Pre-operative pressure pain thresholds do not meaningfully explain satisfaction or improvement in pain after knee replacement: a cohort study.

OBJECTIVES: Pain sensitization could be a risk factor for poor outcomes after knee replacement surgery (KR) for knee osteoarthritis (KOA). We aimed to evaluate the association between pre-operative central and peripheral pain sensitization measured using a digital pressure algometer and KR outcomes. METHODS: Consecutive patients with severe KOA listed for KR were recruited. Sociodemographic and symptoms data were collected prior to surgery. Pre-operative pressure pain thresholds (PPTs) were measured using a digital pressure algometer at the index knee and forearm. Patient satisfaction at 6 and 12 months after KR was assessed using a 4-point Likert scale, and dichotomized to satisfied and dissatisfied to KR. Western Ontario and McMaster Universities Index (WOMAC) Pain and function was assessed. The associations between pre-operative PPTs with KR outcomes at 6 and 12 months were evaluated. RESULTS: Of the 243 patients recruited, response rate at 6 and 12 months were 95.5% and 96.7%. The dissatisfaction rates were 8.2% and 5.1% at 6 and 12 months. There was no statistically significant association between pre-operative index knee or forearm PPTs and patient satisfaction. PPTs measured at the knee, but not the forearm, were weakly associated with change in the WOMAC pain score at 12 months, after adjustment for confounding factors. CONCLUSION: Pre-operative central sensitization, measured by handheld digital algometry, was not statistically significantly associated with satisfaction or change in pain after KR. Pre-operative peripheral sensitization was associated with change in pain symptoms after KR; however, this association was weak and unlikely to be a meaningful predictor of KR outcome in clinical practice.

Outcomes and survivorship of unicondylar knee arthroplasty in patients with severe deformity.

Purpose Patients with severe deformity beyond the standard indications for unicompartmental knee arthroplasty (UKA) may be suitable and benefit from UKA. This study investigated their outcomes to determine whether good function and quality of life (QOL) can be achieved. MATERIALS AND METHODS: Fifty-three patients with severe deformity (40 patients with FFD ≥15° and 13 patients with varus deformity ≥15°, Group A) were matched with 53 patients with less severe deformities who underwent UKA (Group B/controls) in terms of age, sex, BMI and duration of follow-up. Their flexion range, Knee Society scores (KSS), Oxford knee scores (OKS) and SF-36 QOL scores were analysed pre-operatively and at 2 years. RESULTS: Group A patients were largely similar to Group B patients pre-operatively in terms of maximum flexion angle, OKS and SF-36 scores except for knee score and mental health component of SF-36. At 2 years, Group A reported largely similar results compared with Group B in all outcome scores (OKS, KSS, SF-36) and flexion angle. Post-operative mechanical alignment was better for the control group though it is not statistically significant. There were no revisions in the patients with severe pre-operative deformity at 5 years post-operatively. (Survivorship 100 % at 5 years). CONCLUSION: Selected patients with severe deformity can achieve good function and QOL with UKA if satisfactory mechanical alignment is restored. This study supports a broadening of the indications of UKA; however, further follow-up is needed to assess the longer-term durability of the operation. LEVEL OF EVIDENCE: IV.

Alternative migratory locust phenotypes are associated with differences in the expression of genes encoding the methylation machinery.

Despite the importance of locust density-dependent polyphenism as a model system for understanding phenotypic plasticity, there is still much to be learnt about its underlying molecular control. Here we describe the first investigation into the expression of genes encoding the DNA methylation machinery in the migratory locust (Locusta migratoria). We show that the alternative solitarious and gregarious phenotypic states induced by different locust rearing densities are associated with significant differences in the expression of the target genes DNA methyltransferase 1, DNA methyltransferase 2 and methyl-CpG-binding domain protein 2/3. This variation was most pronounced in the embryos of solitarious vs. gregarious mothers. We mapped the embryonic methylation profiles of several intragenic regions and a Long Interspersed Nuclear Element (LINE), each of which is known to be differentially expressed between alternative locust phenotypes or has been directly implicated in phase change. LmI and three genes, adenyl cyclase-associated binding protein 2, choline kinase alpha-like and henna, were methylated. Our results set the stage for future studies investigating the specific role of DNA methylation in the maternal transfer of migratory locust phase polyphenism.

Pathway to mental health recovery: a qualitative and quantitative study on the needs of Chinese psychiatric inpatients.

BACKGROUND: Exploration of the information and participation needs of psychiatric inpatients is an important step for the implementation of recovery-oriented mental health service. The objective of this study was to explore the information and participation needs of Chinese psychiatric inpatients in the largest psychiatric hospital in Hong Kong. METHODS: The study was divided into two parts. In the first part, eight focus groups with patients, patients' relatives and healthcare professionals were held to identify 22 items of information needs and 16 items of participation needs of Chinese psychiatric inpatients. Basing on the items identified in the first part of the study, a questionnaire was developed to survey on the importance of the different information and participation needs in the second part of the study. Participants were asked to rate in rank order their perceived importance of the items in the questionnaire survey. RESULTS: A hundred and eighty three Chinese psychiatric inpatients completed the questionnaire and the majority of them suffered from schizophrenia (68.3 %). For information needs, the top three needs rated by patients as the most important in descending order were: "Information on the classifications of mental illnesses, signs and symptoms and factors contributing to relapse", "Information on the criteria and arrangements for discharge", and "Information on the importance of psychiatric drug taking and its side effects". For participation needs, the top three needs rated by patients as the most important in descending order were: "Enquiring about personal needs and arrangements", "Keeping in touch with the outside world", and "Learning and practising self-management". CONCLUSIONS: This study reveals that Chinese psychiatric inpatients are concerned about information on their mental illness and its treatments as well as the criteria for discharge. On the other hand, patients are concerned about their personal needs, their self-management, as well as their keeping in touch with the outside world during their hospitalisation. Moreover, patients with different socio-demographic and clinical characteristics have different information and participation needs. The results of the present study serve as a reference for designing guidelines, strategies, and programmes to meet the information needs and participation needs of psychiatric inpatients in Hong Kong.

The Human Connectome Project of adolescent anxiety and depression dataset.

This article describes primary data and resources available from the Boston Adolescent Neuroimaging of Depression and Anxiety (BANDA) study, a novel arm of the Human Connectome Project (HCP). Data were collected from 215 adolescents (14-17 years old), 152 of whom had current diagnoses of anxiety and/or depressive disorders at study intake. Data include cross-sectional structural (T1- and T2-weighted), functional (resting state and three tasks), and diffusion-weighted magnetic resonance images. Both unprocessed and HCP minimally-preprocessed imaging data are available within the data release packages. Adolescent and parent clinical interview data, as well as cognitive and neuropsychological data are also included within these packages. Release packages additionally provide data collected from self-report measures assessing key features of adolescent psychopathology, including: anxious and depressive symptom dimensions, behavioral inhibition/activation, exposure to stressful life events, and risk behaviors. Finally, the release packages include 6- and 12-month longitudinal data acquired from clinical measures. Data are publicly accessible through the National Institute of Mental Health Data Archive (ID: #2505).

Duloxetine reduces morphine requirements after knee replacement surgery.

BACKGROUND: Multimodal analgesia is advocated for perioperative pain management to reduce opioid use and its associated adverse effects. Serotonin and norepinephrine are involved in the modulation of endogenous analgesic mechanisms via descending inhibitory pain pathways in the brain and spinal cord. An increase in serotonin and norepinephrine may increase inhibition of nociceptive input and improve pain relief. Duloxetine, a selective serotonin and norepinephrine reuptake inhibitor, has demonstrated efficacy in chronic pain conditions such as painful diabetic neuropathy and post-herpetic neuralgia. The objective of the study was to evaluate the efficacy of duloxetine in reducing morphine requirements in patients after knee replacement surgery. METHODS: Fifty patients received either two doses of oral duloxetine 60 mg (2 h before surgery and on first postoperative day) or placebo. All patients received patient-controlled analgesia with morphine for 48 h after operation. Pain and adverse effects were assessed at 0.5, 1, 2, 6, 12, 24, and 48 h after surgery on an 11-point numeric rating scale. RESULTS: Twenty-three patients in the duloxetine group and 24 patients in the placebo group completed the study. Morphine requirements during the 48 h after surgery were significantly lower in the duloxetine group [19.5 mg, standard deviation (sd) 14.5 mg] compared with the placebo group (30.3 mg, sd 18.1 mg) (P=0.017). There were no statistically significant differences between the groups in pain scores (at rest and on movement) or in adverse effects. CONCLUSIONS: Perioperative administration of duloxetine reduced postoperative morphine requirements during the first 48 h after knee replacement surgery, without significant adverse effects.

Patient-reported Outcome Measures of Revision Total Hip Arthroplasty for Prosthetic Joint Infection is not Inferior to Aseptic Revision Total Hip Arthroplasty.

INTRODUCTION: This study aims to investigate whether patients undergoing two-stage revision total hip arthroplasty (THA) for prosthetic joint infection (PJI) and one-stage revision THA for aseptic reasons have similar clinical outcomes and patient satisfaction during their post-operative follow-up. We hypothesise that the two-stage revision THA for PJI is associated with poorer outcomes as compared to aseptic revision THA. MATERIALS AND METHODS: We reviewed prospectively collected data in our tertiary hospital arthroplasty registry and identified patients who underwent revision THA between 2001 and 2014, with a minimum of two years follow-up. The study group (two-stage revision THA for PJI) consists of 23 patients and the control group (one-stage revision THA for aseptic reasons) consists of 231 patients. Patient demographics, Western Ontario and McMaster Universities Arthritis Index (WOMAC), Oxford Hip Score (OHS), Short Form-36 (SF-36) scores and patient reported satisfaction were evaluated. Student's t-test was used to compare continuous variables between the two groups. Statistical significance was defined as p <0.05. RESULTS: The pre-operative demographics and clinical scores were relatively similar between the two groups of patients. At two years, patients who underwent revision THA for PJI reported a better WOMAC Pain Score and OHS as compared to aseptic revision THA. A similar proportion of patients were satisfied with their results of surgery in both groups (p=0.093). CONCLUSIONS: Although patients who underwent revision THA for PJI had poorer pre-operative functional scores (WOMAC function and SF-36 PF), at two years follow-up, these two groups of patients have comparable post-operative outcomes. Interestingly, patients who had revision THA for PJI reported a better clinical outcome in terms of OHS and WOMAC Pain score as compared to the aseptic group. We conclude that the revision THA for PJI is not inferior to aseptic revision THA in terms of patient satisfaction and clinical outcomes.

Brain function and clinical characterization in the Boston adolescent neuroimaging of depression and anxiety study.

We present a Human Connectome Project study tailored toward adolescent anxiety and depression. This study is one of the first studies of the Connectomes Related to Human Diseases initiative and is collecting structural, functional, and diffusion-weighted brain imaging data from up to 225 adolescents (ages 14-17 years), 150 of whom are expected to have a current diagnosis of an anxiety and/or depressive disorder. Comprehensive clinical and neuropsychological evaluations and longitudinal clinical data are also being collected. This article provides an overview of task functional magnetic resonance imaging (fMRI) protocols and preliminary findings (N = 140), as well as clinical and neuropsychological characterization of adolescents. Data collection is ongoing for an additional 85 adolescents, most of whom are expected to have a diagnosis of an anxiety and/or depressive disorder. Data from the first 140 adolescents are projected for public release through the National Institutes of Health Data Archive (NDA) with the timing of this manuscript. All other data will be made publicly-available through the NDA at regularly scheduled intervals. This article is intended to serve as an introduction to this project as well as a reference for those seeking to clinical, neurocognitive, and task fMRI data from this public resource.

Rasch analysis of the Oxford Knee Score.

OBJECTIVES: Use Rasch analysis to examine the psychometric properties of the Oxford Knee Score (OKS), particularly in respect to unidimensionality, and consistency of item functioning before and after total knee replacement and across age and gender groups. METHODS: The 12-item OKS was administered to 1,712 patients before the surgery, and 1,322 and 855 patients were administered the instrument repeatedly at the 6-month and 2-year postoperative assessments, respectively. Data were fitted to the Rasch partial credit model with the Winsteps program. Differential item functioning (DIF) analysis was performed, and fit statistics in combination with principal components analysis of the residuals were used to test the unidimensionality assumption. The fit criteria were set at 1.5 and 2.0 for infit mean-square (MNSQ) and outfit MNSQ, respectively. RESULTS: At baseline, item difficulty ranged from -1.86 to 1.78 logits, and person measures had a mean+/-SD of -0.01+/-0.89. Misfit items were "limping" and "night pain" in preoperative data and "limping" and "kneeling" in postoperative data. After removing items limping and kneeling and recoding item night pain, none of the items misfit at each of the time points and there was stability of item difficulty ordering across time. In the modified OKS set, five items displayed DIF by age and three by gender. CONCLUSION: The original OKS had adequate targeting and good coverage of knee severity levels in preoperative patients. The modified 10-item OKS data fit the Rasch model and had stable item difficulty ordering over time.

Thromboembolic prophylaxis for total knee arthroplasty in Asian patients: a randomised controlled trial.

PURPOSE: To compare the efficacy and safety of different modes of thromboembolic prophylaxis for elective total knee arthroplasty (TKA) in Asian patients. METHODS: 440 low-risk patients undergoing TKA were randomised into 4 equal groups: (1) no prophylaxis (control), (2) graduated compression stockings (GCS), (3) intermittent pneumatic compression (IPC), and (4) low-molecular-weight heparin (enoxaparin). Duplex ultrasonography was used as an assessment tool. RESULTS: The deep vein thrombosis point prevalence was highest in the control group (22%), which was significantly higher than in patients receiving IPC (8%, p=0.032) or enoxaparin (6%, p=0.001). One patient each in the control and GCS groups developed a non-fatal pulmonary embolism. Patients on enoxaparin received more blood transfusions and 2 of them had major bleeding complications. CONCLUSION: IPC is the preferred method of thromboprophylaxis for TKA in Asian patients.

The influence of obesity on clinical outcomes of fixed-bearing unicompartmental knee arthroplasty: a ten-year follow-up study.

AIMS: The aim of this study was to assess the influence of obesity on the clinical outcomes and survivorship ten years postoperatively in patients who underwent a fixed-bearing unicompartmental knee arthroplasty (UKA). PATIENTS AND METHODS: We prospectively followed 184 patients who underwent UKA between 2003 and 2007 for a minimum of ten years. A total of 142 patients with preoperative body mass index (BMI) of < 30 kg/m2 were in the control group (32 male, 110 female) and 42 patients with BMI of ≥ 30 kg/m2 were in the obese group (five male, 37 female). Pre- and postoperative range of movement (ROM), Knee Society Score (KSS), Oxford Knee Score (OKS), 36-Item Short-Form Health Survey (SF-36), and survivorship were analyzed. RESULTS: Patients in the obese group underwent UKA at a significantly younger mean age (56.5 years (sd 6.4)) than those in the control group (62.4 years (sd 7.8); p < 0.001). There was no significant difference in preoperative functional scores. However, those in the obese group had a significantly lower ROM (116° (sd 15°) vs 123° (sd 17°); p = 0.003). Both groups achieved significant improvement in outcome scores regardless of BMI, ten years postoperatively. All patients achieved the minimal clinically important difference (MCID) for OKS and KSS. Both groups also had high rates of satisfaction (96.3% in the control group and 97.5% in the obese group) and the fulfilment of expectations (94.9% in the control group and 95.0% in the obese group). Multiple linear regression showed a clear association between obesity and a lower OKS two years postoperatively and Knee Society Function Score (KSFS) ten years postoperatively. After applying propensity matching, obese patients had a significantly lower KSFS, OKS, and physical component score (PCS) ten years postoperatively. Seven patients underwent revision to total knee arthroplasty (TKA), two in the control group and five in the obese group, resulting in a mean rate of survival at ten years of 98.6% and 88.1%, respectively (p = 0.012). CONCLUSION: Both groups had significant improvements in functional and quality-of-life scores postoperatively. However, obesity was a significant predictor of poorer improvement in clinical outcome and an increased rate of revision ten years postoperatively.

Validation of the International Classification of Functioning, Disability, and Health (ICF) Brief Core Set for osteoarthritis.

OBJECTIVE: To validate the International Classification of Functioning, Disability, and Health (ICF) Brief Core Set for osteoarthritis (OA) by comparing the preliminary Brief Core Set to a selection of categories from the Comprehensive Core Set that explain most of the variance of functioning and health. METHODS: Patients with knee OA were asked to complete the Case Report Form for Patients, which includes the 36-item Short Form Health Survey (SF-36) and the Self-administered Comorbidity Questionnaire (SCQ). For each patient, the research staff was asked to complete the Case Report Form for Health Professionals, which includes the ICF Comprehensive Core Set for OA. Two individual questions regarding patients' general health and functioning were completed by both the patients and the research staff. The ICF categories to be entered into an initial regression model were selected following systematic steps in accordance with the ICF structure. Based on the initial models, additional models were generated by systematically substituting the ICF categories included in the initial models with other highly intercorrelated categories. RESULTS: A consecutive sample of 122 patients completed this study. Sixteen candidate ICF categories were identified by 15 linear regression models, which accounted for 5.5-57.7% of the total variance. Besides the two categories, b710 and b730, that are already included in the preliminary Brief Core Set, 14 additional categories were identified to be potential candidates for the Core Set. CONCLUSIONS: This study complemented the development of the Brief Core Set, which should be further refined by incorporating the opinions of patients, clinicians, and statisticians.

Midichloria mitochondrii is widespread in hard ticks (Ixodidae) and resides in the mitochondria of phylogenetically diverse species.

The hard tick Ixodes ricinus (Ixodidae) is the sole animal thus far shown to harbour an intra-mitochondrial bacterium, which has recently been named Midichloria mitochondrii. The objectives of this work were (i) to screen ixodid ticks for Midichloria-related bacteria and (ii) to determine whether these bacteria exploit the intra-mitochondrial niche in other tick species. Our main goal was to discover further models of this peculiar form of symbiosis. We have thus performed a PCR screening for Midichloria-related bacteria in samples of ixodid ticks collected in Italy, North America and Iceland. A total of 7 newly examined species from 5 genera were found positive for bacteria closely related to M. mitochondrii. Samples of the tick species Rhipicephalus bursa, found positive in the PCR screening, were analysed with transmission electron microscopy, which revealed the presence of bacteria both in the cytoplasm and in the mitochondria of the oocytes. There is thus evidence that bacteria invade mitochondria in at least 2 tick species. Phylogenetic analysis on the bacterial 16S rRNA gene sequences generated from positive specimens revealed that the bacteria form a monophyletic group within the order Rickettsiales. The phylogeny of Midichloria symbionts and related bacteria does not appear completely congruent with the phylogeny of the hosts.

Peri-articular steroid injection improves the outcome after unicondylar knee replacement: a prospective, randomised controlled trial with a two-year follow-up.

We have performed a prospective double-blind, randomised controlled trial over two years to evaluate the efficacy and safety of an intra-operative peri-articular injection of triamcinolone acetonide in patients undergoing medial unicondylar knee replacement. We randomised 90 patients into two equal groups. The study group received an injection of triamcinolone acetonide, bupivacaine, and epinephrine into the peri-articular tissues at the end of the operation. The control group received the same injection mixture but without the addition of triamcinolone. The peri-operative analgesic regimen was standardised. The study group reported a significant reduction in pain (p = 0.014 at 12 hours, p = 0.031 at 18 hours and p = 0.031 at 24 hours) and had a better range of movement (p = 0.023 at three months). There was no significant difference in the rate of infection and no incidence of tendon rupture in either group. The addition of corticosteroid to the peri-articular injection after unicondylar knee replacement had both immediate and short-term benefits in terms of relief from pain, and rehabilitation with no increased risk of infection.

The influence of obesity on functional outcome and quality of life after total knee arthroplasty: a ten-year follow-up study.

Aims: This study investigated the influence of body mass index (BMI) on patients' function and quality of life ten years after total knee arthroplasty (TKA). Patients and Methods: A total of 126 patients who underwent unilateral TKA in 2006 were prospectively included in this retrospective study. They were categorized into two groups based on BMI: < 30 kg/m2 (control) and ≥ 30 kg/m2 (obese). Functional outcome was assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), and Oxford Knee Score (OKS). Quality of life was assessed using the Physical (PCS) and Mental Component Scores (MCS) of the 36-Item Short-Form Health Survey. Results: Results Patients in the obese group underwent TKA at a younger age (mean, 63.0 years, sd 8.0) compared with the control group (mean, 65.6 years, sd 7.6; p = 0.03). Preoperatively, both groups had comparable functional and quality-of-life scores. Ten years postoperatively, the control group had significantly higher OKS and MCS compared with the obese group (OKS, mean 18 (sd 5) vs mean 22 (sd 10), p = 0.03; MCS, mean 56 (sd 10) vs mean 50 (sd 11), p = 0.01). After applying multiple linear regression with the various outcomes scores as dependent variables and age, gender, and Charlson Comorbidity Index as independent variables, there was a clear association between obesity and poorer outcome in KSFS, OKS, and MCS at ten years postoperatively (p < 0.01 in both KSFS and OKS, and p = 0.03 in MCS). Both groups had a high satisfaction rate (97.8% in the control group vs 87.9% in the obese group, p = 0.11) and fulfillment of expectations at ten years (98.9% in the control group vs 100% in the obese group, p = 0.32). Conclusion: Although both obese and non-obese patients have significant improvements in function and quality of life postoperatively, obese patients tend to have smaller improvements in the OKS and MCS ten years postoperatively. It is important to counsel patients on the importance of weight management to achieve a more sustained outcome after TKA. Cite this article: Bone Joint J 2018;100-B:579-83.

Evidence from multiple gene sequences indicates that termites evolved from wood-feeding cockroaches.

Despite more than half a century of research, the evolutionary origin of termites remains unresolved [1] [2] [3]. A clear picture of termite ancestry is crucial for understanding how these insects evolved eusociality, particularly because they lack the haplodiploid genetic system associated with eusocial evolution in bees, ants, wasps and thrips [4] [5]. Termites, together with cockroaches and praying mantids, constitute the order Dictyoptera, which has been the focus of numerous conflicting phylogenetic studies in recent decades [6] [7] [8] [9] [10] [11] [12]. With the aim of settling the debate over the sister-group of termites, we have determined the sequences of genes encoding 18S ribosomal RNA, mitochondrial cytochrome oxidase subunit II (COII) and endogenous endo-beta-1, 4-glucanase (EG) from a diverse range of dictyopterans. Maximum parsimony and likelihood analyses of these sequences revealed strong support for a clade consisting of termites and subsocial, wood-feeding cockroaches of the genus Cryptocercus. This clade is nested within a larger cockroach clade, implicating wood-feeding cockroaches as an evolutionary intermediate between primitive non-social taxa and eusocial termites.

Revision total knee arthroplasty for failed high tibial osteotomy and unicompartmental knee arthroplasty have similar patient-reported outcome measures in a two-year follow-up study.

AIMS: Little is known about the relative outcomes of revision of unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) to total knee arthroplasty (TKA). The aim of this study is to compare the outcomes of revision surgery for the two procedures in terms of complications, re-revision and patient-reported outcome measures (PROMs) at a minimum of two years follow-up. PATIENTS AND METHODS: This study was a retrospective review of data from an institutional arthroplasty registry for cases performed between 2001 and 2014. A total of 292 patients were identified, of which 217 had a revision of HTO to TKA, and 75 had revision of UKA to TKA. While mean follow-up was longer for the HTO group compared with the UKA group, patient demographics (age, body mass index and Charlson co-morbidity index) and PROMs (Short Form-36, Oxford Knee Score, Knee Society Score, both objective and functional) were similar in the two groups prior to revision surgery. Outcomes included the rate of complications and re-operation, PROMS and patient-reported satisfaction at six months and two years post-operatively. We also compared the duration of surgery and the need for revision implants in the two groups. RESULTS: At two-year follow-up, both groups of patients had made significant improvement in terms of PROMs compared with pre-operative scores. PROMs and satisfaction rates were similar in the two groups. Complications requiring re-operation were significantly more frequent in the HTO group whilst more revision implants were used in the UKA group, resulting in a longer operative duration. CONCLUSION: Revision of HTO and UKA achieve similar post-operative PROMs and satisfaction. Revision of UKA more frequently requires revision components with increased operation duration but fewer complications requiring re-operation compared with revision of HTO. Cite this article: Bone Joint J 2017;99-B:1329-34.

The influence of body mass index on functional outcome and quality of life after total knee arthroplasty.

AIMS: This study investigated the influence of body mass index (BMI) on the post-operative fall in the level of haemoglobin (Hb), length of hospital stay (LOS), 30-day re-admission rate, functional outcome and quality of life, two years after total knee arthroplasty (TKA). PATIENTS AND METHODS: A total of 7733 patients who underwent unilateral primary TKA between 2001 and 2010 were included. The mean age was 67 years (30 to 90). There were 1421 males and 6312 females. The patients were categorised into three groups: BMI < 25.0 kg/m(2) (normal); BMI between 25.0 and 39.9 kg/m(2) (obese); and BMI ≥ 40.0 kg/m(2) (morbidly obese). RESULTS: Compared with the normal and obese groups, the mean LOS was longer by one day (95% confidence interval (CI) 0 to 2) in the morbidly obese group (p = 0.003 and p = 0.001 respectively). The 30-day re-admisison rate was also higher in the morbidly obese group compared to the obese group (OR 2.323, 95% CI 1.101 to 4.900, p = 0.024); and showed a higher trend compared to the normal group (OR 1.850, 95% CI 0.893 to 3.831, p = 0.100). However, the morbidly obese group had a smaller drop in post-operative Hb level by a mean of 0.5 g/dl (0.3 to 0.6) and 0.3 g/dl (0.1 to 0.5), when compared with the normal and obese groups respectively (both p < 0.001). Furthermore, the mean improvement in Oxford Knee Score (OKS) and Knee Society Knee Score (KSKS) at two years follow-up was three points (two to four) and five points (two to seven) more in the morbidly obese group than in the normal group (both p < 0.001). The mean improvement in Knee Society Function Score, and Physical and Mental Component Scores of Short Form-36 were comparable between the three BMI groups (p = 0.736, p = 0.739 and p = 0.731 respectively). The ten-year rate of survival was 98.8% (98.0 to 99.3), 98.9% (98.5 to 99.2) and 98.0% (95.8 to 100), for the normal, obese and morbidly obese groups, respectively (p = 0.703). CONCLUSION: Although morbidly obese patients have a longer LOS and higher 30-day re-admission rate after TKA, they have a smaller drop in post-operative Hb level and larger improvement in OKS and KSKS at two years follow-up. The ten-year rate of survival of TKA was also comparable with those with a normal BMI. TAKE HOME MESSAGE: Morbidly obese patients should not be excluded from the benefits of TKA. Cite this article: Bone Joint J 2016;98-B:780-5.

Metazoan cellulase genes from termites: intron/exon structures and sites of expression.

Endogenous endo-beta-1,4-glucanase (EGase, EC 3.2.1.4) cDNAs were cloned from representatives of the termite families Termitidae and Rhinotermitidae. These EGases are all composed of 448 amino acids and belong to glycosyl hydrolase family 9 (GHF9), sharing high levels of identity (40-52%) with selected bacterial, mycetozoan and plant EGases. Like most plant EGases, they consist of a single catalytic domain, lacking the ancillary domains found in most microbial cellulases. Using a PCR-based strategy, the entire sequence of the coding region of NtEG, a gene putatively encoding an EGase from Nasutitermes takasagoensis (Termitidae), was determined. NtEG consists of 10 exons interrupted by 9 introns and contains typical eukaryotic promoter elements. Genomic fragments of EGase genes from Reticulitermes speratus (Rhinotermitidae) were also sequenced. In situ hybridization of N. takasagoensis guts with an antisense NtEG RNA probe demonstrated that expression occurs in the midgut, which contrasts to EGase expression being detected only in the salivary glands of R. speratus. NtEG, when expressed in Escherichia coli, was shown to have in vitro activity against carboxymethylcellulose.