Session 1: Knee I
Onsdag den 25. oktober
09:00 – 10:30
Lokale: Reykjavik
Chairmen: Frank Madsen og Kirill Gromov
Anders Holsgaard-Larsen, Robin Christensen, Brian Clausen, Jens Søndergaard, Thomas P. Andriacchi, Ewa M. Roos
Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark; Musculoskeletal Statistics Unit, The Parker Institute, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark.; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.; Research Unit for General Practice, Institute of Public Health, University of Southern Denmark, Odense, Denmark. ; Departments of Mechanical Engineering and Orthopaedic Surgery, Stanford University, Stanford, California, USA. VA Joint Preservation Center, Palo Alto, California, USA.; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
Background: Exercise is a preferred treatment of osteoarthritis (OA) due to its anticipated negligible adverse effects while still having clinically relevant effect.
Purpose / Aim of Study: To test whether long-term effectiveness of a neuromuscular exercise (NEMEX) would be superior to instructions in optimized use of analgesics and anti-inflammatory drug use (PHARMA) on knee joint function.
Materials and Methods: Extended follow-up of 12 months results from a randomized controlled trial. Participants with mild-to-moderate medial tibiofemoral knee OA were randomly allocated (1:1) to one of two 8-week treatments. The primary outcome measure at 12 months follow- up was activity of daily living (ADL) subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS). Secondary outcome measures include the other four KOOS subscales, the UCLA Activity Score and the EQ-5D. ClinicalTrials.gov Identifier: NCT01638962 (July 3, 2012).
Findings / Results: Ninety-three patients (57% women, 58 ± 8 years with a body mass index of 27 ± 4) were randomized to NEMEX (n = 47) or PHARMA group (n = 46) with data from 85% (41 and 38 patients, respectively) being available at 12 months follow-up; 49% of the participants in NEMEX and only 7% in PHARMA demonstrated good compliance. We found, with a reasonable precision (excluding any likely benefit), no between-groups difference in patient-reported activities of daily living (KOOS ADL 3.6 [-2.1 to 9.2]; P = 0.216). For the secondary outcome measure KOOS Symptoms, a statistically significant difference of 7.6 points (2.6 to 12.7; P = 0.004) was observed in favor of NEMEX. There were no other statistically significant differences.
Conclusions: The NEMEX group generally demonstrated a trend towards larger self-reported improvements than the PHARMA group, but there was no statistically significant difference on KOOS ADL after 12 months.
Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark; Musculoskeletal Statistics Unit, The Parker Institute, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark.; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.; Research Unit for General Practice, Institute of Public Health, University of Southern Denmark, Odense, Denmark. ; Departments of Mechanical Engineering and Orthopaedic Surgery, Stanford University, Stanford, California, USA. VA Joint Preservation Center, Palo Alto, California, USA.; Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
Background: Exercise is a preferred treatment of osteoarthritis (OA) due to its anticipated negligible adverse effects while still having clinically relevant effect.
Purpose / Aim of Study: To test whether long-term effectiveness of a neuromuscular exercise (NEMEX) would be superior to instructions in optimized use of analgesics and anti-inflammatory drug use (PHARMA) on knee joint function.
Materials and Methods: Extended follow-up of 12 months results from a randomized controlled trial. Participants with mild-to-moderate medial tibiofemoral knee OA were randomly allocated (1:1) to one of two 8-week treatments. The primary outcome measure at 12 months follow- up was activity of daily living (ADL) subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS). Secondary outcome measures include the other four KOOS subscales, the UCLA Activity Score and the EQ-5D. ClinicalTrials.gov Identifier: NCT01638962 (July 3, 2012).
Findings / Results: Ninety-three patients (57% women, 58 ± 8 years with a body mass index of 27 ± 4) were randomized to NEMEX (n = 47) or PHARMA group (n = 46) with data from 85% (41 and 38 patients, respectively) being available at 12 months follow-up; 49% of the participants in NEMEX and only 7% in PHARMA demonstrated good compliance. We found, with a reasonable precision (excluding any likely benefit), no between-groups difference in patient-reported activities of daily living (KOOS ADL 3.6 [-2.1 to 9.2]; P = 0.216). For the secondary outcome measure KOOS Symptoms, a statistically significant difference of 7.6 points (2.6 to 12.7; P = 0.004) was observed in favor of NEMEX. There were no other statistically significant differences.
Conclusions: The NEMEX group generally demonstrated a trend towards larger self-reported improvements than the PHARMA group, but there was no statistically significant difference on KOOS ADL after 12 months.
Martin Lindberg-Larsen, Frederik Taylor Pitter, Henrik Husted, Henrik Kehlet, Christoffer Jørgensen
Department of Orthopaedic Surgery, Odense University Hospital and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty; Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen University Hospital Rigshospitalet; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty; Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen University Hospital Rigshospitalet; Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen University Hospital Rigshospitalet
Background: Bilateral simultaneous total knee arthroplasty (TKA) seems safe in selected patients[1]. However, limited data exists on postoperative morbidity compared to staged bilateral procedures and there are no randomized controlled trials. [1] Lindberg-Larsen M et al. Knee Surg Sports Traumatol Arthrosc 2015, 23: 831-7.
Purpose / Aim of Study: To compare early postoperative morbidity, mortality and length of stay (LOS) between bilateral simultaneous and staged TKA in matched groups.
Materials and Methods: A prospective propensity score matched case-control study in 9 dedicated high-volume centers from Feb. 2010 to Nov. 2015. Bilateral simultaneous and staged TKA (1-6 months between stages) were matched on available patient characteristics in the Lundbeck Foundation Centre for Fast-track THA and TKA Database. 30-days follow-up was acquired from the Danish Patient Registry and patient records.
Findings / Results: A total of 345 (47.2%) simultaneous and 386 (52.8%) staged bilateral TKA procedures were performed. In non- matched analysis 30 day readmission rate was 7.2% after simultaneous vs 8.0% after staged bilateral procedures (ns). No patients died within 30 days postoperatively. 235 simultaneous and 235 staged bilateral TKA patients were matched and LOS was median 4 days (IQR 3-5) after simultaneous vs cumulated 4 days (IQR 4-6) after staged bilateral TKA (p<0.001). 30 day readmission rate was 8.5% after simultaneous vs 8.1% after staged bilateral TKA (ns). Only 2 cases (0.9%) of venous thromboembolic events were found in each of the groups. 4 cases (1.7%) of deep infections requiring revision were found after simultaneous and none after staged bilateral TKA (ns).
Conclusions: Early postoperative morbidity, mortality and LOS may be similar between simultaneous and staged bilateral TKA procedures but further safety data on specific complications is required.
Department of Orthopaedic Surgery, Odense University Hospital and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty; Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen University Hospital Rigshospitalet; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty; Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen University Hospital Rigshospitalet; Section of Surgical Pathophysiology and The Lundbeck Centre for Fast-track Hip and Knee Arthroplasty, Copenhagen University Hospital Rigshospitalet
Background: Bilateral simultaneous total knee arthroplasty (TKA) seems safe in selected patients[1]. However, limited data exists on postoperative morbidity compared to staged bilateral procedures and there are no randomized controlled trials. [1] Lindberg-Larsen M et al. Knee Surg Sports Traumatol Arthrosc 2015, 23: 831-7.
Purpose / Aim of Study: To compare early postoperative morbidity, mortality and length of stay (LOS) between bilateral simultaneous and staged TKA in matched groups.
Materials and Methods: A prospective propensity score matched case-control study in 9 dedicated high-volume centers from Feb. 2010 to Nov. 2015. Bilateral simultaneous and staged TKA (1-6 months between stages) were matched on available patient characteristics in the Lundbeck Foundation Centre for Fast-track THA and TKA Database. 30-days follow-up was acquired from the Danish Patient Registry and patient records.
Findings / Results: A total of 345 (47.2%) simultaneous and 386 (52.8%) staged bilateral TKA procedures were performed. In non- matched analysis 30 day readmission rate was 7.2% after simultaneous vs 8.0% after staged bilateral procedures (ns). No patients died within 30 days postoperatively. 235 simultaneous and 235 staged bilateral TKA patients were matched and LOS was median 4 days (IQR 3-5) after simultaneous vs cumulated 4 days (IQR 4-6) after staged bilateral TKA (p<0.001). 30 day readmission rate was 8.5% after simultaneous vs 8.1% after staged bilateral TKA (ns). Only 2 cases (0.9%) of venous thromboembolic events were found in each of the groups. 4 cases (1.7%) of deep infections requiring revision were found after simultaneous and none after staged bilateral TKA (ns).
Conclusions: Early postoperative morbidity, mortality and LOS may be similar between simultaneous and staged bilateral TKA procedures but further safety data on specific complications is required.
Daan Koppens, Søren Rytter, Stig Munk, Jesper Dalsgaard, Ole Gade Sørensen, Torben Bæk Hansen, Maiken Stilling
Orthopedic department , Regional hospital of Holstebro; Orthopedic department, Aarhus university hospital; Orthopedic department, Regional hospital of Northern Jutland; Orthopedic department, Regional hospital of Holstebro; Orthopedic department, Aarhus university hospital; Orthopedic department, Regional hospital of Holstebro; Orthopedic department, Regional hospital of Holstebro
Background: Medial unicompartmental knee arthroplasty (UKA) makes up 10-20% of all knee arthroplasties and gives good clinical outcomes. However, the revision rate is higher compared to total knee arthroplasty (TKA)[1]. Early implant migration is a predictor of implant loosening/revision and can be measured with radiostereometric analysis (RSA). The mobile- bearing Oxford UKA has been on the marked for 40 years and has a 7-year revision rate of 11.1%, and a 10-year revision rate of 14.9% [2]. The fixed-bearing Sigma UKA has been on the marked since 2010 and presents a low 7-year revision rate of 5.5% in registries. Longtime follow up for the Sigma UKA is yet unknown.
Purpose / Aim of Study: This study aims to evaluate migration of the Sigma and Oxford UKA using RSA.
Materials and Methods: A patient-blinded, randomised controlled RSA study with 24 months follow-up was performed. Between January 2014 and October 2015, 62 patients were randomised to receive either a Sigma (N = 31) or Oxford UKA (N = 31). Stereoradiographs were obtained postoperatively, at 4, 12 and 24 months. Mixed model analysis was used for statistical data evaluation. Currently, follow-up is completed for 43 patients.
Findings / Results: No differences in translations or rotations were found between the Sigma UKA and the Oxford UKA. The size of measured translations and rotations was comparable with reportings in the literature [2]. For maximal total point motion (MTPM) of the tibial component, no difference was shown between groups (Likelihood ratio test) (p = 0.9). A difference in migration over time was though found for both groups (p < 0.01).
Conclusions: Our study shows no difference in migration between the Sigma UKA and the Oxford UKA. This supports the low revision rates of the Sigma UKA in the national registries [2]. Migration stabilises after 12 months.
Orthopedic department , Regional hospital of Holstebro; Orthopedic department, Aarhus university hospital; Orthopedic department, Regional hospital of Northern Jutland; Orthopedic department, Regional hospital of Holstebro; Orthopedic department, Aarhus university hospital; Orthopedic department, Regional hospital of Holstebro; Orthopedic department, Regional hospital of Holstebro
Background: Medial unicompartmental knee arthroplasty (UKA) makes up 10-20% of all knee arthroplasties and gives good clinical outcomes. However, the revision rate is higher compared to total knee arthroplasty (TKA)[1]. Early implant migration is a predictor of implant loosening/revision and can be measured with radiostereometric analysis (RSA). The mobile- bearing Oxford UKA has been on the marked for 40 years and has a 7-year revision rate of 11.1%, and a 10-year revision rate of 14.9% [2]. The fixed-bearing Sigma UKA has been on the marked since 2010 and presents a low 7-year revision rate of 5.5% in registries. Longtime follow up for the Sigma UKA is yet unknown.
Purpose / Aim of Study: This study aims to evaluate migration of the Sigma and Oxford UKA using RSA.
Materials and Methods: A patient-blinded, randomised controlled RSA study with 24 months follow-up was performed. Between January 2014 and October 2015, 62 patients were randomised to receive either a Sigma (N = 31) or Oxford UKA (N = 31). Stereoradiographs were obtained postoperatively, at 4, 12 and 24 months. Mixed model analysis was used for statistical data evaluation. Currently, follow-up is completed for 43 patients.
Findings / Results: No differences in translations or rotations were found between the Sigma UKA and the Oxford UKA. The size of measured translations and rotations was comparable with reportings in the literature [2]. For maximal total point motion (MTPM) of the tibial component, no difference was shown between groups (Likelihood ratio test) (p = 0.9). A difference in migration over time was though found for both groups (p < 0.01).
Conclusions: Our study shows no difference in migration between the Sigma UKA and the Oxford UKA. This supports the low revision rates of the Sigma UKA in the national registries [2]. Migration stabilises after 12 months.
Lina Holm Ingelsrud, Ewa Roos, Kirill Gromov, Henrik Husted, Berend Terluin, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; 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; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: Interpreting changes in Oxford Knee Score (OKS) and Forgotten Joint Score (FJS) after undergoing knee replacement is challenged by lack of methodologically rigorous methods to derive on Minimal Important Change (MIC) values.
Purpose / Aim of Study: To determine MIC values for the OKS and FJS in patients undergoing primary knee replacement in Denmark.
Materials and Methods: Patients undergoing knee replacement between January 2015 and May 2016 were selected from one hospital’s arthroplasty database. OKS and FJS were completed preoperatively and at 1 year postoperatively, accompanied by a 7-point anchor question ranging from “better, an important improvement” to “worse, an important worsening”. MIC improvement values were defined with the predictive modelling approach based on logistic regression, with patients’ decisions on important improvement as dependent variable and change in OKS/FJS as independent variable. Furthermore, the MIC was adjusted for the high proportion of improved patients.
Findings / Results: We identified 341 patients with 1-year follow-up data, with a mean age of 67.4 years (63% female). Complete data for OKS, FJS and anchor questions were found for 307/341 patients (90%), and 85% (n=261) of these patients were importantly improved. The Spearman’s correlation between the anchor and the change score was 0.59 for OKS, and 0.61 for FJS. Adjusted predictive MIC values (95% CI) for improvement were 6.6 (4.6; 9.2) for OKS and 13.0 (8.4; 19.4) for FJS.
Conclusions: The MIC value of 6.6 for OKS and 13.0 for FJS, determined with novel MIC methodology, corresponds to minimal improvements that the average patient finds important. These values may aid in evaluating the clinical relevance of improvement after knee replacement surgery.
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; 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; Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre
Background: Interpreting changes in Oxford Knee Score (OKS) and Forgotten Joint Score (FJS) after undergoing knee replacement is challenged by lack of methodologically rigorous methods to derive on Minimal Important Change (MIC) values.
Purpose / Aim of Study: To determine MIC values for the OKS and FJS in patients undergoing primary knee replacement in Denmark.
Materials and Methods: Patients undergoing knee replacement between January 2015 and May 2016 were selected from one hospital’s arthroplasty database. OKS and FJS were completed preoperatively and at 1 year postoperatively, accompanied by a 7-point anchor question ranging from “better, an important improvement” to “worse, an important worsening”. MIC improvement values were defined with the predictive modelling approach based on logistic regression, with patients’ decisions on important improvement as dependent variable and change in OKS/FJS as independent variable. Furthermore, the MIC was adjusted for the high proportion of improved patients.
Findings / Results: We identified 341 patients with 1-year follow-up data, with a mean age of 67.4 years (63% female). Complete data for OKS, FJS and anchor questions were found for 307/341 patients (90%), and 85% (n=261) of these patients were importantly improved. The Spearman’s correlation between the anchor and the change score was 0.59 for OKS, and 0.61 for FJS. Adjusted predictive MIC values (95% CI) for improvement were 6.6 (4.6; 9.2) for OKS and 13.0 (8.4; 19.4) for FJS.
Conclusions: The MIC value of 6.6 for OKS and 13.0 for FJS, determined with novel MIC methodology, corresponds to minimal improvements that the average patient finds important. These values may aid in evaluating the clinical relevance of improvement after knee replacement surgery.
Mikkel Rathsach Andersen, Nikolaj S. Winther, Thomas Lind, Henrik M. Schrøder, Michael Mørk Petersen
Ortopædkirurgisk afd., Rigshospitalet, Hvidovre Hospital; Ortopædkirurgisk afd., Rigshospitalet; Ortopædkirurgisk afd., Rigshospitalet; Ortopædkirurgisk afd., Næstved Sygehus; Ortopædkirurgisk afd., Rigshospitalet
Background: The fixation of uncemented tibia components in Total Knee Arthroplasty (TKA) may rely on the bone quality of the tibia, however, no previous studies have shown convincing objective proof of this.
Purpose / Aim of Study: To investigate the possible relation between preoperative bone quality and fixation of uncemented tibia components in TKA.
Materials and Methods: We performed 2 year follow up of 92 patients who underwent TKA surgery with an uncmented tibia component. Bone mineral density (BMD) (g/cm2) of the tibia host bone was measured preoperatively using dual energy X-ray absorbtiometry (DEXA). The proximal tibia was divided in to two regions of interest (ROI) in the part of the tibia bone where the components were implanted. Radiostereometric analysis was performed postoperatively and after 3, 6, 12 and 24 months. Primary the outcome was Maximum Total Point Motion (MTPM) (mm). Statistics: Regression analysis was performed to evaluate the relation between preoperative BMD and MTPM.
Findings / Results: We found low preoperative BMD in ROI1 to be significantly related to high MTPM at all follow-ups: After 3 months (R2 = 20%, PBMD=0.017), 6 months (R2=29%, PBMD=0.003), 12 months (R2=33%, PBMD=0.001) and 24 months (R2=27%, PBMD=0.001). We also found a significant relation for low BMD in ROI2 and high MTPM: 3 months (R2=19%, PBMD=0.042), 6 months (R2=28%, PBMD=0.04), 12 months (R2=32%, PBMD=0.004) and 24 months (R2=24%, PBMD=0.005).
Conclusions: Low preoperative BMD in the tibia is related to high MTPM. Thus, high migration of uncemented tibia components is to be expected in patients with poor bone quality. High component migration is relevant as it has been shown to predict aseptic loosening.
Ortopædkirurgisk afd., Rigshospitalet, Hvidovre Hospital; Ortopædkirurgisk afd., Rigshospitalet; Ortopædkirurgisk afd., Rigshospitalet; Ortopædkirurgisk afd., Næstved Sygehus; Ortopædkirurgisk afd., Rigshospitalet
Background: The fixation of uncemented tibia components in Total Knee Arthroplasty (TKA) may rely on the bone quality of the tibia, however, no previous studies have shown convincing objective proof of this.
Purpose / Aim of Study: To investigate the possible relation between preoperative bone quality and fixation of uncemented tibia components in TKA.
Materials and Methods: We performed 2 year follow up of 92 patients who underwent TKA surgery with an uncmented tibia component. Bone mineral density (BMD) (g/cm2) of the tibia host bone was measured preoperatively using dual energy X-ray absorbtiometry (DEXA). The proximal tibia was divided in to two regions of interest (ROI) in the part of the tibia bone where the components were implanted. Radiostereometric analysis was performed postoperatively and after 3, 6, 12 and 24 months. Primary the outcome was Maximum Total Point Motion (MTPM) (mm). Statistics: Regression analysis was performed to evaluate the relation between preoperative BMD and MTPM.
Findings / Results: We found low preoperative BMD in ROI1 to be significantly related to high MTPM at all follow-ups: After 3 months (R2 = 20%, PBMD=0.017), 6 months (R2=29%, PBMD=0.003), 12 months (R2=33%, PBMD=0.001) and 24 months (R2=27%, PBMD=0.001). We also found a significant relation for low BMD in ROI2 and high MTPM: 3 months (R2=19%, PBMD=0.042), 6 months (R2=28%, PBMD=0.04), 12 months (R2=32%, PBMD=0.004) and 24 months (R2=24%, PBMD=0.005).
Conclusions: Low preoperative BMD in the tibia is related to high MTPM. Thus, high migration of uncemented tibia components is to be expected in patients with poor bone quality. High component migration is relevant as it has been shown to predict aseptic loosening.
Anne Mørup-Petersen, Pætur Mikal Holm, Christina Holm, Tobias Wirenfeldt Klausen, Søren T. Skou, Michael Rindom Krogsgaard, Mogens Berg Laursen, Anders Odgaard
Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte; Department of Physiotherapy and Occupational Therapy/ Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse / University of Southern Denmark, Odense; Department of Orthopaedic Surgery, Copenhagen University Hospital, Rigshospitalet; Department of Hematology, Copenhagen University Hospital, Herlev; Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics/ Department of Physiotherapy and Occupational Therapy, University of Southern Denmark, Odense/ Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse; Department of Orthopaedic Surgery, Copenhagen University Hospital, Bispebjerg; Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg & Farsø; Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte
Background: Knee arthroplasty surgery does not always require extensive patient follow-up. For those with good function, follow-up examination mainly focuses on range of motion (ROM). If ROM could be reported reliably by the patient, attendance for follow-up might be replaced by phone calls, emails or even register surveys.
Purpose / Aim of Study: We investigated whether a new, simple, illustration-based scale enables patients to report their own passive knee range of motion in 15° increments.
Materials and Methods: Through an iterative process we created a 2- item scale with 11 illustrations of knee motion neutral for age, sex and race. Reliability was tested in 105 knee arthritis patients (mean age 70.8 years) at different treatment stages. Passive ROM was measured with a long goniometer by a physiotherapist and an orthopaedic resident, both blinded.
Findings / Results:Patients found our scale quick and easy to use. They handed in 100 correctly completed questionnaires. The mean difference between patients’ reports and measurement was -0.72° (SD 12.3°) for flexion and 1.11° (SD 11.6°) for extension. For patients reporting flexion > 110° (n=64), 94% were confirmed by goniometer measurement. For knee flexion < 110° (n=32), the patient-reported ROM had a sensitivity of 88% and a specificity of 88%. If flexion limit was set at 100° the according values were 95 and 81%. For extension deficits > 10° (n=18) we found a sensitivity of 78% and a specificity of 70%. Values were 100 and 66% for a 15° limit. Retest results are underway.
Conclusions: Patient-reported ROM is a feasible and for some purposes reliable alternative to professional ROM measurement. This scale can act as supplement to register surveys and combined with e.g. patient-reported outcomes it may reduce the number of patients who need a follow-up visit, leaving the surgeon more time for those who do.
Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte; Department of Physiotherapy and Occupational Therapy/ Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse / University of Southern Denmark, Odense; Department of Orthopaedic Surgery, Copenhagen University Hospital, Rigshospitalet; Department of Hematology, Copenhagen University Hospital, Herlev; Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics/ Department of Physiotherapy and Occupational Therapy, University of Southern Denmark, Odense/ Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse; Department of Orthopaedic Surgery, Copenhagen University Hospital, Bispebjerg; Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg & Farsø; Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte
Background: Knee arthroplasty surgery does not always require extensive patient follow-up. For those with good function, follow-up examination mainly focuses on range of motion (ROM). If ROM could be reported reliably by the patient, attendance for follow-up might be replaced by phone calls, emails or even register surveys.
Purpose / Aim of Study: We investigated whether a new, simple, illustration-based scale enables patients to report their own passive knee range of motion in 15° increments.
Materials and Methods: Through an iterative process we created a 2- item scale with 11 illustrations of knee motion neutral for age, sex and race. Reliability was tested in 105 knee arthritis patients (mean age 70.8 years) at different treatment stages. Passive ROM was measured with a long goniometer by a physiotherapist and an orthopaedic resident, both blinded.
Findings / Results:Patients found our scale quick and easy to use. They handed in 100 correctly completed questionnaires. The mean difference between patients’ reports and measurement was -0.72° (SD 12.3°) for flexion and 1.11° (SD 11.6°) for extension. For patients reporting flexion > 110° (n=64), 94% were confirmed by goniometer measurement. For knee flexion < 110° (n=32), the patient-reported ROM had a sensitivity of 88% and a specificity of 88%. If flexion limit was set at 100° the according values were 95 and 81%. For extension deficits > 10° (n=18) we found a sensitivity of 78% and a specificity of 70%. Values were 100 and 66% for a 15° limit. Retest results are underway.
Conclusions: Patient-reported ROM is a feasible and for some purposes reliable alternative to professional ROM measurement. This scale can act as supplement to register surveys and combined with e.g. patient-reported outcomes it may reduce the number of patients who need a follow-up visit, leaving the surgeon more time for those who do.
Anne Mørup-Petersen, Søren T. Skou, Christina Holm, Pætur Mikal Holm, Tobias Wirenfeldt Klausen, Michael Rindom Krogsgaard, Mogens Berg Laursen, Anders Odgaard
Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte; Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics/ Department of Physiotherapy and Occupational Therapy, University of Southern Denmark, Odense/ Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse; Department of Orthopaedic Surgery, Copenhagen University Hospital, Rigshospitalet; Department of Physiotherapy and Occupational Therapy/ Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse / University of Southern Denmark, Odense; Department of Hematology, Copenhagen University Hospital, Herlev ; Department of Orthopaedic Surgery, Copenhagen University Hospital, Bispebjerg; Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg & Farsø; Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte
Background: UCLA Activity Scale (UAS) is a brief and widely acknowledged scale assessing physical activity in hip and knee arthroplasty patients on a 10- level scale, where “10” is very active.
Purpose / Aim of Study: We aimed to translate and culturally adapt UAS for use in Denmark and to test its validity in knee arthroplasty patients before or after surgery.
Materials and Methods: Formal translation was made by a physiotherapist, a professional translator and an orthopaedic resident. The version agreed upon was edited, redesigned and culturally adapted through an iterative process including 22 lay persons and 55 patients. In the final test of 76 patients, each patient’s own rating (Pt) was compared to his/her level according to a physiotherapist (Phys) and one of two orthopaedic residents (Ort) based on short, blinded interviews mimicking the normal clinical setting.
Findings / Results: Eleven patients (mean age 67.3 y) were excluded due to marking more than one level. The remaining 65 patients (66.5 y) had average ratings of 5.0 (Pt), 3.8 (Phys) and 4.4 (Ort). In 49% of cases the patient either agreed with one or both examiners, or patient’s rating was between examiners’ ratings. Spearman correlation was 0.65 for Pt vs. Ort and 0.47 for Pt vs. Phys indicating strong and moderate correlations, respectively. At retest (mean 8.3 days later), 21 of 38 patients reported to have “no change in physical activity since the first test”. Thirteen (62%) of the 21 agreed perfectly with their own first test and five (23%) were one level away.
Conclusions: The Danish UAS is a fast and fairly comprehensible tool for assessing patient- reported physical activity level in this population. Mixing time, intensity and frequency is a potential threat to the credibility of UAS, and therefore responsiveness testing and testing against more raters or objective measures is warranted.
Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte; Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics/ Department of Physiotherapy and Occupational Therapy, University of Southern Denmark, Odense/ Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse; Department of Orthopaedic Surgery, Copenhagen University Hospital, Rigshospitalet; Department of Physiotherapy and Occupational Therapy/ Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, Næstved-Slagelse-Ringsted Hospitals, Region Zealand, Slagelse / University of Southern Denmark, Odense; Department of Hematology, Copenhagen University Hospital, Herlev ; Department of Orthopaedic Surgery, Copenhagen University Hospital, Bispebjerg; Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg & Farsø; Department of Orthopaedic Surgery, Copenhagen University Hospital, Gentofte
Background: UCLA Activity Scale (UAS) is a brief and widely acknowledged scale assessing physical activity in hip and knee arthroplasty patients on a 10- level scale, where “10” is very active.
Purpose / Aim of Study: We aimed to translate and culturally adapt UAS for use in Denmark and to test its validity in knee arthroplasty patients before or after surgery.
Materials and Methods: Formal translation was made by a physiotherapist, a professional translator and an orthopaedic resident. The version agreed upon was edited, redesigned and culturally adapted through an iterative process including 22 lay persons and 55 patients. In the final test of 76 patients, each patient’s own rating (Pt) was compared to his/her level according to a physiotherapist (Phys) and one of two orthopaedic residents (Ort) based on short, blinded interviews mimicking the normal clinical setting.
Findings / Results: Eleven patients (mean age 67.3 y) were excluded due to marking more than one level. The remaining 65 patients (66.5 y) had average ratings of 5.0 (Pt), 3.8 (Phys) and 4.4 (Ort). In 49% of cases the patient either agreed with one or both examiners, or patient’s rating was between examiners’ ratings. Spearman correlation was 0.65 for Pt vs. Ort and 0.47 for Pt vs. Phys indicating strong and moderate correlations, respectively. At retest (mean 8.3 days later), 21 of 38 patients reported to have “no change in physical activity since the first test”. Thirteen (62%) of the 21 agreed perfectly with their own first test and five (23%) were one level away.
Conclusions: The Danish UAS is a fast and fairly comprehensible tool for assessing patient- reported physical activity level in this population. Mixing time, intensity and frequency is a potential threat to the credibility of UAS, and therefore responsiveness testing and testing against more raters or objective measures is warranted.
Lone Ramer Mikkelsen, Mette Garval, Carsten Holm, Søren Thorgaard Skou
Interdisciplinary Research Unit, Elective Surgery Centre, Silkeborg Regional Hospital; 2. Department of Physiotherapy, Elective Surgery Centre, Silkeborg Regional Hospital; Elective Surgery Centre, Silkeborg Regional Hospital; Department of Physiotherapy and Occupational Therapy AND Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, Næstved-Slagelse-Ringsted Hospitals AND University of Southern Denmark
Background: Many knee patients referred to outpatient orthopedic clinics (OOC) are not (yet) candidates for surgery and might benefit from conservative treatment. If it is possible to identify relevant patients to refer to the orthopedic surgeon (OS) it could potentially improve efficiency and quality of care in the OOC.
Purpose / Aim of Study: To develop and test a screening algorithm to define appropriateness of referral to OS based on pre-visit patient-reported outcomes and radiographical findings thereby being applicable prior to clinical examination.
Materials and Methods: Prior to clinical examination, 173 consecutive patients with a first-time referral to the OOC completed questionnaires, and radiographic osteoarthritis severity was graded. The gold standard for relevant referral to the OS was based on actual treatments, referral to other medical specialists or further diagnostics. The performance of the algorithm in predicting relevant referrals and total knee replacement (TKR) was assessed using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).
Findings / Results: Of the 173 patients, 40% (n=69) underwent TKR and further 25% (n=44) were considered relevant to refer to OS due to other reasons than surgery. Sensitivity, specificity, PPV and NPV for prediction of relevant referral to OS were 0.70, 0.56, 0.76 and 0.48, respectively. The corresponding performance estimates for prediction of TKR surgery were 0.92, 0.56, 0.55 and 0.92.
Conclusions: The algorithm was able to identify most patients relevant to refer to OS, but was less suitable for identifying those not relevant. The algorithm performed excellent in predicting TKR surgery. With further development, this screening algorithm might be able to improve the referral pattern and thereby improve patient care and efficiency in the OOC.
Interdisciplinary Research Unit, Elective Surgery Centre, Silkeborg Regional Hospital; 2. Department of Physiotherapy, Elective Surgery Centre, Silkeborg Regional Hospital; Elective Surgery Centre, Silkeborg Regional Hospital; Department of Physiotherapy and Occupational Therapy AND Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, Næstved-Slagelse-Ringsted Hospitals AND University of Southern Denmark
Background: Many knee patients referred to outpatient orthopedic clinics (OOC) are not (yet) candidates for surgery and might benefit from conservative treatment. If it is possible to identify relevant patients to refer to the orthopedic surgeon (OS) it could potentially improve efficiency and quality of care in the OOC.
Purpose / Aim of Study: To develop and test a screening algorithm to define appropriateness of referral to OS based on pre-visit patient-reported outcomes and radiographical findings thereby being applicable prior to clinical examination.
Materials and Methods: Prior to clinical examination, 173 consecutive patients with a first-time referral to the OOC completed questionnaires, and radiographic osteoarthritis severity was graded. The gold standard for relevant referral to the OS was based on actual treatments, referral to other medical specialists or further diagnostics. The performance of the algorithm in predicting relevant referrals and total knee replacement (TKR) was assessed using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).
Findings / Results: Of the 173 patients, 40% (n=69) underwent TKR and further 25% (n=44) were considered relevant to refer to OS due to other reasons than surgery. Sensitivity, specificity, PPV and NPV for prediction of relevant referral to OS were 0.70, 0.56, 0.76 and 0.48, respectively. The corresponding performance estimates for prediction of TKR surgery were 0.92, 0.56, 0.55 and 0.92.
Conclusions: The algorithm was able to identify most patients relevant to refer to OS, but was less suitable for identifying those not relevant. The algorithm performed excellent in predicting TKR surgery. With further development, this screening algorithm might be able to improve the referral pattern and thereby improve patient care and efficiency in the OOC.
Rikke Daugaard, Marianne Tjur, Maik Sliepen, Dieter Rosenbaum, Bernd Grimm, Inger Mechlenburg
Ortopaedic Research Unit, Aarhus University Hospital, Denmark; Ortopaedic Research Unit, Aarhus University Hospital, Denmark; Institut für Experimentelle Muskuloskelettale Medizin, Universitätsklinikum Münster, Germany; Institut für Experimentelle Muskuloskelettale Medizin, Universitätsklinikum Münster, Germany; , Zuyderland Medical Center, Heerlen, Netherlands; Ortopaedic Research Unit, Aarhus University Hospital, Denmark
Background: Knee osteoarthritis (KOA) causes impairment through pain, stiffness and malalignment and knee joint replacement (KJR) may be necessary to alleviate such symptoms. There is disagreement whether patients with KJR increases their level of physical activity after surgery.
Purpose / Aim of Study: The aim of this study is to investigate whether patients with KJR have a higher level of physical activity than patients with KOA, as measured by accelerometer-based method. Furthermore, to investigate whether patients achieve the same level of activity as healthy subjects five years post TJR.
Materials and Methods: Fifty-four patients with KOA (29 women, mean age 62±8.6, mean BMI 27±5), 53 patients who had KJR five years earlier (26 women, mean age 66±7.2, mean BMI 30±5) and 171 healthy subjects (76 women, mean age 64±9.7, mean BMI 26±5) were included in this cross sectional study. The level of physical activity was measured over a mean of 5.5 days with a tri-axial accelerometer mounted on the thigh. Number of daily short walking bouts of <10 seconds duration, number of daily steps, and number of daily transfers from sitting to standing were calculated. Data was analyzed through linear regression and adjusted for age, sex and BMI.
Findings / Results: Patients with KJR had 10.1 fewer short walking bouts (p=0.04), 745 fewer steps (p=0.19) and 6.2 fewer transfers (p=0.09) per day than patients with KOA. In addition, patients with KJR performed 21.7 fewer short walking bouts (p=0.001), 281 fewer steps (p=0.60) and 3.2 fewer transfers (p=0.32) per day than healthy subjects.
Conclusions: Patients with KJR do not seem to be more physically active than patients with KOA. Neither do the seem to be as active as healthy subjects, However, the results may suffer from selection bias and thus the results ought to be confirmed in a bigger cohort study.
Ortopaedic Research Unit, Aarhus University Hospital, Denmark; Ortopaedic Research Unit, Aarhus University Hospital, Denmark; Institut für Experimentelle Muskuloskelettale Medizin, Universitätsklinikum Münster, Germany; Institut für Experimentelle Muskuloskelettale Medizin, Universitätsklinikum Münster, Germany; , Zuyderland Medical Center, Heerlen, Netherlands; Ortopaedic Research Unit, Aarhus University Hospital, Denmark
Background: Knee osteoarthritis (KOA) causes impairment through pain, stiffness and malalignment and knee joint replacement (KJR) may be necessary to alleviate such symptoms. There is disagreement whether patients with KJR increases their level of physical activity after surgery.
Purpose / Aim of Study: The aim of this study is to investigate whether patients with KJR have a higher level of physical activity than patients with KOA, as measured by accelerometer-based method. Furthermore, to investigate whether patients achieve the same level of activity as healthy subjects five years post TJR.
Materials and Methods: Fifty-four patients with KOA (29 women, mean age 62±8.6, mean BMI 27±5), 53 patients who had KJR five years earlier (26 women, mean age 66±7.2, mean BMI 30±5) and 171 healthy subjects (76 women, mean age 64±9.7, mean BMI 26±5) were included in this cross sectional study. The level of physical activity was measured over a mean of 5.5 days with a tri-axial accelerometer mounted on the thigh. Number of daily short walking bouts of <10 seconds duration, number of daily steps, and number of daily transfers from sitting to standing were calculated. Data was analyzed through linear regression and adjusted for age, sex and BMI.
Findings / Results: Patients with KJR had 10.1 fewer short walking bouts (p=0.04), 745 fewer steps (p=0.19) and 6.2 fewer transfers (p=0.09) per day than patients with KOA. In addition, patients with KJR performed 21.7 fewer short walking bouts (p=0.001), 281 fewer steps (p=0.60) and 3.2 fewer transfers (p=0.32) per day than healthy subjects.
Conclusions: Patients with KJR do not seem to be more physically active than patients with KOA. Neither do the seem to be as active as healthy subjects, However, the results may suffer from selection bias and thus the results ought to be confirmed in a bigger cohort study.
Thomas Lind-Hansen, Claus Varnum, Lasse Enkebølle Rasmussen
Ortopaedic Department, Vejle Hospital; Ortopaedic Department , Vejle Hospital; Ortopaedic Department Vejle Hospital, Vejle Hospital
Background: The indication for the domed lateral Oxford Unicompartmental Knee Replacement (OUKR) is isolated lateral unicompartmental osteoarthritis. Since the introduction of the implant, dislocation of the mobile bearing has been a concern. Our series represents one of the largest independent series published from non-design centres.
Purpose / Aim of Study: To evaluate the outcome of the first 45 domed lateral OUKR, operated at Vejle Hospital, regarding bearing dislocation and revision in a retrospective cohort study.
Materials and Methods: The files of all patients operated with the domed lateral OUKR in our institution from February 2010 – June 2016 was reviewed regarding implant size, surgeon, revision of any cause, and latest available patient-reported outcome. All patients had at least 1-year follow-up.
Findings / Results: We identified 46 patients (48 knees: 27 females (1 bilateral) and 19 males (1 bilateral)) operated by 6 different surgeons. 6 (13%) bearings dislocated causing open revision with replacement of the bearing. Median time to dislocation was 103 days (range 47-469 days),only one bearing dislocated after one year. 3 (7%) knees were revised to total knee replacement (TKR) due to progression of osteoarthrosis (n=1) and following dislocation (n=2). Of the remaining 45 domed lateral OUKR, 41 (91%) reported that they were satisfied or very satisfied at the one year follow-up.
Conclusions: The domed lateral OUKR is a challenging procedure with concerning rates of dislocation, which was also found in this series. However, it seems that good or excellent performance can be achieved despite early dislocation. But it is concering that 2/6 knees with dislocated bearing had to be revised to TKR, further emphasizing the challenges with the procedure in regards of dislocation.
Ortopaedic Department, Vejle Hospital; Ortopaedic Department , Vejle Hospital; Ortopaedic Department Vejle Hospital, Vejle Hospital
Background: The indication for the domed lateral Oxford Unicompartmental Knee Replacement (OUKR) is isolated lateral unicompartmental osteoarthritis. Since the introduction of the implant, dislocation of the mobile bearing has been a concern. Our series represents one of the largest independent series published from non-design centres.
Purpose / Aim of Study: To evaluate the outcome of the first 45 domed lateral OUKR, operated at Vejle Hospital, regarding bearing dislocation and revision in a retrospective cohort study.
Materials and Methods: The files of all patients operated with the domed lateral OUKR in our institution from February 2010 – June 2016 was reviewed regarding implant size, surgeon, revision of any cause, and latest available patient-reported outcome. All patients had at least 1-year follow-up.
Findings / Results: We identified 46 patients (48 knees: 27 females (1 bilateral) and 19 males (1 bilateral)) operated by 6 different surgeons. 6 (13%) bearings dislocated causing open revision with replacement of the bearing. Median time to dislocation was 103 days (range 47-469 days),only one bearing dislocated after one year. 3 (7%) knees were revised to total knee replacement (TKR) due to progression of osteoarthrosis (n=1) and following dislocation (n=2). Of the remaining 45 domed lateral OUKR, 41 (91%) reported that they were satisfied or very satisfied at the one year follow-up.
Conclusions: The domed lateral OUKR is a challenging procedure with concerning rates of dislocation, which was also found in this series. However, it seems that good or excellent performance can be achieved despite early dislocation. But it is concering that 2/6 knees with dislocated bearing had to be revised to TKR, further emphasizing the challenges with the procedure in regards of dislocation.
Sara Svanholm, Anders Odgaard, Thomas Lind
Ortopædkirurgisk afdeling, Gentofte Hospital; Ortopædkirurgisk afdeling, Gentofte Hospital; Ortopædkirurgisk afdeling, Gentofte Hospital
Background: Post-operative joint stiffness is a common complication to total knee arthroplasty (TKA) and the leading cause of re-hospitalization and manipulation under anaesthesia (MUA).
Purpose / Aim of Study: This study examines the correlation between pre-operative analgesic treatment and the risk of post-operative MUA in order to gain a better understanding of the risk factors associated with post-operative joint stiffness. The goal is to identify and improve the treatment of this group of patients.
Materials and Methods: Design: A retrospective case-control study in which the case population consisted of all patients receiving MUA at Gentofte Hospital from January 2011 to December 2015. Controls were 3-4 patients receiving TKA the same day as the TKA that led to MUA in the case group. Inclusion criteria: All patients from the age of 18 and above receiving MUA following TKA as a result of knee arthrosis, given the details regarding baseline data and analgesic treatment were available. 101 patients undergoing MUA were included and 315 in the control group. Analysis: Analgesic treatment prior to TKA as a risk factor was examined both univariate and adjusted. The relative risk (RR) with 95% CI for all variables were determined through logistic regression.
Findings / Results: Patients using analgesics prior to surgery were twice as likely to receive MUA (RR = 2.14, p = 0,036), particularly when a combination of Paracetamol and Ibuprofen was administered compared to no analgesic treatment (RR = 2.8, p = 0.005).
Conclusions: Analgesic treatment prior to TKA increases the risk of post-operative re-manipulation and can be used as a predictor of outcome in addition to other risk factors associated with post-operative joint stiffness. The results could help clinicians design specialized care following TKA to improve procedures and avoid re-hospitalization.
Ortopædkirurgisk afdeling, Gentofte Hospital; Ortopædkirurgisk afdeling, Gentofte Hospital; Ortopædkirurgisk afdeling, Gentofte Hospital
Background: Post-operative joint stiffness is a common complication to total knee arthroplasty (TKA) and the leading cause of re-hospitalization and manipulation under anaesthesia (MUA).
Purpose / Aim of Study: This study examines the correlation between pre-operative analgesic treatment and the risk of post-operative MUA in order to gain a better understanding of the risk factors associated with post-operative joint stiffness. The goal is to identify and improve the treatment of this group of patients.
Materials and Methods: Design: A retrospective case-control study in which the case population consisted of all patients receiving MUA at Gentofte Hospital from January 2011 to December 2015. Controls were 3-4 patients receiving TKA the same day as the TKA that led to MUA in the case group. Inclusion criteria: All patients from the age of 18 and above receiving MUA following TKA as a result of knee arthrosis, given the details regarding baseline data and analgesic treatment were available. 101 patients undergoing MUA were included and 315 in the control group. Analysis: Analgesic treatment prior to TKA as a risk factor was examined both univariate and adjusted. The relative risk (RR) with 95% CI for all variables were determined through logistic regression.
Findings / Results: Patients using analgesics prior to surgery were twice as likely to receive MUA (RR = 2.14, p = 0,036), particularly when a combination of Paracetamol and Ibuprofen was administered compared to no analgesic treatment (RR = 2.8, p = 0.005).
Conclusions: Analgesic treatment prior to TKA increases the risk of post-operative re-manipulation and can be used as a predictor of outcome in addition to other risk factors associated with post-operative joint stiffness. The results could help clinicians design specialized care following TKA to improve procedures and avoid re-hospitalization.