Low dose compared to variable dose Warfarin and to Fondaparinux as prophylaxis for thromboembolism after elective hip or knee replacement surgery; a randomized, prospective study.

Background: Deep vein thrombosis (DVT) and pulmonary emboli (PE), known together as venous thromboembolic (VTE) disease remain major complications following elective hip and knee surgery. This study compares three chemoprophylactic regimens for VTE following elective primary unilateral hip or knee replacement, one of which was designed to minimize risk of post-operative bleeding.

Methods: Patients were randomized and stratified for hip vs.

Administration of olanzapine to prevent postoperative delirium in elderly joint-replacement patients: a randomized, controlled trial.

Background: Delirium is a serious postoperative condition for which few pharmacologic prevention trials have been conducted.

Objective: The authors tested the efficacy of perioperative olanzapine administration to prevent postoperative delirium in elderly patients after joint-replacement surgery.

Method: The authors conducted a randomized, double-blind, placebo-controlled, prophylaxis trial at an orthopedic teaching hospital, enrolling 495 elderly patients age ≥65 years, who were undergoing elective knee- or hip-replacement surgery; 400 patients received either 5 mg of orally-disintegrating olanzapine or placebo just before and after surgery.

Ceramic-on-ceramic hip outcome at a 5- to 10-year interval: has it lived up to its expectations?

This study reports revision and complication rates of a single cementless double-wedged tapered stem with an alumina-alumina bearing over 10 years since the beginning of premarket clinical trials. Of 930 hips (848 patients) implanted by 9 surgeons, there were 19 revisions at mean follow-up of 5.9 years compared to 10 revisions in the 123 hips implanted with the polyethylene control group at mean 7.

Hemostasis using a bipolar sealer in primary unilateral total knee arthroplasty.

Previous studies have shown that, compared with standard electrocautery, a bipolar sealer reduces tissue damage and smoke production during surgery. We conducted a multicenter, prospective, randomized study to compare a bipolar sealer with standard electrocautery for hemostasis. Sixty-nine primary total knee arthroplasties were performed.

The effect of paraformaldehyde fixation on the delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) measurement.

The delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) method allows for both qualitative and quantitative measurement of the spatial distribution of glycosaminoglycan [GAG] in excised cartilage. The objective of this study was to determine the effect of paraformaldehyde fixation on dGEMRIC measurements. Five bovine and seven human cartilage pieces were punched into 5-mm plugs, fixed for 18 h in 4% paraformaldehyde solution, and washed.

Differential expression of GADD45beta in normal and osteoarthritic cartilage: potential role in homeostasis of articular chondrocytes.

Objective: Our previous study suggested that growth arrest and DNA damage-inducible protein 45beta (GADD45beta) prolonged the survival of hypertrophic chondrocytes in the developing mouse embryo. This study was undertaken, therefore, to investigate whether GADD45beta plays a role in adult articular cartilage.

Methods: Gene expression profiles of cartilage from patients with late-stage osteoarthritis (OA) were compared with those from patients with early OA and normal controls in 2 separate microarray analyses.

Case mix and outcomes of total knee replacement in orthopaedic specialty hospitals.

Objectives: To examine patient characteristics and outcomes of total knee replacement (TKR) in orthopaedic specialty hospitals.

Methods: We performed a retrospective cohort study in the US Medicare population. We defined specialty hospitals for TKR as centers: (1) that performed >75 TKRs in Medicare recipients in 2000; (2) in which TKR accounted for >7% of all Medicare discharges; and (3) that had <300 beds.

Dual proline labeling protocol for individual "baseline" and "response" biosynthesis measurements in human articular cartilage.

Objective: The heterogeneity of biosynthesis in human-derived cartilage explants poses a challenge to its use in experiments. The aim of this study was to determine the consistency with which two consecutive measures of biosynthesis could be made in individual human articular cartilage explants using a dual proline radiolabeling protocol.

Methods: Full-thickness cartilage explants were harvested from young bovine or human (total knee replacement) tibial plateaus.

Role of cell-matrix interactions in osteoclast differentiation.

Osteoclast and their mononuclear cell precursors are present within the bone microenvironment at sites of physiologic and pathologic bone resorption. Analysis of tissues from sites of bone resorption reveal that cells expressing the full morphological and functional properties of mature osteoclasts are restricted to the immediate bone surface. We hypothesize that in addition to cytokines, components of the bone matrix and specific cell surface receptors on osteoclasts and their precursors play an essential role in determining the genetic profile and functional properties of fully differentiated resorbing osteoclasts.

Use of a hydroxyapatite-coated stem in patients with Dorr Type C femoral bone.

Type C bone, as described by Dorr, exhibits both cellular and structural compromise, which presents a challenge for fixation of a total hip arthroplasty (THA). We evaluated the performance of the Omnifit HA stem, a hydroxyapatite-coated titanium alloy stem, by retrospectively reviewing the clinical and radiographic data of 15 patients with femoral Type C bone who received the stem during primary THA between 1991 and 1994. The patients were followed a minimum of 9 years (mean, 11.

Low-dose warfarin coupled with lower leg compression is effective prophylaxis against thromboembolic disease after hip arthroplasty.

Consecutive patients having elective total hip arthroplasty were prescribed 1 mg of warfarin for 7 days preceding surgery, variable doses while in hospital (target international normalized ratio, 1.5-2.0), and discharged to rehabilitation center or home taking 1 mg daily until 4-week to 6-week follow-up visit.

Ceramic-on-ceramic total hip arthroplasty early dislocation rate.

Wear debris from metal-on-polyethylene articulation in conventional total hip arthroplasty can limit the implant's longevity. Modern ceramic material with high wear resistance and low fracture risk has the potential to extend the lifetime of total hip arthroplasty, which makes the procedure potentially more suitable for young, active patients. Concerns with brittle ceramic material include fracture risk, the "squeak" phenomenon, and potentially a higher dislocation rate secondary to limited neck lengths and liner options.

Relationship between cartilage stiffness and dGEMRIC index: correlation and prediction.

We sought to determine if a generalized relationship between the dGEMRIC index (T1Gd relaxation time) and compressive stiffness of articular cartilage could be defined across multiple samples. Osteochondral blocks were cut from 12 human tibial plateaus, six from cadaveric sources and six from total knee replacement surgeries. Each block contained submeniscal ("covered") and extrameniscal ("uncovered") cartilage regions.

Effect of preoperative exercise on measures of functional status in men and women undergoing total hip and knee arthroplasty.

Objective: To evaluate the effect of a short preoperative exercise intervention on the functional status, pain, and muscle strength of patients before and after total joint arthroplasty.

Methods: A total of 108 men and women scheduled for total hip arthroplasty (THA) or total knee arthroplasty (TKA) were randomized to a 6-week exercise or education (control) intervention immediately prior to surgery. We assessed outcomes through questionnaires and performance measures.

Autologous blood donation and subsequent blood use in patients undergoing total knee arthroplasty.

Autologous blood donation is designed to avoid complications from allogeneic blood, leaving units of blood in the general blood supply. It is unclear how efficient these programmes are in accomplishing these goals. It is unclear if autologous donation provokes increased need for any transfusion following surgery and whether it can be avoided in low-risk surgeries.

The role played by cell-substrate interactions in the pathogenesis of osteoclast-mediated peri-implant osteolysis.

Prosthetic wear debris-induced peri-implant osteolysis is a major cause of aseptic loosening after total joint replacement. In this condition, wear particles released from the implant components induce a granulomatous inflammatory reaction at the interface between implant and adjacent bone, leading to progressive bone resorption and loss of fixation. The present study was undertaken to characterize definitively the phenotype of osteoclast-like cells associated with regions of peri-implant focal bone resorption and to compare the phenotypic features of these cells with those of mononucleated and multinucleated cells associated with polyethylene wear particles.

Five-year experience with Crossfire highly cross-linked polyethylene.

Unlabelled: Our purpose was to compare the clinical wear performance of highly cross-linked (Crossfire) polyethylene with conventional (N2Vac) polyethylene total hip bearings. We implanted 56 hips (47 patients) with Crossfire acetabular bearing liners and compared their wear performance with 53 conventional polyethylene inserts. Wear and clinical data were collected retrospectively at a minimum 4-year and average 5-year followup.

A mouse model of human breast cancer metastasis to human bone.

Currently, an in vivo model of human breast cancer metastasizing from the orthotopic site to bone does not exist, making it difficult to study the many steps of skeletal metastasis. Moreover, models used to identify the mechanisms by which breast cancer metastasizes to bone are limited to intracardiac injection, which seeds the cancer cells directly into the circulation, thus bypassing the early steps in the metastatic process. Such models do not reflect the full process of metastasis occurring in patients.

Results of resurfacing a native patella in patients with a painful total knee arthroplasty.

Between 1990 and 2003, 24 patients (28 knees) who had a total knee arthroplasty (TKA) and underwent subsequent patella resurfacing without revision of the tibial or femoral components to alleviate pain were identified. Patient charts were reviewed retrospectively and patients were interviewed after average 2.9-year follow-up (range: 1-12 years) to assess function, pain, and satisfaction with the procedure.

Ceramic-on-ceramic bearings in total hip arthroplasty.

The ideal bearing surface for total hip arthroplasty still is being sought. This bearing would be durable, cost-effective, easy to implant, inert, and produce minimal wear debris. Ceramic-on-ceramic bearings have continued to evolve and have enjoyed success in many European centers throughout the past 3 decades.

Very low dose warfarin as prophylaxis against ultrasound detected deep vein thrombosis following primary hip replacement.

One mg daily warfarin was compared to variable dose warfarin (PT 1.3-1.5 times the normal PT), as prophylaxis against deep vein thrombosis (DVT) following unilateral hip replacement for degenerative joint disease (DJD).

New experience with alumina-on-alumina ceramic bearings for total hip arthroplasty.

A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release. In a prospective randomized study, 514 hips were implanted.