Session 1: Hip I

Onsdag den 24. oktober
11:00 – 12:00
Lokale: Reykjavik
Chairmen: Søren Overgaard og Casper Foldager

1. Low migration in osteoarthritis patients treated with cemented and cementless Avantage Dual Mobility Total Hip Arthroplasty. A 2-Year Blinded Randomized Radiostereometric and Dual-energy X-Ray Absorptiometry Study.
Steffan Tabori Jensen, Sebastian Breddam, Torben Bæk Hansen, Maiken Stilling
University Clinic for Hand, Hip and Knee Surgery, Hospital Unit West, Holstebro, Denmark, Hospital Unit West.; University Clinic for Hand, Hip and Knee Surgery, Hospital Unit West, Holstebro, Denmark, Hospital Unit West.; University Clinic for Hand, Hip and Knee Surgery, Hospital Unit West, Holstebro, Denmark, Hospital Unit West.; University Clinic for Hand, Hip and Knee Surgery, Hospital Unit West, Holstebro, Denmark, Hospital Unit West.

Background: The advantage of cemented over cementless cementing technique of dual-mobility cups in the elderly population is still unclear, and the choice of fixation method is mainly based on surgeons preference
Purpose / Aim of Study: To investigate the early implant migration pattern of cemented and cementless Avantage dual-mobility (DM) cups in elderly patients with osteoarthritis (OA)
Materials and Methods: In a prospective patient-blinded randomized clinical trial 60 patients (33 female) were allocated to cemented (n=30) or cementless (n=30) cup fixation. Osteoporotic patients were excluded by preoperative DXA scans. The lower age-limit was 70 years (mean 75.1,range 70.2-83.0). Patients were followed with radiosterometry, periprosthetic BMD measurements, and PROMs (HHS, OHS, EQ-5D, VAS pain) at post-op, 3, 12 and 24 months
Findings / Results: At 12 and 24 months, cementless cups had higher rotation around the y-axis (p<0.04), total rotation (p<0.04) and maximum total point motion (MTPM) (p<0.02) compared to cemented cups. Proximal cup translation and MTPM did not differ from 12 to 24 month follow-up (FU) within cemented (respectively p=0.61,p=0.52) and cementless (respectively p=0.32, p=0.51) fixation. Proximal cup translation was similar for cemented and cementless cup fixation when stratified for normal or osteopenia bone (p>0.34). Cemented cups had higher BMD in Wilkinson region of interest (ROI) 2 and 3 compared to cementless cups (p<0.003) at postoperative, 3, 12 and 24 months FU. PROMs improved similarly in both groups
Conclusions: The Avantage DM showed low implant migration and good clinical outcomes suggesting that the Avantage DM cup can be used in OA patients older than 70 years both with cemented and cementless cup fixation method. From 12 to 24 months follow-up both fixation methods showed no additional migration suggesting good lasting fixation

2. PANSAID: Paracetamol and NSAID in Combination for Postoperative Analgesia
Kasper Thybo, Daniel Hägi-Pedersen, Jørgen B Dahl, Jørn Wetterslev, Hans Henrik Bülow, Niels Anker Pedersen, Søren Overgaard, Henrik Schrøder, Jan Bjørck, Ole Mathiesen
Anaesthesiology, Næstved Hospital; Anaesthesiology, Næstved Hospital; Anaesthesiology, Bispebjerg Hospital; Copenhagen Trial Unit, Rigshospitalet; Anaesthesiology, Holbæk Hospital; Anaesthesiology, Gilhøj Hospital; Orthopaedic Surgery and Traumatology, Odense Univerity Hospital; Orthopaedic Surgery , Næstved Hospital; Orthopaedic Surgery , Nykøbing Falster Hospital; Anaesthesiology, Zealand University Hospital, Køge

Background: Combinations of paracetamol and non-steroidal anti- inflammatory drugs are frequently used for postoperative pain management, though, with no firm evidence regarding benefit or harm.
Purpose / Aim of Study: The aim of the PANSAID trial was therefore to investigate the analgesic and harmful effects of four multimodal analgesic regimens with paracetamol and/or ibuprofen after total hip arthroplasty.
Materials and Methods: PANSAID was a multicenter, randomized, blinded trial. Participants were randomized to Group A: Paracetamol 1 g and ibuprofen 400 mg; B: Paracetamol 1 g and placebo; C: Ibuprofen 400 mg and placebo; or D: Paracetamol 0.5 g and ibuprofen 200 mg q.i.d. for 24 hours postoperatively. The co- primary outcomes were 24-hours patient-controlled morphine consumption, and proportion of patients with one or more serious adverse event (SAE) within 90 days in groups A, C and D (all receiving ibuprofen) versus group B (paracetamol only).
Findings / Results: We analyzed 556 patient. The median 24-hour morphine consumption in group A, B, C, and D was 20, 36, 26, and 28 mg, respectively. Median differences: 16 mg (99.6% CI: 6.5 to 24, P<0.001) (group A vs. B); 8 mg (99.6% CI: -1 to 14, P=0.0011) (group B vs. D); and 6 mg (99.6% CI: -2 to 16, P=0.0024) (group A vs. C). The proportion of patients with SAEs in groups A+C+D was 15%, and 11% in group B; the relative risk was 1.44 (97.5% CI: 0.79 to 2.45, P=0.18).
Conclusions: The combination of paracetamol and ibuprofen reduced morphine consumption more than each drug alone, however, the predefined minimal important difference of 10 mg was reached between the combination and paracetamol only. Using ibuprofen the first postoperative day does not statistically significantly increase the proportion of SAEs ( number, NCT02571361).

3. The fate of biopsy negative and sonication positive cultures following revisions of total hip and knee arthroplasties
Christen Ravn, Michael Kemp, Per Kjærsgaard-Andersen, Søren Overgaard
Dep. of Orthopaedic Surgery and Traumatology / Dep. of Clinical Research, OUH / Sygehus Lillebælt / University of Southern Denmark; Dep. of Clinical Microbiology / Dep. of Clinical Research, Odense University Hospital / University of Southern Denmark ; Dep. of Orthopaedic Surgery, Sygehus Lillebælt, Vejle; Dep. of Orthopaedic Surgery and Traumatology / Dep. of Clinical Research, Odense University Hospital / University of Southern Denmark

Background: To improve the diagnostic sensitivity of prosthetic joint infection (PJI), sonication has been introduced and may dislodge biofilm bacteria from the implant surface (Trampuz 2007). No previous study has evaluated the clinical course of patients having additional microbiological findings after sonication fluid culture (SFC).
Purpose / Aim of Study: What is the fate of prosthetic join revision, when tissue sample culture (TSC) is negative and SFC is positive, in terms of re-revision?
Materials and Methods: We prospectively cultured tissue samples and sonication fluid of 211 prosthetic revision of THA and TKA during 1 year. Clinicians were blinded to the SFC-results, which were not used for the subsequent treatment. Patients were seen at 3 and 12 months. Medical records were checked for infection and subsequent re-operation
Findings / Results: We identified 11 cases with positive SFC and negative TSC. 8 cases with suspected PJI were treated with revision and empirical antibiotics. Another 3 cases with suspected aseptic failure, partial 1-stage revisions were performed with no subsequent antibiotic therapy. Re-revisions were necessary in 5 cases of expected PJI, and 2 of these ended up with permanent Girdlestone. Antibiotic suppression was implemented in 1 case. 1 patient diseased in circulatory failure. In 3 cases the painful joint prosthesis is still unsolved after 1 year, and only 1 case had an asymptomatic prosthesis at 1-year follow-up. Culture results of the subsequent revisions in this small cohort shows several links to the microbiological findings in SFC.
Conclusions: 5/11 cases were re-revised with positive sonication fluid and negative biopsies within one year after revisions which is discouraging. In perspective, knowledge and treatment of the microorganisms identified by SFC seems to be of value and should be used in the future when available.

4. Effects of supervised exercise compared to home-based exercise early after total hip replacement on patient-reported function, pain, heath-related quality of life and performance-based function - A Meta-Analysis of Randomised Controlled Trials
Sebrina Hansen, Jens Aaboe, Inger Mehlenburg, Søren Overgaard, Lone Mikkelsen
Library , University of Southern Denmark; National Guidelines, Sundhedsstyrelsen ; Centre of Research in Rehabilitation (CORIR), Department of Clinical Medicine, Aarhus Universitetshospital ; Orthopaedic research unit, Department of Orthopaedic Surgery and Traumatology, Department of Ckinical Research, Odense Universitets hospital ; Interdisciplinary Research Unit, Elective Surgery Centre, Silkeborg Regional Hospital

Background: In practice, some patients with primary total hip replacement are offered outpatient home-based exercises and ot others supervised inpatient exercise, however it remains u unknown whether supervised p programmes are more effective.
Purpose / Aim of Study: The study evaluated the effectiveness of supervised exercise compared to home-based exercise after total hip replacement on patient-reported function, hip-pain, health-related quality of life and performance-based function.
Materials and Methods: A systematic review and meta-analysis of randomised controlled trials investigating the effect of supervised exercise to home-based exercise.. A e electronic search was performed on M March 14th 2018 from a predefined p protocol (PROSPERO registration n number: CRD42017055604). The methodological quality was as assessed using the Cochrane Risk of Bi Bias tool. Mean difference (MD) or st standard mean differences (SMD) with 95 95% confidence intervals were ca calculated and pooled using random ef effects models.
Findings / Results: Seven studies was included with a total of 389 participants. A small and non-significant difference in favour of the supervised groups was found in patient-reported function (SMD -0.22 [95% CI -0.46 to 0.02]), hip-related pain (SMD -0.03 [95% CI –0.27 to 0.21]), health-related quality of life (MD - -3.08 [95% CI -6.29 to 0.14]) and performance-based function (SMD - -0.26 [95% CI -0.68 to 0.17]) at end of treatment and in patient-reported function (MD -1.31 [95% CI -3.79 to 1.16]) at the 6 to 12-month follow-up.
Conclusions: In conclusion, supervised exercise was not superior to home-based exercise on patient-reported function, pain, health-related quality of life and performance-based function after primary total hip replacement. This review does not exclude that supervised exercise may be beneficial to some patient sub-groups.

5. Whole blood metal ion concentrations in metal-on-metal total hip arthroplasty and hip resurfacing: A randomised controlled trial with 5-year follow up including 75 patients
Peter Nyby Hersnaes, Kirill Gromov, Peter Henrik Gebuhr, Kristian Stahl Otte, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre

Background: The metal-on-metal large-diameter-head (MoM- LDH) hip replacements increased in popularity during the start of the 21st century. Subsequently reports raised concerns regarding adverse reactions due to elevated chromium (Cr) and cobalt (Co) levels as well as high rates of other complications and revisions.
Purpose / Aim of Study: The purpose was to compare Cr and Co levels at 5- years follow up following Magnum (MoM-LDH total hip arthroplasty) or Recap (MoM-LDH hip resurfacing).
Materials and Methods: The study was conducted between November 2006 to January 2012 in a tertiary health care center in Denmark. Patients with primary or secondary osteoarthritis were randomly assigned to receive a Magnum or Recap prosthesis. Randomization was computer generated and allocation was concealed in an opaque envelope. Patients and surgeons were blinded until day of surgery. Primary outcome was Cr and Co levels at 5-years follow up.
Findings / Results: 75 were included and allocated to the Magnum (n = 39) and Recap (n = 36) group. The study was prematurely stopped due to numerous reports of adverse events in patients with MoM hip replacements. 25 in the Magnum and 20 in the Recap group were eligible for primary outcome analysis. Median Cr levels were 1.36 µg/L (IQR: 0.99 - 3.11) for Magnum and 1.21 µg/L (IQR: 0.88 - 3.03) for ReCap (p = 0.46). Median Co levels were 1.67 µg/L (IQR: 0.86 - 2.31) for Magnum and 0.92 µg/L (IQR: 0.64 - 1.49) for ReCap (p = 0.073).
Conclusions: Metal ion levels were similar in both groups at 5- years follow up. No significant differences were found when comparing Cr and Co levels in Magnum with Recap at 5-years follow up.

6. Increasing risk of post-surgery infections among hip fracture patients: A nationwide study 2005-2016
Kaja E. Kjørholt, Søren P. Johnsen , Nickolaj R. Kristensen , Daniel Prieto-Alhambra , Alma B. Pedersen
Department of Clinical Epidemiology , Aarhus University Hospital; Center for Clinical Health Services Research, Department of Clinical Medicine, Aalborg University ; Department of Clinical Epidemiology , Aarhus Universtiy Hospital ; Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences (NDORMS), University of Oxford ; Department of Clinical Epidemiology , Aarhus University Hospital

Background: Post-surgery infections is a leading cause of death among hip fracture patients, however, data on recent time trends in the risk of infections is lacking.
Purpose / Aim of Study: We aimed to examine trends in the risk of infections following hip fracture surgery, including hospital- treated infections, as well as community-based ones, in Denmark from 2005 to 2016.
Materials and Methods: We conducted a nationwide cohort study based on individual-level record linkage of data from Danish nationwide registries. We calculated cumulative incidence considering death as competing risk and, based on the pseudo-observation method, risk ratios (RRs) with 95% confidence interval (CI).using the period 2005-2006 as a reference. RRs were adjusted or stratified by age, sex and comorbidity measured with Charlson Comorbidity index (CCI).
Findings / Results: A total of 74,771 patients aged 65 years or older with first time hip fracture surgery were included. The 30 days cumulative incidence of all hospital- treated infections increased from 10.8 % (95 % CI: 10.2-11.3) in 2005-2006 to 14.3% (95 % CI: 13.7- 15.0) in 2015-2016 [adjusted RR: 1.32 (95% CI: 1.23-1.42)]. The risk of infectious hospitalization increased irrespective of patient’s age, sex and CCI score. The 30 days cumulative incidence of redeeming community-based antibiotic prescriptions increased from 17.5 % (95 % CI: 16.8-18.2) in 2005- 2006 to 27.1 % (95 % CI: 26.3-27.9) in 2015-2016 [adjusted RR: 1.56 (95 % CI: 1.49-1.64)].
Conclusions: We found an increased risk of infection following hip fracture surgery during the 12- year study period. Given the high mortality following infections in the elderly, further research is needed to identify patients at increased risk to target preventive treatment and potentially reduce complications and mortality in hip fracture patients.

7. Bone remodeling around a short femoral neck stem - 5 years follow up of the Primoris®
Janus Duus Christiansen, Poul Torben Nielsen, Mogens Laursen, Gordon Blunn
Northern Ortopaedic Division, Aalborg University Hospital; Northern Ortopaedic Division, Aalborg University Hospital; Northern Ortopaedic Division, Aalborg University Hospital; University College London RNOHT, Stanmore, United Kingdom

Background: The use of conventional stems in total hip arthroplasty gives a non- physiological load pattern. In case of revision, the bone stock left for reimplantation may be compromised. The Primoris ® stem is a development of earlier conceived bone-saving prosthesis in order to preserve bone stock maintaining normal stress to the proximal femur.
Purpose / Aim of Study: This study includes postoperative changes in bone mineral densities (BMD) in the proximal femur and evaluation of bone stock preservation in patients operated with the Primoris ® stem.
Materials and Methods: A prospective cohort study of 52 patients scheduled for surgery with the femoral neck-preserving Primoris ® stem was carried out. Patients were studied with DXA-scans to evaluate BMD around the implant. Results from DXA-scanner were measured in 4 specific regions of interest (ROI) – the area of the greater trochanter (ROI1), a lateral area below the greater trochanter (ROI2), a distal area of the diaphysis (ROI3) and a medial region of calcar and trochanter minor (ROI4). Postoperative BMD results from day one, 6 weeks, 6 months, 1 year, 2 years and 5 years were analyzed including double measurements at 1 year FU.
Findings / Results: 3 patients were excluded, leaving 49 patients for BMD-analysis. A slightly non significant decrease was found at 5 years FU compared to day 1 in ROI1. A significant decrease was found at 5 year FU compared to day 1 in ROI2. A non significant gain of BMD was found at 5 years FU compared to day 1 in ROI3 and ROI4.
Conclusions: As to bone preservation, the results are encouraging supporting the rationale of the Primoris® implant. With special regard to the calcar area (ROI4), bone stock has remained stable throughout the follow up period. If the proximal femoral bone stock is preserved, the potential for successful future revision is maximized.