Session 3: Hip Arthroplasty
16. November
09:00 - 10:30
Lokale: Vingsal 3
Chair: Ann Ganestam and Thomas Jakobsen
Peter Bo Jørgensen¹ ², Steffan Tabori-Jensen³, Inger Mechlenburg³ 4, Morten Humilius¹ , Torben Bæk Hansen¹ 4, Maiken Stilling¹ ² ³ 4
¹ University Clinic for Hand, Hip and Knee Surgery, Department of Orthopaedics, Gødstrup Hospital, Herning, Denmark. ² AutoRSA Research Group, Orthopeadic Research Unit Aarhus University Hospital, Denmark. ³ Department of Orthopaedic Surgery Aarhus University Hospital, Denmark. 4 Department of Clinical Medicine Aarhus University, Denmark.
Background: Dual mobility (DM) articulation total hip arthroplasty (THA) is used increasingly due to dislocation safety. Recently, concerns were raised specifically for PE wear and metal debris of cementless DM implants due to coating and metal debris particles found in the instrumentation of cementless DM implants, which may be left in the joint during surgery and cause third body wear
Aim: The aim was to investigate cup fixation, polyethylene (PE) wear, serum chromium and cobalt, and their correlation to physical activity in patients with DM implants at 6-year follow- up.
Materials and Methods: In a patient-blinded RCT, 60 patients with hip osteoarthritis at a median age of 74 years (70– 82) were randomly allocated to cemented (n=29) or cementless hydroxyapatite-coated (n=30) fixation of Avantage DM THA with a highly-crosslinked vitamin-E PE liner. Cup migration and PE wear were measured with radiostereometry, chromium and cobalt ions were measured in serum, and physical activity was measured with accelerometers.
Results: PE liner bedding-in was higher for cementless than for cemented cups (p=0.046). The PE wear rate from 1- to 6-year follow-up of 0.06 (CI95% 0.04–0.09) mm/year for cemented cups was similar to 0.07 (CI95% 0.04–0.11) mm/year for cementless cups. At 6-year follow-up, proximal cup migration of 0.14 (CI95% 0.01–0.28) mm for cemented cups and 0.21 (CI95% 0.02–0.39) mm for cementless cups was similar. Serum metal ion levels were undetectable or very low. Physical activity was mainly low intensity and did not correlate to PE wear rate or cup migration.
Interpretation / Conclusion: The findings support that cemented and cementless DM implants with highly crosslinked vitamin E infused liners have similar performance when used for primary THA surgery in elderly patients.
¹ University Clinic for Hand, Hip and Knee Surgery, Department of Orthopaedics, Gødstrup Hospital, Herning, Denmark. ² AutoRSA Research Group, Orthopeadic Research Unit Aarhus University Hospital, Denmark. ³ Department of Orthopaedic Surgery Aarhus University Hospital, Denmark. 4 Department of Clinical Medicine Aarhus University, Denmark.
Background: Dual mobility (DM) articulation total hip arthroplasty (THA) is used increasingly due to dislocation safety. Recently, concerns were raised specifically for PE wear and metal debris of cementless DM implants due to coating and metal debris particles found in the instrumentation of cementless DM implants, which may be left in the joint during surgery and cause third body wear
Aim: The aim was to investigate cup fixation, polyethylene (PE) wear, serum chromium and cobalt, and their correlation to physical activity in patients with DM implants at 6-year follow- up.
Materials and Methods: In a patient-blinded RCT, 60 patients with hip osteoarthritis at a median age of 74 years (70– 82) were randomly allocated to cemented (n=29) or cementless hydroxyapatite-coated (n=30) fixation of Avantage DM THA with a highly-crosslinked vitamin-E PE liner. Cup migration and PE wear were measured with radiostereometry, chromium and cobalt ions were measured in serum, and physical activity was measured with accelerometers.
Results: PE liner bedding-in was higher for cementless than for cemented cups (p=0.046). The PE wear rate from 1- to 6-year follow-up of 0.06 (CI95% 0.04–0.09) mm/year for cemented cups was similar to 0.07 (CI95% 0.04–0.11) mm/year for cementless cups. At 6-year follow-up, proximal cup migration of 0.14 (CI95% 0.01–0.28) mm for cemented cups and 0.21 (CI95% 0.02–0.39) mm for cementless cups was similar. Serum metal ion levels were undetectable or very low. Physical activity was mainly low intensity and did not correlate to PE wear rate or cup migration.
Interpretation / Conclusion: The findings support that cemented and cementless DM implants with highly crosslinked vitamin E infused liners have similar performance when used for primary THA surgery in elderly patients.
Peter Bo Jørgensen¹, Bart L. Kaptein², Kjeld Søballe¹ ³, Stig S. Jakobsen³ , Maiken Stilling¹ ³
¹ AutoRSA Research Group, Orthopeadic Research Unit Aarhus University Hospital, Aarhus, Denmark. ² Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands ³ Department of Orthopaedic Surgery Aarhus University Hospital, Aarhus, Denmark.
Background: Dual mobility hip arthroplasty utilizes a freely rotating polyethylene liner to protect against dislocation. As liner motion has not been confirmed in vivo, we investigated the liner kinematics in vivo using dynamic radiostereometry.
Aim: The aims of the study were; (1) to evaluate if liner movement occurred in DM cups 1 year after primary operation and (2) to describe the movement pattern and range of such movement
Materials and Methods: 16 patients with Anatomical Dual Mobility acetabular components were included. Markers were implanted in the liners using a drill guide. Static RSA recordings and patient reported outcome measures were obtained at post-op and 1-year follow-up. Dynamic RSA recordings were obtained at 1- year follow-up during a passive hip movement: abduction/external rotation, adduction/internal rotation (modified FABER- FADIR), to end-range and at 45° hip flexion. Liner- and neck movements were described as anteversion, inclination and rotation.
Results: Liner movement during modified FABER- FADIR was detected in 12 of 16 patients. Median (range) absolute liner movements were: anteversion 10° (5–20), inclination 6° (2–12), and rotation 11° (5–48) relative to the cup. Median absolute changes in the resulting liner/neck angle (small articulation) was 28° (12–46) and liner/cup angle (larger articulation) was 6° (4–21). Static RSA showed changes in median (range) liner anteversion from 7° (-12–23) postoperatively to 10° (-3–16) at 1-year follow-up and inclination from 42 (35–66) postoperatively to 59 (46–80) at 1-year follow-up. Liner/neck contact was associated with high initial liner anteversion (p=0.01).
Interpretation / Conclusion: The polyethylene liner moves over time. One year after surgery the liner can move with or without liner/neck contact. The majority of movement is in the smaller articulation between head and liner.
¹ AutoRSA Research Group, Orthopeadic Research Unit Aarhus University Hospital, Aarhus, Denmark. ² Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands ³ Department of Orthopaedic Surgery Aarhus University Hospital, Aarhus, Denmark.
Background: Dual mobility hip arthroplasty utilizes a freely rotating polyethylene liner to protect against dislocation. As liner motion has not been confirmed in vivo, we investigated the liner kinematics in vivo using dynamic radiostereometry.
Aim: The aims of the study were; (1) to evaluate if liner movement occurred in DM cups 1 year after primary operation and (2) to describe the movement pattern and range of such movement
Materials and Methods: 16 patients with Anatomical Dual Mobility acetabular components were included. Markers were implanted in the liners using a drill guide. Static RSA recordings and patient reported outcome measures were obtained at post-op and 1-year follow-up. Dynamic RSA recordings were obtained at 1- year follow-up during a passive hip movement: abduction/external rotation, adduction/internal rotation (modified FABER- FADIR), to end-range and at 45° hip flexion. Liner- and neck movements were described as anteversion, inclination and rotation.
Results: Liner movement during modified FABER- FADIR was detected in 12 of 16 patients. Median (range) absolute liner movements were: anteversion 10° (5–20), inclination 6° (2–12), and rotation 11° (5–48) relative to the cup. Median absolute changes in the resulting liner/neck angle (small articulation) was 28° (12–46) and liner/cup angle (larger articulation) was 6° (4–21). Static RSA showed changes in median (range) liner anteversion from 7° (-12–23) postoperatively to 10° (-3–16) at 1-year follow-up and inclination from 42 (35–66) postoperatively to 59 (46–80) at 1-year follow-up. Liner/neck contact was associated with high initial liner anteversion (p=0.01).
Interpretation / Conclusion: The polyethylene liner moves over time. One year after surgery the liner can move with or without liner/neck contact. The majority of movement is in the smaller articulation between head and liner.
André Nis Klenø, Henrik Toft Sørensen, Alma Becic Pedersen
Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark.
Background: Non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are commonly used to treat acute pain after total hip arthroplasty (THA). Towards combating the global opioid epidemic, changes in opioid recommendations in general has occurred. However, it is unclear how these changes have affected analgesic prescription pattern in relation to THA.
Aim: To examine time trends in the use of NSAIDs and opioids for patients with osteoarthritis undergoing total hip arthroplasty (THA) over a 22-year period.
Materials and Methods: Using Danish population-based medical databases, we identified 103,209 THA patients. Proportions of NSAID and opioid use among preoperative users and non-users were calculated in four quarters (Q1-Q4) after THA by calendar periods (1996-2000, 2001-2006, 2007- 2012 and 2013-2018). Prevalence rate ratios (PRR) were adjusted for age and gender.
Results: Among preoperative NSAID users and non-users, NSAID use in Q1 increased from 32.6% in 1996- 2000 to 48.0% in 2013-2018 (PRR=1.49, 95% CI: 1.42-1.55) and from 12.9% to 32.0% (PRR=2.49, CI: 2.32-2.67), respectively. Among preoperative opioid users and non-users, opioid use in Q1 increased from 42.7% in 1996-2000 to 76.9% in 2013-2018 (PRR=1.81, CI: 1.73-1.89) and from 15.2% to 58.2% (PRR=3.85, CI: 3.65-4.05), respectively. NSAID use in Q4 decreased from 24.5% in 1996- 2000 to 21.4% in 2013-2018 (PRR= 0.88, CI: 0.83-0.93) and from 6.9% to 5.6% (PRR=0.81, CI: 0.73-0.91) in preoperative NSAIDs users and non-users, respectively. Opioid use in Q4 increased from 26.6% in 1996-2000 to 28.6% (PRR=1.08, CI: 1.02-1.15) in 2013-2018 and from 4.1% to 5.0% (PRR=1.25, CI: 1.11-1.40) in preoperative opioid users and non-users, respectively.
Interpretation / Conclusion: Although we observed up to a 4-fold increase in NSAID and opioid use in Q1 after THA during 1996-2018, use of NSAIDs and opioids in Q4 did not change substantially since 1996. However, 5-6% of the preoperative non-users of NSAIDs and opioids were users in Q4 after THA, which might relate to inaccurate indication for or timing of THA and the post-surgical phasing out of analgesics use.
Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark.
Background: Non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are commonly used to treat acute pain after total hip arthroplasty (THA). Towards combating the global opioid epidemic, changes in opioid recommendations in general has occurred. However, it is unclear how these changes have affected analgesic prescription pattern in relation to THA.
Aim: To examine time trends in the use of NSAIDs and opioids for patients with osteoarthritis undergoing total hip arthroplasty (THA) over a 22-year period.
Materials and Methods: Using Danish population-based medical databases, we identified 103,209 THA patients. Proportions of NSAID and opioid use among preoperative users and non-users were calculated in four quarters (Q1-Q4) after THA by calendar periods (1996-2000, 2001-2006, 2007- 2012 and 2013-2018). Prevalence rate ratios (PRR) were adjusted for age and gender.
Results: Among preoperative NSAID users and non-users, NSAID use in Q1 increased from 32.6% in 1996- 2000 to 48.0% in 2013-2018 (PRR=1.49, 95% CI: 1.42-1.55) and from 12.9% to 32.0% (PRR=2.49, CI: 2.32-2.67), respectively. Among preoperative opioid users and non-users, opioid use in Q1 increased from 42.7% in 1996-2000 to 76.9% in 2013-2018 (PRR=1.81, CI: 1.73-1.89) and from 15.2% to 58.2% (PRR=3.85, CI: 3.65-4.05), respectively. NSAID use in Q4 decreased from 24.5% in 1996- 2000 to 21.4% in 2013-2018 (PRR= 0.88, CI: 0.83-0.93) and from 6.9% to 5.6% (PRR=0.81, CI: 0.73-0.91) in preoperative NSAIDs users and non-users, respectively. Opioid use in Q4 increased from 26.6% in 1996-2000 to 28.6% (PRR=1.08, CI: 1.02-1.15) in 2013-2018 and from 4.1% to 5.0% (PRR=1.25, CI: 1.11-1.40) in preoperative opioid users and non-users, respectively.
Interpretation / Conclusion: Although we observed up to a 4-fold increase in NSAID and opioid use in Q1 after THA during 1996-2018, use of NSAIDs and opioids in Q4 did not change substantially since 1996. However, 5-6% of the preoperative non-users of NSAIDs and opioids were users in Q4 after THA, which might relate to inaccurate indication for or timing of THA and the post-surgical phasing out of analgesics use.
Joseph El-Sahoury, Kristian Kjærgaard, Ole Ovesen, Christian Hofbauer, Søren Overgaard, Ming Ding
Joseph A. N. El-Sahoury1, Kristian Kjærgaard1, Ole Ovesen1, Christian Hofbauer2, Søren Overgaard*3, Ming Ding*1 1. Orthopaedic Research Laboratory, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Department of Clinical Research, University of Southern Denmark, Odense, Denmark, Odense C, Denmark 2. Department of Orthopaedic Surgery, Vejle Hospital, Vejle, Denmark, Vejle, Denmark 3. Department of Orthopaedic Surgery & Traumatology, Copenhagen University Hospital, Bispebjerg, And Department of Clinical Medicine, University of Copenhagen, 2400, Copenhagen, NV, Denmark, Copenhagen, Denmark *Equal senior authors
Background: Wear of the acetabular polyethylene liner in total hip arthroplasty (THA) may lead to bone osteolysis, aseptic loosening and subsequently revision surgery. Wear may be reduced by using oxidatively stabilized, vitamin E-doped, cross- linked polyethylene (vE-PE) liners instead of annealed or remelted cross-linked polyethylene (XLPE).
Aim: The primary aim was to investigate differences in Head penetration between vE-PE and XLPE liners and between 32- and 36-mm head size. Secondary outcomes included cup migration and PROMs (EQ-5D, SF-36, HHS, UCLA Activity Score)
Materials and Methods: This study(NCT02196792) was comprised of 4 combined intervention groups in a 2X2 setup. Moreover the study was randomized, as patients were randomly assigned to receive a liner material (vE-PE or XLPE) and head size component ( 32 mm or 36 mm). The outcome of the study includes Head penetration and cup migration, both of these were obtained and measured by radiostereometric analysis (RSA). RSA was performed postoperatively at baseline, 3, 12, 24, 60, 84 and 120 months. Patient-reported outcome measures (UCLA Activity Score, Harris Hip Score, and EQ-5D) were acquired at baseline, 3, 12, 24, 36, 60, 84 and 120 months. The Outcomes were calculated by linear mixed-effect analysis. We aimed to include 100 patients in our study powered as a parallel-group design.
Results: A total of 220 patients were assessed for eligibility for this study, but 93 of the patients were excluded. Four patients received screws, 26 patients received cups smaller than 54 mm, 5 patients received other components, 1 patient underwent surgical complications, and 57 patients due to other reasons. 127 patients who underwent randomization into 4 groups and 116 patients received their allocated intervention. Ten years later, 34 patients were lost to follow- up and 82 patients were followed-up. Baseline data was similar between groups in. The following results will be intention-to-treat (ITT) data.
Interpretation / Conclusion: There was significantly lower head penetration in vE-PE compared to XLPE liners at 10 years, and No difference was found between 32 and 36 mm heads. The findings is of clinical importance and may reduce the risk of revision in the long run.
Joseph A. N. El-Sahoury1, Kristian Kjærgaard1, Ole Ovesen1, Christian Hofbauer2, Søren Overgaard*3, Ming Ding*1 1. Orthopaedic Research Laboratory, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Department of Clinical Research, University of Southern Denmark, Odense, Denmark, Odense C, Denmark 2. Department of Orthopaedic Surgery, Vejle Hospital, Vejle, Denmark, Vejle, Denmark 3. Department of Orthopaedic Surgery & Traumatology, Copenhagen University Hospital, Bispebjerg, And Department of Clinical Medicine, University of Copenhagen, 2400, Copenhagen, NV, Denmark, Copenhagen, Denmark *Equal senior authors
Background: Wear of the acetabular polyethylene liner in total hip arthroplasty (THA) may lead to bone osteolysis, aseptic loosening and subsequently revision surgery. Wear may be reduced by using oxidatively stabilized, vitamin E-doped, cross- linked polyethylene (vE-PE) liners instead of annealed or remelted cross-linked polyethylene (XLPE).
Aim: The primary aim was to investigate differences in Head penetration between vE-PE and XLPE liners and between 32- and 36-mm head size. Secondary outcomes included cup migration and PROMs (EQ-5D, SF-36, HHS, UCLA Activity Score)
Materials and Methods: This study(NCT02196792) was comprised of 4 combined intervention groups in a 2X2 setup. Moreover the study was randomized, as patients were randomly assigned to receive a liner material (vE-PE or XLPE) and head size component ( 32 mm or 36 mm). The outcome of the study includes Head penetration and cup migration, both of these were obtained and measured by radiostereometric analysis (RSA). RSA was performed postoperatively at baseline, 3, 12, 24, 60, 84 and 120 months. Patient-reported outcome measures (UCLA Activity Score, Harris Hip Score, and EQ-5D) were acquired at baseline, 3, 12, 24, 36, 60, 84 and 120 months. The Outcomes were calculated by linear mixed-effect analysis. We aimed to include 100 patients in our study powered as a parallel-group design.
Results: A total of 220 patients were assessed for eligibility for this study, but 93 of the patients were excluded. Four patients received screws, 26 patients received cups smaller than 54 mm, 5 patients received other components, 1 patient underwent surgical complications, and 57 patients due to other reasons. 127 patients who underwent randomization into 4 groups and 116 patients received their allocated intervention. Ten years later, 34 patients were lost to follow- up and 82 patients were followed-up. Baseline data was similar between groups in. The following results will be intention-to-treat (ITT) data.
Interpretation / Conclusion: There was significantly lower head penetration in vE-PE compared to XLPE liners at 10 years, and No difference was found between 32 and 36 mm heads. The findings is of clinical importance and may reduce the risk of revision in the long run.
Håvard Dale 1,2, Anne Marie Fenstad 1, Geir Hallan 1,2, Sören Overgaard 3,4,5, Alma B Pedersen 5,6, Nils P Hailer 7,8, Johan Kärrholm 8,9, Ola Rolfson 8,9, Antti Eskelinen 10,11, Keijo T Mäkelä 11,12, Ove Furnes 1,2
1 The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway 3 Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. 4 Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, Denmark 5 The Danish Hip Arthroplasty Register, Århus, Denmark 6 Department of Clinical Epidemiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. 7 Section of Orthopaedics, Department of Surgical Sciences, Uppsala University Hospital, Sweden 8 The Swedish Arthroplasty Register, Gothenburg, Sweden 9 Department of Orthopaedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Sweden 10 Coxa Hospital for Joint Replacement, Tampere; Faculty of Medicine and Health Technologies, University of Tampere, Tampere, Finland 11 The Finnish Hip Arthroplasty Register, Helsinki, Finland 12 Department of Orthopaedics and Traumatology, Turku University Hospital, and University of Turku, Turku, Finland
Background: Previous publications have suggested that the incidence of revisions due to infection after THA.
Aim: We explored trends of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004-2018.
Materials and Methods: Primary THAs reported to the Nordic arthroplasy registers (NARA) from 2004 to 2018 were included. Adjusted Cox regression survival analyses with the first revision due to deep infection after primary THA was performed. The risk of revision as a function of time was investigated. In addition, we explored changes in the time span from primary THA to revision due to infection.
Results: Of 575,502 primary THAs that met the inclusion criteria, 5,703 (1.0%) were revised due to deep infection. The risk of revision due to infection increased through the period studied. Compared to THAs implanted in 2004-2008, the risk of revision due to infection was 1.4 (95%CI 1.3-1.5) for 2009-2013, and 1.8 (1.7-2.0) for 2014-2018. We found an increased risk for all four nations. Compared to 2004-2008, for all THAs, the adjusted risk of revision due to infection 0-30 days postoperatively was 2.5 (1.8-2.8) for 2009- 2013 and 3.3 (2.9-3.8) for 2013-2018. The adjusted risk of revision due to infection 31-90 days postoperatively was 1.5 (1.2-1.9) for 2009- 2013 and 2.4 (2.0-2.9) for 2013-2018, compared to 2004-2008. Beyond 91 days postoperatively, the risk of revision due to infection was similar to 2004-2008 for all 3 time periods.
Interpretation / Conclusion: The risk of revision due to deep infection after THA increased 80% throughout the period 2004-2018. This increase was mainly due to an increased risk of early revisions. The cause for these changes may be multifactorial (patient selection, diagnostics, revision strategy, completeness of reporting, etc.), and are not possible to disclose in the present study.
1 The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway 3 Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. 4 Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, Denmark 5 The Danish Hip Arthroplasty Register, Århus, Denmark 6 Department of Clinical Epidemiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. 7 Section of Orthopaedics, Department of Surgical Sciences, Uppsala University Hospital, Sweden 8 The Swedish Arthroplasty Register, Gothenburg, Sweden 9 Department of Orthopaedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Sweden 10 Coxa Hospital for Joint Replacement, Tampere; Faculty of Medicine and Health Technologies, University of Tampere, Tampere, Finland 11 The Finnish Hip Arthroplasty Register, Helsinki, Finland 12 Department of Orthopaedics and Traumatology, Turku University Hospital, and University of Turku, Turku, Finland
Background: Previous publications have suggested that the incidence of revisions due to infection after THA.
Aim: We explored trends of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004-2018.
Materials and Methods: Primary THAs reported to the Nordic arthroplasy registers (NARA) from 2004 to 2018 were included. Adjusted Cox regression survival analyses with the first revision due to deep infection after primary THA was performed. The risk of revision as a function of time was investigated. In addition, we explored changes in the time span from primary THA to revision due to infection.
Results: Of 575,502 primary THAs that met the inclusion criteria, 5,703 (1.0%) were revised due to deep infection. The risk of revision due to infection increased through the period studied. Compared to THAs implanted in 2004-2008, the risk of revision due to infection was 1.4 (95%CI 1.3-1.5) for 2009-2013, and 1.8 (1.7-2.0) for 2014-2018. We found an increased risk for all four nations. Compared to 2004-2008, for all THAs, the adjusted risk of revision due to infection 0-30 days postoperatively was 2.5 (1.8-2.8) for 2009- 2013 and 3.3 (2.9-3.8) for 2013-2018. The adjusted risk of revision due to infection 31-90 days postoperatively was 1.5 (1.2-1.9) for 2009- 2013 and 2.4 (2.0-2.9) for 2013-2018, compared to 2004-2008. Beyond 91 days postoperatively, the risk of revision due to infection was similar to 2004-2008 for all 3 time periods.
Interpretation / Conclusion: The risk of revision due to deep infection after THA increased 80% throughout the period 2004-2018. This increase was mainly due to an increased risk of early revisions. The cause for these changes may be multifactorial (patient selection, diagnostics, revision strategy, completeness of reporting, etc.), and are not possible to disclose in the present study.
Dennis Vinther¹ ², Aurelie Mailhac¹, Ina Trolle Andersen¹, Søren Overgaard³ 4, Anne Marie Fenstad5, Stein Atle Lie5 6, Jan-Erik Gjertsen5 7, Alma B Pedersen¹ ²
Department of Clinical Epidemiology, Aarhus University Hospital, Denmark¹; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark²; Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, and The Danish Hip Arthroplasty Register, Denmark³; Department of Clinical Medicine, Faculty of Health and Medical Sciences Register, Denmark4; The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway5; Department of Clinical Dentistry, University of Bergen, Bergen, Norway6; Department of Clinical Medicine, University of Bergen, Bergen, Norway7.
Background: There are concerns that bleeding following primary total hip arthroplasty (THA) contributes to prolonged wound drainage and prosthetic joint infection (PJI) and inferior fixation.
Aim: We examined whether short (1-5 days), medium (6- 14 days), and extended (= 14 days) duration of thromboprophylaxis is associated with the 5 year revision rate after THA due to osteoarthritis.
Materials and Methods: Cohort study based on data from hip arthroplasty and administrative registries in Denmark and Norway (2008-2013). The outcome was revision surgery; due to PJI, aseptic loosening, any cause and death. Adjusted cause-specific hazard ratios (HRs) were analyzed with Cox regression analyses.
Results: Among 50,482 THA patients, 8,333 received short, 17,009 received medium, and 25,140 received extended thromboprophylaxis. The HRs for any revision were 1.0 (95% CI 0.9-1.2) and 1.0 (0.9-1.1) for short and extended vs medium thromboprophylaxis. The HRs for revision due to PJI were 0.9 (0.7-1.2) and 1.04 (0.9-1.3) for short and extended vs. medium thromboprophylaxis. The HRs for revision due to aseptic loosening were 1.1 (0.8- 1.5) and 1.3 (1.0-1.6) for short and extended vs. medium thromboprophylaxis. The absolute differences in cumulative incidences at 5 years were <0.5%.
Interpretation / Conclusion: Our data suggest no association between duration of anticoagulant thromboprophylaxis and revision rate within 5 years of THA. There is an indication that the extended thromboprophylaxis might be associated with increased revision rate due to aseptic loosening, but the mechanism of this association is not entirely clear and is a topic that requires further research.
Department of Clinical Epidemiology, Aarhus University Hospital, Denmark¹; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark²; Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, and The Danish Hip Arthroplasty Register, Denmark³; Department of Clinical Medicine, Faculty of Health and Medical Sciences Register, Denmark4; The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway5; Department of Clinical Dentistry, University of Bergen, Bergen, Norway6; Department of Clinical Medicine, University of Bergen, Bergen, Norway7.
Background: There are concerns that bleeding following primary total hip arthroplasty (THA) contributes to prolonged wound drainage and prosthetic joint infection (PJI) and inferior fixation.
Aim: We examined whether short (1-5 days), medium (6- 14 days), and extended (= 14 days) duration of thromboprophylaxis is associated with the 5 year revision rate after THA due to osteoarthritis.
Materials and Methods: Cohort study based on data from hip arthroplasty and administrative registries in Denmark and Norway (2008-2013). The outcome was revision surgery; due to PJI, aseptic loosening, any cause and death. Adjusted cause-specific hazard ratios (HRs) were analyzed with Cox regression analyses.
Results: Among 50,482 THA patients, 8,333 received short, 17,009 received medium, and 25,140 received extended thromboprophylaxis. The HRs for any revision were 1.0 (95% CI 0.9-1.2) and 1.0 (0.9-1.1) for short and extended vs medium thromboprophylaxis. The HRs for revision due to PJI were 0.9 (0.7-1.2) and 1.04 (0.9-1.3) for short and extended vs. medium thromboprophylaxis. The HRs for revision due to aseptic loosening were 1.1 (0.8- 1.5) and 1.3 (1.0-1.6) for short and extended vs. medium thromboprophylaxis. The absolute differences in cumulative incidences at 5 years were <0.5%.
Interpretation / Conclusion: Our data suggest no association between duration of anticoagulant thromboprophylaxis and revision rate within 5 years of THA. There is an indication that the extended thromboprophylaxis might be associated with increased revision rate due to aseptic loosening, but the mechanism of this association is not entirely clear and is a topic that requires further research.
Roshan Latifi¹, Maziar Mohaddes², Nils Hailer³, Anne Marie Fenstad4 5, Geir Hallan4, Antti Eskelinen6, Keijo Mäkelä7, Claus Varnum8, Søren Overgaard?
1. Department of Orthopedic Surgery, Aalborg University Hospital. 2. Department of Orthopedics, Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, Gothenburg; The Swedish Arthroplasty Register, Gothenburg, Sweden; Department of Orthopedics, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden. 3. Department of Surgical Sciences-Orthopedics, Uppsala University, Uppsala, Sweden. 4. The Norwegian Arthroplasty Register; Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway. 5. Department of Clinical Medicine, University of Bergen, Norway. 6. Coxa Hospital for Joint Replacement, and Faculty of Medicine and Health Technologies, University of Tampere, Tampere, Finland. 7. Turku University Hospital and University of Turku, Finland, and the Finnish Arthroplasty Register. 8. Department of Orthopedic Surgery, Lillebaelt Hospital - Vejle, University Hospital of Southern Denmark, Denmark; Department of Regional Health Research, Faculty of Health Science, University of Southern Denmark; The Danish Hip Arthroplasty Register. 9. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, Denmark; University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Denmark; The Danish Hip Arthroplasty Register
Background: Use of uncemented fixation of total hip arthroplasty (THA) components are increasing worldwide. Cemented femoral component fixation in THA has shown better results in older patients, but less is known about the result when focusing on the cup.
Aim: To compare the risk of THA revision due to any reason in patients with cemented or uncemented acetabular cups.
Materials and Methods: We used data from the NARA database; and included in total 174,536 patients divided into 107,320 cemented and 95,981 uncemented cups operated between 1995-2018. Only patients with primary osteoarthritis and 65 years of age or older were included. Metal-on- metal and ceramic-on-ceramic bearings were excluded. We used Cox regression analyses adjusted for period of primary surgery, type of stem fixation, femoral head size and type of bearing to estimate the hazard ratio (HR) of THA revision due to any reason. Data was stratified for sex and age groups of 65- 69,70-74,75-79 and 80+ years and is presented with hazard ratios (HR) and 95% confidence intervals (CI).
Results: Totally 10,427(5.1%) THAs were revised distributed in 4.5% of THAs with uncemented cups and 5.7% with cemented cups. Aseptic loosening was the most frequent cause of revision for cemented cups (45%) and dislocation was for uncemented cups (29%). The risks of revision for women between 65-69, 70-74, 75-79 and 80+ were HR=0.9 (0.7-1.0), HR=0.8 (0.7-1.0), HR=1.2 (1.0-1.3) and HR=1.3 (1.1-1.5) respectively. Risk of revision for male group in corresponding age groups were HR=0.9 (0.7-1.0), HR=0.8 (0.7-1.0), HR=0.9 (0.8-1.1) and HR=1.0 (0.8-1.2) respectively.
Interpretation / Conclusion: There is a slightly increased risk of THA revision for any reason when uncemented cups are used in women over the age of 75 years. Uncemented cups in elderly women should be used with care.
1. Department of Orthopedic Surgery, Aalborg University Hospital. 2. Department of Orthopedics, Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, Gothenburg; The Swedish Arthroplasty Register, Gothenburg, Sweden; Department of Orthopedics, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden. 3. Department of Surgical Sciences-Orthopedics, Uppsala University, Uppsala, Sweden. 4. The Norwegian Arthroplasty Register; Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway. 5. Department of Clinical Medicine, University of Bergen, Norway. 6. Coxa Hospital for Joint Replacement, and Faculty of Medicine and Health Technologies, University of Tampere, Tampere, Finland. 7. Turku University Hospital and University of Turku, Finland, and the Finnish Arthroplasty Register. 8. Department of Orthopedic Surgery, Lillebaelt Hospital - Vejle, University Hospital of Southern Denmark, Denmark; Department of Regional Health Research, Faculty of Health Science, University of Southern Denmark; The Danish Hip Arthroplasty Register. 9. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, Denmark; University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Denmark; The Danish Hip Arthroplasty Register
Background: Use of uncemented fixation of total hip arthroplasty (THA) components are increasing worldwide. Cemented femoral component fixation in THA has shown better results in older patients, but less is known about the result when focusing on the cup.
Aim: To compare the risk of THA revision due to any reason in patients with cemented or uncemented acetabular cups.
Materials and Methods: We used data from the NARA database; and included in total 174,536 patients divided into 107,320 cemented and 95,981 uncemented cups operated between 1995-2018. Only patients with primary osteoarthritis and 65 years of age or older were included. Metal-on- metal and ceramic-on-ceramic bearings were excluded. We used Cox regression analyses adjusted for period of primary surgery, type of stem fixation, femoral head size and type of bearing to estimate the hazard ratio (HR) of THA revision due to any reason. Data was stratified for sex and age groups of 65- 69,70-74,75-79 and 80+ years and is presented with hazard ratios (HR) and 95% confidence intervals (CI).
Results: Totally 10,427(5.1%) THAs were revised distributed in 4.5% of THAs with uncemented cups and 5.7% with cemented cups. Aseptic loosening was the most frequent cause of revision for cemented cups (45%) and dislocation was for uncemented cups (29%). The risks of revision for women between 65-69, 70-74, 75-79 and 80+ were HR=0.9 (0.7-1.0), HR=0.8 (0.7-1.0), HR=1.2 (1.0-1.3) and HR=1.3 (1.1-1.5) respectively. Risk of revision for male group in corresponding age groups were HR=0.9 (0.7-1.0), HR=0.8 (0.7-1.0), HR=0.9 (0.8-1.1) and HR=1.0 (0.8-1.2) respectively.
Interpretation / Conclusion: There is a slightly increased risk of THA revision for any reason when uncemented cups are used in women over the age of 75 years. Uncemented cups in elderly women should be used with care.
Rasmus Tyrsted Mikkelsen¹ ² ³, Claus Varnum¹ ², Trine Torfing4, Ole Graumann4 5 , Henrik Schrøder6, Søren Overgaard³ 5 7 8
Department of Orthopedic Surgery, Lillebaelt Hospital - Vejle¹; Department of Regional Health Research, Faculty of Health Science, University of Southern Denmark²; Department of Orthopedic Surgery and Traumatology, Odense University Hospital, Odense³; Department of Radiology, Odense University Hospital, Odense4; Department of Clinical Research, University of Southern Denmark5; Department of Orthopedic Surgery, Naestved Hospital6; Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg7; University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences8
Background: Metal-on-metal (MoM) total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) may cause adverse reaction to metal debris such as pseudotumors (PT), but PTs can also form around metal-on-polyethylene (MoP) THA. Little is known about the long-term natural history of PT in different types of hip arthroplasty which is important for postoperative follow-up.
Aim: We aimed to investigate how occurrence of PT, metal ion blood levels and patient reported outcome changed over time in HRA, MoM and MoP THA at 4 and 13 years after primary surgery.
Materials and Methods: We conducted a prospective cohort study based on a cohort consisting of 127 HRA, 38 MoM THA and 62 MoP THA who underwent primary surgery between 2005-2010. We included 58 HRA, 16 MoM and 24 MoP THA who twice underwent magnetic resonance imaging (MRI) and had their blood levels of cobalt and chromium and patient reported outcome measure (PROM) scores evaluated at a median of 4 and 13 years after surgery.
Results: There were no differences in PT prevalence between the types of hip arthroplasty at first (p=0.348) or second (p=0.272) MRI. Most PTs were Hauptfleisch type I (11) followed by type III (4) and type II (3) at second examination. 14 out of 26 PTs could not be diagnosed at the latest follow-up. Six new PTs were diagnosed between first and second MRI, 4 of these in MoP THA and 2 in HRA. Median PT volume were 48 cm3 (range 2-126) in HRA, 28 cm3 (range 24-32) in MoM THA and 16 cm3 (range 2-60) in MoP THA (p=0.554) at second examination. HRA had the highest median levels of cobalt and chromium (1.8 ug/L, range 0.24-83 and 1.6 ug/L, range 0.21-47), followed by MoM (1.3 ug/L, range 0.59-3.8 and 1.1 ug/L, range 0.52-2.8) and MoP THA (0.29 ug/L, range 0.12-5.8 and 0.52 ug/L, range 0.21-1.7) (p<0.001 and p<0.001) at second examination. We found no differences in the PROM scores.
Interpretation / Conclusion: PTs were just as common in HRA and MoM THA as in MoP THA. More new PTs were diagnosed in MoP THA. Blood levels of cobalt and chromium was higher in HRA and MoM THA compared to MoP THA, but type of hip arthroplasty and PT had no influence on PROMs. In perspective, we showed a clear change in PT incidence which is important to know when following these patients.
Department of Orthopedic Surgery, Lillebaelt Hospital - Vejle¹; Department of Regional Health Research, Faculty of Health Science, University of Southern Denmark²; Department of Orthopedic Surgery and Traumatology, Odense University Hospital, Odense³; Department of Radiology, Odense University Hospital, Odense4; Department of Clinical Research, University of Southern Denmark5; Department of Orthopedic Surgery, Naestved Hospital6; Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg7; University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences8
Background: Metal-on-metal (MoM) total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) may cause adverse reaction to metal debris such as pseudotumors (PT), but PTs can also form around metal-on-polyethylene (MoP) THA. Little is known about the long-term natural history of PT in different types of hip arthroplasty which is important for postoperative follow-up.
Aim: We aimed to investigate how occurrence of PT, metal ion blood levels and patient reported outcome changed over time in HRA, MoM and MoP THA at 4 and 13 years after primary surgery.
Materials and Methods: We conducted a prospective cohort study based on a cohort consisting of 127 HRA, 38 MoM THA and 62 MoP THA who underwent primary surgery between 2005-2010. We included 58 HRA, 16 MoM and 24 MoP THA who twice underwent magnetic resonance imaging (MRI) and had their blood levels of cobalt and chromium and patient reported outcome measure (PROM) scores evaluated at a median of 4 and 13 years after surgery.
Results: There were no differences in PT prevalence between the types of hip arthroplasty at first (p=0.348) or second (p=0.272) MRI. Most PTs were Hauptfleisch type I (11) followed by type III (4) and type II (3) at second examination. 14 out of 26 PTs could not be diagnosed at the latest follow-up. Six new PTs were diagnosed between first and second MRI, 4 of these in MoP THA and 2 in HRA. Median PT volume were 48 cm3 (range 2-126) in HRA, 28 cm3 (range 24-32) in MoM THA and 16 cm3 (range 2-60) in MoP THA (p=0.554) at second examination. HRA had the highest median levels of cobalt and chromium (1.8 ug/L, range 0.24-83 and 1.6 ug/L, range 0.21-47), followed by MoM (1.3 ug/L, range 0.59-3.8 and 1.1 ug/L, range 0.52-2.8) and MoP THA (0.29 ug/L, range 0.12-5.8 and 0.52 ug/L, range 0.21-1.7) (p<0.001 and p<0.001) at second examination. We found no differences in the PROM scores.
Interpretation / Conclusion: PTs were just as common in HRA and MoM THA as in MoP THA. More new PTs were diagnosed in MoP THA. Blood levels of cobalt and chromium was higher in HRA and MoM THA compared to MoP THA, but type of hip arthroplasty and PT had no influence on PROMs. In perspective, we showed a clear change in PT incidence which is important to know when following these patients.
Rasmus Linnebjerg Knudsen² ¹ , Søren Overgaard² ³, Marc Stegger4, Henrik Calum5, Krassimir Kostadinov²
1. University of Copenhagen, Faculty of Health and Medical Sciences. 2. Copenhagen University Hospital, Bispebjerg, Department of Orthopedic Surgery and Traumatology. 3. University of Copenhagen, Faculty of Health and Medical Sciences, Department of Clinical Medicine 4.Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark 5. Copenhagen University Hospital, Hvidovre, Department of Clinical Microbiology
Background: ostoperative joint infections are a major complication that occur in 1-2% of all total hip arthroplasty and total knee arthroplasty (THA and TKA) leading to increased morbidity and mortality. The knowledge of these infective organisms and their resistance patterns is of great importance for the treatment of the patient and for future prophylactic strategy.
Aim: The main purpose of this study is to investigate the presence of bacteria cultured from revision surgery after THA and TKA. Additionally, we will investigate the phenotypic resistance patterns and describe multidrug-resistance of the different bacterial species.
Materials and Methods: The study is a retrospective review of the patient reports on all revisions of THA and TKA undertaken at Bispebjerg Hospital, Copenhagen, in 2018 and 2019. We noted the organism(s) in cultured biopsies in all cases and their antibiotic resistance patterns. We also investigated the difference in cultures between first-time and all later revisions.
Results: A total of 170 revisions were performed. Here 88 cases had positive culture from biopsies, of which 11% had polymicrobial findings. Staphylococcus aureus was identified in 31% of the cases with 79% of these resistant to Penicillin G. Staphylococcus epidermidis was identified in 11% of cases with high levels of resistance towards Dicloxacillin (75%), Cefuroxime (75%), and Gentamicin (73%). The percentages of S. epidermidis in the study increased from 5% at first-time revision to 16% at later revisions. Only four cases with positive cultures of Corynebacterium striatum (n=1), Enterococcus faecium (n=2) and Enterococcus casseliflavus (n=1) showed resistance to Vancomycin.
Interpretation / Conclusion: In conclusion, we showed that S. aureus and S. epidermidis were the most frequent species cultured from revision THA and TKA. However, importantly the proportion of S. epidermidis increasing when comparing first-time revision with second time and more. Also, the resistance patterns of S. epidermidis showed resistance to several antibiotics, including drugs used in common practice prophylaxis.
1. University of Copenhagen, Faculty of Health and Medical Sciences. 2. Copenhagen University Hospital, Bispebjerg, Department of Orthopedic Surgery and Traumatology. 3. University of Copenhagen, Faculty of Health and Medical Sciences, Department of Clinical Medicine 4.Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark 5. Copenhagen University Hospital, Hvidovre, Department of Clinical Microbiology
Background: ostoperative joint infections are a major complication that occur in 1-2% of all total hip arthroplasty and total knee arthroplasty (THA and TKA) leading to increased morbidity and mortality. The knowledge of these infective organisms and their resistance patterns is of great importance for the treatment of the patient and for future prophylactic strategy.
Aim: The main purpose of this study is to investigate the presence of bacteria cultured from revision surgery after THA and TKA. Additionally, we will investigate the phenotypic resistance patterns and describe multidrug-resistance of the different bacterial species.
Materials and Methods: The study is a retrospective review of the patient reports on all revisions of THA and TKA undertaken at Bispebjerg Hospital, Copenhagen, in 2018 and 2019. We noted the organism(s) in cultured biopsies in all cases and their antibiotic resistance patterns. We also investigated the difference in cultures between first-time and all later revisions.
Results: A total of 170 revisions were performed. Here 88 cases had positive culture from biopsies, of which 11% had polymicrobial findings. Staphylococcus aureus was identified in 31% of the cases with 79% of these resistant to Penicillin G. Staphylococcus epidermidis was identified in 11% of cases with high levels of resistance towards Dicloxacillin (75%), Cefuroxime (75%), and Gentamicin (73%). The percentages of S. epidermidis in the study increased from 5% at first-time revision to 16% at later revisions. Only four cases with positive cultures of Corynebacterium striatum (n=1), Enterococcus faecium (n=2) and Enterococcus casseliflavus (n=1) showed resistance to Vancomycin.
Interpretation / Conclusion: In conclusion, we showed that S. aureus and S. epidermidis were the most frequent species cultured from revision THA and TKA. However, importantly the proportion of S. epidermidis increasing when comparing first-time revision with second time and more. Also, the resistance patterns of S. epidermidis showed resistance to several antibiotics, including drugs used in common practice prophylaxis.
Morten Bøgehøj, Martin Lamm , Thomas Jakobsen
Danish Society for Hip and Knee Arthroplasty
Background: Operation with a total hip arthroplasty (THA) is a well-documented treatment, with a high probability for a good outcome and low risk of serious complications. Dislocation is one of the most frequent complications. Several conditions increase the risk of dislocation of a THA, femoral neck fracture, high age, lumbar fusion and neuromuscular disease. To reduce the risk of dislocation in these high-risk patients the dual mobility cups are often used as an anti-dislocation cup. Studies have reported the use of dual mobility designs as a standard component for patients the gets treated with a THA, in these cases the dislocation rate is reported to be low. A dual mobility cup is designed with two articulations and hence a big surface that is subject to wear. Furthermore, there have been described release of metal debris when the cup is inserted.
Aim: The aim of this short clinical guideline was to answer to PICO-question:” Does patients above the age of 70 years of age, with osteoarthrosis and indication for a THA have better effect when operated with a dualmobility cup than patients operated with a unipolar cup, regarding dislocation, reoperation and function?”
Materials and Methods: A systematic literature search based upon the PICO-question was conducted in Pubmed and Embase. 1283 records were screened. 22 full-text articles were assessed for eligibility. Three systematic reviews and four registry studies were included. Quality assessment of included studies was conducted using AMSTAR for systematic reviews and ROBINS-I for registry studies.
Results: In the literature the comparison of unipolar and dualmobility cup are with different sizes of unipolar heads from 22.2 to 36 mm, many studies compare with 22.2- and 28-mm heads. From the Danish hip registry, we know that the most common head sizes today is 36- and 32-mm and very few 28 mm. On reoperation after 1 and 5 years we find the same risk of revision, but for different reasons.
Interpretation / Conclusion: Dual mobility cups are only to be used after thorough evaluation of the individual patient case, as the benefit for the standard patient with osteoarthrosis is uncertain compared with the unipolar cup. The use of dual mobility cups can be relevant in patients with osteoarthrosis with low level of function and high risk of dislocation (risk of falling, neuromuscular disease or reduced spinopelvin mobility due to lumbar fusion).
Danish Society for Hip and Knee Arthroplasty
Background: Operation with a total hip arthroplasty (THA) is a well-documented treatment, with a high probability for a good outcome and low risk of serious complications. Dislocation is one of the most frequent complications. Several conditions increase the risk of dislocation of a THA, femoral neck fracture, high age, lumbar fusion and neuromuscular disease. To reduce the risk of dislocation in these high-risk patients the dual mobility cups are often used as an anti-dislocation cup. Studies have reported the use of dual mobility designs as a standard component for patients the gets treated with a THA, in these cases the dislocation rate is reported to be low. A dual mobility cup is designed with two articulations and hence a big surface that is subject to wear. Furthermore, there have been described release of metal debris when the cup is inserted.
Aim: The aim of this short clinical guideline was to answer to PICO-question:” Does patients above the age of 70 years of age, with osteoarthrosis and indication for a THA have better effect when operated with a dualmobility cup than patients operated with a unipolar cup, regarding dislocation, reoperation and function?”
Materials and Methods: A systematic literature search based upon the PICO-question was conducted in Pubmed and Embase. 1283 records were screened. 22 full-text articles were assessed for eligibility. Three systematic reviews and four registry studies were included. Quality assessment of included studies was conducted using AMSTAR for systematic reviews and ROBINS-I for registry studies.
Results: In the literature the comparison of unipolar and dualmobility cup are with different sizes of unipolar heads from 22.2 to 36 mm, many studies compare with 22.2- and 28-mm heads. From the Danish hip registry, we know that the most common head sizes today is 36- and 32-mm and very few 28 mm. On reoperation after 1 and 5 years we find the same risk of revision, but for different reasons.
Interpretation / Conclusion: Dual mobility cups are only to be used after thorough evaluation of the individual patient case, as the benefit for the standard patient with osteoarthrosis is uncertain compared with the unipolar cup. The use of dual mobility cups can be relevant in patients with osteoarthrosis with low level of function and high risk of dislocation (risk of falling, neuromuscular disease or reduced spinopelvin mobility due to lumbar fusion).