Poor 10-year survivorship of hip resurfacing arthroplasty: 5,098 replacements from the Finnish Arthroplasty Register

Background and purpose In a previous registry report, short-term implant survival of hip resurfacing arthroplasty (HRA) in Finland was found to be comparable to that of total hip arthroplasty (THA). Since then, it has become evident that adverse reactions to metal debris (ARMDs) may also be associated with HRA, not only with large-diameter head metal-on-metal THA. The aim of the study was to assess medium- to long-term survivorship of HRA based on the Finnish Arthroplasty Register (FAR).Patients and methods 5,068 HRAs performed during the period 2001-2013 in Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities and their 95% confidence intervals (CIs). Cox multiple regression, with adjustment for age, sex, diagnosis, femoral head size, and hospital volume was used to analyze implant survival of HRA devices with revision for any reason as endpoint. The reference group consisted of 6,485 uncemented Vision/Bimetric and ABG II THAs performed in Finland over the same time period.Results The 8-year survival, with any revision as an endpoint, was 93% (CI: 92-94) for Birmingham Hip Resurfacing (BHR), 86% (CI: 78-94) for Corin, 91% (CI: 89-94) for ReCap, 92% (CI: 89-96) for Durom, and was 72% (CI: 69-76) for the Articular Surface Replacement (ASR). The 10-year survival, with any revision as an endpoint, for reference THAs was 92% (CI: 91-92) and for all HRAs it was 86% (CI: 84-87%). Female HRA patients had about twice the revision risk of male patients. ASR had an inferior outcome: the revision risk was 4-fold higher than for BHR, the reference implant.Interpretation The 10-year implant survival of HRAs is 86% in Finland. According to new recommendations from NICE (The National Institute for Health and Care Excellence), an HRA/THA should have a revision rate of 5% or less at 10 years. None of the HRAs studied achieved this goal

Population pharmacokinetic modelling of intravenous paracetamol in fit older people displays extensive unexplained variability

Aims Paracetamol is the analgesic most used by older people. The physiological changes occurring with ageing influence the pharmacokinetics (PK) of paracetamol and its variability. We performed a population PK-analysis to describe the PK of intravenous (IV) paracetamol in fit older people. Simulations were performed to illustrate target attainment and variability of paracetamol exposure following current dosing regimens (1000 mg every 6 h, every 8 h) using steady-state concentration (Css-mean) of 10 mg l(-1) as target for effective analgesia. Methods A population PK-analysis, using NONMEM 7.2, was performed based on 601 concentrations of paracetamol from 30 fit older people (median age 77.3 years, range [61.8-88.5], body weight 79 kg [60-107]). All had received an IV paracetamol dose of 1000 mg (over 15 min) after elective knee surgery. Results A two-compartment PK-model best described the data. Volume of distribution of paracetamol increased exponentially with body weight. Clearance was not influenced by any covariate. Simulations of the standardized dosing regimens resulted in a C-ss of 9.2 mg l(-1) and 7.2 mg l(-1), for every 6 h and every 8 h respectively. Variability in paracetamol PK resulted in C-ss above 5.4 and 4.1 mg l(-1), respectively, in 90% of the population and above 15.5 and 11.7, respectively, in 10% at these dosing regimens. Conclusions The target concentration was achieved in the average patient with 1000 mg every 6 h, while every 8 h resulted in underdosing for the majority of the population. Furthermore, due to a large (unexplained) interindividual variability in paracetamol PK a relevant proportion of the fit older people remained either under- or over exposed.Peer reviewe

Functional results of total-knee arthroplasty versus medial unicompartmental arthroplasty: two-year results of a randomised, assessor-blinded multicentre trial

AbstractObjectiveThe primary objective of the trial was to assess the clinical effectiveness of medial unicompartmental knee arthroplasty versus total knee arthroplasty in patients with isolated medial osteoarthritis of the knee.DesignProspective, randomised, 2 years, assessor-blind, multicentre, superiority trial.SettingThe patients were enrolled between December 2015 and May 2018 from the outpatient clinics of three public high-volume arthroplasty hospitals (Finland).ParticipantsWe recruited 143 patients with symptomatic-isolated medial osteoarthritis of the knee needing an arthroplasty procedure. All the patients were suitable for both unicompartmental and total knee arthroplasties. Population was selected as the end-stage-isolated medial osteoarthritis.InterventionsAll patients, randomized 1:1, received a medial unicompartmental arthroplasty or a total knee arthroplasty through a similar midline skin incision. Patients were blinded to the type of arthroplasty for the whole 2 years of follow-up.Main outcome measuresPrimary outcome measure was between-group differences in the Oxford Knee Score (OKS) and secondary outcome Knee injury and Osteoarthritis Score (KOOS) at 2 years postoperatively. The changes within and between the groups were analysed with analysis of variance for repeated measurements.ResultsThe primary outcome was comparable for medial unicompartmental arthroplasty and total knee arthroplasty at 2 years. The mean difference in the OKS between the groups was 1.6 points (95% CI −0.7 to 3.9). In the KOOS subscales, the mean difference between the groups was 0.1 points (95% CI −4.8 to 5.0) for pain, 7.8 points (95% CI 1.5 to 14.0) for symptoms, 4.3 points (95% CI −0.6 to 9.2) for function in daily living, 4.3 points (95% CI −3.0 to 11.6) for function in sports, and 2.1 points (95% CI −4.8 to 9.1) for knee-related quality of life.ConclusionsThe recovery after unicompartmental knee arthroplasty was faster compared with total knee arthroplasty, but unicompartmental arthroplasty did not provide a better patient-reported outcome at 2 years.</p

Population pharmacokinetic modelling of intravenous paracetamol in fit older people displays extensive unexplained variability.

as target for effective analgesia.A population PK-analysis, using NONMEM 7.2, was performed based on 601 concentrations of paracetamol from 30 fit older people (median age 77.3 years, range [61.8-88.5], body weight 79 kg [60-107]). All had received an IV paracetamol dose of 1000 mg (over 15 min) after elective knee surgery. , respectively, in 90% of the population and above 15.5 and 11.7, respectively, in 10% at these dosing regimens.The target concentration was achieved in the average patient with 1000 mg every 6 h, while every 8 h resulted in underdosing for the majority of the population. Furthermore, due to a large (unexplained) interindividual variability in paracetamol PK a relevant proportion of the fit older people remained either under- or over exposed.AIMSMETHODSRESULTSCONCLUSIONSPharmacolog

Functional results of total-knee arthroplasty versus medial unicompartmental arthroplasty:two-year results of a randomised, assessor-blinded multicentre trial

Abstract Objective:The primary objective of the trial was to assess the clinical effectiveness of medial unicompartmental knee arthroplasty versus total knee arthroplasty in patients with isolated medial osteoarthritis of the knee. Design: Prospective, randomised, 2 years, assessor-blind, multicentre, superiority trial. Setting: The patients were enrolled between December 2015 and May 2018 from the outpatient clinics of three public high-volume arthroplasty hospitals (Finland). Participants: We recruited 143 patients with symptomatic-isolated medial osteoarthritis of the knee needing an arthroplasty procedure. All the patients were suitable for both unicompartmental and total knee arthroplasties. Population was selected as the end-stage-isolated medial osteoarthritis. Interventions: All patients, randomized 1:1, received a medial unicompartmental arthroplasty or a total knee arthroplasty through a similar midline skin incision. Patients were blinded to the type of arthroplasty for the whole 2 years of follow-up. Main outcome measures: Primary outcome measure was between-group differences in the Oxford Knee Score (OKS) and secondary outcome Knee injury and Osteoarthritis Score (KOOS) at 2 years postoperatively. The changes within and between the groups were analysed with analysis of variance for repeated measurements. Results: The primary outcome was comparable for medial unicompartmental arthroplasty and total knee arthroplasty at 2 years. The mean difference in the OKS between the groups was 1.6 points (95% CI −0.7 to 3.9). In the KOOS subscales, the mean difference between the groups was 0.1 points (95% CI −4.8 to 5.0) for pain, 7.8 points (95% CI 1.5 to 14.0) for symptoms, 4.3 points (95% CI −0.6 to 9.2) for function in daily living, 4.3 points (95% CI −3.0 to 11.6) for function in sports, and 2.1 points (95% CI −4.8 to 9.1) for knee-related quality of life. Conclusions: The recovery after unicompartmental knee arthroplasty was faster compared with total knee arthroplasty, but unicompartmental arthroplasty did not provide a better patient-reported outcome at 2 years. Trial registration number: NCT02481427