Osteoarthritis (OA) is the most common form of arthritis. It is a degenerative disease affecting the whole joint. Any joint can be affected but OA most commonly affects the knees, hips, hands, neck and low back. It can be isolated to one joint but usually affects multiple joints. OA can lead to significant problems with mobility and is the most common cause of disability in elderly people in the developed world.¹ 85% of all knee and hip replacements are carried out because of osteoarthritis.²

Most evidence published regarding OA has limitations due to short study duration and the use of single drug treatments.³ Socioeconomic and psychosocial factors have an important role in establishing the disease burden for the individual with OA.⁴ National Institute for Health and Clinical Excellence (NICE) guidelines on the care and management of adults with osteoarthritis were published in February 2008. This article reflects these guidelines.⁵

Pathophysiology

Pathologically in osteoarthritis (OA), there are focal areas of damage to load-bearing articular cartilage, new bone formation at the joint margins (osteophytosis), changes in the subchondral bone (sclerosis), inflammation of the synovium (synovitis) and thickening of the joint capsule.

OA can be seen as a continuum of the normal repair process that takes place in all joint tissues as a result of joint trauma. However, in some people, perhaps because of severe trauma or problems with the repair process, there is continued tissue damage and symptomatic OA results.

Epidemiology

• Prevalence rises with age.
• About 6% of adults aged 30 have frequent knee pain and radiographic evidence of osteoarthritis (OA).⁶
• Symptomatic knee OA affects 12% of people over the age of 65.⁷

Risk factors

• Increasing age.
• Female sex (for knee disease).
• Family history (several chromosomal loci and gene variations have been identified as putting someone at increased risk for OA).⁸
• Previous joint injury including infection, intra-articular fracture and ligament tear causing joint instability.
• Joint malalignment problems such as Perthes' disease, slipped upper femoral epiphysis, and congenital dislocation of the hip.
• Obesity.
• Occupational (knee OA in elite athletes, elbow OA in people working with pneumatic drills).⁹
• Ethnic origin (more common in white Europeans).

Presentation

Structural changes can often occur with no accompanying symptoms. There is not inevitable progression of osteoarthritis (OA).⁵

Symptoms

• Joint pain that is exacerbated by exercise and relieved by rest. Rest and night pain can occur in advanced disease. Knee pain due to OA is usually bilateral and felt in and around the knee. Hip pain due to OA is felt in the groin and anterior or lateral thigh.⁹ Hip OA pain can also be referred to the knee and, in males, to the testicle on the affected side.
• Joint stiffness in the morning or after rest.
• Reduced function and participation restriction.⁵

Signs

• Reduced range of joint movement.
• Pain on movement of the joint or at extremes of joint movement.
• Joint swelling/synovitis (warmth, effusion, synovial thickening).
• Periarticular tenderness.
• Crepitus.
• Absence of systemic features such as fever, and rash.
• Bony swelling and deformity due to osteophytes - in the fingers this presents as swelling at the distal interphalangeal joints (Heberden's nodes, as seen in the picture below) or swelling at the proximal interphalangeal joints (Bouchard's nodes).
  
  
  
  
  
  
• Joint instability.
• Muscle weakness/wasting around the affected joint.

Investigations⁵

• Clinical examination: diagnosis is usually based on clinical examination.
• Plain X-rays: when disease is advanced it can be seen on plain X-rays. The diagnostic features that can be seen on X-ray are shown below:
  
  
  
  
  
  
• Body weight and body mass index: should be recorded.
• MRI: may be useful to distinguish other causes of joint pain.
• Blood tests: are normal in osteoarthritis (OA). Consider checking baseline FBC, creatinine and LFTs before starting a patient on non-steroidal anti-inflammatory drugs (NSAIDs).
• Joint aspiration: may be considered for swollen joints to exclude other causes such as septic arthritis and gout. The synovial fluid in OA is noninflammatory (leukocyte count <2 x 10⁹/L, clear and viscous).²

Differential diagnosis⁹

• Knee osteoarthritis (OA): bursitis; referred pain from the hip or spine.
• Hip OA: bursitis; referred pain from the knee or spine.
• OA of any joint: pseudogout; psoriatic arthritis; septic arthritis; viral arthritis; reactive arthritis such as Reiter's syndrome; rheumatoid arthritis; gout; connective tissue disease; seronegative arthritis such as ankylosing spondylitis; referred pain, and medical conditions presenting with arthropathy such as sarcoidosis and infective endocarditis.

Management⁵

Holistic approach to assessment and management

• The effect of osteoarthritis (OA) on a person's function, quality of life, occupation, mood, relationships and leisure activities should be determined. NICE has produced an aide-mémoire - see NICE quick reference guide.¹⁰ Ask about:
  • Current thoughts and beliefs - their concerns, expectations, knowledge about OA?
  • Their support network - is there a carer? If so, how is the main supporter coping (their ideas, concerns and expectations)?
  • Current mood (screen for depression) - any other stress?
  • Attitude to exercise?
  • Effect of OA on their life (e.g. activities of daily living, family tasks, work, hobbies, sleep, lifestyle expectations). Are are any adjustments required at home or in the workplace?
  • Pain assessment - what has the patient tried, including any drugs used (dose, side-effects, timing)? Are there other treatable sources of pain (e.g. periarticular pain, trigger finger, ganglion or bursitis)? Has a chronic pain syndrome developed?
  • Consider any comorbidities that may affect choice of treatment or fitness for surgery. Is the patient prone to falls - and can this be minimised?
• People with OA should be given the opportunity to make informed decisions about their care and treatment. A patient-centred management plan should be formulated by the healthcare professional and the person with OA.
  • Evidence-based information should be provided by healthcare professionals, in a written form that meets cultural and individual needs.
  • Risks and benefits of treatment options should be explained to the patient.
• People with OA should be reviewed regularly. Information sharing should be ongoing and not a 'one-off'.

Core treatments⁵

These should be offered to everyone with OA.

• Education, advice and access to information: both oral and written information should be provided.
• Exercise: should be encouraged in all people with OA, regardless of their age, comorbidity, pain or disability. This should include exercise for general aerobic fitness and local muscle strengthening. As well as helping weight loss, exercise itself will help to build muscle strength and endurance and can lead to reduced pain and improved joint function. Physiotherapy may be useful.
• Weight loss advice: if the patient is overweight/obese. This will reduce the load on their joints and help to improve pain.

First-line drug treatments⁵

• Paracetamol: either as required or in regular doses.
• Topical NSAIDs: these may be used alone or in conjunction with paracetamol. Topical NSAIDs may be first-line treatment in people with knee or hand OA.

Adjunctive treatments⁵

These are treatments that have either less well-proven efficacy, provide less symptom relief or carry increased risk to the patient. NICE suggests:

Other drug treatments:⁵

• Oral NSAIDs or cyclo-oxygenase 2 (COX-2) inhibitors: these can be used if paracetamol and/or topical NSAIDs provide insufficient pain relief. Standard NSAIDs or COX-2 inhibitors should be first choice (other than etoricoxib 60 mg). They should be co-prescribed with a proton pump inhibitor. They can be prescribed in addition to paracetamol. Prescribe in the lowest effective dose for the shortest period of time. Risks and benefits should be considered, particularly in the elderly. If the patient is already taking low-dose aspirin, other analgesics should be considered before adding an NSAID/COX-2 inhibitor.
• Opioids: may be useful if paracetamol and NSAIDs are not sufficient for pain control.
• Intra-articular corticosteroid injections: these should be considered as an adjunct to core treatment for the relief of moderate-to-severe pain.
• Capsaicin: this topical treatment should be considered as an adjunct to core treatment for people with knee and hand OA.

• Local heat and cold (thermotherapy): can be used as an adjunct to core treatment.
• Assistive devices (e.g. walking sticks, tap turners): occupational therapists or disability equipment assessment centres can offer advice to people whose OA affects their activities of daily living. (A stick held in the hand of the unaffected side can relieve the load through the affected joint and help pain relief as well as improve function.)
• Supports and braces: can be used as an adjunct to core treatment if there is biomechanical joint pain.
• Shock-absorbing shoes or insoles: for people with lower limb OA.
• Transcutaneous electrical nerve stimulation (TENS): can be used as an adjunct to core treatment for pain relief.
• Manual therapy (manipulation and stretching): can be used as an adjunct to core treatment, particularly for OA of the hip.

• Arthroscopic lavage and debridement: should only be carried out if the patient has knee OA with a clear history of mechanical locking. It should not form part of 'standard' treatment.
• Joint arthroplasty: referral for joint surgery should be considered for people with joint symptoms (pain, stiffness and reduced function) that:
  • Have a reduced impact on their quality of life.
  • Have not responded to nonsurgical treatment.

Referral should be made before there is prolonged and established functional limitation and severe pain. A patient's age, gender, smoking status, weight and comorbidities should not be barriers to referral.

Treatments not supported by the National Institute for Health and Clinical Excellence⁵

NICE does not advocate the following:

• The use of electro-acupuncture for people with osteoarthritis (OA).
• The use of glucosamine or chondroitin for the treatment of OA.
• The use of rubefacients for the treatment of OA.
• The use of intra-articular hyaluronan injections for the treatment of OA.

Other points about treatments

The following are further points about some specific treatments, including some of the more controversial treatments not recommended by NICE.

• NSAIDs: a recent BMJ editorial also reported that topical NSAIDs are as effective as oral NSAIDs and that patients prefer them.^11,12
• Opioids:
  • There is no evidence that low-dose opioids combined with paracetamol (co-codamol 8/500, co-dydramol 10/500) have any increased benefit over paracetamol alone.¹³
  • Higher-dose codeine (60 mg) has been shown to provide good analgesic effect when given with 1 g paracetamol.¹⁴
  • Caution should be used if stronger opioids are prescribed, due to the risk of dependency. Moderate/strong opioids may be necessary for those awaiting joint surgery, for those in whom other treatments have not controlled their pain, or for those unsuitable for surgery.
• Intra-articular steroids:
  • May be useful if there is acute pain and joint effusion as long as inflammatory, septic and other forms of arthritis have been excluded.
  • In primary care, intra-articular steroid hip injections should only be given by specialised GPs in a suitable environment.
• Joint replacement surgery:
  • The joint lasts for 15 years in 95% of cases.¹⁵
  • Hip and knee replacements are most common.
• Glucosamine:
  • Glucosamine is found naturally in the body and is one of the building blocks of cartilage. It has been hypothesised that supplements may help to prevent cartilage breakdown and help to rebuild cartilage.
  • Glucosamine can be purchased over-the-counter by the patient.
  • There are shellfish-derived formulations so patients should be warned. Also, it may possibly potentiate the effect of warfarin.
  • The decision not to advocate the use of glucosamine was made by NICE on the basis of evidence from high-quality meta-analyses and randomised controlled trials (RCTs) plus cost-effectiveness analysis.¹⁰
  • However, it is disputed by others who state that there is high-quality evidence that glucosamine 1,500 mg daily has benefit for knee osteoarthritis (OA) pain.^{16,17,18,19,20}
  • A large trial in the USA showed that 24 weeks of treatment with either glucosamine or chondroitin sulfate, or a combination of the two, was no better than placebo for knee OA pain. The side-effects of glucosamine and chondroitin sulfate were similar to placebo.²¹
• Chondroitin:
  • Chondroitin is not licensed for the treatment of OA.
  • A recent meta-analysis has shown that the symptomatic benefit of chondroitin is minimal or nonexistent and concluded that its use in clinical practice should be discouraged.²²
• Intra-articular hyaluronan:
  See separate article Hyaluronates and Viscosupplementation.
  • Viscosupplementation use is controversial and it is not advocated by NICE.
  • It is used, particularly in private care, for those who have not responded to, or cannot tolerate intra-articular steroids, or for those awaiting joint replacement.
  • It is thought to increase the natural hyaluronic acid in the synovial fluid, returning the elasticity and viscosity of the synovial fluid to normal; however, there is limited evidence to support this.⁹

Complications

These can include reduced mobility which can lead to problems with self-care and loss of employment.

Prognosis

• Most people affected by osteoarthritis (OA) do not become severely disabled.
• Knee OA seems to have the worst prognosis with most cases deteriorating over a 10-year period. Hand OA has the best.
• A recent study has shown that generalised OA is associated with the radiological progression of knee OA. Knee pain, baseline radiological severity, sex, quadriceps strength, knee injury and regular sport activities did not seem to be related to the progression of OA in the knee.²³

Prevention

• Weight control.
• Increasing physical activity.
• Avoiding injury.
• Improving education about osteoarthritis (OA) including increased use of expert patient programmes.
• Optimal management of symptoms by GPs to reduce the prevalence of disability due to OA.

Document references

1. Jinks C, Jordan K, Croft P; Measuring the population impact of knee pain and disability with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pain. 2002 Nov;100(1-2):55-64. [abstract]
2. Hunter DJ, Felson DT; Osteoarthritis. BMJ. 2006 Mar 18;332(7542):639-42.
3. Conaghan PG, Dickson J, Grant RL; Care and management of osteoarthritis in adults: summary of NICE guidance. BMJ. 2008 Mar 1;336(7642):502-3.
4. Lohmander LS, Roos EM; Clinical update: treating osteoarthritis. Lancet. 2007 Dec 22;370(9605):2082-4.
5. Osteoarthritis, NICE Clinical Guideline (January 2008); The care and management of osteoarthritis in adults
6. Peach CA, Carr AJ, Loughlin J; Recent advances in the genetic investigation of osteoarthritis. Trends Mol Med. 2005 Apr;11(4):186-91. [abstract]
7. Brion PH, Kalunian KC ; Oxford textbook of medicine. 4th edn. Oxford: Oxford University Press. Section 18.8. Osteoarthritis (2003) Warrell DA, Cox TM, Firth JD, Benz EJ Jr(Eds.)
8. Loughlin J; Genetics of osteoarthritis and potential for drug development. Curr Opin Pharmacol. 2003 Jun;3(3):295-9. [abstract]
9. Osteoarthritis, Clinical Knowledge Summaries (2008)
10. Osteoarthritis Quick Reference Guide - The care and management of osteoarthritis in adults. NICE, February 2008; Contains aide-mémoire covering holistic assessment
11. Dieppe P; Osteoarthritis of the knee in primary care. BMJ. 2008 Jan 19;336(7636):105-6. Epub 2007 Dec 4.
12. Underwood M, Ashby D, Cross P, et al; Advice to use topical or oral ibuprofen for chronic knee pain in older people: randomised controlled trial and patient preference study. BMJ. 2008 Jan 19;336(7636):138-42. Epub 2007 Dec 4. [abstract]
13. de Craen AJ, Di Giulio G, Lampe-Schoenmaeckers JE, et al; Analgesic efficacy and safety of paracetamol-codeine combinations versus paracetamol alone: a systematic review. BMJ. 1996 Aug 10;313(7053):321-5. [abstract]
14. Moore A, Collins S, Carroll D, et al; Paracetamol with and without codeine in acute pain: a quantitative systematic review. Pain. 1997 Apr;70(2-3):193-201. [abstract]
15. Callahan CM, Drake BG, Heck DA, et al; Patient outcomes following tricompartmental total knee replacement. A meta-analysis. JAMA. 1994 May 4;271(17):1349-57. [abstract]
16. Dalbeth N, Arroll B; Commentary: controversies in NICE guidance on osteoarthritis. BMJ. 2008 Mar 1;336(7642):504.
17. Herrero-Beaumont G, Ivorra JA, Del Carmen Trabado M, et al; Glucosamine sulfate in the treatment of knee osteoarthritis symptoms: a randomized, double-blind, placebo-controlled study using acetaminophen as a side comparator. Arthritis Rheum. 2007 Feb;56(2):555-67. [abstract]
18. Richy F, Bruyere O, Ethgen O, et al; Structural and symptomatic efficacy of glucosamine and chondroitin in knee osteoarthritis: a comprehensive meta-analysis.; Arch Intern Med. 2003 Jul 14;163(13):1514-22. [abstract]
19. No authors listed; Is glucosamine worth taking for osteoarthritis? Drug Ther Bull. 2002 Nov;40(11):81-3. [abstract]
20. Towheed TE, Maxwell L, Anastassiades TP, et al; Glucosamine therapy for treating osteoarthritis.; Cochrane Database Syst Rev. 2005 Apr 18;(2):CD002946. [abstract]
21. Clegg DO, Reda DJ, Harris CL, et al; Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis.; N Engl J Med. 2006 Feb 23;354(8):795-808. [abstract]
22. Reichenbach S, Sterchi R, Scherer M, et al; Meta-analysis: chondroitin for osteoarthritis of the knee or hip. Ann Intern Med. 2007 Apr 17;146(8):580-90. [abstract]
23. Belo JN, Berger MY, Reijman M, et al; Prognostic factors of progression of osteoarthritis of the knee: a systematic review of observational studies. Arthritis Rheum. 2007 Feb 15;57(1):13-26. [abstract]

Internet and further reading

• Osteoarthritis Quick Reference Guide - The care and management of osteoarthritis in adults. NICE, February 2008; Contains aide-mémoire covering holistic assessment

Acknowledgements