Knee Pain Predicts Subsequent Shoulder Pain and the Association Is Mediated by Leg Weakness: Longitudinal Observational Data from the Osteoarthritis Initiative.
To assess whether the "spread" of joint pain is related to pain-associated muscle loss in 1 joint leading to increased loading and subsequent pain in other joints.



Associations between persistent knee pain (pain in 1 or 2 knees over 0-3 years vs no persistent pain) and incident shoulder pain at Year 4 were examined in participants from the longitudinal National Institutes of Health Osteoarthritis Initiative. Associations were assessed using log multinomial modeling, adjusted for age, sex, body mass index, depression score, other lower limb pain, and baseline leg weakness (difficulty standing from a sitting position).



In older adults with clinically significant knee osteoarthritis (OA) or at risk of knee OA (n = 3486), the number of painful joints increased yearly, from 2.1 joints (95% CI 2.0-2.2) at baseline increasing by 5.2% (95% CI 2.2-8.3) at Year 4. Shoulders were the next most commonly affected joints after knees (28.5%). Persistent pain in 1 or 2 knees increased risk of bilateral shoulder pain at Year 4 [1 knee: relative risk (RR) 1.59, 95% CI 0.97-2.61; 2 knees: RR 2.02, 95% CI 1.17-3.49] after adjustment for confounders. Further adjustment for leg weakness attenuated effect sizes (1 knee: RR 1.13, 95% CI 0.60-2.11; 2 knees: RR 1.44, 95% CI 0.75-2.77), indicating mediation by functional leg weakness.



Spread of joint pain is not random. Persistently painful knees predict new bilateral shoulder pain, which is likely mediated by leg weakness, suggesting that biomechanical factors influence the spread of pain.
From the Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Leeds Institute of Rheumatic and Musculoskeletal Medicine, and UK National Institute for Health Research (NIHR) Leeds Musculoskeletal Biomedical Research Unit, University of Leeds, Leeds, UK.|L.L. Laslett was funded by an Osteoarthritis Research International Young Investigator Scholarship while at the University of Leeds. She is also supported by an Arthritis Australia - Australian Rheumatology Association Heald Fellowship and a National Health and Medical Research Council Early Career Fellowship (Clinical Research Fellowship; GNT1070586). This study was supported by an Arthritis Research UK project grant (ref 20800), the Arthritis Research UK Experimental Osteoarthritis Treatment Centre (ref 20083), and the NIHR Leeds Musculoskeletal Biomedical Research Unit. The views expressed are those of the authors and not necessarily those of the UK National Health Service, the NIHR, or the Department of Health. The Osteoarthritis Initiative (OAI) is a public-private partnership composed of 5 contracts (N01-AR-2-2258; N01-AR-2-2259; N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the US National Institutes of Health, a branch of the US Department of Health and Human Services and conducted by the OAI Study Investigators. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corp., GlaxoSmithKline, and Pfizer. Private sector funding for the OAI is managed by the Foundation for the National Institutes of Health. This manuscript was prepared using an OAI public use dataset, and does not necessarily reflect the opinions or views of the OAI investigators, the National Institutes of Health, or the private funding partners.|L.L. Laslett, GDPH, PhD, Postdoctoral Research Fellow, Menzies Institute for Medical Research, University of Tasmania, and Visiting Scholar, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P. Otahal, BSc, GDipSc, Statistician, Menzies Institute for Medical Research, University of Tasmania; E.M. Hensor, PhD, Biostatistician, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; S.R. Kingsbury, PhD, Postdoctoral Research Fellow, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P.G. Conaghan, FRACP, FRCP, PhD, Professor of Musculoskeletal Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds.
Laura L
LL
Laslett
From the Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Leeds Institute of Rheumatic and Musculoskeletal Medicine, and UK National Institute for Health Research (NIHR) Leeds Musculoskeletal Biomedical Research Unit, University of Leeds, Leeds, UK.|L.L. Laslett was funded by an Osteoarthritis Research International Young Investigator Scholarship while at the University of Leeds. She is also supported by an Arthritis Australia - Australian Rheumatology Association Heald Fellowship and a National Health and Medical Research Council Early Career Fellowship (Clinical Research Fellowship; GNT1070586). This study was supported by an Arthritis Research UK project grant (ref 20800), the Arthritis Research UK Experimental Osteoarthritis Treatment Centre (ref 20083), and the NIHR Leeds Musculoskeletal Biomedical Research Unit. The views expressed are those of the authors and not necessarily those of the UK National Health Service, the NIHR, or the Department of Health. The Osteoarthritis Initiative (OAI) is a public-private partnership composed of 5 contracts (N01-AR-2-2258; N01-AR-2-2259; N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the US National Institutes of Health, a branch of the US Department of Health and Human Services and conducted by the OAI Study Investigators. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corp., GlaxoSmithKline, and Pfizer. Private sector funding for the OAI is managed by the Foundation for the National Institutes of Health. This manuscript was prepared using an OAI public use dataset, and does not necessarily reflect the opinions or views of the OAI investigators, the National Institutes of Health, or the private funding partners.|L.L. Laslett, GDPH, PhD, Postdoctoral Research Fellow, Menzies Institute for Medical Research, University of Tasmania, and Visiting Scholar, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P. Otahal, BSc, GDipSc, Statistician, Menzies Institute for Medical Research, University of Tasmania; E.M. Hensor, PhD, Biostatistician, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; S.R. Kingsbury, PhD, Postdoctoral Research Fellow, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P.G. Conaghan, FRACP, FRCP, PhD, Professor of Musculoskeletal Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds.
Petr
P
Otahal
From the Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Leeds Institute of Rheumatic and Musculoskeletal Medicine, and UK National Institute for Health Research (NIHR) Leeds Musculoskeletal Biomedical Research Unit, University of Leeds, Leeds, UK.|L.L. Laslett was funded by an Osteoarthritis Research International Young Investigator Scholarship while at the University of Leeds. She is also supported by an Arthritis Australia - Australian Rheumatology Association Heald Fellowship and a National Health and Medical Research Council Early Career Fellowship (Clinical Research Fellowship; GNT1070586). This study was supported by an Arthritis Research UK project grant (ref 20800), the Arthritis Research UK Experimental Osteoarthritis Treatment Centre (ref 20083), and the NIHR Leeds Musculoskeletal Biomedical Research Unit. The views expressed are those of the authors and not necessarily those of the UK National Health Service, the NIHR, or the Department of Health. The Osteoarthritis Initiative (OAI) is a public-private partnership composed of 5 contracts (N01-AR-2-2258; N01-AR-2-2259; N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the US National Institutes of Health, a branch of the US Department of Health and Human Services and conducted by the OAI Study Investigators. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corp., GlaxoSmithKline, and Pfizer. Private sector funding for the OAI is managed by the Foundation for the National Institutes of Health. This manuscript was prepared using an OAI public use dataset, and does not necessarily reflect the opinions or views of the OAI investigators, the National Institutes of Health, or the private funding partners.|L.L. Laslett, GDPH, PhD, Postdoctoral Research Fellow, Menzies Institute for Medical Research, University of Tasmania, and Visiting Scholar, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P. Otahal, BSc, GDipSc, Statistician, Menzies Institute for Medical Research, University of Tasmania; E.M. Hensor, PhD, Biostatistician, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; S.R. Kingsbury, PhD, Postdoctoral Research Fellow, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P.G. Conaghan, FRACP, FRCP, PhD, Professor of Musculoskeletal Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds.
Elizabeth M A
EM
Hensor
From the Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Leeds Institute of Rheumatic and Musculoskeletal Medicine, and UK National Institute for Health Research (NIHR) Leeds Musculoskeletal Biomedical Research Unit, University of Leeds, Leeds, UK.|L.L. Laslett was funded by an Osteoarthritis Research International Young Investigator Scholarship while at the University of Leeds. She is also supported by an Arthritis Australia - Australian Rheumatology Association Heald Fellowship and a National Health and Medical Research Council Early Career Fellowship (Clinical Research Fellowship; GNT1070586). This study was supported by an Arthritis Research UK project grant (ref 20800), the Arthritis Research UK Experimental Osteoarthritis Treatment Centre (ref 20083), and the NIHR Leeds Musculoskeletal Biomedical Research Unit. The views expressed are those of the authors and not necessarily those of the UK National Health Service, the NIHR, or the Department of Health. The Osteoarthritis Initiative (OAI) is a public-private partnership composed of 5 contracts (N01-AR-2-2258; N01-AR-2-2259; N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the US National Institutes of Health, a branch of the US Department of Health and Human Services and conducted by the OAI Study Investigators. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corp., GlaxoSmithKline, and Pfizer. Private sector funding for the OAI is managed by the Foundation for the National Institutes of Health. This manuscript was prepared using an OAI public use dataset, and does not necessarily reflect the opinions or views of the OAI investigators, the National Institutes of Health, or the private funding partners.|L.L. Laslett, GDPH, PhD, Postdoctoral Research Fellow, Menzies Institute for Medical Research, University of Tasmania, and Visiting Scholar, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P. Otahal, BSc, GDipSc, Statistician, Menzies Institute for Medical Research, University of Tasmania; E.M. Hensor, PhD, Biostatistician, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; S.R. Kingsbury, PhD, Postdoctoral Research Fellow, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P.G. Conaghan, FRACP, FRCP, PhD, Professor of Musculoskeletal Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds.
Sarah R
SR
Kingsbury
From the Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia; Leeds Institute of Rheumatic and Musculoskeletal Medicine, and UK National Institute for Health Research (NIHR) Leeds Musculoskeletal Biomedical Research Unit, University of Leeds, Leeds, UK. P.Conaghan@leeds.ac.uk.|L.L. Laslett was funded by an Osteoarthritis Research International Young Investigator Scholarship while at the University of Leeds. She is also supported by an Arthritis Australia - Australian Rheumatology Association Heald Fellowship and a National Health and Medical Research Council Early Career Fellowship (Clinical Research Fellowship; GNT1070586). This study was supported by an Arthritis Research UK project grant (ref 20800), the Arthritis Research UK Experimental Osteoarthritis Treatment Centre (ref 20083), and the NIHR Leeds Musculoskeletal Biomedical Research Unit. The views expressed are those of the authors and not necessarily those of the UK National Health Service, the NIHR, or the Department of Health. The Osteoarthritis Initiative (OAI) is a public-private partnership composed of 5 contracts (N01-AR-2-2258; N01-AR-2-2259; N01-AR-2-2260; N01-AR-2-2261; N01-AR-2-2262) funded by the US National Institutes of Health, a branch of the US Department of Health and Human Services and conducted by the OAI Study Investigators. Private funding partners include Merck Research Laboratories, Novartis Pharmaceuticals Corp., GlaxoSmithKline, and Pfizer. Private sector funding for the OAI is managed by the Foundation for the National Institutes of Health. This manuscript was prepared using an OAI public use dataset, and does not necessarily reflect the opinions or views of the OAI investigators, the National Institutes of Health, or the private funding partners. P.Conaghan@leeds.ac.uk.|L.L. Laslett, GDPH, PhD, Postdoctoral Research Fellow, Menzies Institute for Medical Research, University of Tasmania, and Visiting Scholar, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P. Otahal, BSc, GDipSc, Statistician, Menzies Institute for Medical Research, University of Tasmania; E.M. Hensor, PhD, Biostatistician, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; S.R. Kingsbury, PhD, Postdoctoral Research Fellow, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds; P.G. Conaghan, FRACP, FRCP, PhD, Professor of Musculoskeletal Medicine, Leeds Institute of Rheumatic and Musculoskeletal Medicine and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds. P.Conaghan@leeds.ac.uk.
Philip G
PG
Conaghan
D000368:Aged; D018771:Arthralgia / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D020069:Shoulder Pain / Q000175:diagnosis* / Q000503:physiopathology
BIOMECHANICS; KNEE; OSTEOARTHRITIS; PAIN; SHOULDER DISORDERS