Concordia Joint Replacement Group

Winnipeg, Canada

Concordia Joint Replacement Group

Winnipeg, Canada
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Anderson D.R.,Street Capital | Dunbar M.J.,Queen Elizabeth Health science Center | Bohm E.R.,Concordia Joint Replacement Group | Belzile E.,University of Québec | And 18 more authors.
Annals of Internal Medicine | Year: 2013

Background: The role of aspirin in thromboprophylaxis after total hip arthroplasty (THA) is controversial. Objective: To compare extended prophylaxis with aspirin and dalteparin for prevention of symptomatic venous thromboembolism (VTE) after THA. Design: Multicenter randomized, controlled trial with a noninferiority design based on a minimal clinically important difference of 2.0%. Randomization was electronically generated; patients were assigned to a treatment group through a Web-based program. Patients, physicians, study coordinators, health care team members, outcome adjudicators, and data analysts were blinded to interventions. (Current Controlled Trials: ISRCTN11902170) Setting: 12 tertiary care orthopedic referral centers in Canada. Patients: 778 patients who had elective unilateral THA between 2007 and 2010. Intervention: After an initial 10 days of dalteparin prophylaxis after elective THA, patients were randomly assigned to 28 days of dalteparin (n = 400) or aspirin (n = 386). Measurements: Symptomatic VTE confirmed by objective testing (primary efficacy outcome) and bleeding. Results: Five of 398 patients (1.3%) randomly assigned to dalteparin and 1 of 380 (0.3%) randomly assigned to aspirin had VTE (absolute difference, 1.0 percentage point [95% CI, -0.5 to 2.5 percentage points]). Aspirin was noninferior (P < 0.001) but not superior (P = 0.22) to dalteparin. Clinically significant bleeding occurred in 5 patients (1.3%) receiving dalteparin and 2 (0.5%) receiving aspirin. The absolute between-group difference in a composite of all VTE and clinically significant bleeding events was 1.7 percentage points (CI, -0.3 to 3.8 percentage points; P = 0.091) in favor of aspirin. Limitation: The study was halted prematurely because of difficulty with patient recruitment. Conclusion: Extended prophylaxis for 28 days with aspirin was noninferior to and as safe as dalteparin for the prevention of VTE after THA in patients who initially received dalteparin for 10 days. Given its low cost and greater convenience, aspirin may be considered a reasonable alternative for extended thromboprophylaxis after THA. Primary Funding Source: Canadian Institutes of Health Research. © 2013 American College of Physicians.


Biant L.C.,Royal Infirmary | Gascoyne T.C.,Orthopaedic Innovation Center | Gascoyne T.C.,Concordia Joint Replacement Group | Bohm E.R.,Concordia Joint Replacement Group | Moran M.,Royal Infirmary
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2016

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. Scanning electron microscopy was used to confirm damage features and mechanisms. Severe abrasion to the backside of the buffer was the primary damage feature, while stippling damage was seen on the articular surface of the buffer. Material loss due to backside abrasion was approximated to be between 0.13360.085 g (gravimetric analyses) and 0.19360.053 g (three-dimensional reconstruction). Implantation of the TriboFit buffer against the patient's native acetabulum without a metal backing allowed for significant movement of the buffer against the bone, resulting in the abrasion seen on this implant. The stippling damage on the articular surface indicates an adhesive wear mechanism which exacerbates movement of the buffer against the acetabulum, thereby increasing backside abrasion. © Institution of Mechanical Engineers.


Gascoyne T.C.,Orthopaedic Innovation Center | Teeter M.G.,London Health Sciences Center | Guenther L.E.,Orthopaedic Innovation Center | Burnell C.D.,Concordia Joint Replacement Group | And 2 more authors.
Journal of Arthroplasty | Year: 2016

This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design. © 2016 Elsevier Inc.


PubMed | Orthopaedic Innovation Center, Concordia Joint Replacement Group and London Health Sciences Center
Type: Journal Article | Journal: The Journal of arthroplasty | Year: 2015

This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design.


PubMed | The Innovation Group, Royal Infirmary and Concordia Joint Replacement Group
Type: Case Reports | Journal: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine | Year: 2016

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. Scanning electron microscopy was used to confirm damage features and mechanisms. Severe abrasion to the backside of the buffer was the primary damage feature, while stippling damage was seen on the articular surface of the buffer. Material loss due to backside abrasion was approximated to be between 0.13360.085 g (gravimetric analyses) and 0.19360.053 g (three-dimensional reconstruction). Implantation of the TriboFit buffer against the patients native acetabulum without a metal backing allowed for significant movement of the buffer against the bone, resulting in the abrasion seen on this implant. The stippling damage on the articular surface indicates an adhesive wear mechanism which exacerbates movement of the buffer against the acetabulum, thereby increasing backside abrasion.


Brandt J.-M.,Concordia Joint Replacement Group | Mahmoud K.K.,University of Western Ontario | Mahmoud K.K.,City University of New York | Koval S.F.,University of Western Ontario | And 2 more authors.
Tribology International | Year: 2013

A series of eight wear tests with six different calf serum lubricants were performed on a displacement-controlled knee simulator. The calf serum lubricants varied in constituent fractions, dilutive media, and antimicrobial agent. The difference in low-molecular weight polypeptide concentration was determined in all calf serum lubricants and this allowed exploration of its role in the PE wear process. Sodium azide was not an effective antimicrobial agent. The subsequently used antibiotic-antimycotic mixture was initially effective in eliminating bacterial growth but its efficacy became exhausted as the testing period progressed. In the present pilot study, a predator bacterium Bdellovibrio bacteriovorus was shown to prey on the antibiotic resistant bacterium, suggesting its potential use in knee simulator wear testing. © 2013 Elsevier Ltd. All rights reserved.


Hawker G.,University of Toronto | Bohm E.R.,University of Manitoba | Conner-Spady B.,University of Calgary | De Coster C.,University of Calgary | And 7 more authors.
Arthritis and Rheumatology | Year: 2015

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. The current study reviewed the appropriateness themes that emerged from each group, and a series of statements were developed to reflect each unique theme or criterion. A group of arthroplasty surgeons then indicated their level of agreement with each statement using electronic voting. Where ≤70% agreed or disagreed, the criterion was discussed and revised, and revoting occurred. In standardized telephone interviews, OA patient focus group participants indicated their level of agreement with each revised criterion. Results Qualitative research in 58 OA patients and 14 arthroplasty surgeons identified 11 appropriateness criteria. Member-checking in 15 surgeons (including 5 who had participated in the qualitative study) resulted in agreement on 6 revised criteria. These included evidence of arthritis on joint examination, patient-reported symptoms negatively impacting quality of life, an adequate trial of appropriate nonsurgical treatment, realistic patient expectations of surgery, mental and physical readiness of patient for surgery, and patient-surgeon agreement that potential benefits exceed risks. Thirty-six of the original 58 OA patient focus group participants (62.1%) participated in the member-check interviews and endorsed all 6 criteria. Conclusion Patients and surgeons jointly endorsed 6 criteria for assessment of TJA appropriateness in OA patients. Prospective validation of these criteria (assessed preoperatively) as predictive of postoperative patient-reported outcomes is under way and will inform development of a surgeon-patient decision-support tool for assessment of TJA appropriateness. © 2015, American College of Rheumatology.


Brandt J.-M.,Concordia Joint Replacement Group | Gascoyne T.C.,Concordia Joint Replacement Group | Guenther L.E.,Concordia Joint Replacement Group | Allen A.,Dalhousie University | And 4 more authors.
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2013

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 = 0.573, p < 0.001) and the acetabular cups (R = 0.592, p < 0.001). Increased maximal out-of-roundness values of the femoral heads correlated with both increased metal transfer damage score (R = 0.384, p = 0.023) and increased stripe damage score (R = 0.729, p≤ 0.001) of the acetabular liners. The damage rate (damage score/year) for both the retrieved heads and acetabular liners was at least 2.2-fold greater at inclination angles of >45° than the damage rate at inclination angles of ≤45°. For the retrieved femoral heads only, the linear wear rate of 25.5 ± 21.3 μm/year at inclination angles of >45° was 6-fold greater than the linear wear rate of 4.2 ± 2.3 μm/year at inclination angles of ≤45°. Metal transfer on the ceramic bearing surface could possibly contribute to fluid-film starvation and, in combination with an increased inclination angle, may facilitate an adhesive wear mechanism associated with stripe surface damage. At our institution, the clinical survivorship of ceramicon-ceramic total hip replacements was 98.9% (a total of 9 out of 815 patients were revised within 10 years after total hip arthroplasty) with revision as the end point, suggesting their safe use in younger patients. © IMechE 2013.


Brandt J.-M.,Concordia Joint Replacement Group | Guenther L.,Concordia Joint Replacement Group | O'Brien S.,Concordia Joint Replacement Group | Vecherya A.,Concordia Joint Replacement Group | And 3 more authors.
Knee | Year: 2013

Background: The surface characteristics of the femoral component affect polyethylene wear in modular total knee replacements. In the present retrieval study, the surface characteristics of cobalt-chromium (CoCr) alloy and oxidized zirconium (OxZr) femoral components were assessed and compared. Methods: Twenty-six retrieved CoCr alloy femoral components were matched with twenty-six retrieved OxZr femoral components for implantation period, body-mass index, patient gender, implant type, and polyethylene insert thickness. The surface damage on the retrieved femoral components was evaluated using a semi-quantitative assessment method, scanning electron microscopy, and contact profilometry. Results: The retrieved CoCr alloy femoral components showed less posterior surface gouging than OxZr femoral components; however, at a higher magnification, the grooving damage features on the retrieved CoCr alloy femoral components confirmed an abrasive wear mechanism. The surface roughness values Rp, Rpm, and Rpk for the retrieved CoCr alloy femoral components were found to be significantly higher than those of the retrieved OxZr femoral components (p ≤ 0.031). The surface roughness values were higher on the medial condyles than on the lateral condyles of the retrieved CoCr alloy femoral components; such a difference was not observed on the retrieved OxZr femoral components. Conclusions: The surface roughness of CoCr alloy femoral components increased while the surface roughness of the OxZr femoral components remained unchanged after in vivo service. Therefore, the OxZr femoral components' resistance to abrasive wear may enable lower polyethylene wear and ensure long-term durability in vivo. Level of Evidence: Level IV. © 2013.


PubMed | University of Manitoba and Concordia Joint Replacement Group
Type: Comparative Study | Journal: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine | Year: 2015

Lubricant protein concentration is known to affect crosslinked polyethylene wear in in vitro testing; however, the biochemical nature of these lubricants may also have a significant effect on wear and dictate its clinical relevance. A modified approach to pin-on-disc testing was implemented to explore the effect of four biochemically different lubricants on the wear of two types of crosslinked polyethylene materials (XLK and Marathon; DePuy Synthes, Warsaw, IN, USA). XLK was associated with higher wear rates than Marathon. In comparison to lubricants containing deionized water, lubricants containing phosphate buffered saline solution and hyaluronic acid increased osmolality by up to 1.2 times and thermal stability by up to 1.4 times. This biochemical change reduced wear by up to 12.5 times. Wear rates for XLK and Marathon differed by a factor of 3.2 using lubricants with phosphate buffered saline solution as the dilutive media, but only 2.0 for lubricants with deionized water. Interestingly, varying the concentration of hyaluronic acid did not have a significant effect on wear, and differences between XLK and Marathon wear rates were not found to be statistically significant when hyaluronic acid was added to the lubricant. The findings of this study showed that increasing the osmolality and thermal stability of lubricants to more clinical levels decreased wear; however, the effect of hyaluronic acid on wear may not be apparent in simplistic pin-on-disc testing. It was suggested that phosphate buffered saline solution be used as the dilutive media of choice in order to better differentiate the ranking of materials while maintaining some clinical relevance.

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