The ceramic coated implant (CCI). Evolution total ankle replacements: a retrospective analysis of 40 ankles with 8 years follow-up.

Diminutive data is available on the outcome of several previously used total ankle replacement implants. The purpose of this study was to investigate the medium-term functional and radiological outcome and implant survival of the CCI Evolution implant. Consecutive series of 40 ankles operated in our hospital with primary TAR using the CCI Evolution implant in 2010-2013 were available for follow-up. The prospective clinical and radiographic data including the Kofoed score, subjective satisfaction and standard radiographs were collected preoperatively and at fixed time-points postoperatively. A CT was obtained in cases where osteolysis or loosening were suspected. The improvement of the Kofoed score and subjective satisfaction were statistically significant (p<0.0001). The implant survival was 97% (95% confidence interval (CI) 81%-100 %) at 5 years, and 81 % (95% confidence interval (CI) 60 %-92%) at 8 years. There were altogether 25 (64%) complications. Overall revision rate was 28% and failure rate 13%. The CCI implant outcome was not acceptable. The malposition of prosthetic components, subsidence, and peri-implant osteolysis were recorded often. Although the patient reported outcome measures improved, mostly due to positive changes in pain severity, overall revision and failure rates were high and comparable with previous findings of the CCI implant.

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

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.

Preoperative myocardial troponin T elevation is associated with the fracture type in patients with proximal femoral fracture.

BACKGROUND AND AIMS: Cardiovascular complications are common in hip fracture patients but the role of fracture type and operative method in these is unclear. This prospective cohort study aimed to evaluate the impact of fracture- and operative characteristics on perioperative cardiovascular complications and prognosis in unselected hip fracture patients. MATERIAL AND METHODS: During a 7-month trial registration period, a population of 197 consecutive hip fracture patients (median age 84 years) diagnosed with femoral neck or pertrochanteric fracture was formed. The exclusion criteria were patient refusal, subtrochanteric fracture, or death preoperatively. Pre- and postoperative troponin T (TnT) elevation, perioperative N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) level, perioperative cardiovascular adverse events, and all-cause 30-day and 2- and 5-year mortalities were studied. RESULTS: Femoral neck fracture was independently associated with preoperative myocardial injury witnessed by TnT elevation (HR 2.95, 95% confidence interval 1.21-7.19, p = 0.018). The fracture type, surgery delay, or operative method were not significantly associated with NT-proBNP levels, cardiovascular adverse event diagnoses, or prognosis. Cardiovascular adverse events were clinically diagnosed in 28 (14%) participants, and these had a higher mortality compared to participants without such diagnosis (at 30 days, 32% vs 5%; 2 years, 71% vs 31%; and 5 years, 86% vs 59%; p < 0.001). CONCLUSION: While the femoral neck fracture independently predicts preoperative cardiovascular morbidity, the operative method does not affect perioperative cardiovascular complications or the prognosis, and it may be selected by the treating clinician based on other criteria.

Perioperative platelet rich plasma (PRP) in total hip arthroplasty through the Hardinge approach: protocol to study the effectiveness for gluteus medius healing.

BACKGROUND: Platelet-rich plasma (PRP) has been used to support tendon regeneration mainly in sports medicine. PRP is a concentrate of platelet-rich plasma proteins derived from whole blood by centrifugation to remove erythrocytes and leukocytes. PRP has high amounts of platelets which may promote healing tendons affected by degenerative conditions. These platelets contain growth factors and are known to facilitate the regeneration of injured tendon structures. Total hip arthroplasty (THA) through the Hardinge approach may leave the patient with impaired gait and poor regeneration of the gluteus medius tendon if the tendon is not reattached properly after closure of the surgical wound. METHODS: The study will be a multicenter, double-blinded and randomized study enrolling 90 patients based on power calculations. The efficacy of perioperative PRP treatment will be assessed by subjective and objective outcome variables. The participants will be randomized (sealed envelope) into either a placebo (saline) or a PRP group (1:1). For subjective outcomes, the Oxford Hip Score (OHS) will be collected before surgery and 3 and 12 months after surgery. The objective measures are findings at magnetic resonance imaging and plain radiographs and recorded values of measured strength. DISCUSSION: We present the perioperative use and the ways to measure the clinical efficacy of PRP. As PRP may have benefits regarding degenerative tendon regeneration, studies on the use of PRP in hip arthroplasty are warranted to facilitate postoperative recovery. TRIAL REGISTRATION: This study has been approved by the ethics committee of the Hospital District of Southwest Finland and approved by the local institutional research board. The study has been registered in ClinicalTrials.gov ( NCT02607462 ).

Intraoperative Complications and Mid-Term Follow-Up of Large-Diameter Head Metal-on-Metal Total Hip Arthroplasty and Hip Resurfacing Arthroplasty.

BACKGROUND AND AIMS: Large-diameter head total hip arthroplasty and hip resurfacing arthroplasty were popular in Finland from 2000 to 2012 for the treatment of hip osteoarthritis. The aim of this retrospective study was to investigate the mid-term survival of large-diameter head total hip arthroplasty patients operated on in three university hospitals and to compare these results to the survival of hip resurfacing arthroplasty patients. MATERIAL AND METHODS: A total of 3860 hip arthroplasties (3029 large-diameter head total hip arthroplasties in 2734 patients and 831 hip resurfacing arthroplasties in 757 patients) were operated on between January 2004 and December 2009. The mean follow-up was 4.3 years (range: 0.3-8.0 years) in the total hip arthroplasty group and 5.1 years (range: 1.7-7.9 years) in the hip resurfacing arthroplasty group. Cox multiple regression model and Kaplan-Meier survival analysis were used to study the survival of the total hip arthroplasties and the hip resurfacing arthroplasties. Intraoperative complications and reasons for revisions were also evaluated. RESULTS: In Cox regression analysis, the hazard ratio for revision of hip resurfacing arthroplasty was 1.5 compared with large-diameter head total hip arthroplasty (95% confidence interval: 1.0-2.2) ( p = 0.029). The cumulative Kaplan-Meier survival rate was 90.7% at 7.7 years for the large-diameter head total hip arthroplasty (95% confidence interval: 86.8-94.6) and 92.2% at 7.6 years for hip resurfacing arthroplasty (95% confidence interval: 89.9-94.6). There were a total of 166/3029 (5.5%) intraoperative complications in the large-diameter head total hip arthroplasty group and 20/831 (2.4%) in the hip resurfacing arthroplasty group ( p = 0.001). Revision for any reason was performed on 137/3029 (4.5%) of the arthroplasties in the large-diameter head total hip arthroplasty group and 52/831 (6.3%) in the hip resurfacing arthroplasty group ( p = 0.04). CONCLUSION: The mid-term survival of both of these devices was poor, and revisions due to adverse reactions to metal debris will most likely rise at longer follow-up. There were more intraoperative complications in the large-diameter head total hip arthroplasty group than in the hip resurfacing arthroplasty group.

Relationship between Pelvic Incidence Angle and Blood Concentration of Chromium and Cobalt Ions after Metal-on-Metal Hip Replacement: A Brief Report.

BACKGROUND AND AIMS: The wear of metal-on-metal hip implants may increase chromium or cobalt ion blood level. This phenomenon may depend among other things on the particularity of spinopelvic anatomy. The effect of pelvic incidence angle on the wear of metal-on-metal hip implants is not known. The objective of the study was to investigate whether such effect does exist. MATERIAL AND METHODS: The pelvic incidence and inclination of acetabular component angles of 89 patients after unilateral metal-on-metal hip replacement were compared with blood level of chromium and cobalt ions using Pearson correlation coefficient. RESULTS: No significant correlations between pelvic incidence angle and the metal ion blood levels were observed. The correlation coefficients varied from -0.02 to 0.2 and all p values were >0.05. CONCLUSION: No evidence was found on the effect of pelvic incidence angle on metal wear after metal-on-metal hip replacement when measured by the blood levels of chromium and cobalt ions. It is reasonable to assume that other factors than pelvic tilt may affect the rate of implant wear.

Genetic ablation of carbonic anhydrase IX disrupts gastric barrier function via claudin-18 downregulation and acid backflux.

AIM: This study aimed to explore the molecular mechanisms for the parietal cell loss and fundic hyperplasia observed in gastric mucosa of mice lacking the carbonic anhydrase 9 (CAIX). METHODS: We assessed the ability of CAIX-knockout and WT gastric surface epithelial cells to withstand a luminal acid load by measuring the pHi of exteriorized gastric mucosa in vivo using two-photon confocal laser scanning microscopy. Cytokines and claudin-18A2 expression was analysed by RT-PCR. RESULTS: CAIX-knockout gastric surface epithelial cells showed significantly faster pHi decline after luminal acid load compared to WT. Increased gastric mucosal IL-1ß and iNOS, but decreased claudin-18A2 expression (which confer acid resistance) was observed shortly after weaning, prior to the loss of parietal and chief cells. At birth, neither inflammatory cytokines nor claudin-18 expression were altered between CAIX and WT gastric mucosa. The gradual loss of acid secretory capacity was paralleled by an increase in serum gastrin, IL-11 and foveolar hyperplasia. Mild chronic proton pump inhibition from the time of weaning did not prevent the claudin-18 decrease nor the increase in inflammatory markers at 1 month of age, except for IL-1ß. However, the treatment reduced the parietal cell loss in CAIX-KO mice in the subsequent months. CONCLUSIONS: We propose that CAIX converts protons that either backflux or are extruded from the cells rapidly to CO2 and H2 O, contributing to tight junction protection and gastric epithelial pHi regulation. Lack of CAIX results in persistent acid backflux via claudin-18 downregulation, causing loss of parietal cells, hypergastrinaemia and foveolar hyperplasia.

Contacting co-culture of human retinal microvascular endothelial cells alters barrier function of human embryonic stem cell derived retinal pigment epithelial cells.

Here we evaluated the effects of human retinal microvascular endothelial cells (hREC) on mature human embryonic stem cell (hESC) derived retinal pigment epithelial (RPE) cells. The hESC-RPE cells (Regea08/017, Regea08/023 or Regea11/013) and hREC (ACBRI 181) were co-cultured on opposite sides of transparent membranes for up to six weeks. Thereafter barrier function, small molecule permeability, localization of RPE and endothelial cell marker proteins, cellular fine structure, and growth factor secretion of were evaluated. After co-culture, the RPE specific CRALBP and endothelial cell specific von Willebrand factor were appropriately localized. In addition, the general morphology, pigmentation, and fine structure of hESC-RPE cells were unaffected. Co-culture increased the barrier function of hESC-RPE cells, detected both with TEER measurements and cumulative permeability of FD4 - although the differences varied among the cell lines. Co-culturing significantly altered VEGF and PEDF secretion, but again the differences were cell line specific. The results of this study showed that co-culture with hREC affects hESC-RPE functionality. In addition, co-culture revealed drastic cell line specific differences, most notably in growth factor secretion. This model has the potential to be used as an in vitro outer blood-retinal barrier model for drug permeability testing.

Does hydroxyapatite coating of uncemented cups improve long-term survival? An analysis of 28,605 primary total hip arthroplasty procedures from the Nordic Arthroplasty Register Association (NARA).

OBJECTIVE: It is unclear whether hydroxyapatite (HA) coating of uncemented cups used in primary total hip arthroplasty (THA) improves bone ingrowth and reduces the risk of aseptic loosening. We therefore investigated survival of different uncemented cups that were available with or without HA coating. METHOD: We investigated three different cup types used with or without HA coating registered in the Nordic Arthroplasty Register Association (NARA) database that were inserted due to osteoarthritis (n = 28,605). Cumulative survival rates and adjusted hazard ratios (HRs) for the risk of revision were calculated. RESULTS: Unadjusted 13-year survival for cup revision due to aseptic loosening was 97.9% (CI: 96.5-99.4) for uncoated and 97.8% (CI: 96.3-99.4) for HA-coated cups. Adjusted HRs were 0.66 (CI 0.42-1.04) for the presence of HA coating during the first 10 years and 0.87 (CI 0.14-5.38) from year 10-13, compared with uncoated cups. When considering the endpoint cup revision for any reason, unadjusted 13-year survival was similar for uncoated (92.5% [CI: 90.1-94.9]) and HA-coated (94.7% [CI: 93.2-96.3]) cups. The risk of revision of any component due to infection was higher in THA with HA-coated cups than in THA with uncoated cups (adjusted HR 1.4 [CI 1.1-1.9]). CONCLUSIONS: HA-coated cups have a similar risk of aseptic loosening as uncoated cups, thus the use of HA coating seems to not confer any added value in terms of implant stability. The risk of infection seemed higher in THA with use of HA-coated cups, an observation that must be investigated further.

Systematic Screening of Adverse Reactions to Metal Debris after Recap-M2A-Magnum Metal-on-Metal Total Hip Arthroplasty.

BACKGROUND AND AIMS: An adverse reaction to metal debris is a known complication after large diameter head metal-on-metal total hip arthroplasty. However, the failure rate varies depending on the implant design. Therefore, we investigated the prevalence of adverse reaction to metal debris, as well as the symptoms and risk factors after undergoing a ReCap-M2a-Magnum large diameter head metal-on-metal total hip arthroplasty. MATERIALS AND METHODS: Between 2005 and 2012, 1188 patients (1329 hips) underwent ReCap-M2a-Magnum total hip arthroplasty at our institution. Systematic screening for adverse reaction to metal debris was arranged using the Oxford Hip Score questionnaire, hip and pelvic radiographs, and assessments of the serum chromium and cobalt ion levels. Clinical evaluation and magnetic resonance imaging were performed for the symptomatic patients, as well as those with either chromium or cobalt ion levels ⩾5 µg/L. The prevalence of adverse reaction to metal debris after ReCap-M2a-Magnum total hip arthroplasty was assessed, and the risk factors for adverse reaction to metal debris were evaluated using logistic regression. The mean follow-up time was 5.2 (0.003-9.1) years. This study was an extension of a previous study conducted at our institution with 80 patients. RESULTS: In total, 33 patients (33 hips, 2.5% of all hips) required a revision operation due to adverse reaction to metal debris. Moreover, 157 hips exhibited definitive adverse reaction to metal debris, but a revision operation was not performed (157 of 1329 hips, 11.8% of all hips). Overall, 190 out of 1329 (14.3%) hips had definitive adverse reaction to metal debris. Pain, subluxation sensation, clicking, swelling, a small head size, and a fair/poor Oxford Hip Score were associated with definitive adverse reaction to metal debris. CONCLUSION: We found a high prevalence of adverse reaction to metal debris in the ReCap-M2a-Magnum total hip arthroplasty patients in this study; however, most of the patients did not require revision operations.

Unicompartmental Knee Arthroplasties are Performed on the Patients with Radiologically Too Mild Osteoarthritis.

BACKGROUND: Patient selection for either total knee arthroplasty or unicompartmental knee arthroplasty remains controversial. The latter has several reported advantages over total knee arthroplasty, but it also appears to have significant drawbacks in terms of revision rates. AIMS: This study aimed to determine the influence of the preoperative degree of osteoarthritis on the risk of reoperation following unicompartmental knee arthroplasty. METHODS: Surgery was carried out on 294 knees in 241 patients between 2001 and 2012 at a single institute, using cemented Oxford phase III unicompartmental knee arthroplasty. The mean age at the time of operation was 67 years, and the mean follow-up time was 8.7 years. RESULTS AND CONCLUSION: The knees with a preoperative Kellgren-Lawrence grade of 0-2 osteoarthritis had a higher risk of reoperation than those with a Kellgren-Lawrence grade of 3-4 (odds ratio = 1.89; 95% confidence interval, 1.03-3.45; p = 0.04). In addition, the knees with a medial joint space width of more than 1 mm or a high medial/lateral joint space width ratio had an increased risk of reoperation. In conclusion, we suggest that unicompartmental knee arthroplasty should only be performed in cases showing severe osteoarthritis in preoperative radiographs, with medial bone-on-bone contact, and a medial/lateral ratio of <20%.

Synergistic Expression of Histone Deacetylase 9 and Matrix Metalloproteinase 12 in M4 Macrophages in Advanced Carotid Plaques.

OBJECTIVE/BACKGROUND: Expression patterns and association with cell specific gene expression signatures of the epigenetic regulator histone deacetylase 9 (HDAC9) and matrix metalloproteinase 12 (MMP12) in human plaque are not known. METHODS: This was a prospective cohort study. Genome wide expression analysis was performed in carotid, femoral, aortic plaques (n = 68) and left internal thoracic (LITA) controls (n = 28) and plaque histological severity assessed. Correlation and hierarchical cluster analysis was utilised. RESULTS: HDAC9 was associated with MMP12 expression in carotid plaques (r = .46, p = .012) and controls (r = -.44, p = .034). HDAC9 and MMP12 clustered with inflammatory macrophage markers but not with smooth muscle cell (SMC) rich markers. In plaques from all arterial sites, MMP12 but not HDAC9 showed positive correlation (p < .05) with M2 and M4 polarized macrophage markers, and negative correlation with SMC rich signatures. In the carotid plaques, all M4 macrophage markers associated with MMP12 and HDAC9. The negative association of MMP12 with SMC rich signatures was pronounced in the carotid plaques. Neither HDAC9 nor MMP12 associated consistently with plaque stabilisation or thrombosis related genes. Immunohistochemistry further supported the association between HDAC9 and MMP12 in atherosclerotic plaques. CONCLUSION: M4 macrophages are a possible source for HDAC9 and MMP12 expression in advanced human plaques.

Substantial rise in the lifetime risk of primary total knee replacement surgery for osteoarthritis from 2003 to 2013: an international, population-level analysis.

OBJECTIVE: To estimate and compare the lifetime risk of total knee replacement surgery (TKR) for osteoarthritis (OA) between countries, and over time. METHOD: Data on primary TKR procedures performed for OA in 2003 and 2013 were extracted from national arthroplasty registries in Australia, Denmark, Finland, Norway and Sweden. Life tables and population data were also obtained for each country. Lifetime risk of TKR was calculated for 2003 and 2013 using registry, life table and population data. RESULTS: Marked international variation in lifetime risk of TKR was evident, with females consistently demonstrating the greatest risk. In 2013, Finland had the highest lifetime risk for females (22.8%, 95%CI 22.5-23.1%) and Australia had the highest risk for males (15.4%, 95%CI 15.1-15.6%). Norway had the lowest lifetime risk for females (9.7%, 95%CI 9.5-9.9%) and males (5.8%, 95%CI 5.6-5.9%) in 2013. All countries showed a significant rise in lifetime risk of TKR for both sexes over the 10-year study period, with the largest increases observed in Australia (females: from 13.6% to 21.1%; males: from 9.8% to 15.4%). CONCLUSIONS: Using population-based data, this study identified significant increases in the lifetime risk of TKR in all five countries from 2003 to 2013. Lifetime risk of TKR was as high as 1 in 5 women in Finland, and 1 in 7 males in Australia. These risk estimates quantify the healthcare resource burden of knee OA at the population level, providing an important resource for public health policy development and healthcare planning.

Freedom Constrained Liner for the Treatment and Prevention of Dislocation in Total Hip Arthroplasty.

BACKGROUND AND PURPOSE: Dislocation is one of the most common complications following total hip arthroplasty. The aim of our study was to assess failure rate of the Biomet Freedom constrained liner (Biomet, Warsaw, IN, USA) either in revision surgery for recurrent dislocation, or as a preventive method in high dislocation risk patients. PATIENTS AND METHODS: We assessed retrospectively 105 consecutive surgical procedures in 103 patients where a Freedom constrained liner or cup was used in Turku University Hospital over a 7-year period from 2007 to 2014. The mechanical failure rate of the device was assessed based on medical records. The average age of the patients was 73.4 years. The number of male patients was 53 (51%). Mean follow-up time was 2.5 years. The association between failure of the device and potential risk factors-age, gender, indication, and approach-was analyzed with logistic regression. Results were expressed by odd ratios and 95% confidence intervals. RESULTS: The mechanical failure rate of the Freedom device was 6 out of 105 (5.7%). None of the 11 preventive primary THAs against dislocation failed, 4 out of 52 (7.7%) preventive revision THAs against dislocation failed, and 2 out of 42 (4.8%) of the treated dislocation cases failed. Four out of six failures were dislocations due to impingement and failure of the locking mechanism. Two liners failed because of loosening. The risk factors assessed were not associated with failure of the device. INTERPRETATION: We found out that the mechanical failure rate of a Freedom constrained device was low. These results encourage us to continue using the device.

Association between hospital procedure volume and risk of revision after total hip arthroplasty: a population-based study within the Nordic Arthroplasty Register Association database.

OBJECTIVE: Outcome after total hip arthroplasty (THA) depends on several factors related to the patient, the surgeon and the implant. It has been suggested that the annual number of procedures per hospital affects the prognosis. We aimed to examine if hospital procedure volume was associated with the risk of revision after primary THA in the Nordic countries from 1995 to 2011. DESIGN: The Nordic Arthroplasty Register Association database provided information about primary THA, revision and annual hospital volume. Hospitals were divided into five volume groups (1-50, 51-100, 101-200, 201-300, >300). The outcome of interest was risk of revision 1, 2, 5, 10 and 15 years after primary THA. Multivariable regression was used to assess the relative risk (RR) of revision. RESULTS: 417,687 THAs were included. For the 263,176 cemented THAs no differences were seen 1 year after primary procedure. At 2, 5, 10 and 15 years the four largest hospital volume groups had a reduced risk of revision compared to group 1-50. After 10 years RR was for volume group 51-100 0.79 (CI 0.65-0.95), group 101-200 0.76 (CI 0.61-0.95), group 201-300 0.74 (CI 0.57-0.96) and group >300 0.57 (CI 0.46-0.71). For the uncemented THAs an association between hospital volume and risk of revision were only present for hospitals producing 201-300 THAs per year, beginning at years 2 through 5 and in all subsequent time intervals to 15 years. CONCLUSION: Hospital procedure volume was associated with a long term risk of revision after primary cemented THA. Hospitals operating 50 procedures or less per year had an increased risk of revision after 2, 5, 10 and 15 years follow up.

Acetabular reconstruction with impaction bone grafting and cemented polyethylene socket in total hip revision arthroplasty.

BACKGROUND AND AIMS: Bone deficiency in revision total hip arthroplasty is a challenge to the surgeon. One option for restoration of the bone stock is impaction bone grafting and use of a cemented socket. The aim of this study was to evaluate the mid-term clinical outcome of impaction bone grafting and cemented socket revisions. MATERIAL AND METHODS: A total of 59 patients (60 hips) underwent revision arthroplasty with impaction bone grafting and application of a cemented socket on the acetabular side in the Turku University Hospital from 1999 to 2004. The study end-point was re-revision for any reason. The cumulative percentages for survival were followed and estimated with Kaplan-Meier curves. Associations between occurrence of re-revision and potential risk factors were analyzed with logistic regression. Results were quantified by odd ratios and 95% confidence intervals. The mean age of the patients was 69 years (33% male). A total of 3% of the patients had a class I Paprosky acetabular defect, 38% had class II, and 55% had class III. RESULTS: The overall survival rate was 73%. The mean follow-up time was 7 years. The most common reason for re-revision was aseptic loosening of the acetabular component (13 patients, 81% of re-revisions). Cox's regression analysis did not identify any risk factors for re-revision. CONCLUSION: Our results were inferior compared to some previous studies. Impaction bone grafting of acetabular defects in revision total hip arthroplasty may not always provide a reliable bone stock in long-term.

Operative Results of Periprosthetic Fractures of The Distal Femur In A Single Academic Unit.

BACKGROUND AND AIMS: Periprosthetic supracondylar fractures after total knee arthroplasty are often associated with poor bone stock, fracture comminution, and loose components. Current operative methods include plating, intramedullary nailing, and re-arthroplasty, depending on the fracture type. The aim of the study was to assess the outcome of operatively treated periprosthetic supracondylar fractures at our institute with special interest on the use of strut grafts in association with plating. MATERIALS AND METHODS: In all, 68 patients were included in the study. They had been treated operatively due to a periprosthetic supracondylar fracture at our center between 2000 and 2010. The data of these patients were retrospectively collected from the electronic patient archives. Fractures with a fixed prosthesis component were treated using internal fixation provided that there was enough bone for osteosynthesis in the distal fracture fragment (39 patients). Fractures with a loose prosthesis component were treated using re-arthroplasty (29 patients). The demographics of the two treatment groups did not differ statistically significantly. Death or any re-operation was chosen as the endpoint of follow-up. Cumulative survival percentages were estimated for each treatment group. RESULTS: There was no statistically significant difference between the treatment groups regarding clinical outcome. Clinical outcome was not assessable in nine patients. A positive clinical outcome was reported in 52 cases (88.1%). The survival of both laminofixation and re-arthroplasty was 75% at 3 years, but the survival of laminofixated fractures with strut graft was 80% compared to that of 51% without strut grafts. In all, 16 patients (24%) had a post-operative surgical site complication: seven infections (10%), six non-unions (15%), and three patellar dislocations (11%). CONCLUSIONS: Post-operative surgical site complications were relatively common in these mainly elderly female patients. The survival percentages of the re-arthroplasty and laminofixation groups were similar. The use of strut grafts in association with plating may decrease re-operation rate.

The effect of pregnane X receptor agonists on postprandial incretin hormone secretion in rats and humans.

We recently showed that pregnane X receptor (PXR) agonists cause hyperglycaemia during oral glucose tolerance test (OGTT) in rats and healthy volunteers (Rifa-1 study). We now aimed to determine if the secretion of incretin hormones, especially glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP), are affected by PXR agonists since these gut-secreted hormones are major regulators of postprandial glucose metabolism. The Rifa-2 study had a one-phase, open-label design. Twelve subjects were given 600 mg of rifampicin a day for a week. OGTT with glucose, insulin, and incretin hormone measurements was performed before and after the rifampicin dosing. Incretins and insulin were analysed in previously collected rat OGTT samples after pregnenolone 16α-carbonitrile (PCN) or control treatment for 4 days. Rifampicin treatment did not affect glucose, insulin, GLP-1, GIP, glucagon, and peptide YY levels statistically significantly. Incremental AUCs (AUCincr) of glucose and insulin tended to increase (41% increase in glucose AUCincr, P = 0.21, 95% confidence interval (CI) of the difference -47, 187; 24% increase in insulin AUCincr, P = 0.084, CI of the difference -110, 1493). Glucagon AUC was increased in women (53% increase, P = 0.028) and decreased in men (19% decrease, P < 0.001) after rifampicin dosing. In combined analysis of human Rifa-1 and Rifa-2 studies, glucose AUCincr was elevated by 63% (P = 0.010) and insulin AUCincr by 37% (P = 0.011). PCN increased rat insulin level at 60 min time point but did not affect incretin and insulin AUCs statistically significantly. In conclusion, PXR agonists do not affect the secretion of incretin hormones. The regulation of glucagon secretion by PXR may be sexually dimorphic in humans. The mechanism of disrupted glucose metabolism induced by PXR activation requires further study.

Neuropeptide Y in the noradrenergic neurones induces obesity and inhibits sympathetic tone in mice.

AIM: Neuropeptide Y (NPY) co-localized with noradrenaline in central and sympathetic nervous systems seems to play a role in the control of energy metabolism. In this study, the aim was to elucidate the effects and pathophysiological mechanisms of increased NPY in catecholaminergic neurones on accumulation of body adiposity. METHODS: Transgenic mice overexpressing NPY under the dopamine-beta-hydroxylase promoter (OE-NPY(DßH) ) and wild-type control mice were followed for body weight gain and body fat content. Food intake, energy expenditure, physical activity, body temperature, serum lipid content and markers of glucose homoeostasis were monitored. Thermogenic and lipolytic responses in adipose tissues, and urine catecholamine and tissue catecholamine synthesizing enzyme levels were analysed as indices of sympathetic tone. RESULTS: Homozygous OE-NPY(DßH) mice showed significant obesity accompanied with impaired glucose tolerance and insulin resistance. Increased adiposity was explained by neither increased food intake or fat absorption nor by decreased total energy expenditure or physical activity. Adipocyte hypertrophy and decreased circulating lipid levels suggested decreased lipolysis and increased lipid uptake. Brown adipose tissue thermogenic capacity was decreased and brown adipocytes filled with lipids. Enhanced response to adrenergic stimuli, downregulation of catecholamine synthesizing enzyme expressions in the brainstem and lower adrenaline excretion supported the notion of low basal catecholaminergic activity. CONCLUSION: Increased NPY in catecholaminergic neurones induces obesity that seems to be a result of preferential fat storage. These results support the role of NPY as a direct effector in peripheral tissues and an inhibitor of sympathetic activity in the pathogenesis of obesity.