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Editorial
Pain in Osteoarthritis: Looking beyond the Joint It has been more than a century since William Osler is attributed to have said, “When a patient with arthritis comes in the front door, I try to go out the back door.” Although a lot of advances have been made in the understanding and management of inflammatory arthritis, therapeutic options are still limited for osteoarthritis (OA), and as rheumatologists, we might still want to retain the back door for this set of patients. Therapy of OA has primarily revolved around pain relief with agents such as paracetamol, topical and systemic nonsteroidal anti-inflammatory drugs, intra-articular corticosteroids, and viscosupplementation. Duloxetine, a serotonin-norepinephrine reuptake inhibitor, has been increasingly used in the management of chronic pain in OA suggesting a pathology akin to chronic pain syndromes such as fibromyalgia. The main symptom in OA is pain and it commonly occurs in three stages. Initially, the pain may be intermittent and predictable, brought on by activity (early stage), then progressing to become a regular feature affecting daily activities (mild-moderate stage), and finally in advanced stage, there is a constant dull-aching pain with episodes of intense pain along with severe functional limitations.[1] Pain in OA has been attributed to the structural damage to the joint, but other factors beyond the joint also have a role in producing pain. Focal pain around the joint may also be due to periarticular lesions commonly associated with the disease, for example, anserine bursitis, tender medial fat pad, iliotibial band syndrome, and medial collateral ligament enthesopathy. From the above, it is evident that there is a lot of heterogeneity in the character and source of pain in OA. In this issue of the journal, Vignesh Narayan et al. have studied the presence of neuropathic pain in OA patients.[2] They used the Douleur Neuropathique 4 (neuropathic pain four questions in French: DN4) to diagnose neuropathic pain. This 10-point questionnaire includes both history (pain characteristic and positive/negative sensory phenomenon) and examination (hypo/hyperesthesia and allodynia). DN4 was devised by French investigators who had compared 89 patients with neuropathic pain versus 71 patients with nonneuropathic pain as per opinion of physicians experienced in pain medicine and trained in neurology.[3] Interestingly, of the 71 comparators, majority (56.3%) of the patients had OA, which along with other arthritides was taken as prototype of nonneuropathic pain! However, various studies subsequently have shown that neuropathic pain is not uncommon in OA.[4,5] In the study by Vignesh Narayan et al. published in this issue, all significant number of patients with OA had neuropathic pain (49.1% which reduced to 45.6% if diabetes was excluded). This correlated with greater functional disability
scores. However, it has to be noted that majority of the study population were recruited from outpatient departments, majority were newly diagnosed OA, and mean age was less compared to other studies. This study by Vignesh Narayan et al. has again brought into focus the need for a proper clinical assessment of patients with OA including a meticulous pain history focusing on the severity, character, and localization of pain and a neurological examination focused on peripheral nerves. This has therapeutic implications for initiating other pain modulator drugs such as tricyclic antidepressants, gabapentinoids, or 5-hydroxytryptamine–noradrenaline reuptake inhibitors.[6,7] Further large-scale prospective and cross-sectional studies are required to assess the prevalence of neuropathic pain in Indian patients with OA and to identify clinical predictors such as age, sex, disease duration, and comorbidities along with the use of laboratory tests such as nerve conduction studies. As a continuum, there is a need for assessing the effectiveness of therapy targeted to neuropathic pain in these subsets of patients using well-designed randomized controlled trials. A lot of advances have taken place in recent years in understanding the pathogenesis of OA and we are probably nearer to identifying a disease-modifying OA drug. However, relief of pain will always remain a felt need as this is the primary complaint for which patients approach health-care providers. Probably a multipronged approach is required in the management of OA using various categories of drugs, nonpharmacological approaches targeting the biopsychosocial derangement in these patients. Management of OA with personalized medicine is probably the ultimate future[8] to make the back door redundant for rheumatologists.
Darshan S Bhakuni, Sivasami Kartik1 Senior Consultant Medicine and Rheumatology, HQ Central Command, Lucknow, Uttar Pradesh, 1Senior Advisor Medicine and Rheumatology, Department of Rheumatology, Command Hospital (Southern Command), Pune, Maharashtra, India Address for correspondence: Dr. Sivasami Kartik, Command Hospital (SC), Pune, Maharashtra, India. E-mail:
[email protected]
References 1.
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Hawker GA, Stewart L, French MR, Cibere J, Jordan JM, March L, et al. Understanding the pain experience in hip and knee osteoarthritis – An OARSI/OMERACT initiative. Osteoarthritis Cartilage 2008;16:415-22. Vignesh Narayan R, Thabah MM, Poduval M. Neuropathic pain among patients with primary knee osteoarthritis: Results of a cross‐sectional study from a tertiary care center in Southern India. Indian J Rheumatol 2017;12:132-8. Bouhassira D, Attal N, Alchaar H, Boureau F, Brochet B, Bruxelle J,
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et al. Comparison of pain syndromes associated with nervous or somatic lesions and development of a new neuropathic pain diagnostic questionnaire (DN4). Pain 2005;114:29-36. Duarte RV, Raphael JH, Dimitroulas T, Sparkes E, Southall JL, Ashford RL, et al. Osteoarthritis pain has a significant neuropathic component: An exploratory in vivo patient model. Rheumatol Int 2014;34:315-20. Ohtori S, Orita S, Yamashita M, Ishikawa T, Ito T, Shigemura T, et al. Existence of a neuropathic pain component in patients with osteoarthritis of the knee. Yonsei Med J 2012;53:801-5. Thakur M, Dickenson AH, Baron R. Osteoarthritis pain: Nociceptive or neuropathic? Nat Rev Rheumatol 2014;10:374-80. Dimitroulas T, Duarte RV, Behura A, Kitas GD, Raphael JH. Neuropathic pain in osteoarthritis: A review of pathophysiological mechanisms and implications for treatment. Semin Arthritis Rheum 2014;44:145-54. Sawitzke AD. Personalized medicine for osteoarthritis: Where are we now? Ther Adv Musculoskelet Dis 2013;5:67-75.
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DOI: 10.4103/0973-3698.211946
How to cite this article: Bhakuni DS, Kartik S. Pain in osteoarthritis: Looking beyond the joint. Indian J Rheumatol 2017;12:128-9.
Indian Journal of Rheumatology ¦ Volume 12 ¦ Issue 3 ¦ September 2017
