Highly Cross-Linked Polyethylene Reduces Wear and Revision Rates in Total Hip Arthroplasty: A 10-Year Double-Blinded Randomized Controlled Trial.

Background: Highly cross-linked polyethylene (XLPE) was developed to address the problem of wear and osteolysis associated with metal-on-conventional ultra-high molecular weight polyethylene (UHMWPE) bearing surfaces. The purpose of this study was to compare in vivo wear rates and clinical and radiographic outcomes between XLPE and UHMWPE in a prospective double-blinded randomized controlled trial with a minimum of 10 years of follow-up.

Methods: We randomized 122 patients to receive either a conventional UHMWPE liner (Enduron; DePuy) or an XLPE liner (Marathon; DePuy).

Measuring the migration of the components and polyethylene wear after total hip arthroplasty: beads and specialised radiographs are not necessary.

Aims: This paper describes the methodology, validation and reliability of a new computer-assisted method which uses models of the patient's bones and the components to measure their migration and polyethylene wear from radiographs after total hip arthroplasty (THA).

Materials And Methods: Models of the patient's acetabular and femoral component obtained from the manufacturer and models of the patient's pelvis and femur built from a single computed tomography (CT) scan, are used by a computer program to measure the migration of the components and the penetration of the femoral head from anteroposterior and lateral radiographs taken at follow-up visits. The program simulates the radiographic setup and matches the position and orientation of the models to outlines of the pelvis, the acetabular and femoral component, and femur on radiographs.

Noise from total hip replacements: a case-controlled study.

Objectives: Our study aimed to examine not only the incidence but also the impact of noise from two types of total hip replacement articulations: ceramic-on-ceramic and ceramic-on-polyethylene.

Methods: We performed a case-controlled study comparing subjective and objective questionnaire scores of patients receiving a ceramic-on-ceramic or a ceramic-on-polyethylene total hip replacement by a single surgeon.

Results: There was a threefold higher incidence of noise from patients in the ceramic-on-ceramic group compared with the control group.

Mobile- versus fixed-bearing modern total knee replacements- which is the more patella-friendly design?: The 11-year New Zealand Joint Registry study.

Objectives: Our study aimed to examine if a mobile-bearing total knee replacement (TKR) offered an advantage over fixed-bearing designs with respect to rates of secondary resurfacing of the patella in knees in which it was initially left unresurfaced.

Methods: We examined the 11-year report of the New Zealand Joint Registry and identified all primary TKR designs that had been implanted in > 500 knees without primary resurfacing of the patella. We examined how many of these were mobile-bearing, fixed-bearing cruciate-retaining and fixed-bearing posterior-stabilised designs.

Oxford hip scores at 6 months and 5 years are associated with total hip revision within the subsequent 2 years.

Background: The Oxford hip score (OHS) is commonly reported in research studies as a reflection of pain and function but it is unclear whether it predicts subsequent prosthesis failure.

Questions/purposes: We determined whether OHS obtained at 6 months and 5 years after surgery predicts risk of revision within the subsequent 2 years.

Methods: We reviewed data from the New Zealand Joint Registry between January 1999 and December 2010.

Redefining the cast index: the optimum technique to reduce redisplacement in pediatric distal forearm fractures.

Background: The aim of this study was to identify the optimal cast index (CI) level that reduces the risk of fracture redisplacement. The CI is the ratio of sagittal to coronal width from the inside edges of the cast at the fracture site. Previous studies have used 0.

Do joint registries report true rates of hip dislocation?

Background: Despite advances in primary THA, dislocation remains a common complication. In New Zealand (NZ), dislocations are reported to the National Joint Registry (NJR) only when prosthetic components are revised in the treatment of a dislocation. Closed reductions of dislocated hips are not recorded by the NJR.

Highly crosslinked polyethylene reduces wear in total hip arthroplasty at 5 years.

Background: Although hip arthroplasty reliably relieves pain and improves function, problems have arisen with wear and osteolysis. Highly crosslinked polyethylene has been developed to address this problem although at present there is limited clinical evidence it does so longer term.

Questions/purposes: We compared the in vivo wear of standard versus highly crosslinked polyethylene (HXLP) in primary total hip arthroplasty at a minimum of 5-year followup.

A double-blind, prospective, randomized controlled trial comparing highly cross-linked and conventional polyethylene in primary total hip arthroplasty.

Highly cross-linked polyethylene was developed to reduce articular bearing wear in total hip arthroplasty. In vitro studies have shown reduced wear in comparison with conventional polyethylene. A double-blind, prospective, randomized trial was performed comparing highly cross-linked and conventional polyethylene in 119 patients.

The influence of steroid injections on the incidence of infection following total knee arthroplasty.

Aim: To investigate whether a relationship exists between preoperative intra-articular steroid injections and postoperative wound healing in total knee arthroplasty (TKA). Similar research studies on total hip arthroplasty (THA) have found higher rates of post surgical problems in hips that have been injected with steroids.

Methods: Thirty-eight patients with TKA postoperative wound infection, and 352 TKA patients without postoperative wound infection were compared against corticosteroid injected and non-injected patients.

Hybrid total hip replacement: outcome after a mean follow up of 10 years.

Background: Total hip replacement is one of the most successful surgical procedures of the modern surgical era. The method of fixation of implants continues to evolve, and as cemented acetabular fixation appears to be less durable than anticipated, the use of a cemented stem and an uncemented acetabulum - a so-called 'hybrid hip'- has become more popular. This paper reports the results of hybrid total hip replacement at an average of 10 years postoperatively.

Osteosarcoma in New Zealand: an outcome study comparing survival rates between 1981-1987 and 1994-1999.

Aims: To review the data and outcome of patients with osteosarcoma in New Zealand from 1994 to 1999 and to compare this to data retrieved from a similar study from 1981 to 1987.

Methods: Data from 1994-1999 was obtained from the New Zealand Cancer Registry; raw data was also retrieved from the 1981-1987 study.

Results: There were 96 cases in the 1981-1987 cohort and 84 cases in the 1994-1999 cohort.

Femoral revision with a fluted, tapered, modular stem seventy patients followed for a mean of 3.9 years.

Fluted tapered revision femoral stems have been used successfully in Europe. Modularity makes these implants more versatile, but outcomes of modular designs have not been reported. We report a retrospective review of 70 such stems with a mean follow-up of 47 months.

Does pelvic osteolysis occur with a nonmodular uncemented acetabular component?

We present a radiographic follow-up of an uncemented, nonmodular, pure titanium-backed acetabular component at 6 to 12 years postimplantation. Between 1990 and 1992, 130 primary total hip arthroplasties were carried out by 1 surgeon using this implant, in association with both cemented and uncemented femoral components. There were 19 deaths, 5 revisions, and 19 hips lost to follow-up, leaving 87 hips available for review at a mean of 9.

Waiting for hip arthroplasty: economic costs and health outcomes.

This prospective cohort study of 153 patients aimed to determine the economic and health costs of waiting for total hip arthroplasty (THA). Health-related quality of life, using self-completed WOMAC and EQ-5D questionnaires, was assessed monthly from enrolment preoperatively to 6 months postsurgery. Monthly cost diaries were used to record costs.

Complications and outcomes of single-stage bilateral total knee arthroplasty.

Background: A recent literature review by the senior authors of this study revealed that simultaneous bilateral knee arthroplasty is uncommon and controversial. Reported complications include myocardial infarction, deep venous thrombosis, pulmonary embolus, thromboembolic complications, pseudo-obstruction, postoperative ileus and death. This present study was designed to identify complications of single-stage bilateral total knee arthroplasty to compare with reports in the international literature.

Differentiation of Campylobacter coli, Campylobacter jejuni, Campylobacter lari, and Campylobacter upsaliensis by a multiplex PCR developed from the nucleotide sequence of the lipid A gene lpxA.

We describe a multiplex PCR assay to identify and discriminate between isolates of Campylobacter coli, Campylobacter jejuni, Campylobacter lari, and Campylobacter upsaliensis. The C. jejuni isolate F38011 lpxA gene, encoding a UDP-N-acetylglucosamine acyltransferase, was identified by sequence analysis of an expression plasmid that restored wild-type lipopolysaccharide levels in Escherichia coli strain SM105 [lpxA(Ts)].

An assessment of sleep disturbance in patients before and after total hip arthroplasty.

Patients with osteoarthritis commonly complain of sleep disturbance that may be due to pain. Osteoarthritic hip pain is commonly alleviated by total hip arthroplasty (THA). Forty-eight patients waiting for THA completed a sleep questionnaire and were monitored using actigraphy and sleep diaries for 4 to 5 nights, 1 month before and 3 months after surgery.

Ankle fractures: functional and lifestyle outcomes at 2 years.

Background: Ankle fractures form a high proportion of the total number of fractures treated in New Zealand. International studies show that there are mixed functional outcomes with differing fracture types and subsequently differing lifestyle outcomes.

Methods: Fracture clinic records and orthopaedic admissions books for Wellington Public Hospital, Capital Coast Health, -Wellington, were retrospectively reviewed to gain a population of patients who sustained ankle fractures for the period January--December 1998.

Evaluation of a cardiac prevention and rehabilitation programme for all patients at first presentation with coronary artery disease.

Background: A cardiac prevention and rehabilitation (CP&R) programme was established for patients following their first clinical episode of coronary heart disease and 1-year outcomes were evaluated against British targets for coronary prevention.

Methods: Patients were evaluated 1 year after participation and outcomes compared with patients in the same health district registered with a random half of general practitioners not eligible for the programme (internal reference group) and patients identified in other English centres which participated in the EUROASPIRE II survey (external reference group).

Results: Three hundred and eighteen patients (76% of 417 incident cases) attended for 1-year screening.

Chemical eluates from ultra-high molecular weight polyethylene and fibroblast proliferation.

Although polyethylene wear particles have been implicated in osteolysis and implant loosening, this study is the first to test whether chemical eluates extracted from ultra-high molecular weight polyethylene (UHMWPE) could also be involved in this process. Eluates were prepared from UHMWPE bar stock and examined for their effects on (3)H-thymidine incorporation by human foreskin fibroblasts grown in 96-well culture plates. Low concentrations of eluates stimulated (3)H-thymidine uptake; whereas, high concentrations inhibited uptake in a dose-dependent manner.

The effect of different cement insertion techniques on the bone-cement interface.

Since the introduction of cemented total hip arthroplasty, the method of cement usage has evolved through several generations. These changes may have been responsible for an improvement in femoral component longevity. The nature of the bone-cement interface in first-generation cementing techniques has been described, but the bone-cement interface in more recent cementing techniques has not.

Influence of preoperative medical status and delay to surgery on death following a hip fracture.

Background: A retrospective study of 138 patients with fractured hips was undertaken to determine if a delay to surgery beyond 24 h influenced 1-year mortality. In particular, the results of the subgroup of patients who were in the American Society of Anesthesiologists (ASA) Class 3 or 4 were considered.

Methods: Patients were found using ICD-9 database information.

Polyethylene particles from a hip simulator cause (45)Ca release from cultured bone.

Periprosthetic osteolysis is a dominant factor in the success or failure of total hip prostheses. Polyethylene wear debris has been implicated in the process of bone resorption and subsequent implant loosening. The present study is the first to examine the effect of ultra high molecular weight polyethylene (UHMWPE) wear debris produced by a hip simulator on calvarial bone resorption in vitro.