Knee injury and Osteoarthritis Outcome Score (KOOS) – validation and comparison to the WOMAC in total knee replacement

BACKGROUND: The Knee injury and Osteoarthritis Outcome Score (KOOS) is an extension of the Western Ontario and McMaster Universities Osteoarthrtis Index (WOMAC), the most commonly used outcome instrument for assessment of patient-relevant treatment effects in osteoarthritis. KOOS was developed for younger and/or more active patients with knee injury and knee osteoarthritis and has in previous studies on these groups been the more responsive instrument compared to the WOMAC. Some patients eligible for total knee replacement have expectations of more demanding physical functions than required for daily living. This encouraged us to study the use of the Knee injury and Osteoarthritis Outcome Score (KOOS) to assess the outcome of total knee replacement. METHODS: We studied the test-retest reliability, validity and responsiveness of the Swedish version LK 1.0 of the KOOS when used to prospectively evaluate the outcome of 105 patients (mean age 71.3, 66 women) after total knee replacement. The follow-up rates at 6 and 12 months were 92% and 86%, respectively. RESULTS: The intraclass correlation coefficients were over 0.75 for all subscales indicating sufficient test-retest reliability. Bland-Altman plots confirmed this finding. Over 90% of the patients regarded improvement in the subscales Pain, Symptoms, Activities of Daily Living, and knee-related Quality of Life to be extremely or very important when deciding to have their knee operated on indicating good content validity. The correlations found in comparison to the SF-36 indicated the KOOS measured expected constructs. The most responsive subscale was knee-related Quality of Life. The effect sizes of the five KOOS subscales at 12 months ranged from 1.08 to 3.54 and for the WOMAC from 1.65 to 2.56. CONCLUSION: The Knee injury and Osteoarthritis Outcome Score (KOOS) is a valid, reliable, and responsive outcome measure in total joint replacement. In comparison to the WOMAC, the KOOS improved validity and may be at least as responsive as the WOMAC

The Knee injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis

The Knee injury and Osteoarthritis Outcome Score (KOOS) was developed as an extension of the WOMAC Osteoarthritis Index with the purpose of evaluating short-term and long-term symptoms and function in subjects with knee injury and osteoarthritis. The KOOS holds five separately scored subscales: Pain, other Symptoms, Function in daily living (ADL), Function in Sport and Recreation (Sport/Rec), and knee-related Quality of Life (QOL). The KOOS has been validated for several orthopaedic interventions such as anterior cruciate ligament reconstruction, meniscectomy and total knee replacement. In addition the instrument has been used to evaluate physical therapy, nutritional supplementation and glucosamine supplementation. The effect size is generally largest for the subscale QOL followed by the subscale Pain. The KOOS is a valid, reliable and responsive self-administered instrument that can be used for short-term and long-term follow-up of several types of knee injury including osteoarthritis. The measure is relatively new and further use of the instrument will add knowledge and suggest areas that need to be further explored and improved

Impact of exercise on articular cartilage in people at risk of, or with established, knee osteoarthritis: a systematic review of randomised controlled trials

This project is supported by a European Union Seventh Framework Programme (FP7-PEOPLE-2013-ITN; KNEEMO) under grant agreement number 607510.Peer reviewedPostprin

Muscle function is associated with future patient-reported outcomes in young adults with ACL injury

BACKGROUND/AIM: Consequences of an anterior cruciate ligament (ACL) injury include worse patient-reported outcomes (PROs) and a decrease in activity level. Muscle function can be improved by targeted exercise. Our aims were to investigate cross-sectional and longitudinal associations among lower extremity muscle function and PROs after ACL injury.METHODS: Fifty-four participants (15 women, mean 30 years) with ACL injury or reconstruction, from the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) trial (ISRCTN84752559), were assessed with hop performance, muscle power and postural orientation 3 years (SD 0.85) after ACL injury. PROs at 3 and 5 years after injury included Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales Function in sport and recreation (KOOS Sport/rec) and Knee-related Quality of life (KOOS QoL), KOOS item Q3 (KOOS Q3), Tegner Activity Scale and Activity Rating Scale (ARS). Partial Spearman's rank-order correlation was used to analyse correlations between muscle function and PROs, controlling for gender and treatment.RESULTS: Numerous cross-sectional correlations were observed between muscle function and PROs (rsp≈0.3-0.5, p≤0.045). Worse hop performance and worse postural orientation were associated with worse KOOS scores 2 years later (rsp≥0.280, p≤0.045). Worse muscle power was associated with lower future ARS scores (rsp=0.281, p=0.044).CONCLUSIONS: The moderate associations suggest that improving muscle function during rehabilitation could improve present and future PROs

Effects of neuromuscular training (NEMEX-TJR) on patient-reported outcomes and physical function in severe primary hip or knee osteoarthritis: a controlled before-and-after study

Background: The benefits of exercise in mild and moderate knee or hip osteoarthritis (OA) are apparent, but the evidence in severe OA is less clear. We recently reported that neuromuscular training was well tolerated and feasible in patients with severe primary hip or knee OA. The aims of this controlled before-and-after study were to compare baseline status to an age-matched population-based reference group and to examine the effects of neuromuscular training on patient-reported outcomes and physical function in patients with severe primary OA of the hip or knee. Methods: 87 patients (60-77 years) with severe primary OA of the hip (n = 38, 55% women) or knee (n = 49, 59% women) awaiting total joint replacement (TJR) had supervised, neuromuscular training (NEMEX-TJR) in groups with individualized level and progression of training. A reference group (n = 43, 53% women) was included for comparison with patients' data. Assessments included self-reported outcomes (HOOS/KOOS) and measures of physical function (chair stands, number of knee bends/30 sec, knee extensor strength, 20-meter walk test) at baseline and at follow-up before TJR. Analysis of covariance (ANCOVA) was used for comparing patients and references and elucidating influence of demographic factors on change. The paired t-test was used for comparisons within groups. Results: At baseline, patients reported worse scores than the references in all HOOS/KOOS subscales (hip 27-47%, knee 14-52%, of reference scores, respectively) and had functional limitations (hip 72-85%, knee 42-85%, of references scores, respectively). NEMEX-TJR (mean 12 weeks (SD 5.6) of training) improved self-reported outcomes (hip 9-29%, knee 7-20%) and physical function (hip 3-18%, knee 5-19%) (p = 15%) in HOOS/KOOS subscales by training. The improvement in HOOS/KOOS subscale ADL was greater for patients with knee OA than hip OA, while the improvement in subscale Sport/Rec was greater for patients with hip OA than knee OA. Conclusions: Both self-reported outcomes and physical function were clearly worse compared with the reference group. Neuromuscular training with an individualized approach and gradual progression showed promise for improving patient-reported outcomes and physical function even in older patients with severe primary OA of the hip or knee

Validation of the Rheumatoid and Arthritis Outcome Score (RAOS) for the lower extremity

BACKGROUND: Patients with inflammatory joint diseases tend due to new treatments to be more physically active; something not taken into account by currently used outcome measures. The Rheumatoid and Arthritis Outcome Score (RAOS) is an adaptation of the Knee injury and Osteoarthritis Outcome Score (KOOS) and evaluates functional limitations of importance to physically active people with inflammatory joint diseases and problems from the lower extremities. The aim of the study was to test the RAOS for validity, reliability and responsiveness. METHODS: 119 in-patients with inflammatory joint disease (51% RA) admitted to multidisciplinary care, mean age 56 (±13), 73% women, mean disease duration 18 (±14) yr were consecutively enrolled. They all received the RAOS, the SF-36, the HAQ and four subscales of the AIMS2 twice during their stay for test of validity and responsiveness. Test-retest reliability of the RAOS questionnaire was calculated on 52 patients using the first or second administration and an additional mailed questionnaire. RESULTS: The RAOS met set criteria of reliability and validity. The random intraclass correlation coefficient (ICC (2,1)) for the five subscales ranged from 0.76 to 0.92, indicating that individual comparisons were possible except for the subscale Sport and Recreation Function. Inter-item correlation measured by Cronbach's alpha ranged from 0.78 to 0.95. When measuring construct validity the highest correlations occurred between subscales intended to measure similar constructs. Change over time (24 (± 7) days) due to multidisciplinary care was significant for all subscales (p < 0.001). The effect sizes ranged from 0.30–0.44 and were considered small to medium. All the RAOS subscales were more responsive than the HAQ. Some of the SF-36 subscales and the AIMS2 subscales were more responsive than the RAOS subscales. CONCLUSION: It is possible to adapt already existing outcome measures to assess other groups with musculoskeletal difficulties in the lower extremity. The RAOS is a reliable, valid and responsive outcome instrument for assessment of multidisciplinary care. To fully validate the RAOS further studies are needed in other populations