Experimental study on pressure response to graded spinal canal compromise in an burst fracture mode.

Background: Spinal cord compression is a known cause of spinal cord injury. The purpose of this study is to measure pressure response during graded spinal cord compression. This information will be important in evaluating the amount of canal compromise that can be tolerated before risking neurological injury secondary to cord compression.

The Effects of Age and Hearing Loss on Dual-Task Balance and Listening.

Objectives: Among older adults (OA), hearing loss is associated with an increased risk for falls. The aim of the present study was to experimentally investigate the cognitive compensation hypothesis, wherein decreased auditory and motor functioning are compensated by the recruitment of cognitive resources.

Method: Twenty-nine younger adults (YA), 26 OA, and 32 OA with age-related hearing loss (ARHL) completed a dual-task paradigm consisting of cognitive and balance recovery tasks performed singly and concurrently.

Relationships between lower body strength and the energy cost of treadmill walking in a cohort of healthy older adults: a cross-sectional analysis.

Purpose: Gait speed is associated with survival in older adults and it was suggested that an elevated energy cost of walking (Cw) is an important determinant of gait speed reduction. Thus far, little is known about the factors that contribute to a lower Cw but it was shown that lower body strength training could reduce the Cw. Therefore, the objective of this study was to investigate the relationship between lower body strength and the Cw in a cohort of healthy older adults.

Trends in revision hip and knee arthroplasty observations after implementation of a regional joint replacement registry.

Background: National joint replacement registries outside North America have been effective in reducing revision risk. However, there is little information on the role of smaller regional registries similar to those found in Canada or the United States. We sought to understand trends in total hip (THA) and knee (TKA) arthroplasty revision patterns after implementation of a regional registry.

Assessing the comparability of hip arthroplasty registries in order to improve the recording and monitoring of outcome.

Aims: We aimed to assess the comparability of data in joint replacement registries and identify ways of improving the comparisons between registries and the overall monitoring of joint replacement surgery.

Materials And Methods: We conducted a review of registries that are full members of the International Society of Arthroplasty Registries with publicly available annual reports in English. Of the six registries which were included, we compared the reporting of: mean age, definitions for revision and re-operation, reasons for revision, the approach to analysing revisions, and patient-reported outcome measures (PROMs) for primary and revision total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA).

Retrieval analysis of a failed TriboFit polycarbonate urethane acetabular buffer.

The purpose of this research was to determine the failure mechanisms and damage features of a TriboFit acetabular buffer implanted directly against a native, prepared acetabulum which was revised after 11months. Retrieval analyses were carried out via light microscopy, gravimetric wear assessment, and observer scoring of visible damage features on the buffer. The volume of material abraded from the backside of the buffer was estimated via three-dimensional reconstruction using a laser scanner.

Complete blood count before and after total hip or knee arthroplasty.

Purpose: To validate our transfusion protocol based on pre- and post-operative complete blood count (CBC) data in patients undergoing primary total hip or knee arthroplasty (THA or TKA).

Methods: Records of 113 men and 205 women aged 32 to 94 (mean, 70) years who underwent primary uncemented THA (n=123) or cemented TKA (n=195) for osteoarthritis by 2 senior surgeons were reviewed. A post-surgical drain was used in 29 THA patients and 74 TKA patients, based on the surgeon's preference.

Reduced time to surgery improves mortality and length of stay following hip fracture: results from an intervention study in a Canadian health authority.

Background: Existing literature demonstrating the negative impact of delayed hip fracture surgery on mortality consists largely of observational studies prone to selection bias and may overestimate the negative effects of delay. We conducted an intervention study to assess initiatives aimed at meeting a 48-hour benchmark for hip fracture surgery to determine if the intervention achieved a reduction in time to surgery, and if a general reduction in time to surgery improved mortality and length of stay.

Methods: We compared time to surgery, length of stay and mortality between pre- and postintervention patients with a hip fracture using the Kaplan-Meier estimator and Cox proportional hazards model adjusting for age, sex, comorbidities, type of surgery and year.

Perspectives of Canadian Stakeholders on Criteria for Appropriateness for Total Joint Arthroplasty in Patients With Hip and Knee Osteoarthritis.

Objective: As rates of total joint arthroplasty (TJA) for osteoarthritis (OA) rise, there is a need to ensure appropriate use. We undertook this study to develop criteria for appropriate use of TJA.

Methods: In prior work, we used qualitative methods to separately assess OA patients' and arthroplasty surgeons' perceptions regarding appropriateness of patient candidates for TJA.

A longitudinal study of quality of life and functional status in total hip and total knee replacement patients.

Background: Primary total hip and primary total knee surgeries are commonly performed to improve patients' quality of life and functional status.

Aim: This longitudinal retrospective study (N = 851) examined self-reported quality of life and functional status over the preoperative and postoperative periods: 12 months prior to surgery, one month prior to surgery and 12 months following surgery.

Methods: A linear mixed effects model was used to analyze the changes in quality of life and functional status over the sampling period.

Corrosion on the acetabular liner taper from retrieved modular metal-on-metal total hip replacements.

Eight retrieved metal-on-metal total hip replacements displayed corrosion damage along the cobalt-chromium alloy liner taper junction with the Ti alloy acetabular shell. Scanning electron microscopy indicated the primary mechanism of corrosion to be grain boundary and associated crevice corrosion, which was likely accelerated through mechanical micromotion and galvanic corrosion resulting from dissimilar alloys. Coordinate measurements revealed up to 4.

Patient factors in referral choice for total joint replacement surgery.

Background: Although the option of next available surgeon can be found on surgeon referral forms for total joint replacement surgery, its selection varies across surgical practices.

Objectives: Objectives are to assess the determinants of (a) a patient's request for a particular surgeon; and (b) the actual referral to a specific versus the next available surgeon.

Methods: Questionnaires were mailed to 306 consecutive patients referred to orthopedic surgeons.

The effect of patient positioning on the precision of model-based radiostereometric analysis.

A repeatable method for in vivo and in vitro measurement of polyethylene wear in total knee replacement (TKA) is needed. This research examines the model-based radiostereometric analysis' (MBRSA) in vitro precision under different patient-radiograph orientations and flexion angles of the knee using a TKA phantom. Anterior-posterior and medial-lateral imaging orientations showed the highest precision; better than 0.

Wear testing of crosslinked polyethylene: wear rate variability and microbial contamination.

The wear performance of two types of crosslinked polyethylene (Marathon™ and XLK™, DePuy Synthes Inc., Warsaw, IN) was evaluated in a pin-on-disc wear tester, a hip wear simulator, and a knee wear simulator. Sodium azide was used as the microbial inhibitor in the calf serum-based lubricant.

Clinical failure analysis of contemporary ceramic-on-ceramic total hip replacements.

The present study investigates the performance of ceramic-on-ceramic total hip replacements by combining a retrieval analysis with a survivorship analysis to elucidate mechanisms that led to clinical failure. Semiquantitative surface damage assessment, contact profilometry, contour measurements, and scanning electron microscopy were performed to characterize the types and quantify the extent of surface damage on the retrieved ceramic components. The implantation period was positively correlated with both damage scores of the femoral heads (R = 0.

Beyond sleep duration: distinct sleep dimensions are associated with obesity in children and adolescents.

Objective: Short sleep duration is recognized as a significant risk factor in childhood obesity; however, the question as to how sleep contributes to the development of obesity remains largely unknown. The majority of pediatric studies have relied on sleep duration as the exclusive measure of sleep; this insular approach may be misleading given that sleep is a dynamic multidimensional construct beyond sleep duration, including sleep disturbances and patterns. Although these sleep dimensions partly overlap, it is necessary to determine their independent relation with obesity, which in turn, may inform a more comprehensive understanding of putative pathophysiological mechanisms linking sleep and obesity.

The operative management of osteoporotic fractures of the knee: to fix or replace?

This review considers the surgical treatment of displaced fractures involving the knee in elderly, osteoporotic patients. The goals of treatment include pain control, early mobilisation, avoidance of complications and minimising the need for further surgery. Open reduction and internal fixation (ORIF) frequently results in loss of reduction, which can result in post-traumatic arthritis and the occasional conversion to total knee replacement (TKR).

Calf serum constituent fractions influence polyethylene wear and microbial growth in knee simulator testing.

Calf serum lubricants consisting of various polypeptide constituent fractions are routinely used in knee wear simulators as part of the standardized test protocol. Three calf sera (bovine, new-born and alpha) were diluted as per the recommendation of ISO 14243-3 and used in displacement-controlled knee wear simulators to investigate their effects on polyethylene wear. Biochemical analyses included measuring total polypeptide degradation, electrophoretic profiles and low-molecular weight polypeptide concentrations to elucidate their involvement in the wear process.

Abrasive wear and metallosis associated with cross-linked polyethylene in total hip arthroplasty.

A 34-year-old female patient received a cobalt-chromium (CoCr) alloy femoral head on cross-linked polyethylene total hip replacement for the revision of her fractured ceramic-on-ceramic total hip replacement. The CoCr alloy femoral head became severely worn due to third-body abrasive wear by ceramic particles that could not be removed by synovectomy or irrigation at revision surgery. Ceramic particles were found embedded in the cross-linked polyethylene liner.

The effect of adding tobramycin to Simplex P cement on femoral stem micromotion as measured by radiostereometric analysis: a 2-year randomized controlled trial.

Background: Previous in vitro research on addition of antibiotics to bone cement has found no statistically significant deterioration in mechanical properties. However, no clinical studies have compared the performance of tobramycin-laden bone cement with that of standard bone cement (Simplex P).

Patients And Methods: 23 patients (25 hips) were randomized to receive an Exeter (Stryker Orthopaedics) femoral stem cemented with either Simplex P (standard) or Simplex T (tobramycin-laden) cement.

Commissioning of a displacement-controlled knee wear simulator and exploration of some issues related to the lubricant.

A six-station displacement-controlled knee simulator with separately controlled left (L) and right (R) banks (three wear implants per bank) was commissioned for a total of three million cycles (Mc) following ISO 14243-3. A commissioning protocol was applied to compare the polyethylene wear among the six wear stations by exchanging the implants between wear stations. Changes in lubricant characteristics during wear testing, such as polypeptide degradation, low-molecular-weight polypeptide concentration, and possible microbial contamination were also assessed.

Retrieval analysis of modular total knee replacements: factors influencing backside surface damage.

Retrieved knee implants were examined to investigate the influence of patient and implant related factors on backside damage. Fifty-two implants of three different models were examined that all had cemented tibial trays without screw holes. A semi-quantitative grading system supplied backside damage scores (BDS) for each polyethylene (PE) tibial insert.

Rehospitalizations, early revisions, infections, and hospital resource use in the first year after hip and knee arthroplasties.

We examined 3 negative outcomes for 58 351 hip and knee arthroplasty patients: rehospitalization, revision and infection, and their impact on resource use in the year after surgery. In the year before surgery, 12.9% of elective hip and 10.