The John Charnley Award: Metal-on-metal hip resurfacing versus large-diameter head metal-on-metal total hip arthroplasty: a randomized clinical trial.

Unlabelled: Resurfacing arthroplasty has become an attractive option for young patients who want to maintain a high activity level. One recent study reported modestly increased activity levels for patients with resurfacing compared to standard total hip arthroplasty (THA). We conducted a prospective randomized clinical trial to compare clinical outcomes of resurfacing versus large-head metal-on-metal total hip arthroplasty.

Biomechanical consequences of patellar component medialization in total knee arthroplasty.

The optimal amount of patellar component medialization in knee arthroplasty is unknown. We measured the impact, on patellofemoral kinematics and contact force distribution, of 0.0-, 2.

[Apelin signalisation and vascular physiopathology].

The formation of the vascular system is an early step in organogenesis that involves the participation of various signalling pathways. Integration of the extracellular signals decoded by their cognate membrane receptors orchestrate the cell events, which act at different stages, from the primitive network formed by vasculogenesis to the arborescent network remodeled by angiogenesis. Our laboratory showed the participation of a new signalling pathway in physiological angiogenesis and tumour neovascularisation.

Computed tomography topographic mapping of subchondral density (CT-TOMASD) in osteoarthritic and normal knees: methodological development and preliminary findings.

Objectives: To develop a precise imaging tool which measures three-dimensional (3D) subchondral bone mineral density (BMD), and investigate its ability to distinguish subchondral bone properties in osteoarthritic and normal cadaveric tibiae.

Methods: We developed a novel imaging tool [Computed tomography topographic mapping of subchondral density (CT-TOMASD)], which employs a surface projection image processing technique to map 3D subchondral BMD measured in relation to depth from the joint surface. Sixteen intact cadaver knees from 10 donors (8M:2F; age: 77.

Vancouver type B3 periprosthetic fractures: evaluation and treatment.

Periprosthetic fracture with preexisting severe loss of bone stock is a challenging condition to treat. Available surgical options can be divided into three categories: complex reconstruction of the deficient proximal femur with secure distal fixation; segmental substitution of the proximal femur with a megaprosthesis or allograft/stem composite; and distally fixed replacement with a modular stem, which acts as a scaffold around which the remaining deficient proximal bone can be assembled, to unite and possibly reconstitute.

Severe femoral bone loss in infected total hip arthroplasty: surgical management.

The management of severe bone loss in a patient with a chronically infected total hip arthroplasty is a complex surgical challenge. The surgical alternatives are numerous and include the use of allografts, both structural and morcellized; cemented and cementless femoral components; and segmental replacement megaprostheses.

Osteoblast-derived factors induce an expression signature that identifies prostate cancer metastasis and hormonal progression.

Identification of gene expression signatures associated with metastases provides a tool to discern mechanisms and potential therapeutic targets and may lead toward a molecular classification system in pathology. Prostate cancer (CaP) frequently metastasizes to the bone to form osteoblastic lesions. Correlative clinical data and in vitro evidence have led to the hypothesis that osteoblast-derived factors promote hormonal progression of CaP cells.

Reduced D2-mediated signaling activity and trans-synaptic upregulation of D1 and D2 dopamine receptors in mice overexpressing the dopamine transporter.

The dopamine transporter (DAT) regulates the temporal and spatial actions of dopamine by reuptaking this neurotransmitter into the presynaptic neurons. We recently generated transgenic mice overexpressing DAT (DAT-tg) that have a 3-fold increase in DAT protein levels which results in a 40% reduction of the extracellular DA concentration in the striatum. The aim of this study was to examine the effect of this reduction in dopaminergic tone on postsynaptic responses mediated by dopamine receptors.

Modular tantalum augments for acetabular defects in revision hip arthroplasty.

Unlabelled: Large acetabular defects can be reconstructed with various methods depending on size and location of the defect. We prospectively followed our first 37 patients in whom we reconstructed the acetabulum with a trabecular metal augment combined with a trabecular metal shell. Three patients died before completing the minimum 24 months followup while the remaining 34 were followed a minimum of 24 months (mean, 34 months; range, 24-55 months).

Antagonism of dopamine D2 receptor/beta-arrestin 2 interaction is a common property of clinically effective antipsychotics.

Since the unexpected discovery of the antipsychotic activity of chlorpromazine, a variety of therapeutic agents have been developed for the treatment of schizophrenia. Despite differences in their activities at various neurotransmitter systems, all clinically effective antipsychotics share the ability to interact with D2 class dopamine receptors (D2R). D2R mediate their physiological effects via both G protein-dependent and independent (beta-arrestin 2-dependent) signaling, but the role of these D2R-mediated signaling events in the actions of antipsychotics remains unclear.

Intraoperative periprosthetic fractures during total hip arthroplasty. Evaluation and management.

Intraoperative periprosthetic fractures are becoming more common given the increased prevalence of revision total hip arthroplasty and increased use of cementless fixation. Risk factors for intraoperative periprosthetic fractures include the use of minimally invasive techniques; the use of press-fit cementless stems; revision operations, especially when a long cementless stem is used or when a short stem with impaction allografting is used; female sex; metabolic bone disease; bone diseases leading to altered morphology such as Paget disease; and technical errors at the time of the operation. Appropriate treatment of intraoperative periprosthetic fractures does not compromise the long-term results of total hip arthroplasty unless the bone damage precludes stable fixation of the implant.

To resurface or not to resurface the patella in total knee arthroplasty.

Unlabelled: The management of the patellar articular surface at the time of primary total knee arthroplasty (TKA) is controversial. We used expected-value decision analysis to determine whether the patella should be resurfaced in TKA, and also whether secondary resurfacing on an unresurfaced patella is worthwhile. Outcome probabilities and utility values were derived from randomized controlled trials only.

Porous tantalum uncemented acetabular shells in revision total hip replacement: two to four year clinical and radiographic results.

In cementless revision total hip arthroplasty (THA), achieving initial implant stability and maximising host bone contact is key to the success of reconstruction. Porous tantalum acetabular shells may represent an improvement from conventional porous coated uncemented cups in revision acetabular reconstruction associated with severe acetabular bone defects. We reviewed the results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects done with a hemispheric, tantalum acetabular shell and multiple supplementary screws.

Ossifying lipoma of the thigh.

Lipomas are common soft-tissue tumours that are usually found in the subcutaneous adipose tissue. Occasionally, they may contain mesenchymal elements other than adipose tissue, including osseous components. These ossifying lipomas are usually located near or within bone, and it is very rare for a lipoma with no connection to bone to contain mature osseous tissue.

Mechanical aspects of degree of cement bonding and implant wedge effect.

Background: The degree of bonding between the femoral stem and cement in total hip replacement remains controversial. Our objective was to determine the wedge effect by debonding and stem taper angle on the structural behavior of axisymmetric stem-cement-bone cylinder models.

Methods: Stainless steel tapered plugs with a rough (i.

A comparison between patient recall and concurrent measurement of preoperative quality of life outcome in total hip arthroplasty.

The objective is to evaluate the reliability of patients' recall of preoperative pain and function during the immediate postoperation period after total hip arthroplasty. A prospective cohort of 104 patients completed a survey about their quality of life before operation, and recalled preoperative status at 3 days, 6 weeks, and 12 weeks after operation. Quality of life was measured by the Western Ontario and McMaster University Osteoarthritis Index, the Oxford-12 hip score, and the 12-item Short-Form score.

The effect of an augmentation patella prosthesis versus patelloplasty on revision patellar kinematics and quadriceps tendon force: an ex vivo study.

The purpose of this study was to assess the effect of 2 revision reconstructive interventions on patellofemoral joint mechanics in comparison to control. We flexed 8 cadaver knee specimens from 0 degrees to 60 degrees of flexion in a test rig designed to simulate weight-bearing flexion and extension (Oxford rig). Quadriceps tendon extensor force and patellar kinematics were recorded for control total knee arthroplasty (TKA) (normal primary TKA with patella resurfaced) and then for each of the 2 revision patellar interventions (after patelloplasty of typical revision knee patellar bone defect to leave a simple bony shell, and after TKA with augmentation patella resurfacing).

Outcome of unicompartmental knee arthroplasty in patients receiving worker's compensation.

Nineteen patients with a worker's compensation board (WCB) claim treated by unicompartmental knee arthroplasty for medial compartment osteoarthritis were compared to 20 patients who had no WCB claim. In WCB patients, the mean Knee Society Score (KSS) improved from 47.4 to 76.

Pharmacological characterization of membrane-expressed human trace amine-associated receptor 1 (TAAR1) by a bioluminescence resonance energy transfer cAMP biosensor.

Trace amines are neurotransmitters whose role in regulating invertebrate physiology has been appreciated for many decades. Recent studies indicate that trace amines may also play a role in mammalian physiology by binding to a novel family of G protein-coupled receptors (GPCRs) that are found throughout the central nervous system. A major obstacle impeding the careful pharmacological characterization of trace amine associated receptors (TAARs) is their extremely poor membrane expression in model cell systems, and a molecular basis for this phenomenon has not been determined.

Determinants of patellar tracking in total knee arthroplasty.

Background: Optimizing patellar tracking in total knee arthroplasty is a surgical priority. Despite this, a comparison of the effects of different component placements on patellar tracking is not available; the biomechanical impact of the patellar resection angle has not been studied; and the similarity between intraoperative and postoperative effects, fundamental to improving patellar tracking, is unknown. Our objective was to compare the impact of the major controllable femoral, tibial and patellar component positions on patellar kinematics during both passive and loaded flexion.

Local excision without radiation for high-grade soft-tissue sarcoma of the extremity and superficial trunk.

Purpose. Limb-sparing surgery combined with radiation treatment has become the accepted treatment for patients with high-grade soft-tissue sarcoma. Adjuvant radiation was not routinely used at this institution for patients with clear margins after surgery.

Quality of life outcomes in revision vs primary total hip arthroplasty: a prospective cohort study.

This study included 143 patients who had revision total hip arthroplasty (THA) and 144 patients who had primary THA. The primary outcome variable in this study was the Western Ontario and McMaster Universities Osteoarthritis Index scores. Univariate and multivariate regression models were used to assess the relationship between surgical procedure and postoperative health related quality of life outcomes.

Impaction allografting--the effect of impaction force and alternative compaction methods on the mechanical characteristics of the graft.

Revision total hip replacement with impaction allografting has an attractive potential for restoring bone stock, however, fractures and implant migration remain problematic. Postoperative graft deformation is believed to contribute to migration. Under compressive loading, the fluid in the graft takes up the load initially through fluid pressure that dissipates over time.

Enhanced gap filling and osteoconduction associated with alendronate-calcium phosphate-coated porous tantalum.

Background: Porous tantalum has been shown to be effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity may be insufficient to allow adequate bone ingrowth. We hypothesized that local delivery of alendronate from porous tantalum would enhance the ability of the tantalum to achieve bone ingrowth when there is a gap between the implant and bone.

Resolving inconsistencies in defining the target orientation for the acetabular cup angles in total hip arthroplasty.

Background: Dislocation following total hip arthroplasty is a major complication and malorientation of the acetabular cup is one of the primary factors affecting dislocation. Different conventions used to describe the cup orientation produce significant variations in the recommendations for correct positioning, which in turn make it difficult for clinicians to properly interpret and apply previously reported studies.

Methods: We examined nine articles presenting recommendations for the range of target orientations of the acetabular cup to minimize the risk of dislocation (referred to as the 'safe zone').