Adverse reactions to metal debris in metal-on-polyethylene total hip arthroplasty using a titanium-molybdenum-zirconium-iron alloy stem.

We report a series of three patients who underwent uncemented total hip arthroplasty with a modular titanium-molybdenum-zirconium-iron stem and a cobalt-chrome-molybdenum head on an ultra-high molecular weight highly cross-linked polyethylene liner bearing. All three cases subsequently developed pain and adverse reaction to metal debris, leading to revision of the implants within thirty-six months. They were subsequently found to have hypersensitivity to cobalt or chromium. However where tested, blood metal ion levels were within MHRA guideline limits. Corrosion was noted at the taper-trunnion junction. It is possible, that the multi alloy head-neck combination may lead to corrosion. Hypersensitivity to metal ions may result to ARMD at lower metal ion levels. The use of ceramic heads may help avoid this risk.

Osteoid osteoma.

Osteoid osteomas consist of a nidus with surrounding sclerotic bone. The differential diagnosis covers a wide range of conditions due to the variable presentation of osteoid osteoma. The natural history is for regression to occur within 6 to 15 years with no treatment; however, this can be reduced to 2 to 3 years with the use of aspirin and non-steroidal anti-inflammatory drugs. Computed tomography-guided percutaneous techniques, including trephine excision, cryoablation, radiofrequency ablation, and laser thermocoagulation, are described.

Emergence of large scale structure in barotropic ß-plane turbulence.

In this Letter, we use a nonequilibrium statistical theory, the stochastic structural stability theory (SSST), to show that an extended version of this theory can make predictions for the formation of nonzonal as well as zonal structures (lattice and stripe patterns) in forced homogeneous turbulence on a barotropic ß plane. Comparison of the theory with nonlinear simulations demonstrates that SSST predicts the parameter values for the emergence of coherent structures and their characteristics (scale, amplitude, phase speed) as they emerge and at finite amplitude. It is shown that nonzonal structures (lattice states or zonons) emerge at lower energy input rates of the stirring compared to zonal flows (stripe states) and their emergence affects the dynamics of jet formation.

Outcomes of total hip arthroplasty in the octogenarian population.

BACKGROUND: The outcomes of total hip arthroplasty (THA) in the elderly population are uncertain. With the rapid expansion of this population group, this study aims to determine whether increasing age affects the outcomes of THA by utilising the largest patient cohort and follow-up period within the literature. PATIENTS AND METHODS: All patients of 80 years and over who underwent primary THA between 1994 and 2004 at the authors' institution were compared to a cohort aged under 80 with the same diagnoses and during the same time period. Mean follow-up time was 5.9 years with a select group being reviewed at year 10. RESULTS: Pain scores were comparable at year five, whilst mean Harris hip scores were significantly lower in the octogenarians. Median hospital stay was three days longer in the elderly group. Complication rates were also higher (38.1% cf 28.7%) however fewer cases of revision were noted (1.4% cf 3.8%). Patient satisfaction was comparable between groups. CONCLUSION: This study suggests pain improvement, low revision rates and high satisfaction are sufficient to justify THA in the elderly population.

Total knee arthroplasty in the elderly: does age affect pain, function or complications?

BACKGROUND: TKA is one of the most commonly performed procedures in the elderly, yet whether age influences postoperative pain, function, and complication rates is not fully understood for this group. This is because the current literature has limited followup, small sample sizes, and no comparator group. QUESTIONS/PURPOSES: We therefore asked if increasing age adversely affects postoperative pain, Knee Society Scores(©), and complication rates. METHODS: We retrospectively reviewed all 438 patients 80 years or older who underwent primary TKA between 1995 and 2005. We established a comparator group of 2754 patients younger than 80 years. We assessed pain, the Knee Society Score(©) (KSS), and the Knee Society Function Score(©) (KSFS). The number and type of complications were recorded and those graded 2 or more using the classification of Dindo et al. were analyzed. Minimum followup was 5 years (mean, 6 years; range, 5-15.5 years). RESULTS: We found no difference in pain scores at 3, 5, and 10 years between the two groups. The KSS was comparable between groups at Year 5, but the KSFS was lower in the octogenarians. Major complications rates were higher in the octogenarian group (19% versus 15%). CONCLUSIONS: When compared with younger patients, octogenarians can expect comparable pain relief and KSS but lower function and more complications.

Management of periacetabular bone loss in revision hip arthroplasty.

The goals of acetabular revision surgery are to restore the anatomy and achieve stable fixation for the new acetabular component. The existing bone stock and the type of defect are determining factors in the surgical decision making. When necessary, and especially in younger patients, attempts should be made to restore the bone stock by grafting. The advent of modern reconstruction options, like the trabecular metal revision system and the cup-cage construct, provide more options in addressing the management of severe defects. Trabecular metal has a porosity similar to bone and provides an environment more favorable to bone graft remodeling than conventional metals. We present an overview of our experience and current approach to acetabular revision. In addition, we report our preliminary results with trabecular metal cups and trabecular metal cup-cage constructs used in conjunction with bone graft for addressing major bone defects.

Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty. Surgical technique.

BACKGROUND: Periprosthetic femoral fractures following total hip arthroplasty are becoming more prevalent. When a fracture occurs in a femur with substantial proximal bone deficiency, the surgical options for revision are limited. One option includes the use of a proximal femoral allograft. METHODS: We retrospectively assessed the results and complications of the use of a proximal femoral allograft to treat twenty-five Vancouver type-B3 periprosthetic fractures in twenty-four patients. The mean duration of follow-up was 5.1 years. Clinical results were graded with use of the Harris hip score. Radiographs were assessed for evidence of trochanteric union, host-allograft union, allograft resorption, and component loosening or fracture. Failure of the procedure was defined as the need for revision surgery requiring graft removal. RESULTS: The mean postoperative Harris hip score was 70.8. At the time of the final follow-up, twenty-one of the twenty-four patients reported no or mild pain and twenty-three patients were able to walk; fifteen required a walking aid. The greater trochanter united in seventeen of the twenty-five hips (68%), and osseous union of the allograft to the host femur occurred in twenty hips (80%). There was mild graft resorption in four hips and moderate graft resorption in two. Four (16%) of the twenty-five hips required repeat revision. CONCLUSIONS: The use of a proximal femoral allograft for the treatment of a Vancouver type-B3 periprosthetic femoral fracture can provide a satisfactory result in terms of pain relief and function at five years.

Ubiquitin E3 ligase WWP1 as an oncogenic factor in human prostate cancer.

The gene for E3 ubiquitin ligase WWP1 is located at 8q21, a region frequently amplified in human cancers, including prostate cancer. Recent studies have shown that WWP1 negatively regulates the TGFbeta tumor suppressor pathway by inactivating its molecular components, including Smad2, Smad4 and TbetaR1. These findings suggest an oncogenic role of WWP1 in carcinogenesis, but direct supporting evidence has been lacking. In this study, we examined WWP1 for gene dosage, mRNA expression, mutation and functions in a number of human prostate cancer samples. We found that the WWP1 gene had copy number gain in 15 of 34 (44%) xenografts and cell lines from prostate cancer and 15 of 49 (31%) clinical prostate cancer samples. Consistently, WWP1 was overexpressed in 60% of xenografts and cell lines from prostate cancer. Mutation of WWP1 occurred infrequently in prostate cancer. Functionally, WWP1 overexpression promoted colony formation in the 22Rv1 prostate cancer cell line. In PC-3 prostate cancer cells, WWP1 knockdown significantly suppressed cell proliferation and enhanced TGFbeta-mediated growth inhibition. These findings suggest that WWP1 is an oncogene that undergoes genomic amplification at 8q21 in human prostate cancer, and WWP1 overexpression is a common mechanism involved in the inactivation of TGFbeta function in human cancer.

Integrating simulation into a surgical residency program: is voluntary participation effective?

OBJECTIVE: Surgical training programs nationwide are struggling with the integration of simulation training into their curriculum given the constraints of the 80-h work week. We examine the effectiveness of voluntary training in a simulation lab as part of the surgical curriculum. METHODS: The ProMIS simulator was introduced into the general surgery residency at Boston University Medical Center. All categorical residents (28) and non-categorical residents (23) were offered a 2-h training session and curriculum review. After the introductory session, time spent in the lab was encouraged, but voluntary. Use of the simulator was tracked for all residents. Participation in the simulation curriculum was defined as three or more uses of the simulator. After 3 months, all residents completed a survey regarding the simulation lab and their simulator usage. RESULTS: Twenty-six (93%) categorical residents and three (6%) non-categorical residents completed the introductory simulator training session. Over a 3 month period, use of the simulator at least once was 31% among all eligible residents; 80% of postgraduate year (PGY)1, 40% of PGY2, 60% of PGY3, and 0% of PGY4 and PGY5. Four residents (14%) participated in the simulation curriculum. Overall, 70% of simulator usage was during working hours, and 30% was completed post-call or when the resident was off duty. Most residents agreed that the simulator was easy to use and that its use improved their operative skills, but they did not think it was a good substitute for actual operative experience. Reported reasons for not using the simulator included off-site rotation (44%), no time (30%), and no interest (11%). CONCLUSIONS: Voluntary use of a surgical simulation lab leads to minimal participation in a training curriculum. Participation should be mandatory if it is to be an effective part of a residency curriculum.

Surgical options for articular defects of the knee.

Cartilage and osteochondral defects of the knee can in most cases be treated with total knee replacement in the elderly population. However, these lesions pose a difficult treatment problem in the younger patient. A number of surgical options are available today to address this increasingly common condition and each has its own indications and limitations. This article reviews debridement and microfracture, fixation, metallic spacing devices, autologous chondrocyte implantation, osteochondral autograft transplantation, fresh cadaveric allografts and osteotomies. In addition, possible future developments are discussed.

Advances in molecular classification of renal neoplasms.

Kidney neoplasms are classified by light microscopy using the World Health Organization (WHO) system. The WHO system defines histopathologic tumor subtypes with distinct clinical behavior and underlying genetic mutations. In adults, the common malignant subtypes are variants of renal cell carcinoma (RCC). Histopathologic classification is critical for clinical management of RCC, but is becoming more complex with recognition of novel tumor subtypes, development of procedures yielding small diagnostic biopsies, and emergence of molecular therapies directed at tumor gene activity. Therefore, classification systems based on gene expression are likely to become essential for diagnosis, prognosis and treatment of kidney tumors. Recent DNA microarray studies have shown that clinically relevant renal tumor subtypes are characterized by distinct gene expression profiles, which are useful for discovery of novel diagnostic and prognostic biomarkers. In this review, we summarize the WHO classification system for renal tumors, general applications of microarray technology in cancer research, and specific microarray studies that have advanced knowledge of renal tumor diagnosis, prognosis, therapy and pathobiology.

Prediction of Cobb angle in idiopathic adolescent scoliosis.

We did a prospective study of 291 children and adolescents with idiopathic scoliosis to identify possible correlations between clinical (scoliometer value, age, height) and radiographic (Cobb angle, Nash-Moe rotation, Risser iliac apophysis classification) parameters to predict the curve angle. There was a statistically significant correlation between thoracic, thoracolumbar, and lumbar scoliometer values and the thoracic, thoracolumbar, and lumbar Cobb angles, respectively (Pearson's r-0.685, 0.572, and 0.677, respectively). There was a statistically significant correlation between Cobb angle in the thoracic, thoracolumbar, and lumbar spine and the patients' age and height. Mathematical formulas that predict the Cobb angle of thoracic, thoracolumbar, and lumbar scoliosis using the scoliometer measurements are reported.

Greek versions of the Oswestry and Roland-Morris Disability Questionnaires.

Disability questionnaires are increasingly used for clinical assessment, outcome measurement of treatment and research methodology of low back pain. Their use in different countries and cultural groups must follow certain guidelines for translation and cross-cultural adaptation. The translation of such an instrument must be tested for its reliability and validity to be applied and to allow comparability of data. The Oswestry Disability Index and the Roland-Morris Disability Questionnaire are two disability questionnaires most commonly used as outcome measures in patients with low back pain. The two questionnaires were translated for use with the Greek population, were back translated and tested, and became available in a final version. The Greek versions of the Oswestry Disability Index and the Roland-Morris Disability Questionnaire were tested in 697 patients with low back pain. Internal consistency reliability for the Greek translation of the Oswestry Disability Index and the Roland-Morris Disability Questionnaire reached a Cronbach's alpha coefficient of 0.833 and 0.885 respectively. Face validity and content validity were ensured. Concurrent validity was assessed using a six-point pain scale as a criterion. The correlation of both scales was significant. The Greek translation of these disability questionnaires provided reliable and valid instruments for the evaluation of Greek-speaking patients with low back pain.

Multiple level noncontiguous fractures of the spine.

From 1970 to 2000, 81 patients with noncontiguous fractures of the spine were evaluated. Of these 81 patients, 36 had a neurologic deficit. Sixty-six patients with stable injuries were treated conservatively, whereas 15 patients with unstable injuries required surgical stabilization. There was no neurologic deterioration either in the patients who had surgical stabilization or in the patients who were treated conservatively. Thirteen patients with an A score on the American Spinal Injury Association neurologic impairment scale did not improve and had a high mortality rate (61.5%). Although multiple level noncontiguous fractures of the spine are uncommon, they constitute a threat to neurologic function, and therefore warrant radiographic evaluation of the entire spine with multiple injuries.

Accumulation of mitochondrial DNA deletions in the malignant prostate of patients of different ages.

It has been shown that mitochondrial DNA (mtDNA) deletion mutations accumulate with age in many tissues of the body. However, to date no one has shown that these deletions occur in the malignant prostate. Therefore, we hypothesize that such deletions do occur in the prostate and increasingly so with advanced age. To test this hypothesis, DNA was isolated from 34 radical prostatectomy specimens, and the entire mitochondrial genome (16.5kb) was amplified using long range PCR (LXPCR). The LXPCR products were visualized by gel electrophoresis, and the presence of low molecular weight (<16kb) bands was considered evidence of large mtDNA deletions. In order to show that these lower molecular weight LXPCR bands were not simply PCR artifact, we also digested mtDNA from a subset of the same patients and did Southern analysis with a mtDNA probe. Southern blots confirmed the existence of large deletions in every sample tested. Furthermore, several of the specific deletions identified by LXPCR were also seen in the Southern blots. From the LXPCR data, we found that as the age of the specimen increased, so did the average number of low molecular weight bands (i.e. deletions). In particular, one prominent band was seen at 1.2kb and became more consistent with advanced age.

Isolation and characterization of the major form of human MUC18 cDNA gene and correlation of MUC18 over-expression in prostate cancer cell lines and tissues with malignant progression.

Ectopical expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the development and malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. We cloned and characterized the human MUC18 (huMUC18) cDNA gene from three human prostate cancer cell lines and three human melanoma cell lines. The cDNA sequences from the six human cancer cell lines were identical except differences in one to five nucleotides. The deduced amino acid sequences of the longest ORF were 646 amino acids that were identical in these cDNAs except for one to three amino acid residues. The amino acid sequences of all our huMUC18 cDNA genes are similar to that cloned by other group (GenBank access #M28882) except differences in the same seven amino acids. We conclude that huMUC18 cDNA gene reported here represents the gene product from a major allele. The MUC18 mRNA and protein was expressed in three metastatic prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one non-metastatic prostate cancer cell line (LNCaP.FGC). The expression of huMUC18 in these four cell lines is positively related to their extent of in vitro motility and invasiveness and in vivo metastasis in nude mice. HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from cultured primary normal prostatic epithelial cells and the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas, and in cells of a perineural invasion, a lymph node, and a lung metastases compared to that in normal or benign hyperplastic epithelium (BPH). We therefore conclude that MUC18 expression is increased during prostate cancer initiation (high grade PIN) and progression to carcinoma, and in metastatic cell lines and metastatic carcinoma. Increased expression of MUC18 is implicated to play an important role in developing and malignant progression of human prostate cancer. Furthermore, the lacking of predominant cytoplasmic membrane expression of MUC18 appeared to correlate with malignant progression of prostate cancer.