Healio
Healio
December 19, 2011
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Epidemiology and Impact of OA

Osteoarthritis (OA) is an extremely common and disabling chronic condition. The World Health Organization estimates that worldwide approximately 10% of men and 18% of women ages 60 and older have symptomatic OA of any site; specific regional estimates for knee OA are shown in the Figure.1

Figure. Prevalence of Osteoarthritis of the Knee, by Age Group, Sex, and Region (2000)
Figure. Prevalence of Osteoarthritis of the Knee, by Age Group, Sex, and Region (2000)
Source: Woolf AD, Pfl eger B. Burden of major musculoskeletal conditions. Bulletin of the World Health Organization. 2003;81(9):646-656.


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Globally, OA was the sixth leading cause of years living with disability as of 1990.1 The global burden is expected to ncrease disproportionately in developing countries, where the greatest gains in life expectancy are being made, but access to care such as joint replacement is limited. A recent report estimates that the proportion of the population older than 65 in Singapore, India, Malaysia, Bangladesh and the Philippines will increase by more than 250% over the next 3 decades, adding to the burden of OA in these countries.2

OA is highly prevalent in Europe and the United States. An estimated 8.5 million people in the United Kingdom3 and 27 million adults in the United States have OA of at least one joint.4 Arthritis, of which OA is the most common type, is the most frequent cause of disability among U.S. adults,5 and a large proportion of individuals with arthritis report related activity limitations, which increase with age, in both the United States and the United Kingdom.3,6 In addition to reduced function and increased disability, people with OA have reduced quality of life and increased mortality compared with those without the condition. Among U.S. adults ages 50 to 84, an average of 1.7 quality-adjusted life-years per person, or a population total of 10 million quality-adjusted life-years, are lost to symptomatic knee OA.7 This impact increases to a total of 86 million quality-adjusted life-years lost if obesity, knee OA, or their combination, is considered, with a disproportionate effect on African-American and Hispanic women.7 Therefore, OA imposes a substantial burden of disease at the global, regional and individual levels that is likely to increase with time as the world’s populations age and experience ever increasing rates of obesity.

Clinical Exam and Imaging

OA is a clinical diagnosis with affected joints (most often hands, particularly the base of the thumb, knees, hips, great toe and spine) demonstrating pain, crepitus, bony enlargement and morning stiffness of short duration (< 30 minutes).8-10 Risk factors include age, overweight or obesity, sedentary lifestyle, joint injury and malalignment, certain occupations requiring repetitive or extreme physical demands, and congenital and genetic factors.

Conventional radiography, long used for assessment due to cost-effectiveness and wide availability, can demonstrate osteophytes (bony spurs), narrowing of the joint space, bony sclerosis and cysts. However, radiographic findings do not always correlate with symptoms, are not sensitive to change, and generally reflect late manifestations of disease when damage has already occurred. Magnetic resonance imaging (MRI) can demonstrate changes earlier in disease, such as synovitis and bone marrow lesions, before damage is apparent on conventional radiographs; these findings are associated with joint pain11 and provide more sensitivity for early diagnosis and response to treatment. While MRI is extremely useful for research purposes, this type of imaging is not generally needed for routine diagnosis or management of OA. Ultrasound has a sensitivity between that of radiographs and MRI for most features and can provide point-of-care assessments and improved accuracy for intra-articular interventions.11

Nonsurgical Management

No cure has been discovered for OA, and no agent has yet been proven to prevent or reduce structural damage over time. Guidelines for management have been published by the Osteoarthritis Research Society International12 and the European League Against Rheumatism,13 among others. The recommendations are overall quite consistent, with a combination of nonpharmacologic and pharmacologic treatments thought to be optimal, focusing on education and exercise with weight loss, self-management techniques and appropriate assistive devices.

Acetaminophen (para​cetamol) has a modest effect size and overall good side-effect profile and is therefore recommended as first-line pharmacologic management with oral NSAIDs as a second-line therapy. Topical NSAIDs are emerging as a potentially effective and safer alternative to oral; either can be utilized depending on the situation. For refractory pain, or where other agents are contraindicated, opioid analgesics may be an option. Other agents, such as glucosamine and chondroitin, remain controversial due to conflicting evidence, but may be considered in some cases. Modest short-term benefits may be seen with intra-articular treatment with glucocorticoids (1 to 3 weeks) or hyaluronan (up to 6 months).14

More recently, nonpharmacologic therapies such as acupuncture and tai chi have shown promise in reducing pain in OA.15 Newer agents, such as duloxetine, approved for use in chronic musculoskeletal pain in 2010, may provide additional avenues of symptomatic relief by addressing central pain pathways. Tanezumab, a monoclonal antibody against nerve growth factor, showed promise in clinical trials for OA pain relief, although adverse events (paresthesias and progressive destructive arthritis) led to suspension of further trials.

Quality Care Indicators

Despite the numerous and consistent recommendations available, clinical uptake of treatment guidelines has been disappointing.16 Quality indicators are one way to demonstrate implementation of recommendations, with the goal of improving patient care. Such indicators have been suggested by several entities, including the Arthritis Foundation, ACOVE (Assessing Care Of Vulnerable Elders) and the American Medical Association.16,17 Examples of quality indicators would be a yearly prescription or review of an appropriate exercise program, or for overweight patients, yearly advice to lose weight.17 The few studies to date of nonpharmacologic interventions have shown suboptimal quality of care based on such indicators.18

Surgical Management

Total joint replacement can provide substantial benefit for pain and functional status where more conservative treatments have failed. The vast majority of joint replacements at the knee (97%) and hip (86%) are performed for OA.19 In 2006, 542,000 primary knee and 231,000 hip replacements were performed in the United States,20 and these figures are expected to increase to 3.5 million primary total knee and 570,000 total hip replacements annually by 2030, with a potential cost of more than $100 billion, or 1% of the U.S. gross domestic product, in 2007 dollars.19

Joint-sparing techniques are also available for subgroups of patients. Surgical reconstruction for basal thumb joint OA can relieve pain and improve function.21 While arthroscopic debridement is no longer recommended for knee OA alone, trials are underway to assess the usefulness of arthroscopic meniscal repair.21 Osteotomy to correct malalignment at the knee or a dysplastic acetabulum can be done in patients for whom joint replacement is not optimal, although no controlled studies have been performed to determine whether OA is slowed or prevented by such procedures. Advances in tissue engineering have led to promising treatments such as autologous chondrocyte implantation, in which a patient’s own chondrocytes are cultured and implanted into a chondral defect, resulting in growth of new hyaline cartilage.21

Future Directions

Active research areas in OA include disease pathogenesis, biomechanical factors, genetic contributions, biochemical markers and imaging techniques and interpretation, in addition to therapeutic interventions. In response to such studies, specific disease phenotypes and the very definition of OA are changing. New MRI definitions are in development22 to improve diagnosis and monitoring of structural changes over shorter times, particularly for clinical trials. Interest has increased in the way that pain and psychosocial factors are assessed.23 Improved disease definitions, along with carefully designed trials and methodologic advances, promise to provide more meaningful results from intervention trials, leading to improved care.

References

  1. Woolf AD, Pfleger B. Burden of major musculoskeletal conditions. Bull World Health Organ. 2003;81(9):646-656.
  2. Fransen M, Bridgett L, March L, Hoy D, Penserga E, Brooks P. The epidemiology of osteoarthritis in Asia. Int J Rheum Dis. 2011;14(2):113-121.
  3. Arthritis Care. OA Nation Report. 2004. http://www.arthritiscare.org.uk/PublicationsandResources/Forhealthprofessionals/OANation. Accessed September 26, 2011.
  4. Lawrence RC, Felson DT, Helmick CG, Arnold LM, Choi H, Deyo RA, et al. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis Rheum. 2008;58(1):26-35.
  5. Centers for Disease Control and Prevention (CDC). Prevalence and most common causes of disability among adults—United States, 2005. MMWR. 2009;58(16):421-426.
  6. Centers for Disease Control and Prevention (CDC). Prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation—United States, 2007-2009. MMWR. 2010;59(39):1261-1265.
  7. Losina E, Walensky RP, Reichmann WM, Holt HL, Gerlovin H, Solomon DH, et al. Impact of obesity and knee osteoarthritis on morbidity and mortality in older Americans. Ann Intern Med. 2011;15;154(4):217-226.
  8. Altman R, Alarcon G, Appelrouth D, Bloch D, Borenstein D, Brandt K, et al. The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hip. Arthritis Rheum. 1991;34(5):505-514.
  9. Altman R, Alarcon G, Appelrouth D, Bloch D, Borenstein D, Brandt K, et al. The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hand. Arthritis Rheum. 1990;33(11):1601-1610.
  10. Altman R, Asch E, Bloch D, Bole G, Borenstein D, Brandt K, 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. Arthritis Rheum. 1986;29(8):1039-1049.
  11. Guermazi A, Roemer FW, Hayashi D. Imaging of osteoarthritis: update from a radiological perspective. Curr Opin Rheumatol. 2011;23(5):484-491.
  12. Zhang W, Moskowitz RW, Nuki G, Abramson S, Altman RD, Arden N, et al. OARSI recommendations for the management of hip and knee osteoarthritis, Part II: OARSI evidence-based, expert consensus guidelines. Osteoarthritis Cartilage. 2008;16(2):137-162.
  13. Jordan KM, Arden NK, Doherty M, Bannwarth B, Bijlsma JW, Dieppe P, et al. EULAR Recommendations 2003: an evidence based approach to the management of knee osteoarthritis: Report of a Task Force of the Standing Committee for International Clinical Studies Including Therapeutic Trials (ESCISIT). Ann Rheum Dis. 2003;62(12):1145-1155.
  14. Bellamy N, Campbell J, Welch V, Gee TL, Bourne R, et al. Intraarticular corticosteroid for treatment of osteoarthritis of the knee. Cochrane Database of Systematic Reviews. 2006;2:CD005328.
  15. Hawker GA, Mian S, Bednis K, Stanaitis I. Osteoarthritis year 2010 in review: non-pharmacologic therapy. Osteoarthritis Cartilage. 2011;19(4):366-74.
  16. Hunter DJ, Neogi T, Hochberg MC. Quality of osteoarthritis management and the need for reform in the US. Arthritis Care Res (Hoboken). 2011;63(1):31-38.
  17. Hochberg MC. Quality measures in osteoarthritis. Clin Exp Rheumatol. 2007;25(6 suppl 47):102-106.
  18. Li LC, Sayre EC, Kopec JA, Esdaile JM, Bar S, Cibere J. Quality of Nonpharmacological Care in the Community for People with Knee and Hip Osteoarthritis. J Rheumatol. 2011;38:2230-2237.
  19. United States Bone and Joint Decade. The Burden of Musculoskeletal Diseases in the United States. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2008.
  20. Buie V.C, Owings MF, DeFrances CJ, Golosinskiy A. National Hospital Discharge Survey: 2006 Summary. Vital Health Stat. 2010;13:168.
  21. Katz JN, Earp BE, Gomoll AH. Surgical management of osteoarthritis. Arthritis Care Res (Hoboken). 2010;62(9):1220-1228.
  22. Hunter DJ, Arden N, Conaghan PG, Eckstein F, Gold G, Grainger A, et al. Definition of osteoarthritis on MRI: results of a Delphi exercise. Osteoarthritis Cartilage. 2011;19(8):963-969.
  23. Hawker GA, Davis AM, French MR, Cibere J, Jordan JM, March L, et al. Development and preliminary psychometric testing of a new OA pain measure—an OARSI/OMERACT initiative. Osteoarthritis Cartilage. 2008;16(4):409-414.