Improved knee biomechanics among patients reporting a good outcome in knee-related quality of life one year after total knee arthroplasty

• Published in: BMC musculoskeletal disorders 2017-03, Vol.18 (1), p.122-122, Article 122
• Main Authors: Naili, Josefine E, Wretenberg, Per, Lindgren, Viktor, Iversen, Maura D, Hedström, Margareta, Broström, Eva W
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Analysis of Variance; Arthralgia - etiology; Arthralgia - physiopathology; Arthralgia - prevention & control; Arthralgia - psychology; Arthritis; Arthroplasty (knee); Arthroplasty, Replacement, Knee - adverse effects; Biomechanical Phenomena; Biomechanics; Disability Evaluation; Female; Function; Gait; Humans; Joint replacement; Joint surgery; Knee; Knee Joint - diagnostic imaging; Knee Joint - physiopathology; Knee Joint - surgery; Male; Medicin och hälsovetenskap; Middle Aged; Minimal Clinically Important Difference; Orthopaedics; Ortopedi; Osteoarthritis; Osteoarthritis, Knee - diagnosis; Osteoarthritis, Knee - physiopathology; Osteoarthritis, Knee - psychology; Osteoarthritis, Knee - surgery; Pain; Pain Measurement; Pain, Postoperative - etiology; Pain, Postoperative - physiopathology; Pain, Postoperative - prevention & control; Pain, Postoperative - psychology; Patient satisfaction; Quality of Life; Recovery of Function; Surgery; Surveys and Questionnaires; Sweden; Time Factors; Treatment Outcome; Visual perception; Walking
• ISSN: 1471-2474; 1471-2474
• DOI: 10.1186/s12891-017-1479-3

It is not well understood why one in five patients report poor outcomes following knee arthroplasty. This study evaluated changes in knee biomechanics, and perceived pain among patients reporting either a good or a poor outcome in knee-related quality of life after total knee arthroplasty. Twenty-eight patients (mean age 66 (SD 7) years) were included in this prospective study. Within one month of knee arthroplasty and one year after surgery, patients underwent three-dimensional (3D) gait analysis, completed the Knee Injury and Osteoarthritis Outcome Score (KOOS), and rated perceived pain using a visual analogue scale. A "good outcome" was defined as a change greater than the minimally detectable change in the KOOS knee-related quality of life, and a "poor outcome" was defined as change below the minimally detectable change. Nineteen patients (68%) were classified as having a good outcome. Groups were analyzed separately and knee biomechanics were compared using a two-way repeated measures ANOVA. Differences in pain between groups were evaluated using Mann Whitney U test. Patients classified as having a good outcome improved significantly in most knee gait biomechanical outcomes including increased knee flexion-extension range, reduced peak varus angle, increased peak flexion moment, and reduced peak valgus moment. The good outcome group also displayed a significant increase in walking speed, a reduction (normalization) of stance phase duration (% of gait cycle) and increased passive knee extension. Whereas, the only change in knee biomechanics, one year after surgery, for patients classified as having a poor outcome was a significant reduction in peak varus angle. No differences in pain postoperatively were found between groups. Patients reporting a good outcome in knee-related quality of life improved in knee biomechanics during gait, while patients reporting a poor outcome, despite similar reduction in pain, remained unchanged in knee biomechanics one year after total knee arthroplasty. With regards to surgeon-controlled biomechanical factors, surgery may most successfully address frontal plane knee alignment. However, achieving a good outcome in patient-reported knee-related quality of life may be related to dynamic improvements in the sagittal plane.