Molecular characterisation of osteoblasts from bone obtained from people of Polynesian and European ancestry undergoing joint replacement surgery.

Population studies in Aotearoa New Zealand found higher bone mineral density and lower rate of hip fracture in people of Polynesian ancestry compared to Europeans. We hypothesised that differences in osteoblast proliferation and differentiation contribute to the differences in bone properties between the two groups. Osteoblasts were cultured from bone samples obtained from 30 people of Polynesian ancestry and 25 Europeans who had joint replacement surgeries for osteoarthritis.

The effect of age on the microarchitecture and profile of gene expression in femoral head and neck bone from patients with osteoarthritis.

Ageing of the skeleton is characterised by decreased bone mineral density, reduced strength, and increased risk of fracture. Although it is known that these changes are determined by the activities of bone cells through the processes of bone modelling and remodelling, details of the molecular mechanisms that underlie age-related changes in bone are still missing. Here, we analysed age-related changes in bone microarchitecture along with global gene expression in samples obtained from patients with osteoarthritis (OA).

The John N. Insall Award: Higher Tissue Concentrations of Vancomycin Achieved With Intraosseous Regional Prophylaxis in Revision TKA: A Randomized Controlled Trial.

Background: In primary TKA, prophylaxis with low-dose vancomycin through intraosseous regional administration (IORA) achieves tissue concentrations six to 10 times higher than systemic administration and was shown to provide more effective prophylaxis in an animal model. However, in revision TKA, the presence of a tibial implant may compromise IORA injection, and tourniquet deflation during a prolonged procedure may lower tissue concentrations.

Questions/purposes: (1) Does low-dose IORA reliably provide equal or higher tissue concentrations of vancomycin compared with systemic IV administration in revision TKA? (2) Are tissue concentrations of vancomycin after IORA maintained for the duration of the revision TKA despite a period of tourniquet deflation? (3) Is there any difference in early postoperative (< 6 weeks) complications between IORA and systemic IV administration in revision TKA?

Methods: Twenty patients undergoing aseptic revision TKA were randomized to two groups.

Periprosthetic Joint Infection in Hip Arthroplasty: Is There an Association Between Infection and Bearing Surface Type?

Background: Preliminary studies have raised the question of whether certain prosthetic biomaterials used in total hip arthroplasty (THA) bearings are associated with increased risk of periprosthetic joint infection (PJI). For example, some observational data suggest the risk of PJI is higher with metal-on-metal bearings. However, it is not known whether other bearings-including ceramic bearings or metal-on-polyethylene bearings-may be associated with a higher or lower risk of PJI.

Analyzing bone remodeling patterns after total hip arthroplasty using quantitative computed tomography and patient-specific 3D computational models.

Background: Computational models in the form of finite element analysis technique that incorporates bone remodeling theories along with DEXA scans has been extensively used in predicting bone remodeling patterns around the implant. However, majority of such studies used generic models. Therefore, the aim of this study is to develop patient-specific finite element models of total hip replacement patients using their quantitative computed tomography (QCT) scans and accurately analyse bone remodelling patterns after total hip arthroplasty (THA).

Are ceramic-on-ceramic bearings in total hip arthroplasty associated with reduced revision risk for late dislocation?

Background: Dislocation is a major complication after primary total hip arthroplasty (THA), but little is known about the potential relationships between bearing materials and risk of dislocation. Dislocation within the first year after surgery is typically related to either surgical error or patient inattention to precautions, but the reasons for dislocation after the first year are often unclear, and whether ceramic bearings are associated with an increased or decreased likelihood of late dislocation is controversial.

Questions/purposes: The purpose of this study was to use a national registry to assess whether the choice of bearings-metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)-is associated with differences in the risk of late dislocation.

Flowtron foot-pumps for prevention of venous thromboembolism in total hip and knee replacement.

Introduction: Mechanical prophylaxis with foot-pumps provides an interesting alternative to chemical agents in the prevention of venous thomboembolism following major orthopaedic surgery procedures. The aim of this prospective study was to assess efficacy and safety of the Flowtron(®) foot-pumps system following total hip and knee replacement. The foot pumps were used as main tool for prevention of thromboembolic events, in most cases in association with a variety of chemicals.

CORR Insights™: Is limited incision better than standard total hip arthroplasty? A meta-analysis.

This CORR Insights™ is a commentary on the article "Is Limited Incision Better Than Standard Total Hip Arthroplasty? A Meta-analysis" by Joseph T. Moskal MD and Susan G. Capps PhD available at DOI 10.

Quantitative CT with finite element analysis: towards a predictive tool for bone remodelling around an uncemented tapered stem.

Purpose: We used quantitative CT in conjunction with finite element analysis to provide a new tool for assessment of bone quality after total hip arthroplasty in vivo. The hypothesis of this prospective five-year study is that the combination of the two modalities allows 3D patient-specific imaging of cortical and cancellous bone changes and stress shielding.

Method: We tested quantitative CT in conjunction with finite elements on a cohort of 29 patients (31 hips) who have been scanned postoperatively and at one year, two years and five years follow-up.

Infection in total hip replacement: meta-analysis.

While total hip arthroplasty has progressed to become one of the most successful surgical procedures ever developed, infection remains a serious complication. We have conducted a review of the literature pertaining to management of deep infection in total hip arthroplasty, specifically focusing on clinically relevant articles published in the last five years. A search was conducted using MEDLINE and PubMed, as well as a review of the Cochrane database, using the terms "total hip arthroplasty", "total hip replacement" and "infection".

Femoral bone density changes after total hip arthroplasty with uncemented taper-design stem: a five year follow-up study.

We measured bone density (BD) changes to assess adaptive bone remodelling five years after uncemented total hip arthroplasty with taper-design femoral component using quantitative computed-tomography-assisted osteodensitometry (qCT). Nineteen consecutive patients (21 hips) with degenerative joint disease were enrolled in the study. A press-fit cup and a tapered uncemented stem ceramic-ceramic pairing were used in all patients.

Accuracy of computer-assisted navigation for femoral head resurfacing decreases in hips with abnormal anatomy.

Computer-assisted navigation systems for hip resurfacing arthroplasty are designed to minimize the chance of implant malposition. However, there is little evidence computer navigation is useful in the presence of anatomical deformity. We therefore determined the accuracy of an image-free resurfacing hip arthroplasty navigation system in the presence of a pistol grip deformity of the head and femoral neck junction and of a slipped upper femoral epiphysis deformity.

Loss of tibial bone density in patients with rotating- or fixed-platform TKA.

Little is known about tibial bone remodeling with TKA and its clinical relevance. We performed a randomized clinical trial to compare tibial bone density changes in cemented components with different bearing designs. Bone density changes were assessed using quantitative computed tomography (qCT)-assisted osteodensitometry.

Development and validation of patient-specific finite element models of the hemipelvis generated from a sparse CT data set.

To produce a patient-specific finite element (FE) model of a bone such as the pelvis, a complete computer tomographic (CT) or magnetic resonance imaging (MRI) geometric data set is desirable. However, most patient data are limited to a specific region of interest such as the acetabulum. We have overcome this problem by providing a hybrid method that is capable of generating accurate FE models from sparse patient data sets.

Absence of somatic SQSTM1 mutations in Paget's disease of bone.

Background: Paget's disease is a common focal bone disorder that appears to be caused by a combination of genetic and environmental factors. Mutations in the SQSTM1 gene are found in about one third of families with Paget's disease and 8% of sporadic cases. Other potential loci linked to the disease have also been identified, and a number of environmental factors have been suggested to be involved in the disease.