Session 11: Hip I and Knee II
Torsdag d. 27. oktober
13:00-14:30
Lokale: Stockholm/Copenhagen
Chairmen: Henrik Daugard / Claus Emmeluth
Timothy Hunt Batter, Christian Skovgaard Nielsen, Vincent Galea , Huddleston James , Henrik Malchau, Anders Troelsen
The Harris Orthopaedic Laboratory, Orthopaedic Department, Massachusetts General Hospital, Boston, USA ; Department of Orthopaedic surgery , University Hospital Hvidovre, Copenhagen, Denmark; The Harris Orthopaedic Laboratory, Orthopaedic Department, Massachusetts General Hospital, Boston, USA ; Department of Orthopaedic Surgery, Stanford University Medical Center, Stanford, California, USA; The Harris Orthopaedic Laboratory, Orthopaedic Department, Massachusetts General Hospital, Boston, USA ; Department of Orthopaedic surgery , University Hospital Hvidovre, Copenhagen, Denmark
Background: E-vitamin infused polyethylene is expected to have reduced rate of wear in TKA due to anti-oxidant effects compared to highly crosslinked polyethylene. This is supported by in vitro TKA studies and clinical studies in THA, however never evaluated in vivo for TKA.
Purpose / Aim of Study: The aim of this prospective multicenter study was to investigate E-vitamin infused polyethylene used in TKA after 3 years for 1) risk potential to develop osteolytic lesions and radiolucent lines as measured by radiological assessment and 2) the quality of life and functionality as measured by patient reported outcome measures (PROMs).
Materials and Methods: 499 patients from centers in Europa, USA, Asia and Australia received TKA. Surgery was performed from January 2011 to December 2014. Demographic data, postoperative radiographs, and PROMs were collected at 3 years ± 6 months. Radiological analysis was performed according to outlined by the American Knee Society (AKS) for radiolucency and osteolytic lesions. PROMs measured the clinical outcomes (KOOS, UCLA, AKS and EQ5D score).
Findings / Results: For the 127 patients who received 3 year radiographs, 73.4% were females, mean BMI was 30.4 (SD ± 6.7), and mean age was 63 (SD ± 8.6). 80.7% of patients had no signs of radiolucent lines in any of the AKS zones. For radiolucent lines, 15.0% and 3.4% had a maximal depth between 1-2mm, and 2-3mm, respectively. 1.3% had osteolytic lesions, however no osteolytic lesions extending into adjacent zones. PROMs demonstrated high performance for UCLA, AKS knee, and all KOOS subscales scores regarding functionality, and for EQ5D regarding life quality. 3 patients were revised due to sepsis and early instability.
Conclusions: E-vitamin infused polyethylene showed low rate of complications and osteolytic potential at this 3-year follow-up study.
The Harris Orthopaedic Laboratory, Orthopaedic Department, Massachusetts General Hospital, Boston, USA ; Department of Orthopaedic surgery , University Hospital Hvidovre, Copenhagen, Denmark; The Harris Orthopaedic Laboratory, Orthopaedic Department, Massachusetts General Hospital, Boston, USA ; Department of Orthopaedic Surgery, Stanford University Medical Center, Stanford, California, USA; The Harris Orthopaedic Laboratory, Orthopaedic Department, Massachusetts General Hospital, Boston, USA ; Department of Orthopaedic surgery , University Hospital Hvidovre, Copenhagen, Denmark
Background: E-vitamin infused polyethylene is expected to have reduced rate of wear in TKA due to anti-oxidant effects compared to highly crosslinked polyethylene. This is supported by in vitro TKA studies and clinical studies in THA, however never evaluated in vivo for TKA.
Purpose / Aim of Study: The aim of this prospective multicenter study was to investigate E-vitamin infused polyethylene used in TKA after 3 years for 1) risk potential to develop osteolytic lesions and radiolucent lines as measured by radiological assessment and 2) the quality of life and functionality as measured by patient reported outcome measures (PROMs).
Materials and Methods: 499 patients from centers in Europa, USA, Asia and Australia received TKA. Surgery was performed from January 2011 to December 2014. Demographic data, postoperative radiographs, and PROMs were collected at 3 years ± 6 months. Radiological analysis was performed according to outlined by the American Knee Society (AKS) for radiolucency and osteolytic lesions. PROMs measured the clinical outcomes (KOOS, UCLA, AKS and EQ5D score).
Findings / Results: For the 127 patients who received 3 year radiographs, 73.4% were females, mean BMI was 30.4 (SD ± 6.7), and mean age was 63 (SD ± 8.6). 80.7% of patients had no signs of radiolucent lines in any of the AKS zones. For radiolucent lines, 15.0% and 3.4% had a maximal depth between 1-2mm, and 2-3mm, respectively. 1.3% had osteolytic lesions, however no osteolytic lesions extending into adjacent zones. PROMs demonstrated high performance for UCLA, AKS knee, and all KOOS subscales scores regarding functionality, and for EQ5D regarding life quality. 3 patients were revised due to sepsis and early instability.
Conclusions: E-vitamin infused polyethylene showed low rate of complications and osteolytic potential at this 3-year follow-up study.
Øivind Jans , Khan Nissa , Christian Skovgaard Nielsen , Kirill Gromow, Anders Trolsen, Henrik Husted
Section for Surgical Pathophysiology 4074, Rigshospitalet, Copenhagen University, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark
Background: Preoperative anemia is prevalent in elderly patients undergoing major orthopaedic surgery and has been associated with increased risk of blood transfusion and postoperative morbidity. Current guidelines recommend correcting anemia and iron deficiency prior to surgery. However, the causes of preoperative anemia in hip- (THA) and knee (TKA) arthroplasty are sparsely studied.
Purpose / Aim of Study: Investigating the causes for preoperative anemia prior to THA and TKA.
Materials and Methods: Preoperative hemoglobin and biochemical markers of anemia and iron status were prospectively collected from 900 patients scheduled for elective fast-track THA and TKA. Anemia was defined using WHO criteria (Hb < 12 g/dl in females or < 13 g/dl in males). Iron deficiency (ID) and other possible anemia causes were classified using ferritin, transferrin saturation (TSAT), P-Cobalamine,, P- Folate, C-reactive-protein and creatinine. ID was defined as absolute (ferritin < 30 ng/ml) or functional (ferritin 30-100 ng/ml & TSAT < 20%).
Findings / Results: 96 (10.7%) patients were anemic preoperatively. 329 (37%) had absolute or functional iron deficiency, 44 % vs. 34 % in anemic and non- anemic patients, respectively (p = 0.09). Anemic patients were transfused more frequently, 42 vs. 12 %; p < 0.001). 90 day readmission rate was 24 vs. 17 % in anemic vs. non-anemic patients (p = 0.14). Among anemic patients, 43 (44.8%) had ID; 22 (22.9%) had ID alone and 21 (21.9%) patients had mixed anemia (ID + chronic inflammation or possible nephrogenic anemia). In a further 25 (26.0%) patients without ID, anemia was possibly due to inflammation, renal failure or both. In the remaining 28 (29.2%) patients, the anemia was of indeterminate origin.
Conclusions: Anemia is prevalent prior to THA or TKA with potentially reversible iron deficiency as a possible cause in 45% of anemic patients.
Section for Surgical Pathophysiology 4074, Rigshospitalet, Copenhagen University, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Orthopaedic surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark
Background: Preoperative anemia is prevalent in elderly patients undergoing major orthopaedic surgery and has been associated with increased risk of blood transfusion and postoperative morbidity. Current guidelines recommend correcting anemia and iron deficiency prior to surgery. However, the causes of preoperative anemia in hip- (THA) and knee (TKA) arthroplasty are sparsely studied.
Purpose / Aim of Study: Investigating the causes for preoperative anemia prior to THA and TKA.
Materials and Methods: Preoperative hemoglobin and biochemical markers of anemia and iron status were prospectively collected from 900 patients scheduled for elective fast-track THA and TKA. Anemia was defined using WHO criteria (Hb < 12 g/dl in females or < 13 g/dl in males). Iron deficiency (ID) and other possible anemia causes were classified using ferritin, transferrin saturation (TSAT), P-Cobalamine,, P- Folate, C-reactive-protein and creatinine. ID was defined as absolute (ferritin < 30 ng/ml) or functional (ferritin 30-100 ng/ml & TSAT < 20%).
Findings / Results: 96 (10.7%) patients were anemic preoperatively. 329 (37%) had absolute or functional iron deficiency, 44 % vs. 34 % in anemic and non- anemic patients, respectively (p = 0.09). Anemic patients were transfused more frequently, 42 vs. 12 %; p < 0.001). 90 day readmission rate was 24 vs. 17 % in anemic vs. non-anemic patients (p = 0.14). Among anemic patients, 43 (44.8%) had ID; 22 (22.9%) had ID alone and 21 (21.9%) patients had mixed anemia (ID + chronic inflammation or possible nephrogenic anemia). In a further 25 (26.0%) patients without ID, anemia was possibly due to inflammation, renal failure or both. In the remaining 28 (29.2%) patients, the anemia was of indeterminate origin.
Conclusions: Anemia is prevalent prior to THA or TKA with potentially reversible iron deficiency as a possible cause in 45% of anemic patients.
Dana Li, Anders Troelsen, Lina Ingelsrud, Henrik Husted, Kirill Gromov
Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital
Background: Low knee awareness, evaluated using Forgotten Joint Score (FJS) has been suggested as the ultimate goal following Total Knee Arthroplasty (TKA). FJS has been validated in several countries and in patients post-operation but knowledge is sparse on preoperative levels of FJS in patients undergoing primary TKA. By identifying factors that predict preoperative FJS levels, the clinician could better prioritize most affected patients and with more precision single out patients who would benefit most from TKA
Purpose / Aim of Study: The aim of this study was to identify factors that predict preoperative FJS levels and evaluate the correlation between preoperative levels of FJS and Oxford Knee Score (OKS) in patients undergoing primary TKA
Materials and Methods: 437 consecutive patients undergoing primary TKA between April 2014 and April 2016 were included in the study. All patients completed a validated Danish version of FJS and a validated Danish version of OKS. Recorded patient demographics included age, gender and BMI. Kellgren-Lawrence (K-L) grade, overall alignment and Joint Space Width (JSW) were evaluated on preoperative x-rays. Multiple regression was run to predict FJS from gender, age, BMI, K-L grade, alignment and JSW. Spearman’s rank order testing was done between FJS and OKS
Findings / Results: Gender, age and BMI significantly predicted preoperative FJS (p < 0.005). OKS also significantly predicted preoperative FJS (p < 0.005) and there was a strong positive correlation between FJS and OKS according to the Spearman’s rank order test (p < 0.005)
Conclusions: Age, gender and BMI significantly predicted FJS. In addition, FJS has a strong positive correlation to OKS in patients undergoing primary TKA. This information can be used for improved patient selection prior to primary TKA
Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital; Department of Orthopaedic Surgery, Hvidovre Hospital
Background: Low knee awareness, evaluated using Forgotten Joint Score (FJS) has been suggested as the ultimate goal following Total Knee Arthroplasty (TKA). FJS has been validated in several countries and in patients post-operation but knowledge is sparse on preoperative levels of FJS in patients undergoing primary TKA. By identifying factors that predict preoperative FJS levels, the clinician could better prioritize most affected patients and with more precision single out patients who would benefit most from TKA
Purpose / Aim of Study: The aim of this study was to identify factors that predict preoperative FJS levels and evaluate the correlation between preoperative levels of FJS and Oxford Knee Score (OKS) in patients undergoing primary TKA
Materials and Methods: 437 consecutive patients undergoing primary TKA between April 2014 and April 2016 were included in the study. All patients completed a validated Danish version of FJS and a validated Danish version of OKS. Recorded patient demographics included age, gender and BMI. Kellgren-Lawrence (K-L) grade, overall alignment and Joint Space Width (JSW) were evaluated on preoperative x-rays. Multiple regression was run to predict FJS from gender, age, BMI, K-L grade, alignment and JSW. Spearman’s rank order testing was done between FJS and OKS
Findings / Results: Gender, age and BMI significantly predicted preoperative FJS (p < 0.005). OKS also significantly predicted preoperative FJS (p < 0.005) and there was a strong positive correlation between FJS and OKS according to the Spearman’s rank order test (p < 0.005)
Conclusions: Age, gender and BMI significantly predicted FJS. In addition, FJS has a strong positive correlation to OKS in patients undergoing primary TKA. This information can be used for improved patient selection prior to primary TKA
Erik Malchau, Ola Rolfson, Magnus Karlsson, Adina Welander, Peter Grant, Maziar Mohaddes
Department of Orthopaedics, Sahlgrenska University Hospital; Department of Orthopaedics, Sahlgrenska University Hospital; Department of Orthopaedics, Sahlgrenska University Hospital; , Boston Consulting Group; Department of Orthopaedics, Sahlgrenska University Hospital; Department of Orthopaedics, Sahlgrenska University Hospital
Background: During the last decade the annual numbers of primary total hip replacements (THR) have increased by 30% in Sweden. The statutory health care guarantee stipulates the patient a right to treatment within 90 days. The public health system has had difficulties meeting the increasing demand, resulting in an emerging market of private providers of THR. In mid 2012, we initiated a systematic review of the care processes in elective THR at Sahlgrenska University Hospital’s (SU) joint replacement unit. As part of this effort, value-based healthcare (VBHC) management was introduced in our unit in late 2013.
Purpose / Aim of Study: To improve quality of care and availability to treatment for patients in need of THR.
Materials and Methods: Starting in mid 2012, THR care processes were gradually overhauled according to the Fast Track concept. A multiprofessional workgroup involved in the treatment of THR patient was assembled. The first step was to identify which outcomes to monitor. Outcomes were subcategorized into three groups: 1) clinical outcomes reported to the Swedish Hip Arthroplasty Register and local databases 2) cost & resource utilization measures and 3) process measures. Available data were analyzed and areas of improvement were identified.
Findings / Results: During years 2011-2015 the number of elective THRs increased from 317 to 498. The cost per patient decreased from SEK 75,000 to 65,000. Length of stay decreased from mean 6.4 days to 3.2 days. Satisfaction with the outcome of surgery one year after THA increased from 76% to 88%. Adverse events decreased from 28% to 10%. Re-operations within 2 years decreased from 2,4% to 1,8%.
Conclusions: Value-based healthcare management and a systematic approach to review THR care processes have contributed to improved quality of care and availability of treatment whilst decreasing cost per patient.
Department of Orthopaedics, Sahlgrenska University Hospital; Department of Orthopaedics, Sahlgrenska University Hospital; Department of Orthopaedics, Sahlgrenska University Hospital; , Boston Consulting Group; Department of Orthopaedics, Sahlgrenska University Hospital; Department of Orthopaedics, Sahlgrenska University Hospital
Background: During the last decade the annual numbers of primary total hip replacements (THR) have increased by 30% in Sweden. The statutory health care guarantee stipulates the patient a right to treatment within 90 days. The public health system has had difficulties meeting the increasing demand, resulting in an emerging market of private providers of THR. In mid 2012, we initiated a systematic review of the care processes in elective THR at Sahlgrenska University Hospital’s (SU) joint replacement unit. As part of this effort, value-based healthcare (VBHC) management was introduced in our unit in late 2013.
Purpose / Aim of Study: To improve quality of care and availability to treatment for patients in need of THR.
Materials and Methods: Starting in mid 2012, THR care processes were gradually overhauled according to the Fast Track concept. A multiprofessional workgroup involved in the treatment of THR patient was assembled. The first step was to identify which outcomes to monitor. Outcomes were subcategorized into three groups: 1) clinical outcomes reported to the Swedish Hip Arthroplasty Register and local databases 2) cost & resource utilization measures and 3) process measures. Available data were analyzed and areas of improvement were identified.
Findings / Results: During years 2011-2015 the number of elective THRs increased from 317 to 498. The cost per patient decreased from SEK 75,000 to 65,000. Length of stay decreased from mean 6.4 days to 3.2 days. Satisfaction with the outcome of surgery one year after THA increased from 76% to 88%. Adverse events decreased from 28% to 10%. Re-operations within 2 years decreased from 2,4% to 1,8%.
Conclusions: Value-based healthcare management and a systematic approach to review THR care processes have contributed to improved quality of care and availability of treatment whilst decreasing cost per patient.
Paul Lee
ortopedics, The Robert Jones & Agnes Hunt Hospital
Background: Offloading knee braces can provide good short-term pain relief for some patients with unicompartmental osteoarthritis. Their cost is relatively small compared to surgical interventions. However, there has not been any study reporting their use over five years
Purpose / Aim of Study: 1. Can wearing the offloading brace delay the need for surgery? 2. is the knee brace a costeffective treatment choicwe?
Materials and Methods: Prospective data was collected for 63 consecutive patients who presented with unicompartmental osteoarthritic pain between 2007-2009; after conservative management with painkillers and physiotherapy, they were offered an offloading knee brace. Patient-reported outcome measures and radiological assessments were performed yearly and the primary endpoint was surgical intervention
Findings / Results: the mean follow up was seven years (6-8). A total of 33.9% (21/62) of patients are still using the offloading brace.There was no significant radiological progression of disease. 38.1% of patients did not have surgery in the six to eight years follow up. The average successful patient wore the brace for 54.9 months. Gender, BMI, age, compartment, or leg did not affect the chance of success. However the longer the patient wore the brace determined the chance of success. 50% of patients who underwent surgery had a total knee replacement, 37% a unicompartmental knee replacement, and 13% a high tibial osteotomy. The EuroQol score showed the brace had a significant effect on quality of life. The offloader brace gained 0.42 QALY’s. Cost per QALY is £150.71
Conclusions: Offloading knee braces are a cost- effective management for unicompartmental arthritis, which can significantly reduce pain, anxiety, and increase patient’s daily activities. If it can be tolerated for over two years, surgical intervention is highly unlikely.
ortopedics, The Robert Jones & Agnes Hunt Hospital
Background: Offloading knee braces can provide good short-term pain relief for some patients with unicompartmental osteoarthritis. Their cost is relatively small compared to surgical interventions. However, there has not been any study reporting their use over five years
Purpose / Aim of Study: 1. Can wearing the offloading brace delay the need for surgery? 2. is the knee brace a costeffective treatment choicwe?
Materials and Methods: Prospective data was collected for 63 consecutive patients who presented with unicompartmental osteoarthritic pain between 2007-2009; after conservative management with painkillers and physiotherapy, they were offered an offloading knee brace. Patient-reported outcome measures and radiological assessments were performed yearly and the primary endpoint was surgical intervention
Findings / Results: the mean follow up was seven years (6-8). A total of 33.9% (21/62) of patients are still using the offloading brace.There was no significant radiological progression of disease. 38.1% of patients did not have surgery in the six to eight years follow up. The average successful patient wore the brace for 54.9 months. Gender, BMI, age, compartment, or leg did not affect the chance of success. However the longer the patient wore the brace determined the chance of success. 50% of patients who underwent surgery had a total knee replacement, 37% a unicompartmental knee replacement, and 13% a high tibial osteotomy. The EuroQol score showed the brace had a significant effect on quality of life. The offloader brace gained 0.42 QALY’s. Cost per QALY is £150.71
Conclusions: Offloading knee braces are a cost- effective management for unicompartmental arthritis, which can significantly reduce pain, anxiety, and increase patient’s daily activities. If it can be tolerated for over two years, surgical intervention is highly unlikely.
Sarah E Plews, Randi L. Nielsen, Søren Overgaard, Carsten Jensen
University of Southern Denmark, Institute of Clinical Research; University of Southern Denmark, Institute of Clinical Research; Ortopeadic surgery and traumatology, Odense University Hospital; Ortopeadic surgery and traumatology, Odense University Hospital
Background: Few studies have combined preoperative patient-reported and objective outcome measures to predict outcomes after total hip arthroplasty (THA).
Purpose / Aim of Study: to identify predictors of outcome 3 and 12 months after THA
Materials and Methods: A cohort of 107 consecutive patients with primary hip osteoarthritis responded to Hip dysfunction and Osteoarthritis Outcome Score (HOOS) questionnaires prior to and 3 and 12 months after THA. Preoperative pain intensity; joint space width (JSW), age, gender, and body mass index (BMI) were used to predict changes in pain and physical function after surgery. Preoperative pain level scores were categorized into; none (76-100, reference), mild (51-75), moderate (26- 50) and severe (0-25). Single and multilevel repeated measures random effects linear regression models (MLM) were used
Findings / Results: Preoperative pain levels predicted improvement in postoperative pain in such a way that patients with mild pain improved; 20 points (95% CI: 2.5 to 36.8), while patients with moderate and severe pain improved; 32 (95% CI: 15.5 to 48.7) and 47 (95% CI: 29.3 to 64.3), points, respectively. Preoperative pain also predicted improvements in postoperative physical function scores; mild improved; 18 (-2.6 to 38.3), moderate 26 (6.7 to 46.2) and severe 44 points (23.2 to 64.9), respectively. Age, gender, BMI, and JSW had no predictive value. The patients achieved the same postoperative level of pain and function irrespective of pre- operative score.
Conclusions: Preoperative pain predicted changes in pain and physical function up to one year after THA. Such knowledge should be taken into consideration, when assessing OA patients prior to surgery. This study provides useful insight for clinicians, regarding the overall improvement patients can expect to achieve following their total hip arthroplasty
University of Southern Denmark, Institute of Clinical Research; University of Southern Denmark, Institute of Clinical Research; Ortopeadic surgery and traumatology, Odense University Hospital; Ortopeadic surgery and traumatology, Odense University Hospital
Background: Few studies have combined preoperative patient-reported and objective outcome measures to predict outcomes after total hip arthroplasty (THA).
Purpose / Aim of Study: to identify predictors of outcome 3 and 12 months after THA
Materials and Methods: A cohort of 107 consecutive patients with primary hip osteoarthritis responded to Hip dysfunction and Osteoarthritis Outcome Score (HOOS) questionnaires prior to and 3 and 12 months after THA. Preoperative pain intensity; joint space width (JSW), age, gender, and body mass index (BMI) were used to predict changes in pain and physical function after surgery. Preoperative pain level scores were categorized into; none (76-100, reference), mild (51-75), moderate (26- 50) and severe (0-25). Single and multilevel repeated measures random effects linear regression models (MLM) were used
Findings / Results: Preoperative pain levels predicted improvement in postoperative pain in such a way that patients with mild pain improved; 20 points (95% CI: 2.5 to 36.8), while patients with moderate and severe pain improved; 32 (95% CI: 15.5 to 48.7) and 47 (95% CI: 29.3 to 64.3), points, respectively. Preoperative pain also predicted improvements in postoperative physical function scores; mild improved; 18 (-2.6 to 38.3), moderate 26 (6.7 to 46.2) and severe 44 points (23.2 to 64.9), respectively. Age, gender, BMI, and JSW had no predictive value. The patients achieved the same postoperative level of pain and function irrespective of pre- operative score.
Conclusions: Preoperative pain predicted changes in pain and physical function up to one year after THA. Such knowledge should be taken into consideration, when assessing OA patients prior to surgery. This study provides useful insight for clinicians, regarding the overall improvement patients can expect to achieve following their total hip arthroplasty
Søren Glud Skousgaard, Lars Peter Andreas Brandt, Søren Overgaard, Sören Möller, Axel Skytthe
1Department of Occupational and Environmental Medicine, Odense University Hospital, 5000 Odense C, Denmark. 2Department of Orthopaedic Surgery and Traumatology & Orthopedic Research Unit, Institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark. 3Clinical Institute, University of Southern Denmark, 5000 Odense C, Denmark., Odense University Hospital; 1Department of Occupational and Environmental Medicine, Odense University Hospital, 5000 Odense C, Denmark. Clinical Institute, University of Southern Denmark, 5000 Odense C, Denmark. , Odense University Hospital; Department of Orthopaedic Surgery and Traumatology & Orthopedic Research Unit, Institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark. Clinical Institute, University of Southern Denmark, 5000 Odense C, Denmark., Odense University Hospital; Department of Epidemiology, Biostatistics and Biodemography, The Danish Twin Registry, University of Southern Denmark, 5000 Odense C, Denmark., University of Southern Denmark; Department of Epidemiology, Biostatistics and Biodemography, The Danish Twin Registry, University of Southern Denmark, 5000 Odense C, Denmark, University of Southern Denmark
Background: No previous studies has examined if genetic factors interacts in the relationship between causal risk factors and hip and knee OA
Purpose / Aim of Study: To examine occupational and environmental risk factors for Hip and Knee OA leading to THA and TKA, and if gene-exposure interaction affects the risk factor-outcome relationships
Materials and Methods: In October 2012 all twin pairs alive in the Danish Twin Register (DTR) with at least one in the pair registered in the Danish Hip or the Danish Knee Arthroplasty Registers (DHA/DKA) with a diagnosis of primary OA were sent a detailed questionnaire regarding previous occupation, related exposures and complementary environmental factors. The analyses included cumulated exposures, McNemar`s X2 tests, and conditional logistic regression including gene-exposure-interaction variables.
Findings / Results: 1181 twins responded (rate 58.9 %). Responder analyses did not display any significant difference with non-responders with respect to diagnosis, zygosity and sex. We found a gene-exposure effect modification in hip OA-lifting and lifting-walking with OR`s 17.7 (1.1-280.2) and 10.4 (1.00-107.1), and a clear dose-response relationship between hip OA and prolonged standing-walking. BMI>25 was a significant risk factor in knee osteoarthritis as was kneeling, but no gene-kneeling or gene-BMI interaction was detectable
Conclusions: Gene-exposure effect modification may be important in the development of hip OA in particular exposures to lifting and lifting-walking, but not in knee OA.
1Department of Occupational and Environmental Medicine, Odense University Hospital, 5000 Odense C, Denmark. 2Department of Orthopaedic Surgery and Traumatology & Orthopedic Research Unit, Institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark. 3Clinical Institute, University of Southern Denmark, 5000 Odense C, Denmark., Odense University Hospital; 1Department of Occupational and Environmental Medicine, Odense University Hospital, 5000 Odense C, Denmark. Clinical Institute, University of Southern Denmark, 5000 Odense C, Denmark. , Odense University Hospital; Department of Orthopaedic Surgery and Traumatology & Orthopedic Research Unit, Institute of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark. Clinical Institute, University of Southern Denmark, 5000 Odense C, Denmark., Odense University Hospital; Department of Epidemiology, Biostatistics and Biodemography, The Danish Twin Registry, University of Southern Denmark, 5000 Odense C, Denmark., University of Southern Denmark; Department of Epidemiology, Biostatistics and Biodemography, The Danish Twin Registry, University of Southern Denmark, 5000 Odense C, Denmark, University of Southern Denmark
Background: No previous studies has examined if genetic factors interacts in the relationship between causal risk factors and hip and knee OA
Purpose / Aim of Study: To examine occupational and environmental risk factors for Hip and Knee OA leading to THA and TKA, and if gene-exposure interaction affects the risk factor-outcome relationships
Materials and Methods: In October 2012 all twin pairs alive in the Danish Twin Register (DTR) with at least one in the pair registered in the Danish Hip or the Danish Knee Arthroplasty Registers (DHA/DKA) with a diagnosis of primary OA were sent a detailed questionnaire regarding previous occupation, related exposures and complementary environmental factors. The analyses included cumulated exposures, McNemar`s X2 tests, and conditional logistic regression including gene-exposure-interaction variables.
Findings / Results: 1181 twins responded (rate 58.9 %). Responder analyses did not display any significant difference with non-responders with respect to diagnosis, zygosity and sex. We found a gene-exposure effect modification in hip OA-lifting and lifting-walking with OR`s 17.7 (1.1-280.2) and 10.4 (1.00-107.1), and a clear dose-response relationship between hip OA and prolonged standing-walking. BMI>25 was a significant risk factor in knee osteoarthritis as was kneeling, but no gene-kneeling or gene-BMI interaction was detectable
Conclusions: Gene-exposure effect modification may be important in the development of hip OA in particular exposures to lifting and lifting-walking, but not in knee OA.
Anders Holsgaard-Larsen, Brian Clausen, Jens Søndergaard, Robin Christensen, Thomas P. Andriacchi, Ewa M. Roos
Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark; Research Unit for General Practice, Institute of Public Health, University of Southern Denmark; Musculoskeletal Statistics Unit, e Parker Institute, Bispebjerg & Frederiksberg Hospital; Departments of Mechanical Engineering and Orthopaedic Surgery, Stanford University, Stanford, California, USA; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark
Background: Although pain-reducing pharmacologic agents are widely used treatments for knee osteoarthritis (OA) they also have adverse effects and may increase knee-joint load which has a central role in symptoms and OA progression
Purpose / Aim of Study: To investigate the effect of a NEuro- Muscular EXercise (NEMEX) therapy program compared with instructions in optimized analgesics and anti- inflammatory drug use (PHARMA), on measures of knee-joint load in people with mild to moderate knee OA. We hypothesized that knee joint loading during walking would be reduced more by NEMEX than by PHARMA.
Materials and Methods: Single-blind, RCT comparing NEMEX therapy twice a week with PHARMA. Participants with mild-to-moderate medial tibiofemoral knee osteoarthritis were randomly allocated (1:1) to one of two 8-week treatments. Primary outcome was change in knee load during walking (Knee Index, a composite score from all three planes based on 3D movement analysis) after 8 weeks of intervention. Secondary outcomes were frontal peak knee adduction moment (KAM), Knee Injury and Osteoarthritis Outcome Scores (KOOS) and functional performance tests.
Findings / Results: 93 (57% women, 58 ± 8 years with a BMI of 27 ± 4 (mean ± SD)) were randomized to the NEMEX group (n = 47) or the PHARMA (n = 46); data from 44(94%) and 41(89%) participants respectively, were available at follow- up. We found no statistically significant or clinically relevant difference in the primary outcome knee joint load as evaluated by the Knee Index -0.07 [-0.17; 0.04]. Secondary outcomes largely supported this primary finding.
Conclusions: No difference in joint load modifying effects during walking from a neuromuscular exercise program versus information on the recommended use of analgesics and anti-inflammatory drugs was observed.
Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark; Research Unit for General Practice, Institute of Public Health, University of Southern Denmark; Musculoskeletal Statistics Unit, e Parker Institute, Bispebjerg & Frederiksberg Hospital; Departments of Mechanical Engineering and Orthopaedic Surgery, Stanford University, Stanford, California, USA; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark
Background: Although pain-reducing pharmacologic agents are widely used treatments for knee osteoarthritis (OA) they also have adverse effects and may increase knee-joint load which has a central role in symptoms and OA progression
Purpose / Aim of Study: To investigate the effect of a NEuro- Muscular EXercise (NEMEX) therapy program compared with instructions in optimized analgesics and anti- inflammatory drug use (PHARMA), on measures of knee-joint load in people with mild to moderate knee OA. We hypothesized that knee joint loading during walking would be reduced more by NEMEX than by PHARMA.
Materials and Methods: Single-blind, RCT comparing NEMEX therapy twice a week with PHARMA. Participants with mild-to-moderate medial tibiofemoral knee osteoarthritis were randomly allocated (1:1) to one of two 8-week treatments. Primary outcome was change in knee load during walking (Knee Index, a composite score from all three planes based on 3D movement analysis) after 8 weeks of intervention. Secondary outcomes were frontal peak knee adduction moment (KAM), Knee Injury and Osteoarthritis Outcome Scores (KOOS) and functional performance tests.
Findings / Results: 93 (57% women, 58 ± 8 years with a BMI of 27 ± 4 (mean ± SD)) were randomized to the NEMEX group (n = 47) or the PHARMA (n = 46); data from 44(94%) and 41(89%) participants respectively, were available at follow- up. We found no statistically significant or clinically relevant difference in the primary outcome knee joint load as evaluated by the Knee Index -0.07 [-0.17; 0.04]. Secondary outcomes largely supported this primary finding.
Conclusions: No difference in joint load modifying effects during walking from a neuromuscular exercise program versus information on the recommended use of analgesics and anti-inflammatory drugs was observed.
Morten S Wad
Orthopedic department, Zealand University Hospital Koege.
Background: Early radiological signs of aseptic loosening of the cup less than 5 years after implantation, together with an increased rate og revision.
Purpose / Aim of Study: To assess te quality of implantation of the cemented RimFit X3 cup with the use of a rim cutter: radiological and clinical results.
Materials and Methods: 375 patients operated from 05.04.2011 to 09.09.2015. TraumaCAD was used to measure thicknes of the cement mantle in DeLee & Charley 3 zones. Radiolucent lines was classified according to Hodgkinson (grade 0 - 4). Inclination of the cup was measured.
Findings / Results: 5 % revision, mostly infection. Cement mantle tickness most pronouced in Zone 2 An increase in radiolucent lines was found.
Conclusions: An elevated rate of revision has resulted in cessation of the use of the Rimfit cup at our department.
Orthopedic department, Zealand University Hospital Koege.
Background: Early radiological signs of aseptic loosening of the cup less than 5 years after implantation, together with an increased rate og revision.
Purpose / Aim of Study: To assess te quality of implantation of the cemented RimFit X3 cup with the use of a rim cutter: radiological and clinical results.
Materials and Methods: 375 patients operated from 05.04.2011 to 09.09.2015. TraumaCAD was used to measure thicknes of the cement mantle in DeLee & Charley 3 zones. Radiolucent lines was classified according to Hodgkinson (grade 0 - 4). Inclination of the cup was measured.
Findings / Results: 5 % revision, mostly infection. Cement mantle tickness most pronouced in Zone 2 An increase in radiolucent lines was found.
Conclusions: An elevated rate of revision has resulted in cessation of the use of the Rimfit cup at our department.
Dana Cotong, Anders Troelsen, Henrik Husted, Kirill Gromov
Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: Dislocation is a well-known complication following total hip arthroplasty (THA). The Lewinnek and Callanan “safe zones”, respectively, have been widely used to minimize dislocation frequency. However, recent studies have questioned the association between “safe zones” and lower dislocation rates.
Purpose / Aim of Study: The purpose of this study is to investigate (1) if Danish hip surgeons agree on a specific “safe zone” for cup positioning and (2) surgeons’ surgical practice patterns concerning recurring instability in primary THA.
Materials and Methods: A survey was performed among attending hip surgeons during the 2015 Annual Meeting of the Danish Orthopaedic Society. The questionnaire contained questions regarding optimal component positioning, operative practice patterns in primary THA, indications for revision THA and surgical techniques used in revisions for dislocation.
Findings / Results: 42 questionnaires were gathered, 2 were excluded, thus leaving 40 for analyses. 97 % of the surgeons indicated optimum cup anteversion within both the Lewinnek and Callanan “safe zones”, while 97 % and 83 % reported optimum cup inclination within the Lewinnek and Callanan “safe zones”, respectively. Reported range on optimal cup positioning varied from 30-55° of inclination and 15-30° of anteversion. Minimum and maximum accepted inclination and anteversion angles within the Lewinnek “safe zone” were 68 % and 67 %, respectively.
Conclusions: Danish hip surgeons agree that optimum cup positioning should lie within the Lewinnek “safe zone”, but do not agree on exact optimal cup positioning concerning inclination and anteversion. Current surgical practice patterns among the majority of surgeons are supported by existing literature. However, as 1/3 of the accepted “safe zones” are outside the Lewinnek “safe zone”, behavioural changes through education are advised
Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: Dislocation is a well-known complication following total hip arthroplasty (THA). The Lewinnek and Callanan “safe zones”, respectively, have been widely used to minimize dislocation frequency. However, recent studies have questioned the association between “safe zones” and lower dislocation rates.
Purpose / Aim of Study: The purpose of this study is to investigate (1) if Danish hip surgeons agree on a specific “safe zone” for cup positioning and (2) surgeons’ surgical practice patterns concerning recurring instability in primary THA.
Materials and Methods: A survey was performed among attending hip surgeons during the 2015 Annual Meeting of the Danish Orthopaedic Society. The questionnaire contained questions regarding optimal component positioning, operative practice patterns in primary THA, indications for revision THA and surgical techniques used in revisions for dislocation.
Findings / Results: 42 questionnaires were gathered, 2 were excluded, thus leaving 40 for analyses. 97 % of the surgeons indicated optimum cup anteversion within both the Lewinnek and Callanan “safe zones”, while 97 % and 83 % reported optimum cup inclination within the Lewinnek and Callanan “safe zones”, respectively. Reported range on optimal cup positioning varied from 30-55° of inclination and 15-30° of anteversion. Minimum and maximum accepted inclination and anteversion angles within the Lewinnek “safe zone” were 68 % and 67 %, respectively.
Conclusions: Danish hip surgeons agree that optimum cup positioning should lie within the Lewinnek “safe zone”, but do not agree on exact optimal cup positioning concerning inclination and anteversion. Current surgical practice patterns among the majority of surgeons are supported by existing literature. However, as 1/3 of the accepted “safe zones” are outside the Lewinnek “safe zone”, behavioural changes through education are advised
Eva Natalia Glassou, Torben Bæk Hansen, Alma Becic Pedersen
University clinic of hand, hip and knee surgery, Department of Orthopedic Surgery, Regional Hospital West Jutland; University clinic of hand, hip and knee surgery, Department of Orthopedic Surgery, Regional Hospital West Jutland; Department of Clinical Epidemiology, Aarhus University Hospital
Background: Pneumonia and urinary tract infection (UTI) are common infections causing increased morbidity and mortality. Both infections are standard complications after total hip arthroplasty (THA).
Purpose / Aim of Study: We examined the risk of postoperative pneumonia and UTI after THA and the impact on survival.
Materials and Methods: We used the Danish Hip Arthroplasty Register to identify THAs due to OA from 2000 to 2013. From administrative databases we collected data about comorbidity, mortality and infections in relation to the primary hospitalization and potential predictive variables. Regression models were used to estimate associations between potential risk factors and infections and between infections and 90-day mortality. The latter presented as relative risk (RR) with 95% confidence intervals (CI).
Findings / Results: In total 84,812 THAs were included. The risk of pneumonia and UTI within 30 days of the primary procedure were 0.47 (CI 0.42 – 0.52) and 0.56 (CI 0.51 – 0.61), respectively. Common patient related risk factors for infections were age of 80 years or more and a comorbidity burden at time of surgery. For pneumonia, individual risk factors were male gender, diabetes and CPD. For UTI, female gender was an individual risk factor. For patients with pneumonia, the RR of 90 days mortality was 13.12 (7.94 – 21.68). For patients with UTI, the RR was 1.23 (0.30 – 4.96).
Conclusions: The risks of pneumonia and UTI within 30 days of the primary procedure were low but when experiencing specially pneumonia the short term risk of dying increased. Age and comorbidity were the most important risk factors for pneumonia and UTI. Individual initiatives to reduce the risk of especially pneumonia in selected patient groups can be essential in the effort to optimize the outcome after THA.
University clinic of hand, hip and knee surgery, Department of Orthopedic Surgery, Regional Hospital West Jutland; University clinic of hand, hip and knee surgery, Department of Orthopedic Surgery, Regional Hospital West Jutland; Department of Clinical Epidemiology, Aarhus University Hospital
Background: Pneumonia and urinary tract infection (UTI) are common infections causing increased morbidity and mortality. Both infections are standard complications after total hip arthroplasty (THA).
Purpose / Aim of Study: We examined the risk of postoperative pneumonia and UTI after THA and the impact on survival.
Materials and Methods: We used the Danish Hip Arthroplasty Register to identify THAs due to OA from 2000 to 2013. From administrative databases we collected data about comorbidity, mortality and infections in relation to the primary hospitalization and potential predictive variables. Regression models were used to estimate associations between potential risk factors and infections and between infections and 90-day mortality. The latter presented as relative risk (RR) with 95% confidence intervals (CI).
Findings / Results: In total 84,812 THAs were included. The risk of pneumonia and UTI within 30 days of the primary procedure were 0.47 (CI 0.42 – 0.52) and 0.56 (CI 0.51 – 0.61), respectively. Common patient related risk factors for infections were age of 80 years or more and a comorbidity burden at time of surgery. For pneumonia, individual risk factors were male gender, diabetes and CPD. For UTI, female gender was an individual risk factor. For patients with pneumonia, the RR of 90 days mortality was 13.12 (7.94 – 21.68). For patients with UTI, the RR was 1.23 (0.30 – 4.96).
Conclusions: The risks of pneumonia and UTI within 30 days of the primary procedure were low but when experiencing specially pneumonia the short term risk of dying increased. Age and comorbidity were the most important risk factors for pneumonia and UTI. Individual initiatives to reduce the risk of especially pneumonia in selected patient groups can be essential in the effort to optimize the outcome after THA.