Session 13: Hip II
Fredag d. 27. oktober
09:00-10:30
Lokale: Reykjavik
Chairmen: Kjeld Søballe og Claus Varnum
Roshan Latifi, Bjørn Gliese Jakobsen, Henrik Husted, Thomas Kallemose, Anders Troelsen, Kirill Gromov
Orthopaedics, Hvidovre Hospital; Clinical Orthopaedic Research Hvidovre, Hvidovre Hospital; Orthopaedics, Hvidovre Hospital; Clinical Orthopaedic Research Hvidovre, Hvidovre Hospital; Orthopaedics, Hvidovre Hospital; Orthopaedics, Hvidovre Hospital
Background: Acetabular component orientation is a crucial parameter in predicting unfavourable clinical results following primary Total Hip Arthroplasty (THA), such as dislocation or bearing surface wear. Therefor factors, which can potentially influence cup positioning following THA, should be substantially studied.
Purpose / Aim of Study: Study of influence of easily identifiable preoperative radiographic features and demographic parameters on cup malpositioning after primary THA.
Materials and Methods: 1326 consecutive and unselected patients received primary uncemented THA, between 2011 and 2015. Standardized posterolateral approach, by 9 high volume surgeons was used. Sex, age, American Society of Anesthesiologists score (ASA), BMI, Tönnis score, Lateral Center Edge angle (LCE) and Anterior Center edge angle (ACE) were registered. Postoperative features such as abduction and version of the cup recorded. Logistic regression models were used to analyse probability of cup malpositioning.
Findings / Results: There was not any significant higher risk of cup malpositioning in patients with BMI over 30 when compared with patients with lower BMI (Odds Ratio: 0.89, 0.67-1.20, P-value: 0.45). Patients with preoperative severe osteoarthritis did not have a higher risk of postoperative cup malpositioning (Odds Ratio: 1.10, 0.80-1.49,P-value: 0.56). Neither ACE between 30 and 50 degrees (OR: 0.76, 0.55-1.05, p: 0.09) nor ACE > 50 (OR: 0.70, 0.46-1.05, P: 0.08) pose a special risk to cup malpositioning.
Conclusions: Neither BMI nor preoperative anatomical status seems to be a predictive preoperative factor for malpositioning of the cup after primary THA.This could be explained by the posterolateral approach, which allows the surgeon excellent visibility or the experience of high volume surgeons might play a role.
Orthopaedics, Hvidovre Hospital; Clinical Orthopaedic Research Hvidovre, Hvidovre Hospital; Orthopaedics, Hvidovre Hospital; Clinical Orthopaedic Research Hvidovre, Hvidovre Hospital; Orthopaedics, Hvidovre Hospital; Orthopaedics, Hvidovre Hospital
Background: Acetabular component orientation is a crucial parameter in predicting unfavourable clinical results following primary Total Hip Arthroplasty (THA), such as dislocation or bearing surface wear. Therefor factors, which can potentially influence cup positioning following THA, should be substantially studied.
Purpose / Aim of Study: Study of influence of easily identifiable preoperative radiographic features and demographic parameters on cup malpositioning after primary THA.
Materials and Methods: 1326 consecutive and unselected patients received primary uncemented THA, between 2011 and 2015. Standardized posterolateral approach, by 9 high volume surgeons was used. Sex, age, American Society of Anesthesiologists score (ASA), BMI, Tönnis score, Lateral Center Edge angle (LCE) and Anterior Center edge angle (ACE) were registered. Postoperative features such as abduction and version of the cup recorded. Logistic regression models were used to analyse probability of cup malpositioning.
Findings / Results: There was not any significant higher risk of cup malpositioning in patients with BMI over 30 when compared with patients with lower BMI (Odds Ratio: 0.89, 0.67-1.20, P-value: 0.45). Patients with preoperative severe osteoarthritis did not have a higher risk of postoperative cup malpositioning (Odds Ratio: 1.10, 0.80-1.49,P-value: 0.56). Neither ACE between 30 and 50 degrees (OR: 0.76, 0.55-1.05, p: 0.09) nor ACE > 50 (OR: 0.70, 0.46-1.05, P: 0.08) pose a special risk to cup malpositioning.
Conclusions: Neither BMI nor preoperative anatomical status seems to be a predictive preoperative factor for malpositioning of the cup after primary THA.This could be explained by the posterolateral approach, which allows the surgeon excellent visibility or the experience of high volume surgeons might play a role.
Alexander Dastrup, Anton Pottegård, Søren Overgaard, Jesper Hallas
Department of Orthopaedic Surgery, Odense University Hospital; Clinical Pharmacology and Pharmacy, University of Southern Denmark; Department of Orthopaedic Surgery, Odense University Hospital; Clinical Pharmacology and Pharmacy, University of Southern Denmark
Background: Statins may reduce the risk of postsurgical cardiovascular complications following non-vascular surgery.
Purpose / Aim of Study: To determine whether short-term preoperative statin treatment was associated with a reduced risk of cardiovascular events after total hip arthroplasty (THA).
Materials and Methods: Using the Danish Hip Arthroplasty Register, the Danish National Patient Register and the Danish National Database of Prescriptions we included 60073 primary THA patients without a history of statin use. Of these 2227 were prescribed statins during the 365 days before their primary THA. 1:4 Propensity score matching new users to non- users of statins on age, gender, year of surgery, known risk factors for cardiovascular disease, the Elixhauser Comorbidity Index and income resulted in a final cohort of 1674 and 6696 individuals. The primary outcome was venous thromboembolism (VTE). Secondary outcomes were deep venous thrombosis (DVT), pulmonary embolism (PE), myocardial infarction (MI), ischemic stroke and all-cause mortality. Cox regression survival analysis was used to calculate hazard ratios (HR) and 95% confidence intervals (CI).
Findings / Results: We found no statistically significant effect on VTE (HR = 1.0; 95% CI, 0.50-1.9), DVT (HR = 1.1; 95% CI, 0.6-2.3), PE (HR = 0.7; 95% CI, 0.1-3.0), MI (HR = 1.2; 95% CI, 0.5-3.0), ischemic stroke (HR = 1.0; 95% CI, 0.2-4.7) or all-cause mortality (HR = 0.3; 95% CI, 0.1-1.1).
Conclusions: Short term statin use before primary THA is not associated with a reduced risk of VTE, DVT, PE, ischemic stroke, MI or death from all causes.
Department of Orthopaedic Surgery, Odense University Hospital; Clinical Pharmacology and Pharmacy, University of Southern Denmark; Department of Orthopaedic Surgery, Odense University Hospital; Clinical Pharmacology and Pharmacy, University of Southern Denmark
Background: Statins may reduce the risk of postsurgical cardiovascular complications following non-vascular surgery.
Purpose / Aim of Study: To determine whether short-term preoperative statin treatment was associated with a reduced risk of cardiovascular events after total hip arthroplasty (THA).
Materials and Methods: Using the Danish Hip Arthroplasty Register, the Danish National Patient Register and the Danish National Database of Prescriptions we included 60073 primary THA patients without a history of statin use. Of these 2227 were prescribed statins during the 365 days before their primary THA. 1:4 Propensity score matching new users to non- users of statins on age, gender, year of surgery, known risk factors for cardiovascular disease, the Elixhauser Comorbidity Index and income resulted in a final cohort of 1674 and 6696 individuals. The primary outcome was venous thromboembolism (VTE). Secondary outcomes were deep venous thrombosis (DVT), pulmonary embolism (PE), myocardial infarction (MI), ischemic stroke and all-cause mortality. Cox regression survival analysis was used to calculate hazard ratios (HR) and 95% confidence intervals (CI).
Findings / Results: We found no statistically significant effect on VTE (HR = 1.0; 95% CI, 0.50-1.9), DVT (HR = 1.1; 95% CI, 0.6-2.3), PE (HR = 0.7; 95% CI, 0.1-3.0), MI (HR = 1.2; 95% CI, 0.5-3.0), ischemic stroke (HR = 1.0; 95% CI, 0.2-4.7) or all-cause mortality (HR = 0.3; 95% CI, 0.1-1.1).
Conclusions: Short term statin use before primary THA is not associated with a reduced risk of VTE, DVT, PE, ischemic stroke, MI or death from all causes.
Claus Varnum, Per Hviid Gundtoft, Lasse Enkebølle Rasmussen, Per Kjærsgaard-Andersen
Department of Orthopaedic Surgery, Vejle Hospital; Department of Orthopaedic Surgery, Klding Hospital; Department of Orthopaedic Surgery, Vejle Hospital; Department of Orthopaedic Surgery, Vejle Hospital
Background: In 2010, the cementless Echo Bimetric hip stem was introduced in Denmark. This stem was a redesigned version of the cementless Bimetric stem with a smooth, tapered stem tip; distal extension of the circumferential porous plasma splay; and 2 metaphyseal geometeric options.
Purpose / Aim of Study: We aimed to compare the 5-years revision risk of the total hip arthroplasty (THA) in patients operated with the cementless Echo Bimetric stem and its predecessor, the Bimetric stem.
Materials and Methods: Based on data from the Danish Hip Arthroplasty Register, all cementless THAs with the cementless Echo Bimetric or Bimetric stem were identified. Patients were followed until revision, death, emigration, or end of study period (May 1, 2017). We performed regression with the pseudo-value approach with death as a competing risk to estimate the relative risk (RR) of any revision with 95% confidence intervals at 5–years follow-up, and adjustments were made for sex, age, primary diagnosis femoral head size, and duration of surgery.
Findings / Results: A total of 28,223 cementless THAs were identified: 2,307 (8%) had the Echo Bimetric stem and 25,916 (92%) the Bimetric stem. The mean follow-up was 2.8 (2.7-2.9) for Echo Bimetric and 7.1 (7.1-7.2) years for Bimetric. At 5-years, the cumulative incidence for any revision was 4.4% (3.1-6.3) for Echo Bimetric and 4.8% (4.6-5.1) for Bimetric. The adjusted RR for any revision of the Echo Bimetric stem was 0.92 (0.75-1.13) compared to the Bimetric stem. Also the adjusted RR for revision due to aseptic loosening of the stem was similar in the two groups (p=0.96).
Conclusions: There was no difference in revision risk between the Echo Bimetric and the Bimetric stem in THA in this study period. Whether the Echo Bimetric stem is superior to the Bimetric stem on the longer term remains to be established.
Department of Orthopaedic Surgery, Vejle Hospital; Department of Orthopaedic Surgery, Klding Hospital; Department of Orthopaedic Surgery, Vejle Hospital; Department of Orthopaedic Surgery, Vejle Hospital
Background: In 2010, the cementless Echo Bimetric hip stem was introduced in Denmark. This stem was a redesigned version of the cementless Bimetric stem with a smooth, tapered stem tip; distal extension of the circumferential porous plasma splay; and 2 metaphyseal geometeric options.
Purpose / Aim of Study: We aimed to compare the 5-years revision risk of the total hip arthroplasty (THA) in patients operated with the cementless Echo Bimetric stem and its predecessor, the Bimetric stem.
Materials and Methods: Based on data from the Danish Hip Arthroplasty Register, all cementless THAs with the cementless Echo Bimetric or Bimetric stem were identified. Patients were followed until revision, death, emigration, or end of study period (May 1, 2017). We performed regression with the pseudo-value approach with death as a competing risk to estimate the relative risk (RR) of any revision with 95% confidence intervals at 5–years follow-up, and adjustments were made for sex, age, primary diagnosis femoral head size, and duration of surgery.
Findings / Results: A total of 28,223 cementless THAs were identified: 2,307 (8%) had the Echo Bimetric stem and 25,916 (92%) the Bimetric stem. The mean follow-up was 2.8 (2.7-2.9) for Echo Bimetric and 7.1 (7.1-7.2) years for Bimetric. At 5-years, the cumulative incidence for any revision was 4.4% (3.1-6.3) for Echo Bimetric and 4.8% (4.6-5.1) for Bimetric. The adjusted RR for any revision of the Echo Bimetric stem was 0.92 (0.75-1.13) compared to the Bimetric stem. Also the adjusted RR for revision due to aseptic loosening of the stem was similar in the two groups (p=0.96).
Conclusions: There was no difference in revision risk between the Echo Bimetric and the Bimetric stem in THA in this study period. Whether the Echo Bimetric stem is superior to the Bimetric stem on the longer term remains to be established.
Graversen Anders Elneff, Varnum Claus, Pedersen Alma Becic, Overgaard Søren
Dept. of Orthopaedic Surgery and Traumatology, Odense University Hospital ; Dept. of Orthopaedic Surgery, Vejle Hospital; Department of Clinical Epidemiology, Aarhus University Hospital; Dept. of Orthopaedic Surgery and Traumatology & Department of Clinical Research, Odense University Hospital & University of Southern Denmark
Background: The percentage of patients who received cemented total hip arthroplasty (THA) in Denmark decreased by 60 % from 1995 to 2015. This could affect the outcome of cemented THA due to less experience with the cementing technique.
Purpose / Aim of Study: We aimed to compare the revision risk of cemented THA operated in 4 different time periods from 1995 to 2015 in order to explore time trends in revision risk.
Materials and Methods: All cemented THA registered in the DHR (n=44,254) were included. Dual mobility cups (n=1,731), cancers (n=535), and missing data on confounders (n=61) were excluded. We defined 4 time periods: 1995-1999 (Period 1=reference), 2000-2004 (Period 2), 2005-2009 (Period 3), and 2010-2015 (Period 4). Using regression with the pseudo-value approach with death as a competing risk we estimated the relative risk (RR) of any revision with 95% confidence intervals at 3-months and 6–years follow-up. RRs were adjusted for sex, age, primary diagnosis, femoral head size, and duration of surgery.
Findings / Results: We included 14,366 (34%), 12,210 (29%), 9,442 (22%), and 5,925 (14%) THAs in Periods 1-4, respectively. The cumulative incidences of any revision at 6-years follow-up were 3.5% (3.2-3.8), 2.9% (2.7-3.3), 3.7% (3.3-4.1), and 4.3% (3.8-5.0) for Periods 1-4, respectively. At 3-months follow-up, the adjusted RRs of any revision were 1.67 (1.03- 2.72); 2.80 (1.67-4.69); and 4.36 (1.87-10.2) for Periods 2-4 compared to Period 1. At 6-years follow- up, the adjusted RRs were 0.89 (0.76-1.04) for Period 2; 1.20 (1.02-1.42) for Period 3; and 1.53 (1.18-2.01) for Period 4.d 4.
Conclusions: The RR for any revision was increased for the recent time periods in the immediate postoperative phase and decreased for Periods 2-4 with longer follow-up. The findings may be a result of less experience with cemented THA and possible unmeasured confounding.
Dept. of Orthopaedic Surgery and Traumatology, Odense University Hospital ; Dept. of Orthopaedic Surgery, Vejle Hospital; Department of Clinical Epidemiology, Aarhus University Hospital; Dept. of Orthopaedic Surgery and Traumatology & Department of Clinical Research, Odense University Hospital & University of Southern Denmark
Background: The percentage of patients who received cemented total hip arthroplasty (THA) in Denmark decreased by 60 % from 1995 to 2015. This could affect the outcome of cemented THA due to less experience with the cementing technique.
Purpose / Aim of Study: We aimed to compare the revision risk of cemented THA operated in 4 different time periods from 1995 to 2015 in order to explore time trends in revision risk.
Materials and Methods: All cemented THA registered in the DHR (n=44,254) were included. Dual mobility cups (n=1,731), cancers (n=535), and missing data on confounders (n=61) were excluded. We defined 4 time periods: 1995-1999 (Period 1=reference), 2000-2004 (Period 2), 2005-2009 (Period 3), and 2010-2015 (Period 4). Using regression with the pseudo-value approach with death as a competing risk we estimated the relative risk (RR) of any revision with 95% confidence intervals at 3-months and 6–years follow-up. RRs were adjusted for sex, age, primary diagnosis, femoral head size, and duration of surgery.
Findings / Results: We included 14,366 (34%), 12,210 (29%), 9,442 (22%), and 5,925 (14%) THAs in Periods 1-4, respectively. The cumulative incidences of any revision at 6-years follow-up were 3.5% (3.2-3.8), 2.9% (2.7-3.3), 3.7% (3.3-4.1), and 4.3% (3.8-5.0) for Periods 1-4, respectively. At 3-months follow-up, the adjusted RRs of any revision were 1.67 (1.03- 2.72); 2.80 (1.67-4.69); and 4.36 (1.87-10.2) for Periods 2-4 compared to Period 1. At 6-years follow- up, the adjusted RRs were 0.89 (0.76-1.04) for Period 2; 1.20 (1.02-1.42) for Period 3; and 1.53 (1.18-2.01) for Period 4.d 4.
Conclusions: The RR for any revision was increased for the recent time periods in the immediate postoperative phase and decreased for Periods 2-4 with longer follow-up. The findings may be a result of less experience with cemented THA and possible unmeasured confounding.
Jeppe Lange
CORIHA RESEARCH GROUP,Lundbeck Foundation center for fast-track hip and knee surgery.
Background: Cementless one-stage revision in chronic periprosthetic hip joint infections has been limited evaluated.
Purpose / Aim of Study: The purpose of this study was to evaluate a specific treatment protocol (CORIHA protocol) in this patient group in regards to re-infection, mortality, revisions for other causes than PJI and to perform failure analysis in the cases of re-infection.
Materials and Methods: The study was performed as a multicentre, proof- of-concept, observational study with prospective data collection. Patients included were treated with a cementless one-stage revision according to an a priori defined treatment algorithm at 8 participating departments of orthopaedic surgery between 2009 -2014 and enrolled in a 2-year follow-up program. 10 surgeons performed the procedures with no correlation between surgeon and final outcome. 56 patients were included. All patients had a minimum of 2 years follow-up with a mean follow-up time from the procedure of 4 years.
Findings / Results: The cumulative incidence of re-revision due to infection was 8.9% (CI 3.2%-18.1%). The 1 and 5 year survival incidence was 96% (CI 86%-99%) and 89% (CI 75%-95%). Three patients had an aseptic revision performed: two patients suffered post-operative periprosthetic fractures managed with a relevant osteosynthesis and one patient had stem subsidence with exchange performed, none resulted in re-infection. Failure analysis of the 5 re-infections did not detect a clear pattern as to the cause of failure.
Conclusions: We found that cementless one-stage revision in chronic periprosthetic hip joint infections has low re- reinfection rates in selected patients and is readily comparable to published success rates following a two-stage revision. Cementless one-stage revision in chronic periprosthetic hip joint infections can be used as a valuable first-line treatment strategy.
CORIHA RESEARCH GROUP,Lundbeck Foundation center for fast-track hip and knee surgery.
Background: Cementless one-stage revision in chronic periprosthetic hip joint infections has been limited evaluated.
Purpose / Aim of Study: The purpose of this study was to evaluate a specific treatment protocol (CORIHA protocol) in this patient group in regards to re-infection, mortality, revisions for other causes than PJI and to perform failure analysis in the cases of re-infection.
Materials and Methods: The study was performed as a multicentre, proof- of-concept, observational study with prospective data collection. Patients included were treated with a cementless one-stage revision according to an a priori defined treatment algorithm at 8 participating departments of orthopaedic surgery between 2009 -2014 and enrolled in a 2-year follow-up program. 10 surgeons performed the procedures with no correlation between surgeon and final outcome. 56 patients were included. All patients had a minimum of 2 years follow-up with a mean follow-up time from the procedure of 4 years.
Findings / Results: The cumulative incidence of re-revision due to infection was 8.9% (CI 3.2%-18.1%). The 1 and 5 year survival incidence was 96% (CI 86%-99%) and 89% (CI 75%-95%). Three patients had an aseptic revision performed: two patients suffered post-operative periprosthetic fractures managed with a relevant osteosynthesis and one patient had stem subsidence with exchange performed, none resulted in re-infection. Failure analysis of the 5 re-infections did not detect a clear pattern as to the cause of failure.
Conclusions: We found that cementless one-stage revision in chronic periprosthetic hip joint infections has low re- reinfection rates in selected patients and is readily comparable to published success rates following a two-stage revision. Cementless one-stage revision in chronic periprosthetic hip joint infections can be used as a valuable first-line treatment strategy.
Birgitte Bramming, Signe Kierkegaard, Bent Lund , Stig S. Jakobsen, Inger Mechlenburg
Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark; Department of Orthopaedic Surgery, Horsens Regional Hospital; Department of Orthopaedic Surgery, Horsens Regional Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital
Background: The forgotten joint score-12 (FJS-12) may be an advantageous questionnaire in young patients with high hip function and a low level of pain.
Purpose / Aim of Study: We investigated the reliability and the responsiveness of the FJS-12 in patients with femoroacetabular impingement (FAI) undergoing hip arthroscopic treatment.
Materials and Methods: 50 patients were included in the reliability study and 34 patients were included in the responsiveness study. Test-retest reliability was assessed with intra class correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC). Responsiveness was assessed from testing correlations between the FJS-12 and the Copenhagen Hip and Groin Outcome Score (HAGOS) of the change score, effect size (ES) and standardized response mean (SRM). Floor and ceiling effect was defined as present if the amount of patients obtaining the maximum (100) and minimum score (0) exceeded 15%.
Findings / Results: The relative reliability was high (ICC = 0.9, 95% CI: 0.8-0.9) and the absolute reliability was low (SEM = 11, MDCindividual = 32, MDCgroup = 4.5). The responsiveness was high and the change score was highly correlated with the subscale “pain” from the HAGOS and moderately correlated with the subscale “ADL”. Furthermore, the FJS-12 exceeded or equalled the HAGOS subscales in ES and SRM. Below 15% of the patients scored the maximum or minimum score.
Conclusions: The FJS-12 has high reliability, high responsiveness to change and shows no floor or ceiling effect.
Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark; Department of Orthopaedic Surgery, Horsens Regional Hospital; Department of Orthopaedic Surgery, Horsens Regional Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital
Background: The forgotten joint score-12 (FJS-12) may be an advantageous questionnaire in young patients with high hip function and a low level of pain.
Purpose / Aim of Study: We investigated the reliability and the responsiveness of the FJS-12 in patients with femoroacetabular impingement (FAI) undergoing hip arthroscopic treatment.
Materials and Methods: 50 patients were included in the reliability study and 34 patients were included in the responsiveness study. Test-retest reliability was assessed with intra class correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC). Responsiveness was assessed from testing correlations between the FJS-12 and the Copenhagen Hip and Groin Outcome Score (HAGOS) of the change score, effect size (ES) and standardized response mean (SRM). Floor and ceiling effect was defined as present if the amount of patients obtaining the maximum (100) and minimum score (0) exceeded 15%.
Findings / Results: The relative reliability was high (ICC = 0.9, 95% CI: 0.8-0.9) and the absolute reliability was low (SEM = 11, MDCindividual = 32, MDCgroup = 4.5). The responsiveness was high and the change score was highly correlated with the subscale “pain” from the HAGOS and moderately correlated with the subscale “ADL”. Furthermore, the FJS-12 exceeded or equalled the HAGOS subscales in ES and SRM. Below 15% of the patients scored the maximum or minimum score.
Conclusions: The FJS-12 has high reliability, high responsiveness to change and shows no floor or ceiling effect.
Maartje Belt, Omar Muharemovic, Bjørn Gliese, Hendrik Husted, Kirill Gromov, Anders Troelsen
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; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre
Background: Progressive radiolucency is often used as a measure of the performance of the cup and bearing surface in total hip arthroplasty (THA). Traditionally, radiolucency is assessed on plain x-rays, but CT scans can accurately assess gaps around the acetabular component. However, it is time consuming. Therefore, a faster measurement protocol was developed to measure total gap dimensions on postoperative CT scans.
Purpose / Aim of Study: The aim was to validate the measurement protocol in terms of accuracy, and intra- and inter-observer variability.
Materials and Methods: Patients (N=41) receiving a primary cementless THA between July 2015 and March 2016 at one hospital that were enrolled in a RCT were included in this study. Post-operative CT scans were analyzed for gaps around the acetabular cup. The protocol is a manual segmentation in axial view at 0%, 12.5%, 25%, 37.5%, 50%, 67.5%, 75%, 87.5%, and 100% of the gap. The slices in between were interpolated by the software. Two observers individually measured the gap volume, and it was compared to full segmentation.
Findings / Results: In 95% of the subjects a gap was found, volume ranging from 0.18 to 7.33 ml (median 2.05 ml). The ICC for intra-observer variability was 0.988 and 0.997. The inter-observer ICC was 0.962. Using linear mixed model, a difference of 0.42 ml (p=0.017) was observed in gap volume between the observers. There was no statistically significant difference observed in volume between the protocol and assessment by full segmentation.
Conclusions: The measurement method is accurate in assessing the gap volume when compared to full segmentation of CT scans. The intra-observer variability is good, and the inter-observer variability is within the levels of expected precision. As bearing surfaces improve and the osteolytic potential decreases, assessment of gaps by CT-scan is a useful tool.
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; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre
Background: Progressive radiolucency is often used as a measure of the performance of the cup and bearing surface in total hip arthroplasty (THA). Traditionally, radiolucency is assessed on plain x-rays, but CT scans can accurately assess gaps around the acetabular component. However, it is time consuming. Therefore, a faster measurement protocol was developed to measure total gap dimensions on postoperative CT scans.
Purpose / Aim of Study: The aim was to validate the measurement protocol in terms of accuracy, and intra- and inter-observer variability.
Materials and Methods: Patients (N=41) receiving a primary cementless THA between July 2015 and March 2016 at one hospital that were enrolled in a RCT were included in this study. Post-operative CT scans were analyzed for gaps around the acetabular cup. The protocol is a manual segmentation in axial view at 0%, 12.5%, 25%, 37.5%, 50%, 67.5%, 75%, 87.5%, and 100% of the gap. The slices in between were interpolated by the software. Two observers individually measured the gap volume, and it was compared to full segmentation.
Findings / Results: In 95% of the subjects a gap was found, volume ranging from 0.18 to 7.33 ml (median 2.05 ml). The ICC for intra-observer variability was 0.988 and 0.997. The inter-observer ICC was 0.962. Using linear mixed model, a difference of 0.42 ml (p=0.017) was observed in gap volume between the observers. There was no statistically significant difference observed in volume between the protocol and assessment by full segmentation.
Conclusions: The measurement method is accurate in assessing the gap volume when compared to full segmentation of CT scans. The intra-observer variability is good, and the inter-observer variability is within the levels of expected precision. As bearing surfaces improve and the osteolytic potential decreases, assessment of gaps by CT-scan is a useful tool.
Dana Li, Anders Troelsen, Lina Ingelsrud , Henrik Husted, Kirill Gromov
Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital
Background: The Forgotten Joint Score (FJS) is a measurement for patients’ awareness of their joint in daily life. Identifying factors that can explain preoperative FJS levels, can potentially help the clinician to better prioritize patients for THA (Total Hip Arthroplasty).
Purpose / Aim of Study: The purpose of this study was to identify possible factors that explain the variance of preoperative FJS levels and evaluate the relationship between preoperative FJS and other preoperative Patient Reported Outcome Measures (PROMs) such as Oxford Hip Score (OHS), Harris Hip Score (HHS), EQ-5D and EQ-VAS.
Materials and Methods: Four-hundred and fourty-four hips with completed preoperative PROMs and radiographs undergoing primary unilateral Total Hip Arthroplasty (THA) between December 2014 and June 2016 were included in the study. Age, gender, Body Mass Index (BMI), FJS, OHS, HHS, EQ-5D, EQ-VAS were obtained prior to surgery. Tönnis osteoarthritis grade and joint space width were evaluated on preoperative radiographs. A multiple regression analysis was performed to identify factors that could explain the variance of preoperative FJS and simple linear regressions were performed to predict preoperative FJS from other preoperative PROMs.
Findings / Results: Females and patients with high BMI had the lowest preoperative FJS (p < 0.005). Preoperative FJS was best predicted by OHS (R^2=49.3) followed by HHS (R^2=40.3), EQ-5D (R^2=22.7) and lastly by EQ-VAS (R^2=7.9)(p < 0.005).
Conclusions: Women and patients with high BMI had the lowest preoperative forgotten hip joint score and were hence more aware of their hip. FJS had the best correlation to OHS followed by HHS and had the worst correlation to EQ-VAS. This information may be used for improved patient selection.
Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital; Department of orthopedic surgery, Hvidovre hospital
Background: The Forgotten Joint Score (FJS) is a measurement for patients’ awareness of their joint in daily life. Identifying factors that can explain preoperative FJS levels, can potentially help the clinician to better prioritize patients for THA (Total Hip Arthroplasty).
Purpose / Aim of Study: The purpose of this study was to identify possible factors that explain the variance of preoperative FJS levels and evaluate the relationship between preoperative FJS and other preoperative Patient Reported Outcome Measures (PROMs) such as Oxford Hip Score (OHS), Harris Hip Score (HHS), EQ-5D and EQ-VAS.
Materials and Methods: Four-hundred and fourty-four hips with completed preoperative PROMs and radiographs undergoing primary unilateral Total Hip Arthroplasty (THA) between December 2014 and June 2016 were included in the study. Age, gender, Body Mass Index (BMI), FJS, OHS, HHS, EQ-5D, EQ-VAS were obtained prior to surgery. Tönnis osteoarthritis grade and joint space width were evaluated on preoperative radiographs. A multiple regression analysis was performed to identify factors that could explain the variance of preoperative FJS and simple linear regressions were performed to predict preoperative FJS from other preoperative PROMs.
Findings / Results: Females and patients with high BMI had the lowest preoperative FJS (p < 0.005). Preoperative FJS was best predicted by OHS (R^2=49.3) followed by HHS (R^2=40.3), EQ-5D (R^2=22.7) and lastly by EQ-VAS (R^2=7.9)(p < 0.005).
Conclusions: Women and patients with high BMI had the lowest preoperative forgotten hip joint score and were hence more aware of their hip. FJS had the best correlation to OHS followed by HHS and had the worst correlation to EQ-VAS. This information may be used for improved patient selection.
Julie Sandell Jacobsen, Per Hölmich, Kristian Thorborg, Bolvig Lars, Stig Storgaard Jakobsen, Kjeld Soballe, Inger Mechlenburg
Department of Physiotherapy, Faculty of Health Sciences, VIA University College Aarhus; Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital, Amager and Hvidovre; Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital, Amager and Hvidovre; Department of Radiology, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Centre of Research in Rehabilitation (CORIR), Institute of Clinical Medicine, Aarhus University
Background: Intra-articular injury has been described as primary cause of pain in hip dysplasia. At this point, it is unknown whether external muscle-tendon related pain coexists with intra-articular pathology.
Purpose / Aim of Study: The primary aim was to identify muscle- tendon related pain in 100 patients with hip dysplasia. The secondary aim was to test if muscle-tendon related pain is linearly associated to self-reported hip disability and muscle strength in patients with hip dysplasia.
Materials and Methods: One hundred patients (17 men) with a mean age of 29 +/-9 years were included. Clinical entity approach was carried out to identify muscle-tendon related pain. Muscle strength was assessed with a handheld dynamometer and self-reported hip disability was recorded with the Copenhagen Hip and Groin Outcome Score (HAGOS).
Findings / Results: Iliopsoas- and abductor-related pain were frequently identified with prevalences of 56% (CI 46; 66) and 42% (CI 32; 52), respectively. Adductor-, hamstrings- and rectus abdominis-related pain were less common. There was a significant inverse linear association between muscle- tendon related pain and self-reported hip disability ranging from -3.35 to -7.51 points in the adjusted analysis (p<0.05). Likewise an inverse linear association between muscle-tendon related pain and muscle strength was found ranging from -0.11 Nm/kg to -0.12 Nm/kg in the adjusted analysis (p<0.05).
Conclusions: Muscle-tendon related pain seems to exist in about half of patients with hip dysplasia with a high prevalence of muscle-tendon related pain in the iliopsoas and the hip abductors and affects patients’ self-reported hip disability and muscle strength negatively.
Department of Physiotherapy, Faculty of Health Sciences, VIA University College Aarhus; Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital, Amager and Hvidovre; Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital, Amager and Hvidovre; Department of Radiology, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Centre of Research in Rehabilitation (CORIR), Institute of Clinical Medicine, Aarhus University
Background: Intra-articular injury has been described as primary cause of pain in hip dysplasia. At this point, it is unknown whether external muscle-tendon related pain coexists with intra-articular pathology.
Purpose / Aim of Study: The primary aim was to identify muscle- tendon related pain in 100 patients with hip dysplasia. The secondary aim was to test if muscle-tendon related pain is linearly associated to self-reported hip disability and muscle strength in patients with hip dysplasia.
Materials and Methods: One hundred patients (17 men) with a mean age of 29 +/-9 years were included. Clinical entity approach was carried out to identify muscle-tendon related pain. Muscle strength was assessed with a handheld dynamometer and self-reported hip disability was recorded with the Copenhagen Hip and Groin Outcome Score (HAGOS).
Findings / Results: Iliopsoas- and abductor-related pain were frequently identified with prevalences of 56% (CI 46; 66) and 42% (CI 32; 52), respectively. Adductor-, hamstrings- and rectus abdominis-related pain were less common. There was a significant inverse linear association between muscle- tendon related pain and self-reported hip disability ranging from -3.35 to -7.51 points in the adjusted analysis (p<0.05). Likewise an inverse linear association between muscle-tendon related pain and muscle strength was found ranging from -0.11 Nm/kg to -0.12 Nm/kg in the adjusted analysis (p<0.05).
Conclusions: Muscle-tendon related pain seems to exist in about half of patients with hip dysplasia with a high prevalence of muscle-tendon related pain in the iliopsoas and the hip abductors and affects patients’ self-reported hip disability and muscle strength negatively.
Maartje Belt, Bjørn Gliese, Omar Muharemovic, Hendrik Husted, Anders Troelsen, 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; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre
Background: In clinical settings, implant performance of cementless THA is often evaluated by radiolucency on plain X-rays. Radiolucency on direct post- operative radiographs is often classified as interference gaps. Studies use different criteria to define a gap. However, the diagnostic performance of plain radiographs and the optimal definition for gaps is unknown.
Purpose / Aim of Study: The aim was to evaluate the diagnostic performance of radiographic assessment of post-operative interference gaps after primary THA by comparing it with CT confirmed gaps. The secondary aim was to define optimal cut-off criteria for assessing interference gaps on plain radiographs.
Materials and Methods: Patients (N=40) with a primary cementless THA performed between July 2015 and March 2016 were enrolled in the study. Acetabular radiolucency was assessed on post-operative AP pelvic digital radiographic images by two observers independently. The maximum width and percentage of coverage in the three Delee and Charnley zones were reported. Gap volume was measured by manual segmentation on CT images.
Findings / Results: 95% of patients had a gap on CT. When defining a gap as a lucency >50% of a zone, the interrater agreement was 0.241. Sensitivity was 65.8% for observer 1 (Kappa= 0.432), and 86.8% for observer 2 (Kappa=0.383). When defining a gap as a lucency with a width >1mm, the interrater agreement was 0.302. The sensitivity was 55.3% (kappa=0.452) and 50% (kappa=0.95) for observer 1 and observer 2. The ROC-curve resulted in an optimal threshold of 0.65mm (AUROC=0.888) and 0.31 mm (AUROC=0.961) for the two observers.
Conclusions: The diagnostic performance of plain radiographs to detect interference gaps is not optimal. Evaluating progression of radiolucency on radiographs should be performed in the light of these findings.
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; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre; Dept. of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre
Background: In clinical settings, implant performance of cementless THA is often evaluated by radiolucency on plain X-rays. Radiolucency on direct post- operative radiographs is often classified as interference gaps. Studies use different criteria to define a gap. However, the diagnostic performance of plain radiographs and the optimal definition for gaps is unknown.
Purpose / Aim of Study: The aim was to evaluate the diagnostic performance of radiographic assessment of post-operative interference gaps after primary THA by comparing it with CT confirmed gaps. The secondary aim was to define optimal cut-off criteria for assessing interference gaps on plain radiographs.
Materials and Methods: Patients (N=40) with a primary cementless THA performed between July 2015 and March 2016 were enrolled in the study. Acetabular radiolucency was assessed on post-operative AP pelvic digital radiographic images by two observers independently. The maximum width and percentage of coverage in the three Delee and Charnley zones were reported. Gap volume was measured by manual segmentation on CT images.
Findings / Results: 95% of patients had a gap on CT. When defining a gap as a lucency >50% of a zone, the interrater agreement was 0.241. Sensitivity was 65.8% for observer 1 (Kappa= 0.432), and 86.8% for observer 2 (Kappa=0.383). When defining a gap as a lucency with a width >1mm, the interrater agreement was 0.302. The sensitivity was 55.3% (kappa=0.452) and 50% (kappa=0.95) for observer 1 and observer 2. The ROC-curve resulted in an optimal threshold of 0.65mm (AUROC=0.888) and 0.31 mm (AUROC=0.961) for the two observers.
Conclusions: The diagnostic performance of plain radiographs to detect interference gaps is not optimal. Evaluating progression of radiolucency on radiographs should be performed in the light of these findings.
Eva Natalia Glassou, Alma Becic Pedersen, Peter Kloster Aalund, Torben Bæk Hansen
University clinic of hand, hip and knee surgery, Department of Orthopedic Surgery, Regional Hospital West Jutland; Department of Clinical Epidemiology, Aarhus University Hospital; 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
Background: By reducing pain and improving hip function, a total hip arthroplasty (THA) improves the health related quality of life (HRQol). However, using patient reported outcome measures, approximately 10% of patients report some degree of dissatisfaction after surgery. The pre- operative comorbidity burden may play a role in predicting THA patients with little or no benefit of a THA.
Purpose / Aim of Study: We examined whether the post-operative patient reported HRQol measured with the EQ-5D at 3 and 12 month of follow-up was dependent of the comorbidity burden in THA patients treated due to osteoarthritis.
Materials and Methods: THA patients treated at the Regional Hospital West Jutland from September 2008 to December 2013 formed the basis for the study. Comorbidity burden was measured with the Charlson Comorbidity Index (CCI). Pre- surgery hospital history for all patients was collected using an administrative database. Patients were divided into three groups; no comorbidity burden, low comorbidity burden (CCI 1-2) and a high comorbidity burden (CCI 3+). Patient reported HRQol was measured using the EQ-5D pre-operative and at 3 and 12 month follow-up. Analysis were carried out with multiple linear regressions and adjusted for age and gender.
Findings / Results: In total 1,582 THA patients were included (86%). A positive association between comorbidity burden and HRQoL was found at 3 month follow up for THA patients with a high comorbidity burden (coef: 0.09 (CI: 0.03 – 0.16) compared to patients with no comorbidity burden. After 12 month follow up there was no association between comorbidity burden and HRQoL.
Conclusions: After 3 month, patients with a high comorbidity burden gained the most from a THA. The lack of association after 12 month may be a consequence of the additional comorbid conditions having a stronger impact on the patient reported HRQol.
University clinic of hand, hip and knee surgery, Department of Orthopedic Surgery, Regional Hospital West Jutland; Department of Clinical Epidemiology, Aarhus University Hospital; 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
Background: By reducing pain and improving hip function, a total hip arthroplasty (THA) improves the health related quality of life (HRQol). However, using patient reported outcome measures, approximately 10% of patients report some degree of dissatisfaction after surgery. The pre- operative comorbidity burden may play a role in predicting THA patients with little or no benefit of a THA.
Purpose / Aim of Study: We examined whether the post-operative patient reported HRQol measured with the EQ-5D at 3 and 12 month of follow-up was dependent of the comorbidity burden in THA patients treated due to osteoarthritis.
Materials and Methods: THA patients treated at the Regional Hospital West Jutland from September 2008 to December 2013 formed the basis for the study. Comorbidity burden was measured with the Charlson Comorbidity Index (CCI). Pre- surgery hospital history for all patients was collected using an administrative database. Patients were divided into three groups; no comorbidity burden, low comorbidity burden (CCI 1-2) and a high comorbidity burden (CCI 3+). Patient reported HRQol was measured using the EQ-5D pre-operative and at 3 and 12 month follow-up. Analysis were carried out with multiple linear regressions and adjusted for age and gender.
Findings / Results: In total 1,582 THA patients were included (86%). A positive association between comorbidity burden and HRQoL was found at 3 month follow up for THA patients with a high comorbidity burden (coef: 0.09 (CI: 0.03 – 0.16) compared to patients with no comorbidity burden. After 12 month follow up there was no association between comorbidity burden and HRQoL.
Conclusions: After 3 month, patients with a high comorbidity burden gained the most from a THA. The lack of association after 12 month may be a consequence of the additional comorbid conditions having a stronger impact on the patient reported HRQol.