randomized to receive either verum PTN (n = 9) or placebo PTN (n = 11). Bi-Digital O-Ring Test (BDORT) was used to select the acupoints for each participant. Autonomic function and oxidative stress level were analyzed before and after the treatment via heart rate variability (HRV) and free radical analysis system (FRAS4), respectively. Pre- and post-treatment WBC count was also evaluated. Verum PTN group had a statistically significant increase (p = 0.008) in Ln TP, an index of overall autonomic activity. Subjects in this group also had a significantly greater (p = 0.006) variation in Ln TP than the placebo PTN group in response to the treatment. Similarly, Ln HF of subjects receiving verum PTN showed a marked increase (p = 0.0026) after the treatment. Moreover, a significantly greater (p < 0.001) variation in mean Ln HF before and after the treatment was noted in the verum group than the placebo group, reflecting a greater parasympathetic activation in the former. In contrast, sympathetic activity was not significantly influenced by verum PTN based on the lack of observed changes in LF/HF ratio. In addition, both groups failed to demonstrate significant variations in pre- and post-treatment mean Ln LF/HF ratio. Further, no significant intergroup difference was found with regard to mean variation in Ln LF/HF ratio. Verum PTN did not induce significant changes in WBC count and markers of oxidative stress, namely reactive oxygen species (ROM) and biological antioxidant potential (BAP). However, a comparison of variations in pre- and post-treatment mean WBC count showed a significant difference (p = 0.020) between the two treatment modes: verum group showed a slight increase (225 ± 384.5), while placebo group showed a minimal decrease (–190 ± 272.6). Our findings suggest that PTN increases overall autonomic activity, particularly the parasympathetic function.

Bilateral Symptomatic Lateral Parapatellar Synovial Plica of the Knee in an Adolescent Athlete: A Case Report

We report herein a rare case of lateral parapatellar synovial plica that developed simultaneously in both knees. A 15-year-old competitive soccer player visited our institution with a six-month history of anterolateral pain and catching sensation in both knee joints. On physical examination, he complained of tenderness along the joint line of bilateral patellofemoral joint (PFJ). Visible and palpable popping was observed at the lateral margin of each patella during active knee motion. Magnetic resonance imaging showed obvious synovial soft nodules in the lateral side of the PFJ. On arthroscopy, a yellowish, thick, tongue-shaped tissue extending transversely from the lateral parapatellar synovium was identified in both knees, and parts of this tissue showed avascular hypertrophy. Arthroscopic findings of both knees are almost symmetrical in anatomical location, but no similar in size. After arthroscopic excision, the patient became asymptomatic. At 24-month follow up, he demonstrated full knee function, without evidence of local recurrence.

Use of Nonlinear Finite Element Analysis of Bone Density to Investigate the Biomechanical Effect in the Bone around Intervertebral Cages in Posterior Lumbar Interbody Fusion

Preventing subsidence of intervertebral cages in posterior lumbar interbody fusion (PLIF) requires understanding its mechanism, which is yet to be done. We aimed to describe the mechanism of intervertebral cage subsidence by using finite element analysis through simulation of the osteoporotic vertebral bodies of an elderly woman. The data from computed tomography scans of L2-L5 vertebrae in a 72-year-old woman with osteoporosis were used to create 2 FE models: one not simulating implant placement (LS-INT) and one simulating L3/4 PLIF using polyetheretherketone (PEEK) cages (LS-PEEK). Loads and moments simulating the living body were applied to these models, and the following analyses were performed: 1) Drucker-Prager equivalent stress distribution at the cage contact surfaces;2) the distribution of damage elements in L2-L5 during incremental loading;and 3) the distribution of equivalent plastic strain at the cage contact surfaces. In analysis 1, the Drucker-Prager equivalent stress on the L3 and L4 vertebral endplates was greater for LS-PEEK than for LS-INT under all loading conditions and tended to be particularly concentrated at the contact surfaces. In analysis 2, compared with LS-INT, LS-PEEK showed more damage elements along the bone around the cages in the L3 vertebral body posterior to the cage contact surfaces, followed by the area of the L4 vertebral body posterior to the cage contact surfaces. In analysis 3, in the L3 inferior surface in LS-PEEK the distribution of equivalent plastic strain was visualized as gradually expanding along the cages from the area posterior to the cages to the area anterior to them with increased loading. These analyses suggested that in PLIF for osteoporotic vertebral bodies, the localized stress concentration generated by the use of PEEK cages may cause accumulation of microscopic damage in the fragile osteoporotic vertebral bodies around the cages, which may result in cage subsidence.

Metastatic Soft Tissue Tumors

Between 1998 and 2007, we treated 157 patients with malignant soft tissue tumors. Patients with obvious lymph node metastasis, metastasis from bone or soft tissue sarcoma, and with obvious advanced stage disease which had multiple metastases were excluded from the present analysis. Finally, sixteen of the 157 patients were diagnosed to have soft tissue metastasis from carcinomas or hematopoietic malignancies. There were 10 males and 6 females with an average age of 65 (range, 50 - 83) years. Four lesions were located in the abdomen and back, 3 in the thigh, 2 in the chest, and 1 lesion each in the upper arm, lower leg and buttock. There were 9 intramuscular and 7 subcutaneous metastases. The average tumor size was 6 cm (range 2 - 17 cm). The initial diagnoses were a primary soft tissue tumor in 8 cases, primary soft tissue tumor or metastatic soft tissue tumor in 6, and inflammatory lesions in 2. Four of the 6 cases were suspected to be a metastatic soft tissue tumor in the initial diagnosis based on a past history of malignancy. There were no characteristic findings of metastatic soft tissue tumors in the imaging studies. The primary origins were lung cancer in 6 cases, malignant lymphoma in 5, gastric cancer in 2, and esophageal cancer, pancreatic cancer and uterine cancer in 1 patient each. Treatments were administered to all cases, including radiotherapy and chemotherapy in 11, chemotherapy in 2, wide resection and chemotherapy in 1, radiotherapy in 1 and palliative therapy in 1. The final oncological status was continuous disease free survival in 1 patient, no evidence of disease in 1, alive with disease in 7, and dead of disease in 7 patients. The estimated one-year survival was 47% and the two-year survival was 0%.

Classification of Intervertebral Disc Degeneration in Low Back Pain Using Diffusional Kurtosis Imaging

Degenerative disc disease is the most common cause of low back pain. Intervertebral disc abnormalities are commonly evaluated by magnetic resonance imaging (MRI), and Pfirrmann’s system involves the use of T2-weighted images (T2WI) to classify disc degeneration. However, as this classification is based on visual evaluation, it is not possible to quantify degeneration using this method. The present study was performed to establish an MRI-based intervertebral disc classification system using diffusional kurtosis imaging (DKI), to quantify intervertebral disc water content according to the Pfirrmann classification. Sagittal mean diffusional kurtosis (MK) mapping was performed for the L3/4, L4/5, and L5/S1 intervertebral discs in 32 patients (15 female, 17 male;age range, 24 - 82 years;mean age, 57.7 years). The degree of disc degeneration was assessed in the midsagittal section on T2WI according to the Pfirrmann classification (grade I - V). The relationships between MK values, which are correlated with intervertebral disc composition changes, and grade of degeneration determined using the Pfirrmann classification were analyzed. The MK values tended to decrease with increasing grade of degeneration, and differed significantly between grades I and IV, but not between grade IV and V (P < 0.05, Mann-Whitney U test). DKI is an effective means of detecting the early stages of disc degeneration. Therefore, DKI may be a useful diagnostic tool for quantitative assessment of intervertebral disc degeneration.

A Rare Case of Cervical Dumbbell Meningioma with the C2 Spinous Process Preservation

Dumbbell growth is often observed in schwannoma but rarely in meningioma. In particular, the occurrence of dumbbell meningioma at the cervical cord level in Japan is markedly rare. We reported an elderly case with symptomatic meningioma that developed in a dumbbell shape from cervical spine and was treated successfully by surgery.

Treatment of Bilateral Proximal Humeral Fracture in Patients with Parkinson’s Disease: A Case Report

There are only a few reports about upper extremity fractures in patients with Parkinson’s disease (PD). This is a case report of a PD patient with severe tremors who had proximal humeral fracture. We performed surgery for the left side and conservative treatment for the right side. The patient was a 73-year-old woman who had been diagnosed with PD 10 years prior to presentation. Open reduction internal fixation was conducted for the left proximal humeral fracture. 7 months after the left shoulder fracture, she fell resulting in a right proximal humeral fracture for which she underwent conservative treatment. Although bone union was obtained bilaterally, anterior subluxation occurred in the operated side 9 months postoperative. Screw remove was performed because perforation of the screw was observed in the humeral head and was causing pain. Currently, restriction in range of motion and subluxation may be seen on the side that received conservative treatment, although pain is absent and patient satisfaction is high. On the operated side, there is a marked restriction in range of motion, subluxation, and pain. Our experience revealed that conservative treatment was effective for proximal humeral fractures and that optimal bone union might be obtained even in patients with suboptimal PD control.