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The Bone & Joint Journal
Vol. 103-B, Issue 9 | Pages 1479 - 1487
1 Sep 2021
Davis ET Pagkalos J Kopjar B

Aims

The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs).

Methods

We undertook a registry study combining the National Joint Registry dataset with polyethylene manufacturing characteristics as supplied by the manufacturers. The primary endpoint was revision for any reason. We performed further analyses on other reasons including instability, aseptic loosening, wear, and liner dissociation. The primary analytic approach was Cox proportional hazard regression.


Our previous work presented at BHS revealed a reduced risk of revision for all reasons in THAs using lipped (asymmetric) liners. Some audience members felt that this finding may be due to unaccounted confounders and the hip surgery community remains sceptical.

A fully adjusted Cox model was built after exploratory Kaplan-Meier analyses. The following surgical approaches were included in the analysis: Posterior, Hardinge/anterolateral, Other. The variables included in the final Cox model included: Gender, liner asymmetry, age, head composition, stem fixation method, head diameter, indication for implantation and surgical approach. An additional analysis of the 3 most commonly used polyethylene liners with both a flat and asymmetric version was performed.

In the fully adjusted Cox model, the use of a flat liner was associated with increased risk of revision for instability (HR: 1.79, 95%CI: 1.52–2.10) and increased risk of revision for all reasons (HR 1.195, 95%CI: 1.104 – 1.293) when compared to THAs utilising flat liners. This finding was upheld in the product specific analysis.

When utilising flat liners, the Hardinge/anterolateral approach was associated with a reduced risk of revision for instability compared to the posterior approach (HR 0.56, 95%CI: 0.446 to 0.706). When an asymmetric liner was used, there was no significant difference in the risk of revision for instability between the Hardinge/anterolateral approach and the posterior approach (HR 0.838, 95%CI: 0.633 – 1.110).

The use of polyethylene-based bearings gives the surgeon the option to use asymmetric liners. The reduced risk of revision in THAs with asymmetric liners was seen in the analysis of the complete dataset and in the product specific analysis. Our results demonstrate that the posterior approach, when used with asymmetric XLPE liners, is not associated with a higher risk of revision for instability as historical data suggested.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_4 | Pages 52 - 52
1 Mar 2021
Harris A O'Grady C Sensiba P Vandenneucker H Huang B Cates H Christen B Hur J Marra D Malcorps J Kopjar B
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Patients ≤ 55 years have a high primary TKA revision rate compared to patients >55 years. Guided motion knee devices are commonly used in younger patients yet outcomes remain unknown. In this sub-group analysis of a large multicenter study, 254 TKAs with a second-generation guided motion knee implant were performed between 2011–2017 in 202 patients ≤ 55 years at seven US and three European sites. Revision rates were compared with Australian Joint Registry (AOANJRR) 2017 data. Average age 49.7 (range 18–54); 56.4% females; average BMI 34 kg/m2; 67.1% obese; patellae resurfaced in 98.4%. Average follow-up 4.2 years; longest follow-up six years; 27.5% followed-up for ≥ five years. Of eight revisions: total revision (one), tibial plate replacements (three), tibial insert exchanges (four). One tibial plate revision re-revised to total revision. Revision indications were mechanical loosening (n=2), infection (n=3), peri-prosthetic fracture (n=1), and instability (n=2). The Kaplan-Meier revision estimate was 3.4% (95% C.I. 1.7% to 6.7%) at five years compared to AOANJRR rate of 6.9%. There was no differential risk by sex. The revision rate of the second-generation guided motion knee system is lower in younger patients compared to registry controls.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_4 | Pages 51 - 51
1 Mar 2021
Harris A O'Grady C Sensiba P Vandenneucker H Huang B Cates H Christen B Hur J Marra D Malcorps J Kopjar B
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Outcomes for guided motion primary total knee arthroplasty (TKA) in obese patients are unknown. 1,684 consecutive patients underwent 2,059 primary TKAs with a second-generation guided motion implant between 2011–2017 at three European and seven US sites. Of 2,003 (97.3%) TKAs in 1,644 patients with BMI data: average age 64.5 years; 58.4% females; average BMI 32.5 kg/m2; 13.4% had BMI ≥ 40 kg/m2. Subjects with BMI ≥ 40 kg/m2 had longest length of hospital stay (LOS) at European sites; LOS similar at US sites. Subjects with BMI ≥ 40 kg/m2 (P=0.0349) had longest surgery duration. BMI ≥ 40 kg/m2 had more re-hospitalizations or post-TKA reoperations than BMI < 40 kg/m2 (12.7% and 9.2% at five-year post-TKA, P<0.0495). Surgery duration and long-term complication rates are higher in patients with BMI ≥ 40 kg/m2, but device revision risk is not elevated.


Aims

To investigate the effect of polyethylene manufacturing characteristics and irradiation dose on the survival of cemented and reverse hybrid total hip arthroplasties (THAs).

Methods

In this registry study, data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man (NJR) were linked with manufacturing data supplied by manufacturers. The primary endpoint was revision of any component. Cox proportional hazard regression was a primary analytic approach adjusting for competing risk of death, patient characteristics, head composition, and stem fixation.


Aim

To assess the effect of different polyethylene modifications on Total Hip Replacement survival.

Methods

We combined the NJR dataset with polyethylene manufacturing properties as supplied by the manufacturers. Cause specific and overall reasons for revisions were analysed using Kaplan-Meier and multi-variate Cox proportional hazard regression survival analyses. Revision for aseptic loosening was the primary endpoint. Modification variables included resin type, radiation source, multiple cross-linking treatments, cross-linking dose, terminal sterilisation method, terminal sterilisation radiation dose, stabilisation treatment, total radiation dose, and packaging.


Aim

To assess the effect of the bearing surface and head size on the survival of total hip replacements with modern bearing surface combinations.

Methods

We combined the NJR dataset with polyethylene manufacturing properties as supplied by the manufacturers to sub-divide polyethylene into conventional (PE) and highly crosslinked (XLPE). Cause specific and overall reasons for revisions were analysed using Kaplan-Meier and multi-variate Cox proportional hazard regression survival analyses. The bearing surface analysis was repeated in patients undergoing THR under the age of 55.


The Bone & Joint Journal
Vol. 102-B, Issue 3 | Pages 400 - 400
1 Mar 2020
Davis ET Pagkalos J Kopjar B


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 96 - 96
1 Feb 2020
Harris A Christen B Malcorps J O'Grady C Sensiba P Vandenneucker H Huang B Cates H Hur J Marra D Kopjar B
Full Access

Introduction

Patients ≤ 55 years have a high primary TKA revision rate compared to patients >55 years. Guided motion knee devices are commonly used in younger patients yet outcomes remain unknown.

Materials and Methods

In this sub-group analysis of a large multicenter study, 254 TKAs with a second-generation guided motion knee implant (Journey II Bi-Cruciate Stabilized Knee System, Smith & Nephew, Inc., Memphis) were performed between 2011–2017 in 202 patients ≤ 55 years at seven US and three European sites. Revision rates were compared with Australian Joint Registry (AOANJRR) 2017 data.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 95 - 95
1 Feb 2020
Harris A Christen B Malcorps J O'Grady C Sensiba P Vandenneucker H Huang B Cates H Hur J Marra D Kopjar B
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Introduction/Aim

Outcomes for guided motion primary total knee arthroplasty (TKA) in obese patients are unknown.

Materials and Methods

1,684 consecutive patients underwent 2,059 primary TKAs with a second-generation guided motion implant (Journey II Bi-Cruciate Stabilized Knee System, Smith & Nephew, Inc., Memphis) between 2011–2017 at three European and seven US sites.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 138 - 138
1 Feb 2020
Schwarzkopf R Chow J Burkhardt J Gittins M Kaper B Fabi D Hanson B Kopjar B
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Background

The JOURNEY™ II Cruciate-Retaining Total Knee System (JIICR) and the JOURNEY™ II Bi-Cruciate Stabilized Total Knee System (JIIBCS) (both, Smith & Nephew, Memphis, TN, USA) are used for the treatment of end-stage degenerative knee arthritis. Belonging to the JOURNEY family of knee implants, the relatively new devices are designed to provide guided motion. Studies suggest that long-term outcomes of robotic-assisted navigation in total knee arthroplasty (TKA) are superior to the classical approach. This is the first report describing early postoperative outcomes of the NAVIO® robotic-assisted surgical navigation using the JOURNEY™ II family of knee implants.

Materials & Methods

In this ongoing study, six investigational sites in the US prospectively enrolled 122 patients (122 TKAs, 64 JIIBCS and 58 JIICR). Patients underwent TKA using the NAVIO system (Figure 1), a next-generation semi-autonomous tool that uses handheld miniaturized robotic-assisted instrumentation that the surgeon manipulates in 6 degrees of freedom, but restricts cutting to within the confines of the pre-designated resection area of the patient's bone. The primary outcome was postoperative mechanical alignment on long leg X-ray at one month postoperative compared to operative target alignment. Alignment within ±3 degrees of the target alignment was considered a success.


The Bone & Joint Journal
Vol. 102-B, Issue 1 | Pages 90 - 101
1 Jan 2020
Davis ET Pagkalos J Kopjar B

Aims

The aim of this study was to identify the effect of the manufacturing characteristics of polyethylene acetabular liners on the survival of cementless and hybrid total hip arthroplasty (THA).

Methods

Prospective cohort study using linked National Joint Registry (NJR) and manufacturer data. The primary endpoint was revision for aseptic loosening. Cox proportional hazard regression was the primary analytical approach. Manufacturing variables included resin type, crosslinking radiation dose, terminal sterilization method, terminal sterilization radiation dose, stabilization treatment, total radiation dose, packaging, and face asymmetry. Total radiation dose was further divided into G1 (no radiation), G2 (> 0 Mrad to < 5 Mrad), G3 (≥ 5 Mrad to < 10 Mrad), and G4 (≥ 10 Mrad).


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 17 - 18
1 Mar 2009
Dettori J Norvell D Hanson B Kopjar B
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Objectives: An evidence-based trauma database that rated the level-of-evidence for the majority of orthopedic trauma literature would be useful to orthopedic trauma surgeons and researchers. Currently, the development of a database using evidence ratings for such a large body of literature is a time-consuming and expensive endeavor. However, if an accurate rating could be obtained from an abstract without reading the full text, such an endeavor would be feasible. Thus, the purpose of this study is to determine if a reviewer can successfully ascertain the level-of-evidence from the article’s abstract without reading the full text article.

Methods: We compared the level-of-evidence rating obtained from reading an article’s full text with the rating obtained from reading the abstract alone. We reviewed 162 clinical articles published from January 2000 through April 2004 in five orthopedic trauma journals. To establish a full text rating, two reviewers independently rated the full text of each article for study type (therapeutic, prognostic or diagnostic) and level-of-evidence (I through V). The ratings from the two reviewers were compared and disagreements were reconciled through discussion to form a final full text rating. A third reviewer rated the abstracts of each article without access to the full text or full text rating.

Results: Of the 162 articles, 118 (73%) were therapeutic, 40 (25%) were prognostic and 4 (3%) were diagnostic. Most studies represented level IV evidence (65%), with only 15% representing the highest level-of-evidence, level I. Kappa values for agreement between the two reviewers rating the full text were 0.81 for study type and 0.79 for level-of-evidence, and the kappa values for agreement between the final full text rating and the abstract rating were 0.68 for study type and 0.75 for level-of-evidence, respectively. Thirteen of the discordant abstracts (8% of the entire set) lacked sufficient or correct evidence compared with the full text to render an accurate rating.

Conclusion: Accurate study type and level-of-evidence rating in trauma articles can be obtained in most orthopedic trauma articles from reading an article’s abstract alone. Thus, developing an evidence-based trauma database that uses abstracts to rate the level-of-evidence of the orthopedic trauma literature appears feasible and appropriate.

This research was supported by a grant from the AO Foundation, Clinical Investigation and Documentation, Clavadelerstrasse, 7270 Davos Platz, Switzerland