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  • The effects of age on patient-reported outcome measures in total knee replacements.

    18 September 2018

    We present a comparison of patient-reported outcomes (PROMs) in relation to patient age, in patients who had received a total (TKR) or unicompartmental knee replacement (UKR). The outcome was evaluated using the Oxford knee score (OKS), EuroQol (EQ-5D) and satisfaction scores. Patients aged 65 to 84 years demonstrated better pre-operative function scores than those aged < 65 years (OKS, p = 0.03; EQ-5D, p = 0.048) and those aged ≥ 85 years (OKS, p = 0.03). Post-operative scores were comparable across age groups, but a linear trend for greater post-operative improvement in OKS and EQ-5D was seen with decreasing age (p < 0.033). The overall mean satisfaction score at six months was 84.9, but those aged < 55 years exhibited a lower mean level of satisfaction (78.3) compared with all other age groups (all p < 0.031). The cumulative overall two-year revision rate was 1.3%. This study demonstrates that good early outcomes, as measured by the OKS and EQ-5D, can be anticipated following knee replacement regardless of the patient's age, although younger patients gain greater improvement. However, the lower satisfaction in those aged < 55 years is a concern, and suggests that outcome is not fully encapsulated by the OKS and EQ-5D evaluation, and raises the question whether the OKS alone is an appropriate measure of pain and function in younger, more active individuals.

  • No evidence of an association between mitochondrial DNA variants and osteoarthritis in 7393 cases and 5122 controls.

    18 September 2018

    OBJECTIVES: Osteoarthritis (OA) has a complex aetiology with a strong genetic component. Genome-wide association studies implicate several nuclear genes in the aetiology, but a major component of the heritability has yet to be defined at the molecular level. Initial studies implicate maternally inherited variants of mitochondrial DNA (mtDNA) in subgroups of patients with OA based on gender and specific joint involvement, but these findings have not been replicated. METHODS: The authors studied 138 maternally inherited mtDNA variants genotyped in a two cohort genetic association study across a total of 7393 OA cases from the arcOGEN consortium and 5122 controls genotyped in the Wellcome Trust Case Control consortium 2 study. RESULTS: Following data quality control we examined 48 mtDNA variants that were common in cohort 1 and cohort 2, and found no association with OA. None of the phenotypic subgroups previously associated with mtDNA haplogroups were associated in this study. CONCLUSIONS: We were not able to replicate previously published findings in the largest mtDNA association study to date. The evidence linking OA to mtDNA is not compelling at present.

  • Lower limbs composition and radiographic knee osteoarthritis (RKOA) in Chingford sample--a longitudinal study.

    18 September 2018

    Our aim in this longitudinal study was to evaluate to what extent fat and lean tissue mass variations are associated and can predict RKOA in a large sample of British women followed-up over 10 years. Kellgren/Lawrence (K/L), joint space narrowing (JSN) and osteophyte (OSP) grades were scored from radiographs of both knees in 909 middle-aged women from the Chingford registry. Body composition components were assessed using the dual energy X-ray absorptiometry (DXA) method. In cross-sectional analysis, combined effect of age, BMI and leg tissue composition was required for best fitting model explaining variations of K/L scoring and osteophytes at lateral compartment. To explain medial osteophytes, age and BMI were sufficient to generate the best fitting model. In prediction analysis, leg lean mass was the more powerful predictor of K/L, medial osteophytes than BMI. In conclusion, BMI appears to influence the development of knee OA through both fat and/or lean mass, depending on RKOA phenotype.

  • The effect of hip and knee arthroplasty on oral anti-inflammatory use and the relationship to body mass index: results from the UK general practice research database.

    18 September 2018

    OBJECTIVE: To determine the use of oral anti-inflammatory drugs in the year before and the 2 years after primary total hip (THR) or knee (TKR) replacement, and whether this varies according to Body mass Index (BMI). DESIGN: 28,068 THR's and 24,364 TKR's, with five matched controls per case were identified from the General Practitioner Research Database. Anti-inflammatory usage was categorized into "zero coverage" - no prescribed anti-inflammatory medication and ">80% coverage" - prescribed anti-inflammatory medication for greater than 80% of the days in the year. Secondary subset analysis was performed according to BMI. RESULTS: 1 year post-surgery the proportion of cases on >80% coverage reduced from 21% (95%confidence interval (CI): 20-22%) to 8% (95%CI: 7-10%) for THR and 21% (95%CI: 20-22%) to 13% (95%CI: 11-14%) for TKR, with no ongoing reduction at 2 years. Zero coverage increased at one and both time points. The proportion of THR's on >80% coverage increased with BMI pre-op. The magnitude in reduction post-op was similar across all BMI groups. The proportion of TKR's on >80% coverage pre-op was greatest in extreme BMI categories. The magnitude in reduction post-op was similar across all BMI groups. CONCLUSION: THR/TKR's reduce the need for anti-inflammatory medication with most benefit observed in the first post-operative year. Increasing BMI affects anti-inflammatory use both in the general population and those undergoing THR/TKR surgery but without strong evidence of a detrimental effect on the benefits of pain relief.

  • Changes in hip fracture rate before and after total knee replacement due to osteoarthritis: a population-based cohort study.

    18 September 2018

    OBJECTIVES: Patients with knee osteoarthritis have an increase in bone mass but no corresponding decrease in risk of fracture. This study describes the rates of hip fracture in subjects with knee osteoarthritis before and after having a total knee replacement (TKR), compared with matched controls. METHODS: A population-based prospective cohort study was conducted. The study population included, from the General Practice Research Database (UK), patients 40 years and older, undergoing TKR between 1986 and end-2006 for knee osteoarthritis as 'cases' (n=20,033). Five disease-free controls (n=100,165) were randomly selected, and matched for age, gender and practice. Hip fractures were ascertained using READ codes, and yearly rates of hip fracture and rate differences were calculated for the 5 years before and after surgery, using Poisson regression. Stratified analyses were performed by age and history of fracture. RESULTS: Hip fracture rates were non-significantly reduced compared with controls before the operation. In the year after TKR, risk increased significantly (RR 1.58; 95% CI 1.14 to 2.19). Rates then declined to equal those of controls by 3 years, and continued decreasing until the end of follow-up; corresponding RR were not significant. The increased risk is greatest in younger ages and in those without previous fracture. CONCLUSIONS: The association between knee osteoarthritis and fractures is time-dependent, which may explain the current controversy in the literature. The association is also modified by TKR: subjects have a higher rate of hip fracture than matched controls after TKR, although the rates may eventually decrease.

  • Low maternal vitamin D status and fetal bone development: cohort study.

    18 September 2018

    Recent findings suggest that maternal vitamin D insufficiency during pregnancy has consequences for the offspring's bone health in later life. To investigate whether maternal vitamin D insufficiency affects fetal femur growth in ways similar to those seen in childhood rickets and study the timing during gestation of any effect of maternal vitamin D status, we studied 424 pregnant women within a prospective longitudinal study of maternal nutrition and lifestyle before and during pregnancy (Southampton Women's Survey). Using high-resolution 3D ultrasound, we measured fetal femur length and distal metaphyseal cross-sectional area, together with the ratio of femoral metaphyseal cross-sectional area to femur length (femoral splaying index). Lower maternal 25-hydroxyvitamin vitamin D concentration was not related to fetal femur length but was associated with greater femoral metaphyseal cross-sectional area and a higher femoral splaying index at 19 weeks' gestation [r = -0.16, 95% confidence interval (CI) -0.25 to -0.06 and r = -0.17, 95% CI -0.26 to -0.07, respectively] and at 34 weeks' gestation (r = -0.10, 95% CI -0.20 to 0.00 and r = -0.11, 95% CI -0.21 to -0.01, respectively). Three groups of women were identified with 25-hydroxyvitamin vitamin D concentrations that were sufficient/borderline (> 50 nmol/L, 63.4%), insufficient (25 to 50 nmol/L, 30.7%), and deficient (< or = 25 nmol/L, 5.9%). Across these groups, the geometric mean femoral splaying indices at 19 weeks' gestation increased from 0.074 (sufficient/borderline) to 0.078 (insufficient) and 0.084 (deficient). Our observations suggest that maternal vitamin D insufficiency can influence fetal femoral development as early as 19 weeks' gestation. This suggests that measures to improve maternal vitamin D status should be instituted in early pregnancy.

  • Temporal trends in hip and knee replacement in the United Kingdom: 1991 to 2006.

    18 September 2018

    Using the General Practice Research Database, we examined the temporal changes in the rates of primary total hip (THR) and total knee (TKR) replacement, the age at operation and the female-to-male ratio between 1991 and 2006 in the United Kingdom. We identified 27 113 patients with THR and 23 843 with TKR. The rate of performance of THR and TKR had increased significantly (p < 0.0001 for both) during the 16-year period and was greater for TKR, especially in the last five years. The mean age at operation was greater for women than for men and had remained stable throughout the period of study. The female-to-male ratio was higher for THR and TKR and had remained stable. The data support the notion that the rate of joint replacement is increasing in the United Kingdom with the rate of TKR rising at the highest rate. The perception that the mean age for TKR has decreased over time is not supported.

  • EULAR evidence-based recommendations for the diagnosis of hand osteoarthritis: report of a task force of ESCISIT.

    18 September 2018

    OBJECTIVES: To develop evidence-based recommendations for the diagnosis of hand osteoarthritis (OA). METHODS: The multidisciplinary guideline development group, representing 15 European countries, generated 10 key propositions regarding diagnosis using a Delphi consensus approach. For each recommendation, research evidence was searched for systematically. Whenever possible, the sensitivity, specificity and likelihood ratio (LR) were calculated; relative risk and odds ratios were estimated for risk factors for hand OA. Quality of evidence was categorised using the European League Against Rheumatism (EULAR) hierarchy, and strength of recommendation was assessed by the EULAR visual analogue scale. RESULTS: Diagnostic topics included clinical manifestations, radiographic features, subgroups, differential diagnosis, laboratory tests, risk factors and comorbidities. The sensitivity, specificity and LR varied between tests depending upon the cut-off level, gold standard and controls. Overall, no single test could be used to define hand OA on its own (LR <10) but a composite of the tests greatly increased the chance of the diagnosis. The probability of a subject having hand OA was 20% when Heberden nodes alone were present, but this increased to 88% when in addition the subject was over 40 years old, had a family history of nodes and had joint space narrowing in any finger joint. CONCLUSION: Ten key recommendations for diagnosis of hand OA were developed using research evidence and expert consensus. Diagnosis of hand OA should be based on assessment of a composite of features.

  • Effective measurement of knee alignment using AP knee radiographs.

    18 September 2018

    The gold standard for measuring knee alignment is mechanical axis determined using full-limb radiographs (FLR). Measurement of joint alignment using antero-posterior (AP) knee radiographs is more accessible, economical and involves less radiation exposure to the patient compared with using full-limb radiographs. The aim of this study was to compare and assess the reproducibility of knee joint axial alignment on full-limb radiographs and conventional AP knee radiographs. Knee alignment was measured in 40 subjects (80 knees) from the TwinsUK registry. Measurement of mechanical knee alignment was from FLR, and anatomic knee alignment from weight-bearing AP knee radiographs. Reproducibility was assessed by intra-class correlation coefficients and kappa statistics. Reproducibility of knee alignment for both methods was good, with intra-observer ICC's of 0.99 for both FLR and AP radiographs. The mean alignment angle on FLR was 178.9 degrees (SD 2.1, range 173-183 degrees ), and 179.0 degrees (SD 2.1, range 173-185 degrees ) on AP films. 58.8% of knees on FLR and 66.3% on AP films were of varus alignment. Good correlations were seen between results for FLR and AP radiographs, with ICC ranging from 0.87-0.92 for left and right knees, and kappa statistics of 0.65-0.74. Standard AP knee radiographs can be used to measure knee alignment with good reproducibility, and provide comparable results to those obtained from FLR. This will facilitate measurement of knee alignment in existing cohort studies to assess malalignment as a risk factor of incident OA, and in clinical practice.