Session 16: Knee III
Fredag den 26. oktober
13:30 - 15:00
Lokale: Centersal
Chairmen: Anders Odgaard og Kirill Gromov
Anders Overgaard
Parker Institute, Bispebjerg og Frederiksberg hospital
Background: As the number of primary knee arthroplasties, as well as the number of obese patients undergoing total knee arthroplasty (TKA), continues to increase, there has been more interest in the role of obesity as a risk factor for poor outcomes after TKA. In the literature, the influence of obesity on knee arthroplasty outcome diverges. We compared pain, function, quality of life, general health preoperatively and 1 year postoperatively, in patients operated on with TKA for knee OA.
Purpose / Aim of Study: Patient reported outcome (PRO) in total knee arthroplasty (TKA) patients with high body mass index (BMI) is controversial. We compared pain, function, quality of life, general health and satisfaction among different BMI categories preoperatively and 1 year after primary TKA
Materials and Methods: 4,318 patients were operated with a TKA for knee osteoarthritis in the Region of Skane 2013- 2015. 3,327 patients (77%) had complete PRO data and information on BMI and were included. Preoperatively the patients filled in the Knee injury and Osteoarthritis Outcome Score (KOOS) and EQ-VAS (general health). 1 year postoperatively the same questionnaires were filled in together with the question if they were satisfied with the surgery. Information on age, sex, BMI and ASA grade were obtained from the Swedish Knee Arthroplasty Register. Each patient was classified as Outcome Measures in Rheumatology - Osteoarthritis Research Society International (OMERACT-OARSI) responder or not based on a combination of absolute and relative changes in scores. Welch’s t-test and Chi2-test were used in the statistical analysis.
Findings / Results: Both preoperatively and 1 year postoperatively the obese patients reported somewhat worse scores than normal- and over-weighted. The differences were small with 1 exception, the KOOS sport- and recreation function postoperatively where normal- and over-weighted patients reported fewer problems than obese patients with a BMI over 35 (40 and 39 points vs 31 points, p<0.001). Similar proportions of patients were satisfied and categorized as OMERACT-OARSI responders in the different BMI categories.
Conclusions: The degree of improvement in PRO’s 1-year after TKA surgery does not seem to be affected by BMI.
Parker Institute, Bispebjerg og Frederiksberg hospital
Background: As the number of primary knee arthroplasties, as well as the number of obese patients undergoing total knee arthroplasty (TKA), continues to increase, there has been more interest in the role of obesity as a risk factor for poor outcomes after TKA. In the literature, the influence of obesity on knee arthroplasty outcome diverges. We compared pain, function, quality of life, general health preoperatively and 1 year postoperatively, in patients operated on with TKA for knee OA.
Purpose / Aim of Study: Patient reported outcome (PRO) in total knee arthroplasty (TKA) patients with high body mass index (BMI) is controversial. We compared pain, function, quality of life, general health and satisfaction among different BMI categories preoperatively and 1 year after primary TKA
Materials and Methods: 4,318 patients were operated with a TKA for knee osteoarthritis in the Region of Skane 2013- 2015. 3,327 patients (77%) had complete PRO data and information on BMI and were included. Preoperatively the patients filled in the Knee injury and Osteoarthritis Outcome Score (KOOS) and EQ-VAS (general health). 1 year postoperatively the same questionnaires were filled in together with the question if they were satisfied with the surgery. Information on age, sex, BMI and ASA grade were obtained from the Swedish Knee Arthroplasty Register. Each patient was classified as Outcome Measures in Rheumatology - Osteoarthritis Research Society International (OMERACT-OARSI) responder or not based on a combination of absolute and relative changes in scores. Welch’s t-test and Chi2-test were used in the statistical analysis.
Findings / Results: Both preoperatively and 1 year postoperatively the obese patients reported somewhat worse scores than normal- and over-weighted. The differences were small with 1 exception, the KOOS sport- and recreation function postoperatively where normal- and over-weighted patients reported fewer problems than obese patients with a BMI over 35 (40 and 39 points vs 31 points, p<0.001). Similar proportions of patients were satisfied and categorized as OMERACT-OARSI responders in the different BMI categories.
Conclusions: The degree of improvement in PRO’s 1-year after TKA surgery does not seem to be affected by BMI.
Anders Overgaard
Parker Institute, Bispebjerg og Frederiksberg hospital
Background: Obesity is the major risk factors for developing and progression of knee osteoarthritis that may lead to the need for arthroplasty surgery. As obesity among the population increases the number of operations is expected to follow similar patterns. The increasing strain on public healthcare costs from treating late- stage osteoarthritis patients, yields a need for studies on the association between obesity and the need for total joint arthroplasty.
Purpose / Aim of Study: This study aims to quantify the relative risk for total knee arthroplasty in the Swedish population for specific body mass index categories and age intervals to investigate whether the TKA use is attributable to changes in the prevalence of obesity and the growing elder-population.
Materials and Methods: The Swedish Nationwide Health Survey (SNHS) provided BMI data for a representative sample of the Swedish population and the Swedish Knee Arthroplasty Register (SKAR) to calculate Relative Risk (RR) of TKA surgery by age and BMI. Age groups of interest are middle-aged 45- 64 and elderly 65-84 years of age and patients were divided according to BMI categories (BMI 18.5-24.9 normal-weight; BMI 25.0-29.9 over- weight; BMI>30 obese). The RR for TKA surgery was applied to the demographic forecasts for the Swedish population as a forecasting model. We assumed unchanged indications and utilization patterns for TKA among obese and non-obese individuals.
Findings / Results: There was observed increases in population size of 5.1% from 2009 to 2015 (roughly 40.000 middle- aged and 250.000 elderly) and an increase in prevalence of obesity from 16 to 18% in the two age categories. Compared to normal-weight, the RR for TKA was 2.7 higher for over-weight and 7.3 higher for persons classified as obese, aged 45-64. The corresponding figures for individuals aged 65-84 were 2.1 higher and 4.0 higher respectively. Applying the RR to the demographical changes in prevalence of obesity and an increase in the elderly population accounted for an estimated increase of approximately 1300 TKAs.
Conclusions: The increase in the prevalence of obesity and the number of middle-aged and elderly in the population may to some extent explain the rapid increase in TKAs in Sweden over the last seven years.
Parker Institute, Bispebjerg og Frederiksberg hospital
Background: Obesity is the major risk factors for developing and progression of knee osteoarthritis that may lead to the need for arthroplasty surgery. As obesity among the population increases the number of operations is expected to follow similar patterns. The increasing strain on public healthcare costs from treating late- stage osteoarthritis patients, yields a need for studies on the association between obesity and the need for total joint arthroplasty.
Purpose / Aim of Study: This study aims to quantify the relative risk for total knee arthroplasty in the Swedish population for specific body mass index categories and age intervals to investigate whether the TKA use is attributable to changes in the prevalence of obesity and the growing elder-population.
Materials and Methods: The Swedish Nationwide Health Survey (SNHS) provided BMI data for a representative sample of the Swedish population and the Swedish Knee Arthroplasty Register (SKAR) to calculate Relative Risk (RR) of TKA surgery by age and BMI. Age groups of interest are middle-aged 45- 64 and elderly 65-84 years of age and patients were divided according to BMI categories (BMI 18.5-24.9 normal-weight; BMI 25.0-29.9 over- weight; BMI>30 obese). The RR for TKA surgery was applied to the demographic forecasts for the Swedish population as a forecasting model. We assumed unchanged indications and utilization patterns for TKA among obese and non-obese individuals.
Findings / Results: There was observed increases in population size of 5.1% from 2009 to 2015 (roughly 40.000 middle- aged and 250.000 elderly) and an increase in prevalence of obesity from 16 to 18% in the two age categories. Compared to normal-weight, the RR for TKA was 2.7 higher for over-weight and 7.3 higher for persons classified as obese, aged 45-64. The corresponding figures for individuals aged 65-84 were 2.1 higher and 4.0 higher respectively. Applying the RR to the demographical changes in prevalence of obesity and an increase in the elderly population accounted for an estimated increase of approximately 1300 TKAs.
Conclusions: The increase in the prevalence of obesity and the number of middle-aged and elderly in the population may to some extent explain the rapid increase in TKAs in Sweden over the last seven years.
Anne Mørup-Petersen, Sofia Mitropolskaya, Anders Odgaard
Ortopædkirurgisk Afdeling, Herlev og Gentofte Hospital; Ortopædkirurgisk Afdeling, Herlev og Gentofte Hospital; Ortopædkirurgisk Afdeling, Herlev og Gentofte Hospital
Background: Patient-reported outcome measures (PROMs) concern patients’ symptom states either currently or in the preceding e.g. four weeks, as in the case of Oxford Knee Score (OKS). Symptoms recorded retrospectively are generally perceived as less reliable, but, to our knowledge, no studies have reported recall bias in Danish knee arthroplasty patients
Purpose / Aim of Study: We sought to explore how well patients were able to remember their preoperative knee status one year after primary knee arthroplasty (pKA). Also, we aimed to find factors influencing recollection error.
Materials and Methods: 128 pKA patients, who had provided electronic preoperative PROM answers as part of a large prospective cohort study, were contacted by email two weeks after completion of their 1-year follow-up PROM set. An email titled, “Do you remember how your knee was before the operation?” contained OKS (0-48) along with Copenhagen Knee ROM Scale and a question regarding use of analgesics, all in past-time wording.
Findings / Results: 95 patients (74.2%) responded. Recalled OKS was 22.3 [CI: 20.9; 23.6] (SD 6.8, range 7-37), whereas true preoperative OKS was 24.4 [23.1; 25.7] (SD 6.5, range 8-41). The majority of patients (n=58, 61.1%) recalled a score worse than the actual score, and 9 (9.5%) reported the same overall score. The mean recall difference was -2.1 OKS points [-3.2; -1.1] (SD 4.9, range -16 to 10, P<0.001). This was more pronounced in females (insignificant in males) and in patients with high preoperative OKS level (P<0.03), but independent of age and OKS result at 1 year. Knee flexion was 1 score worse (median) at recall (corresponding to 10-20°, P<0.001). Knee extension and frequency of analgesics use did not differ significantly between the two tests.
Conclusions: One year after knee replacement, patients recalled their preoperative knee symptoms worse than originally reported. Though the reported difference in OKS is lower than the smallest possible detectable change (4 points), this should be kept in mind whenever recall OKS is used to replace real-time data.
Ortopædkirurgisk Afdeling, Herlev og Gentofte Hospital; Ortopædkirurgisk Afdeling, Herlev og Gentofte Hospital; Ortopædkirurgisk Afdeling, Herlev og Gentofte Hospital
Background: Patient-reported outcome measures (PROMs) concern patients’ symptom states either currently or in the preceding e.g. four weeks, as in the case of Oxford Knee Score (OKS). Symptoms recorded retrospectively are generally perceived as less reliable, but, to our knowledge, no studies have reported recall bias in Danish knee arthroplasty patients
Purpose / Aim of Study: We sought to explore how well patients were able to remember their preoperative knee status one year after primary knee arthroplasty (pKA). Also, we aimed to find factors influencing recollection error.
Materials and Methods: 128 pKA patients, who had provided electronic preoperative PROM answers as part of a large prospective cohort study, were contacted by email two weeks after completion of their 1-year follow-up PROM set. An email titled, “Do you remember how your knee was before the operation?” contained OKS (0-48) along with Copenhagen Knee ROM Scale and a question regarding use of analgesics, all in past-time wording.
Findings / Results: 95 patients (74.2%) responded. Recalled OKS was 22.3 [CI: 20.9; 23.6] (SD 6.8, range 7-37), whereas true preoperative OKS was 24.4 [23.1; 25.7] (SD 6.5, range 8-41). The majority of patients (n=58, 61.1%) recalled a score worse than the actual score, and 9 (9.5%) reported the same overall score. The mean recall difference was -2.1 OKS points [-3.2; -1.1] (SD 4.9, range -16 to 10, P<0.001). This was more pronounced in females (insignificant in males) and in patients with high preoperative OKS level (P<0.03), but independent of age and OKS result at 1 year. Knee flexion was 1 score worse (median) at recall (corresponding to 10-20°, P<0.001). Knee extension and frequency of analgesics use did not differ significantly between the two tests.
Conclusions: One year after knee replacement, patients recalled their preoperative knee symptoms worse than originally reported. Though the reported difference in OKS is lower than the smallest possible detectable change (4 points), this should be kept in mind whenever recall OKS is used to replace real-time data.
Veronique Vestergaard, Yhan Emid Colon Iban, Vincent P Galea, Christopher Melnic, Hany Bedair, James I 3rd Huddleston, Charles R Bragdon, Henrik Malchau, Anders Troelsen
Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Stanford University; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Clinical Orthopaedic Research Hvidovre, Copenhagen University Hospital Hvidovre
Background: Patient-reported outcome measures i.e. Knee Injury and Osteoarthritis Outcome Score (KOOS) validly measure surgical outcome. Knowing if knee osteoarthritis (OA) compartment patterns affect KOOS is essential for risk-stratification and TKA- outcome evaluation.
Purpose / Aim of Study: Analyze: 1)association between knee OA patterns and patient demographics as well as pre-operative KOOS 2)whether knee OA patterns are associated with post-operative KOOS
Materials and Methods: An international multicenter study included 391 TKA patients (median age:65.0; 65.0% females). Compartment OA in pre-operative anterior- posterior and lateral/sunrise radiographs with Kellgren-Lawrence grade III/IV and joint-space width<2.5mm were classified into 5 groups: 1)medial 2)medial+patellofemoral, 3)lateral 4)lateral+patellofemoral and 5)medial+lateral (bi- compartmental) or bi- compartmental+patellofemoral (tri- compartmental). KOOS Symptoms, Pain, Function in Daily Living (ADL), Sports and Recreation (Sports/Rec) and Quality of Life (QOL) were collected pre-, 1-, 3- and 5-years post-operatively.
Findings / Results: 282 patients had medial, 46 medial+patellofemoral, 34 lateral, 7 lateral+patellofemoral, and 22 bi/tri- compartmental OA. Patient demographics were similar in all groups; however, bi/tri- compartmental OA patients had fewer females. Medial OA patients had the lowest ADL scores pre-operatively. Medial+patellofemoral OA patients reported the least pain at 5-years. Lateral OA patients reported the lowest Sports/Rec scores at 3-5 years. Lateral+patellofemoral OA patients reported the lowest scores in all subscales except for KOOS Sports/Rec at 5-years and the most pain at 3-5 years. Bi/tri-compartmental OA patients reported the lowest Symptoms score pre-operatively, but reported the highest 1-year scores. At 5-years, these patients reported the highest score in all but the Pain subscale.
Conclusions: Presence of patellofemoral OA is not associated with pre-operative KOOS in patients with medial and lateral OA patterns, possibly diminishing the clinical importance of patellofemoral OA in the knee arthroplasty setting. Lateral OA and lateral+patellofemoral OA patients report lower post- operative KOOS signifying that these cases present with unique surgical challenges.
Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Stanford University; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Harris Orthopaedics Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital; Department of Orthopaedic Surgery, Clinical Orthopaedic Research Hvidovre, Copenhagen University Hospital Hvidovre
Background: Patient-reported outcome measures i.e. Knee Injury and Osteoarthritis Outcome Score (KOOS) validly measure surgical outcome. Knowing if knee osteoarthritis (OA) compartment patterns affect KOOS is essential for risk-stratification and TKA- outcome evaluation.
Purpose / Aim of Study: Analyze: 1)association between knee OA patterns and patient demographics as well as pre-operative KOOS 2)whether knee OA patterns are associated with post-operative KOOS
Materials and Methods: An international multicenter study included 391 TKA patients (median age:65.0; 65.0% females). Compartment OA in pre-operative anterior- posterior and lateral/sunrise radiographs with Kellgren-Lawrence grade III/IV and joint-space width<2.5mm were classified into 5 groups: 1)medial 2)medial+patellofemoral, 3)lateral 4)lateral+patellofemoral and 5)medial+lateral (bi- compartmental) or bi- compartmental+patellofemoral (tri- compartmental). KOOS Symptoms, Pain, Function in Daily Living (ADL), Sports and Recreation (Sports/Rec) and Quality of Life (QOL) were collected pre-, 1-, 3- and 5-years post-operatively.
Findings / Results: 282 patients had medial, 46 medial+patellofemoral, 34 lateral, 7 lateral+patellofemoral, and 22 bi/tri- compartmental OA. Patient demographics were similar in all groups; however, bi/tri- compartmental OA patients had fewer females. Medial OA patients had the lowest ADL scores pre-operatively. Medial+patellofemoral OA patients reported the least pain at 5-years. Lateral OA patients reported the lowest Sports/Rec scores at 3-5 years. Lateral+patellofemoral OA patients reported the lowest scores in all subscales except for KOOS Sports/Rec at 5-years and the most pain at 3-5 years. Bi/tri-compartmental OA patients reported the lowest Symptoms score pre-operatively, but reported the highest 1-year scores. At 5-years, these patients reported the highest score in all but the Pain subscale.
Conclusions: Presence of patellofemoral OA is not associated with pre-operative KOOS in patients with medial and lateral OA patterns, possibly diminishing the clinical importance of patellofemoral OA in the knee arthroplasty setting. Lateral OA and lateral+patellofemoral OA patients report lower post- operative KOOS signifying that these cases present with unique surgical challenges.
Anne Mørup-Petersen, Mogens Laursen, Frank Madsen, Michael R. Krogsgaard, Matilde Winther-Jensen, Anders Odgaard
Department of Orthopaedic Surgery, Herlev and Gentofte Hospital; Department of Orthopaedic Surgery, Aalborg University Hospital, Farsoe; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Section for Sports Traumatology, Bispebjerg and Frederiksberg Hospitals; Center for Clinical Research and Prevention, Department of Clinical Epidemiology, Bispebjerg and Frederiksberg Hospitals; Department of Orthopaedic Surgery, Herlev and Gentofte Hospital
Background: The SPARK study was initiated to explore whether the persistent differences in revisions rates after primary knee replacement across Danish regions were a sign of varying surgical quality. Our hypothesis was that patient-reported outcome measures (PROMs) could offer new aspects to the debate. So far, we have documented no variation in preoperative symptoms but some variations in patient selection between regions.
Purpose / Aim of Study: This study compares 1-year results after primary knee replacement in three centers traditionally known to differ in revision rates.
Materials and Methods: In a prospective cohort study of 1452 patients undergoing primary knee arthroplasty of any kind in Aarhus (n=321), Farsoe (202) or Gentofte (929), PROM sets were emailed pre- and postoperatively (6 weeks, 3, 6 and 12 months). Main outcome was Oxford Knee Score (OKS) at 1 year; secondary outcomes were patient satisfaction, EQ-5D, UCLA Activity Scale, Forgotten Joint Score, global knee rating (0- 100) and Copenhagen Knee ROM Scale.
Findings / Results: Within the first year, 32 patients were excluded due to revision: 22 in Gentofte (2.4%) 2 in Aarhus (0.6%) and 4 in Farsoe (2.0%). One-year answers were provided by 1307 patients (90% of all, or 93% of contacted patients). Overall OKS at 1 y. was 39.0 (SD 7.4) with no significant regional difference (P=0.092). Mean change in OKS was 15.4 (8.1). In Aarhus, it was lower but when adjusted age, sex and preoperative value, this was insignificant. Assigning imputed low OKS-values to revised (excluded) patients revealed no regional difference either. Patients were equally willing to repeat surgery (92%, P=0.124) and equally satisfied across regions (86%, P=0.642). A small, yet significant difference in knee extension was noted in Aarhus, where unicompartmental implants were used more frequently.
Conclusions: Despite well-known differences in revision rates, we found no differences in surgical quality between Danish high-volume knee replacement centers from a patients’ perspective. Our study outlines that traditional registers, however well they contribute to the surveillance of joint replacement, cannot stand alone in the evaluation of surgery. Further studies should explore regional variations in thresholds for revision.
Department of Orthopaedic Surgery, Herlev and Gentofte Hospital; Department of Orthopaedic Surgery, Aalborg University Hospital, Farsoe; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Section for Sports Traumatology, Bispebjerg and Frederiksberg Hospitals; Center for Clinical Research and Prevention, Department of Clinical Epidemiology, Bispebjerg and Frederiksberg Hospitals; Department of Orthopaedic Surgery, Herlev and Gentofte Hospital
Background: The SPARK study was initiated to explore whether the persistent differences in revisions rates after primary knee replacement across Danish regions were a sign of varying surgical quality. Our hypothesis was that patient-reported outcome measures (PROMs) could offer new aspects to the debate. So far, we have documented no variation in preoperative symptoms but some variations in patient selection between regions.
Purpose / Aim of Study: This study compares 1-year results after primary knee replacement in three centers traditionally known to differ in revision rates.
Materials and Methods: In a prospective cohort study of 1452 patients undergoing primary knee arthroplasty of any kind in Aarhus (n=321), Farsoe (202) or Gentofte (929), PROM sets were emailed pre- and postoperatively (6 weeks, 3, 6 and 12 months). Main outcome was Oxford Knee Score (OKS) at 1 year; secondary outcomes were patient satisfaction, EQ-5D, UCLA Activity Scale, Forgotten Joint Score, global knee rating (0- 100) and Copenhagen Knee ROM Scale.
Findings / Results: Within the first year, 32 patients were excluded due to revision: 22 in Gentofte (2.4%) 2 in Aarhus (0.6%) and 4 in Farsoe (2.0%). One-year answers were provided by 1307 patients (90% of all, or 93% of contacted patients). Overall OKS at 1 y. was 39.0 (SD 7.4) with no significant regional difference (P=0.092). Mean change in OKS was 15.4 (8.1). In Aarhus, it was lower but when adjusted age, sex and preoperative value, this was insignificant. Assigning imputed low OKS-values to revised (excluded) patients revealed no regional difference either. Patients were equally willing to repeat surgery (92%, P=0.124) and equally satisfied across regions (86%, P=0.642). A small, yet significant difference in knee extension was noted in Aarhus, where unicompartmental implants were used more frequently.
Conclusions: Despite well-known differences in revision rates, we found no differences in surgical quality between Danish high-volume knee replacement centers from a patients’ perspective. Our study outlines that traditional registers, however well they contribute to the surveillance of joint replacement, cannot stand alone in the evaluation of surgery. Further studies should explore regional variations in thresholds for revision.
Anne Mørup-Petersen, Michael Krogsgaard, Rasmus Nielsen, Aksel Paulsen, Anders Odgaard
Dept. of Orthopaedics, Copenhagen University Hospital Herlev-Gentofte; Dept. of Orthopaedics, Copenhagen University Hospital Bispebjerg; Dept. of Orthopaedics, Copenhagen University Hospital Herlev-Gentofte; Dept. of Orthopaedics, Stavanger University Hospital; Dept. of Orthopaedics, Copenhagen University Hospital Herlev-Gentofte
Background: The Oxford Knee Score (OKS) a is a joint specific questionnaire, developed for the assessment of knee osteoarthritis patients. A Danish version was developed in 2007 but has not undergone formal validation.
Purpose / Aim of Study: To translate and validate the Danish version using the classical test theory validation techniques.
Materials and Methods: The original version was translated into Danish using a forward/backward protocol. Electronic patient-reported outcomes (PROMs) of 351 patients undergoing unicompartmental or total knee arthroplasty from Sept. 2016 to May 2018 were studied. Preoperative OKS was repeated after 2-7 days along with EQ-5D and a global knee anchor question. 1 year after surgery (± 2 mo.), PROMs were reassessed and patients were asked about satisfaction and willingness to repeat.
Findings / Results: Mean OKS difference from test to retest was 0.29, SD 3.85, P=0.16). A Bland-Altman plot revealed no systematic deviation and 95 % of patients were less than 7 points from their first answer. None of the preoperative measurements reached floor (0) or ceiling (48), while 7 postoperative measurements (2.0%) reached the ceiling. Internal consistency was appropriately high (Cronbachs alpha 0.83 preop., and 0.90 postop.). Construct validity measured by Spearman rank correlation between OKS and the anchor question was strong/moderate (rho=0.79/0.66, pre- and postop., respectively). Between OKS and EQ-5D dimensions mobility, activity and pain, correlations were fair/strong/strong preop. (r= -0.47/-0.72/-0.75) and moderate postop. (r=-0.70/-0.67/-0.71) while, as expected, correlations to self-care and anxiety/depression were fair/poor (rho=-0.51/-0.23 and -0.36/-0.20). OKS changed from 20.6 (SD 6.2) preoperatively to 38.0 (6.4) postoperatively, with an individual improvement of 17.4 (7.2). Postoperative OKS was moderately correlated to satisfaction (rho=-0.71) and willingness to repeat (rho=0.62), as was OKS improvement to global improvement (rho=0.63).
Conclusions: The Danish OKS was comparable to other versions regarding construct validity, reliability (test-retest and floor/ceiling effects) and responsiveness. We suggest further validation based on item response theory, e.g. Rasch analysis, for different knee pathologies.
Dept. of Orthopaedics, Copenhagen University Hospital Herlev-Gentofte; Dept. of Orthopaedics, Copenhagen University Hospital Bispebjerg; Dept. of Orthopaedics, Copenhagen University Hospital Herlev-Gentofte; Dept. of Orthopaedics, Stavanger University Hospital; Dept. of Orthopaedics, Copenhagen University Hospital Herlev-Gentofte
Background: The Oxford Knee Score (OKS) a is a joint specific questionnaire, developed for the assessment of knee osteoarthritis patients. A Danish version was developed in 2007 but has not undergone formal validation.
Purpose / Aim of Study: To translate and validate the Danish version using the classical test theory validation techniques.
Materials and Methods: The original version was translated into Danish using a forward/backward protocol. Electronic patient-reported outcomes (PROMs) of 351 patients undergoing unicompartmental or total knee arthroplasty from Sept. 2016 to May 2018 were studied. Preoperative OKS was repeated after 2-7 days along with EQ-5D and a global knee anchor question. 1 year after surgery (± 2 mo.), PROMs were reassessed and patients were asked about satisfaction and willingness to repeat.
Findings / Results: Mean OKS difference from test to retest was 0.29, SD 3.85, P=0.16). A Bland-Altman plot revealed no systematic deviation and 95 % of patients were less than 7 points from their first answer. None of the preoperative measurements reached floor (0) or ceiling (48), while 7 postoperative measurements (2.0%) reached the ceiling. Internal consistency was appropriately high (Cronbachs alpha 0.83 preop., and 0.90 postop.). Construct validity measured by Spearman rank correlation between OKS and the anchor question was strong/moderate (rho=0.79/0.66, pre- and postop., respectively). Between OKS and EQ-5D dimensions mobility, activity and pain, correlations were fair/strong/strong preop. (r= -0.47/-0.72/-0.75) and moderate postop. (r=-0.70/-0.67/-0.71) while, as expected, correlations to self-care and anxiety/depression were fair/poor (rho=-0.51/-0.23 and -0.36/-0.20). OKS changed from 20.6 (SD 6.2) preoperatively to 38.0 (6.4) postoperatively, with an individual improvement of 17.4 (7.2). Postoperative OKS was moderately correlated to satisfaction (rho=-0.71) and willingness to repeat (rho=0.62), as was OKS improvement to global improvement (rho=0.63).
Conclusions: The Danish OKS was comparable to other versions regarding construct validity, reliability (test-retest and floor/ceiling effects) and responsiveness. We suggest further validation based on item response theory, e.g. Rasch analysis, for different knee pathologies.
Lina Holm Ingelsrud, Kirill Gromov, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: The Oxford Knee Score – Activity and Participation Questionnaire (OKS- APQ) was developed in 2014 as a supplement to the OKS, intended to measure higher levels of activity and participation of patients undergoing total knee replacement (TKR).
Purpose / Aim of Study: The purpose of this study was to translate and cross-culturally adapt the 8-item OKS-APQ into Danish.
Materials and Methods: Translation to Danish was performed according to international translation guidelines. The translation procedure included two forward- and two backwards translations by independent translators, followed by a consensus meeting. To ensure high face- and content validity, the translated version was pre-tested on seven patients attending orthopedic consultations either on the waiting list for a TKR or for a 3-months or 1-year postoperative control after TKR. Psychometric evaluations included Rasch analysis, Differential Item Functioning (DIF) and internal consistency evaluations. Analyses were performed on randomly extracted 1-year postoperative data from one hospitals’ arthroplasty database, from 400 patients (mean age 69.3, 61.5% female) undergoing primary TKR between August 2016 and February 2018.
Findings / Results: The Danish OKS-APQ was found to be relevant and comprehensive by patients in the pre-test, however some difficulty in interpreting the response options, resulting in reversing the response scale, was reported. Floor and ceiling effects were observed for 5% and 10%, respectively. A predefined hypothesis of convergent validity with the OKS was confirmed (Spearman correlation 0.76). Internal consistency was found high (Chronbachs alpha 0.95). Good fit to the Rasch model was observed when evaluating individual item fit statistics and no local dependence was found (Yen’s Q3 0.05). There was evidence of DIF for gender in two items and for age (>= 60 vs. < 60 years) for one item, however the impact on the total score was considered small.
Conclusions: The Danish OKS-APQ show promising psychometric properties at 1 year after a TKR and can be used in conjunction with the 12-item OKS. Future psychometric analyses are needed to evaluate reliability and responsiveness of the OKS-APQ.
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: The Oxford Knee Score – Activity and Participation Questionnaire (OKS- APQ) was developed in 2014 as a supplement to the OKS, intended to measure higher levels of activity and participation of patients undergoing total knee replacement (TKR).
Purpose / Aim of Study: The purpose of this study was to translate and cross-culturally adapt the 8-item OKS-APQ into Danish.
Materials and Methods: Translation to Danish was performed according to international translation guidelines. The translation procedure included two forward- and two backwards translations by independent translators, followed by a consensus meeting. To ensure high face- and content validity, the translated version was pre-tested on seven patients attending orthopedic consultations either on the waiting list for a TKR or for a 3-months or 1-year postoperative control after TKR. Psychometric evaluations included Rasch analysis, Differential Item Functioning (DIF) and internal consistency evaluations. Analyses were performed on randomly extracted 1-year postoperative data from one hospitals’ arthroplasty database, from 400 patients (mean age 69.3, 61.5% female) undergoing primary TKR between August 2016 and February 2018.
Findings / Results: The Danish OKS-APQ was found to be relevant and comprehensive by patients in the pre-test, however some difficulty in interpreting the response options, resulting in reversing the response scale, was reported. Floor and ceiling effects were observed for 5% and 10%, respectively. A predefined hypothesis of convergent validity with the OKS was confirmed (Spearman correlation 0.76). Internal consistency was found high (Chronbachs alpha 0.95). Good fit to the Rasch model was observed when evaluating individual item fit statistics and no local dependence was found (Yen’s Q3 0.05). There was evidence of DIF for gender in two items and for age (>= 60 vs. < 60 years) for one item, however the impact on the total score was considered small.
Conclusions: The Danish OKS-APQ show promising psychometric properties at 1 year after a TKR and can be used in conjunction with the 12-item OKS. Future psychometric analyses are needed to evaluate reliability and responsiveness of the OKS-APQ.
Lina Holm Ingelsrud, Kirill Gromov, Berend Terluin, Andrew Price, David Beard, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of General Practice and Elderly Care Medicine, VU University Medical Center, Amsterdam, Netherlands; Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, United Kingdom; Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, United Kingdom; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: Meaningful interpretation of postoperative Oxford Knee Score (OKS) is challenged due to a lack of knowledge about the patients’ perspectives on the threshold for having a successful or unsuccessful treatment outcome.
Purpose / Aim of Study: To determine Patient Acceptable Symptoms State (PASS) and Treatment Failure (TF) values for the OKS in patients undergoing primary total knee replacement (TKR) in Denmark.
Materials and Methods: Data from patients undergoing primary TKR between February 2015 and January 2019 were extracted from one hospital’s arthroplasty database. Patients completed the OKS at 3, 12 and 24 months postoperatively, accompanied by two anchor questions asking whether they considered their symptom level to be acceptable (yes/no), and if not, whether their symptom level was so unsatisfactory that they considered the treatment to have failed (yes/no). PASS and TF threshold values were calculated using the predictive modeling method, which is based on logistic regression, with the PASS and TF anchors as dependent variables and postoperative OKS as the independent variable. Non- parametric bootstrapping was used to derive 95% confidence intervals (CI).
Findings / Results: Complete data were obtained for 187 out of 209 (89%), 884 out of 915 (97%) and 575 out of 586 (98%) patients at 3, 12 and 24 months postoperatively, with a median age ranging from 68 to 70 years (59 to 64% female). The proportions of patients achieving a PASS were 72%, 77% and 79%, while 6%, 11% and 11% considered the treatment to have failed, at 3, 12 and 24 months postoperatively, respectively. OKS PASS values (95% CI) were 27.13 (25.82; 28.45), 30.18 (29.39; 30.99) and 30.45 (29.37; 31.39) at 3, 12 and 24 months postoperatively. Corresponding TF values were 26.67 (25.48; 27.83) at 12 months, and 27.28 (25.87; 28.63) at 24 months postoperatively. The absolute number of patients considering TF at 3 months was too low to calculate that TF value.
Conclusions: These PASS values, determined with novel methodology, can be used to guide the interpretation of the outcome of TKR, when measured with the OKS. PASS and TF thresholds were very close, suggesting that treatment outcome can be dichotomized into successful and not successful outcome using the PASS values.
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of General Practice and Elderly Care Medicine, VU University Medical Center, Amsterdam, Netherlands; Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, United Kingdom; Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, United Kingdom; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: Meaningful interpretation of postoperative Oxford Knee Score (OKS) is challenged due to a lack of knowledge about the patients’ perspectives on the threshold for having a successful or unsuccessful treatment outcome.
Purpose / Aim of Study: To determine Patient Acceptable Symptoms State (PASS) and Treatment Failure (TF) values for the OKS in patients undergoing primary total knee replacement (TKR) in Denmark.
Materials and Methods: Data from patients undergoing primary TKR between February 2015 and January 2019 were extracted from one hospital’s arthroplasty database. Patients completed the OKS at 3, 12 and 24 months postoperatively, accompanied by two anchor questions asking whether they considered their symptom level to be acceptable (yes/no), and if not, whether their symptom level was so unsatisfactory that they considered the treatment to have failed (yes/no). PASS and TF threshold values were calculated using the predictive modeling method, which is based on logistic regression, with the PASS and TF anchors as dependent variables and postoperative OKS as the independent variable. Non- parametric bootstrapping was used to derive 95% confidence intervals (CI).
Findings / Results: Complete data were obtained for 187 out of 209 (89%), 884 out of 915 (97%) and 575 out of 586 (98%) patients at 3, 12 and 24 months postoperatively, with a median age ranging from 68 to 70 years (59 to 64% female). The proportions of patients achieving a PASS were 72%, 77% and 79%, while 6%, 11% and 11% considered the treatment to have failed, at 3, 12 and 24 months postoperatively, respectively. OKS PASS values (95% CI) were 27.13 (25.82; 28.45), 30.18 (29.39; 30.99) and 30.45 (29.37; 31.39) at 3, 12 and 24 months postoperatively. Corresponding TF values were 26.67 (25.48; 27.83) at 12 months, and 27.28 (25.87; 28.63) at 24 months postoperatively. The absolute number of patients considering TF at 3 months was too low to calculate that TF value.
Conclusions: These PASS values, determined with novel methodology, can be used to guide the interpretation of the outcome of TKR, when measured with the OKS. PASS and TF thresholds were very close, suggesting that treatment outcome can be dichotomized into successful and not successful outcome using the PASS values.
Annemette Krintel Petersen, Julie Sandell Jacobsen, Marianne Godt Hansen, Randi Gram Rasmussen, Birgitte Blaabjerg, Martin Carøe Lind, Lisa Gregersen Oestergaard
Department of Physiotherapy and Occupational Therapy,, Aarhus University Hospital, Denmark; Department of Physiotherapy and Research Centre in Health and Welfare Technology, Via University College, Denmark; Department of Administration, Aarhus University Hospital, Denmark; Department of Physiotherapy and Occupational Therapy, Aarhus University Hospital, Denmark; Department og Physiotherapy and Occupational Therapy, Aarhus University Hospital, Denmark; Department of Orthopaedic Surgery, Aarhus University Hospital, Denmark; Department of Physiotherapy and Occupational Therapy, Aarhus University Hospital, Denmark
Background: The International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) is a widely used regions- specific patient-oriented outcome measure of symptoms, function, and sport activities in patients with knee disorders. Translation and assessment properties of a Danish version of the IKDC-SKF have not been established.
Purpose / Aim of Study: We aimed to translate the IKDC-SKF into Danish and test its reproducibility and responsiveness in patients with a variety of knee disorders.
Materials and Methods: The translation process followed international guidelines. Reproducibility and responsiveness were assessed in a clinical study on 86 adults with a median age of 25 (range 18-80) years. The most prevalent condition among the study population was anterior cruciate ligament lesion (n=50, 58%), either isolated or in combination with other lesions or osteoarthritis (N=14, 16 Reproducibility was assessed in 56 adults responding the IKDC-SKF questionnaire twice within 9 days. For analysis of responsiveness, 64 adults responded the IKDC-SKF again after 6 months after surgical treatment of ACL lesion, patella instability and cartilage lesion. Evaluating responsiveness, the change in scores was correlated to the Global Rating Scale. The scale consists of answers from “a very great deal worse “to “a very great deal better”.
Findings / Results: The standardized response mean showed a large effect in patients reporting better condition. The minimal important change was 7.0 points. Evaluating reproducibility, the Intra class correlation coefficient (ICC) was 0.94, standard error of measurement (SEM) was 2.6 (2.2; 3.3) points, and smallest detectable change was 7.2 points. Evaluating responsiveness, the change in scores was correlated to the Global Rating Scale (Spearman`s rho= 0.32).
Conclusions: In conclusion, the Danish IKDC-SKF demonstrated excellent test retest reproducibility both at group and individual level. The IKDC-SKF showed adequate responsiveness and is suitable for assessing improvement or deterioration in adults with a variety of knee disorders.
Department of Physiotherapy and Occupational Therapy,, Aarhus University Hospital, Denmark; Department of Physiotherapy and Research Centre in Health and Welfare Technology, Via University College, Denmark; Department of Administration, Aarhus University Hospital, Denmark; Department of Physiotherapy and Occupational Therapy, Aarhus University Hospital, Denmark; Department og Physiotherapy and Occupational Therapy, Aarhus University Hospital, Denmark; Department of Orthopaedic Surgery, Aarhus University Hospital, Denmark; Department of Physiotherapy and Occupational Therapy, Aarhus University Hospital, Denmark
Background: The International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) is a widely used regions- specific patient-oriented outcome measure of symptoms, function, and sport activities in patients with knee disorders. Translation and assessment properties of a Danish version of the IKDC-SKF have not been established.
Purpose / Aim of Study: We aimed to translate the IKDC-SKF into Danish and test its reproducibility and responsiveness in patients with a variety of knee disorders.
Materials and Methods: The translation process followed international guidelines. Reproducibility and responsiveness were assessed in a clinical study on 86 adults with a median age of 25 (range 18-80) years. The most prevalent condition among the study population was anterior cruciate ligament lesion (n=50, 58%), either isolated or in combination with other lesions or osteoarthritis (N=14, 16 Reproducibility was assessed in 56 adults responding the IKDC-SKF questionnaire twice within 9 days. For analysis of responsiveness, 64 adults responded the IKDC-SKF again after 6 months after surgical treatment of ACL lesion, patella instability and cartilage lesion. Evaluating responsiveness, the change in scores was correlated to the Global Rating Scale. The scale consists of answers from “a very great deal worse “to “a very great deal better”.
Findings / Results: The standardized response mean showed a large effect in patients reporting better condition. The minimal important change was 7.0 points. Evaluating reproducibility, the Intra class correlation coefficient (ICC) was 0.94, standard error of measurement (SEM) was 2.6 (2.2; 3.3) points, and smallest detectable change was 7.2 points. Evaluating responsiveness, the change in scores was correlated to the Global Rating Scale (Spearman`s rho= 0.32).
Conclusions: In conclusion, the Danish IKDC-SKF demonstrated excellent test retest reproducibility both at group and individual level. The IKDC-SKF showed adequate responsiveness and is suitable for assessing improvement or deterioration in adults with a variety of knee disorders.
Lasse E. Rasmussen, Thomas Lind-Hansen, Bjørn Gotlieb Jensen
Orthopedic Dept , Sygehus Lillebælt, Vejle Sygehus; Orthopedic Dept , Sygehus Lillebælt, Vejle Sygehus; Orthopedic Dept , Sygehus Lillebælt, Vejle Sygehus
Background: When shifting total knee arthroplasty (TKA) brand, a 2-3-fold increase in early revisions occur as a result of a learning curve, most evident during the first 15 procedures (1). The Stryker Triathlon knee has previously shown a learning curve (1). Our unit consists of highly dedicated knee arthroplasty surgeons with more than 10 years of experience, with the Vanguard knee. We shifted from the Vanguard knee (Zimmer Biomet) to the Triathlon knee (Stryker) in May 2018.
Purpose / Aim of Study: To investigate whether the learning curve can be reduced when changing implant, this study describes outcome regarding early revisions, oxford knee score (OKS) and forgotten joint score (FJS) from the initial 3 months after changing primary implant and compared to the previous Vanguard knee.
Materials and Methods: Retrospective cohort study. Preoperative, 3 month and 1 year OKS and FJS was measured and compared between the two implants. Revisions for any cause for patients operated after the introduction of the implant was measured and compared to early revisions with the previous implant. All surgeons participated in an education program, provided by the manufacturer (Stryker), consisting of a 2-day course with theoretical education and cadaveric surgery, before May 2018. A company representative was present during the surgery for the first 10 procedures by each surgeon
Findings / Results: Triathlon knee: 138 procedures (5 Surgeons, May 2018 – Sept 2018). Vanguard knees: 128 procedures (same surgeons) from August 2017 – Oktober 2017. Early revisions (within 3 months) in the triathlon group = 0. The first revision was observed 7 months after introduction due to hematogenous infection from pneumococcus pneumonia. Re-admission within 30 days = 0 in both groups. 3 patients were revised within the first year in the Vanguard group. No difference was seen in FJS and OKS, when comparing the Triathlon to the Vanguard.
Conclusions: Introduction of a new implant can be done without a learning curve, with satisfactory outcome and without any increase in revisions if care is taken to properly educate surgeons prior to the introduction. (1) J Bone Joint Surg Am. 2013 Dec 4;95(23):2097- 103. doi: 10.2106/JBJS.L.01296.
Orthopedic Dept , Sygehus Lillebælt, Vejle Sygehus; Orthopedic Dept , Sygehus Lillebælt, Vejle Sygehus; Orthopedic Dept , Sygehus Lillebælt, Vejle Sygehus
Background: When shifting total knee arthroplasty (TKA) brand, a 2-3-fold increase in early revisions occur as a result of a learning curve, most evident during the first 15 procedures (1). The Stryker Triathlon knee has previously shown a learning curve (1). Our unit consists of highly dedicated knee arthroplasty surgeons with more than 10 years of experience, with the Vanguard knee. We shifted from the Vanguard knee (Zimmer Biomet) to the Triathlon knee (Stryker) in May 2018.
Purpose / Aim of Study: To investigate whether the learning curve can be reduced when changing implant, this study describes outcome regarding early revisions, oxford knee score (OKS) and forgotten joint score (FJS) from the initial 3 months after changing primary implant and compared to the previous Vanguard knee.
Materials and Methods: Retrospective cohort study. Preoperative, 3 month and 1 year OKS and FJS was measured and compared between the two implants. Revisions for any cause for patients operated after the introduction of the implant was measured and compared to early revisions with the previous implant. All surgeons participated in an education program, provided by the manufacturer (Stryker), consisting of a 2-day course with theoretical education and cadaveric surgery, before May 2018. A company representative was present during the surgery for the first 10 procedures by each surgeon
Findings / Results: Triathlon knee: 138 procedures (5 Surgeons, May 2018 – Sept 2018). Vanguard knees: 128 procedures (same surgeons) from August 2017 – Oktober 2017. Early revisions (within 3 months) in the triathlon group = 0. The first revision was observed 7 months after introduction due to hematogenous infection from pneumococcus pneumonia. Re-admission within 30 days = 0 in both groups. 3 patients were revised within the first year in the Vanguard group. No difference was seen in FJS and OKS, when comparing the Triathlon to the Vanguard.
Conclusions: Introduction of a new implant can be done without a learning curve, with satisfactory outcome and without any increase in revisions if care is taken to properly educate surgeons prior to the introduction. (1) J Bone Joint Surg Am. 2013 Dec 4;95(23):2097- 103. doi: 10.2106/JBJS.L.01296.