Mechanical factors relate to pain in knee osteoarthritis.

BACKGROUND Pain experienced by people with knee osteoarthritis is related to psychosocial factors and damage to articular tissues and/or the pain pathway itself. Mechanical factors have been speculated to trigger this pain experience; yet mechanics have not been identified as a source of pain in this population. The purpose of this study was to identify whether mechanics could explain variance in pain intensity in people with knee osteoarthritis. METHODS Data from 53 participants with physician-diagnosed knee osteoarthritis (mean age=68.5 years; standard deviation=8.6 years) were analyzed. Pain intensity was reported on the Western Ontario and McMaster Universities Osteoarthritis Index. Mechanical measures included weight-bearing varus-valgus alignment, body mass index and isokinetic quadriceps torque. Gait analysis captured the range of adduction-abduction angle, range of flexion-extension angle and external knee adduction moment during level walking. FINDINGS Pain intensity was significantly related to the dynamic range of flexion-extension during gait and body mass index. A total of 29% of the variance in pain intensity was explained by mechanical variables. The range of flexion-extension explained 18% of variance in pain intensity. Body mass index added 11% to the model. The knee adduction moment was unrelated to pain intensity. INTERPRETATION The findings support that mechanical factors are related to knee osteoarthritis pain. Because limitations in flexion-extension range of motion and body size are modifiable factors, future research could examine whether interventions targeting these mechanics would facilitate pain management.

[1]  David T Felson,et al.  The effect of body weight on progression of knee osteoarthritis is dependent on alignment. , 2004, Arthritis and rheumatism.

[2]  P. Costigan,et al.  Radiographic and non-invasive determination of the hip joint center location: effect on hip joint moments. , 1999, Clinical biomechanics.

[3]  T. Hortobágyi,et al.  Aberrations in the control of quadriceps muscle force in patients with knee osteoarthritis. , 2004, Arthritis and rheumatism.

[4]  C. Goldsmith,et al.  Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. , 1988, The Journal of rheumatology.

[5]  U P Wyss,et al.  A procedure to validate three-dimensional motion assessment systems. , 1993, Journal of biomechanics.

[6]  J. Reveille,et al.  Radiographic assessment and psychologic variables as predictors of pain and functional impairment in osteoarthritis of the knee or hip. , 1988, Arthritis and rheumatism.

[7]  M. Morris,et al.  The relationship between the knee adduction moment and knee pain in middle-aged women without radiographic osteoarthritis. , 2006, Journal of Rheumatology.

[8]  K. Brandt,et al.  A comparison of lower extremity muscle strength, obesity, and depression scores in elderly subjects with knee pain with and without radiographic evidence of knee osteoarthritis. , 2000, The Journal of rheumatology.

[9]  Annegret Mündermann,et al.  The role of ambulatory mechanics in the initiation and progression of knee osteoarthritis , 2006, Current opinion in rheumatology.

[10]  F. Cicuttini,et al.  Knee cartilage loss in symptomatic knee osteoarthritis over 4.5 years , 2006, Arthritis research & therapy.

[11]  Michael T. Gross,et al.  Intramachine and Intermachine Reliability of the Biodex and Cybex® II for Knee Flexion and Extension Peak Torque and Angular Work , 1991 .

[12]  B B Seedhom,et al.  Conditioning of cartilage during normal activities is an important factor in the development of osteoarthritis. , 2006, Rheumatology.

[13]  A. Mündermann,et al.  Implications of increased medio-lateral trunk sway for ambulatory mechanics. , 2008, Journal of biomechanics.

[14]  M. Hochberg,et al.  The relationship of anxiety and depression with self-reported knee pain in the community: data from the Baltimore Longitudinal Study of Aging. , 1999, Arthritis care and research : the official journal of the Arthritis Health Professions Association.

[15]  E. C. Moura,et al.  Socioeconomic status and obesity in adult populations of developing countries: a review. , 2004, Bulletin of the World Health Organization.

[16]  T. Andriacchi,et al.  Potential strategies to reduce medial compartment loading in patients with knee osteoarthritis of varying severity: reduced walking speed. , 2004, Arthritis and rheumatism.

[17]  Mao‐Hsiung Huang,et al.  The effects of weight reduction on the rehabilitation of patients with knee osteoarthritis and obesity. , 2000, Arthritis care and research : the official journal of the Arthritis Health Professions Association.

[18]  L. Sharma,et al.  The role of knee alignment in disease progression and functional decline in knee osteoarthritis. , 2001, JAMA.

[19]  L. Kazis,et al.  Periarticular lesions detected on magnetic resonance imaging: prevalence in knees with and without symptoms. , 2003, Arthritis and rheumatism.

[20]  E. Roos,et al.  The effect of patient characteristics on variability in pain and function over two years in early knee osteoarthritis , 2005, Health and quality of life outcomes.

[21]  G. Bennett.  Can We Distinguish between Inflammatory and Neuropathic Pain , 2006 .

[22]  T. Andriacchi,et al.  The knee adduction moment during gait in subjects with knee osteoarthritis is more closely correlated with static alignment than radiographic disease severity, toe out angle and pain , 2002, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[23]  R. Moskowitz,et al.  Development of criteria for the classification and reporting of osteoarthritis. Classification of osteoarthritis of the knee. Diagnostic and Therapeutic Criteria Committee of the American Rheumatism Association. , 1986, Arthritis and rheumatism.

[24]  David A. Winter,et al.  Biomechanics and Motor Control of Human Movement , 1990 .

[25]  F Angst,et al.  Smallest detectable and minimal clinically important differences of rehabilitation intervention with their implications for required sample sizes using WOMAC and SF-36 quality of life measurement instruments in patients with osteoarthritis of the lower extremities. , 2001, Arthritis and rheumatism.

[26]  Johanne Martel-Pelletier,et al.  Long term evaluation of disease progression through the quantitative magnetic resonance imaging of symptomatic knee osteoarthritis patients: correlation with clinical symptoms and radiographic changes , 2005, Arthritis research & therapy.

[27]  U. P. Wyss,et al.  Semiautomatic three-dimensional knee motion assessment system , 1992, Medical and Biological Engineering and Computing.

[28]  S. Jebb,et al.  Behavioural determinants of obesity. , 2005, Best practice & research. Clinical endocrinology & metabolism.

[29]  T. Andriacchi,et al.  Effect of piroxicam on gait in patients with osteoarthritis of the knee. , 1993, Arthritis and rheumatism.

[30]  A Guermazi,et al.  The relationship between specific tissue lesions and pain severity in persons with knee osteoarthritis. , 2006, Osteoarthritis and cartilage.

[31]  Mao‐Hsiung Huang,et al.  Use of ultrasound to increase effectiveness of isokinetic exercise for knee osteoarthritis. , 2005, Archives of physical medicine and rehabilitation.

[32]  T D Cooke,et al.  A standardized technique for lower limb radiography. Practice, applications, and error analysis. , 1991, Investigative radiology.

[33]  Sarah E Lamb,et al.  Association between radiographic joint space narrowing, function, pain and muscle power in severe osteoarthritis of the knee , 2004, Clinical rehabilitation.

[34]  E S Grood,et al.  A joint coordinate system for the clinical description of three-dimensional motions: application to the knee. , 1983, Journal of biomechanical engineering.

[35]  Patrick A Costigan,et al.  Role of knee kinematics and kinetics on performance and disability in people with medial compartment knee osteoarthritis. , 2006, Clinical biomechanics.

[36]  J. Bloem,et al.  Osteoarthritis of the knee: association between clinical features and MR imaging findings. , 2006, Radiology.

[37]  D. Felson.  The sources of pain in knee osteoarthritis , 2005, Current opinion in rheumatology.

[38]  P. Dieppe,et al.  Associations between pain, function, and radiographic features in osteoarthritis of the knee. , 2006, Arthritis and rheumatism.

[39]  Seungbum Koo,et al.  A Framework for the in Vivo Pathomechanics of Osteoarthritis at the Knee , 2004, Annals of Biomedical Engineering.

[40]  M. Hochberg,et al.  Determinants of pain severity in knee osteoarthritis: effect of demographic and psychosocial variables using 3 pain measures. , 1999, The Journal of rheumatology.

[41]  T. Andriacchi,et al.  Knee pain and joint loading in subjects with osteoarthritis of the knee , 2000, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[42]  C. E. Clauser,et al.  Weight, volume, and center of mass of segments of the human body , 1969 .

[43]  Patrick A Costigan,et al.  Determinants of self-report outcome measures in people with knee osteoarthritis. , 2006, Archives of physical medicine and rehabilitation.

[44]  M. Wong,et al.  Approaching the shared biology of obesity and depression: the stress axis as the locus of gene–environment interactions , 2006, Molecular Psychiatry.

[45]  M. Sevick,et al.  Exercise and dietary weight loss in overweight and obese older adults with knee osteoarthritis: the Arthritis, Diet, and Activity Promotion Trial. , 2004, Arthritis and rheumatism.

[46]  U P Wyss,et al.  An integrated procedure to assess knee-joint kinematics and kinetics during gait using an optoelectric system and standardized X-rays. , 1993, Journal of biomedical engineering.

[47]  L. Sharma,et al.  Full-limb and knee radiography assessments of varus-valgus alignment and their relationship to osteoarthritis disease features by magnetic resonance imaging. , 2007, Arthritis and rheumatism.

[48]  M. Shrader,et al.  Effects of Knee Pain Relief in Osteoarthritis on Gait and Stair-Stepping , 2004, Clinical orthopaedics and related research.

[49]  E M Braunstein,et al.  Reduced quadriceps strength relative to body weight: a risk factor for knee osteoarthritis in women? , 1998, Arthritis and rheumatism.

[50]  C. Hui-Chan,et al.  Would the addition of TENS to exercise training produce better physical performance outcomes in people with knee osteoarthritis than either intervention alone? , 2004, Clinical rehabilitation.

[51]  P. Dieppe,et al.  The Bristol 'OA500 study': progression and impact of the disease after 8 years. , 2000, Osteoarthritis and cartilage.