Short-Term functional comparison of three total knee arthroplasties-Journey II, Genesis II and Profix.

AIM OF THE STUDY: To compare the outcomes of three knee arthroplasty design philosophies and surface tribology.• A zirconium-surfaced, bicruciate-stabilised implant designed to mimic kinematic movement and improve flexion and outcomes;• A cobalt-chrome surfaced, multi-radius design with built-in femoral external rotation to aid balancing and patella tracking through a deeper trochlea groove;• A zirconium-surfaced, single-radius implant designed on surface conformity, particularly within the patello-femoral joint. METHODS: 313 knee replacements - 103 Journey II, 103 Genesis II and 107 Profix - were statistically assessed at a minimum of 2 years using WOMAC, Oxford and SF-12 scores, and range of movement. RESULTS: There was no difference between the actual or unit change in WOMAC scores (p = 0.140 and p = 0.287), SF-12 physical (p = 0.088) or mental scores (p = 0.975) between the three implants; or between the actual or unit change in Oxford score (p = 0.912 and p = 0.874) for the Journey II or Genesis II. The Journey II produced more flexion and range of movement than the Genesis II (p < 0.001 and p = 0.018) and Profix (p < 0.001 and <0.001) with no difference between the latter two (p = 0.402 and 0.568); with no difference in extension between the three implants (p = 0.086). There was no difference between those with or without a resurfaced patella. CONCLUSION: The three design philosophies and surfaces yielded no difference in outcome scores at 2 years post-operatively. The Journey II demonstrated better post-operative flexion. Resurfacing the patella did not alter the outcome scores or flexion.

The Medium-Term Survival Analysis of an All-Polyethylene Tibia in a Single-Series Cohort of Over 1000 Knees.

BACKGROUND: Total knee arthroplasty is a successful elective orthopedic procedure with an increasing number being undertaken. Original knee arthroplasties used an all-polyethylene tibia; however, with concerns over tibial loosening, the trend moved toward the metal-backed variety. Modern designs providing more conformity and changes in manufacturing of the polyethylene make it an equivalent but cheaper option. METHODS: We analyzed the medium-term outcome in 1092 patients with an all-polyethylene tibial component in their total knee arthroplasty. RESULTS: Twenty-six patients had further surgery on their knee for a variety of reasons. Assessing reoperation for any reason, the 7-year survival rate was 96.96% with an overall infection rate of 0.37%. Seven-year survival analysis using aseptic loosening as a criteria was 99.28%. Both the Short Form 12 physical score and Western Ontario and McMaster Universities Osteoarthritis Index score significantly improved and was sustained at 7 years. Body mass did not correlate to either outcomes or complications. CONCLUSION: An all-polyethylene tibia in a total knee arthroplasty has good outcome data and high patient satisfaction with good survivorship in the medium term, coupled with potential cost-saving benefits.

Mid- to long-term survivorship of oxidised zirconium total knee replacements performed in patients under 50years of age.

BACKGROUND: Oxidised zirconium has the wear properties of ceramic with the breakage resistance of metal. This results in less wear and is of benefit to younger, higher demand patients. We report the short- to mid-term survival of 103 Profix zirconium total knee replacements performed in patients under 50years of age at time of surgery. METHODS: Data was collected prospectively and survival analysis undertaken with strict end points used. SF (Short Form) 12 and WOMAC (Western Ontario and McMaster University) scores were recorded at pre-operatively and at twelve months, one, three, five, seven and ten years. RESULTS: The average age at operation was 43.21years (range 20-50years) with a mean follow-up of 8.56years (range five to 15years). No patients died with one patient lost to follow-up after seven year review. The mean WOMAC score improved from 53 to 29, and the mean SF12 physical component improved from 29 to 36. The five year survivorship for implant related complications was 99.03% (95% CI 94.64-100.0) due to tibial component aseptic loosening at year one. Reoperation for any cause at five years including stiffness was 94.09% (95% CI 88.69-98.11). Forty-four patients were at least ten years post-operative at the time of analysis, with no aseptic loosening of either component giving 10year femoral component survival of 100% and all cause revision of 95.4%. The only zirconium femoral failure was at 12years. CONCLUSIONS: Our data shows excellent mid-term survivorship of oxidised zirconium total knee replacements in younger, higher demand patients.

Reporting on the Strategies Needed to Implement Proven Interventions: An Example From a "Real-World" Cross-Setting Implementation Study.

UNLABELLED: The objective of this study was to empirically demonstrate the use of a new framework for describing the strategies used to implement quality improvement interventions and provide an example that others may follow. Implementation strategies are the specific approaches, methods, structures, and resources used to introduce and encourage uptake of a given intervention's components. Such strategies have not been regularly reported in descriptions of interventions' effectiveness, or in assessments of how proven interventions are implemented in new settings. This lack of reporting may hinder efforts to successfully translate effective interventions into "real-world" practice. A recently published framework was designed to standardize reporting on implementation strategies in the implementation science literature. We applied this framework to describe the strategies used to implement a single intervention in its original commercial care setting, and when implemented in community health centers from September 2010 through May 2015. Per this framework, the target (clinic staff) and outcome (prescribing rates) remained the same across settings; the actor, action, temporality, and dose were adapted to fit local context. The framework proved helpful in articulating which of the implementation strategies were kept constant and which were tailored to fit diverse settings, and simplified our reporting of their effects. Researchers should consider consistently reporting this information, which could be crucial to the success or failure of implementing proven interventions effectively across diverse care settings. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02299791.

Five year survival analysis of an oxidised zirconium total knee arthroplasty.

BACKGROUND: Zirconium total knee arthroplasties theoretically have a low incidence of failure as they are low friction, hard wearing and hypoallergenic. We report the five year survival of 213 Profix zirconium total knee arthroplasties with a conforming all polyethylene tibial component. METHODS: Data was collected prospectively and multiple strict end points were used. SF12 and WOMAC scores were recorded pre-operatively, at three months, at twelve months, at 3 years and at 5 years. RESULTS: Eight patients died and six were "lost to follow-up". The remaining 199 knees were followed up for five years. The mean WOMAC score improved from 56 to 35 and the mean SF12 physical component score improved from 28 to 34. The five year survival for failure due to implant related reasons was 99.5% (95% CI 97.4-100). This was due to one tibial component becoming loose aseptically in year zero. CONCLUSIONS: Our results demonstrate that the Profix zirconium total knee arthroplasty has a low medium term failure rate comparable to the best implants. Further research is needed to establish if the beneficial properties of zirconium improve long term implant survival.