Current Concepts in Osteoarthritis

This article was originally written as a review article by Gordon Cameron for Update magazine in 2000. Update is a magazine mainly written for family doctors. The article has been updated in 2005

Case Study

Richard is a 57-year-old publican and an ex professional footballer. He has had right knee pain for three years and now finds it difficult to work. His sleep has been disturbed by pain for the last four months and he gains only partial relief from a combination of Naproxen and Tramadol.He has complained of dyspepsia for the last six weeks.

Examination reveals him to be overweight, to have poor leg muscle tone and he stands on a flexed right knee. There is a small cool effusion in the knee and he has lost both flexion and extension on passive testing.

When did you last inject an arthritic knee? What about an ankle? A wrist? If a patient faces a long wait for surgery are steroid injections likely to be helpful or harmful?Which patients benefit most from joint replacement surgery? At what stage in their illness should you refer them? When might the risks outweigh the benefit?What can a physiotherapist offer? Will their intervention prevent or delay the need for surgery?These questions highlight a problem in today's general practice. Only a few GP's are skilled in the assessment and treatment of joint pain and training is often deficient. Knowledge of the modern orthopaedic surgeon's approach is gleaned in limited fashion from clinic letters and, for most general practitioners, the workings of a physiotherapy department are shrouded in mystery.But we all see a lot of patients with musculoskeletal pain!An audit in my practice showed that only respiratory symptoms are more prevalent than joint or soft tissue pain and the cost of drug prescribing is astonishing. The figures below give an indication of the costs of pain management in general practice. They refer only to Scotland but can almost certainly be generalized to the rest of the UK.

 2,972,010 NSAID prescriptions written in Scotland during 1999:   at a cost of £23,858,000

 5,586,018 Analgesic prescriptions written in Scotland during 1999:   at a cost of £26,863,000

• 808,000 prescriptions for diclofenac were dispensed in Scotland during 1999 at a cost to the NHS of £8,999,000
• 146 million tablets of Coproxamol were dispensed in Scotland during 1999 at a cost to the NHS of £1,693,000

• The most expensive analgesic item was tramadol: 185,000 prescriptions cost  £3,028,000

(Figures obtained from PRISMS software via the Common Services Division Pricing Agency, Scotland)

But price of a tablet is not the whole story. The true cost of any drug must include the expense of treating its side effects! Non steroidal anti-inflammatory drugs are directly responsible for many hospital admissions every year.

DIAGNOSING OSTEOARTHRITIS

In general practice the diagnosis of osteoarthritis is usually based on the result of an X-ray although the first clues may be clinical. But how the bones look is only part of the picture. The osteoarthritis disease process begins in cartilage and the joint often becomes painful long before typical features are seen on X-ray. Indeed the appearance of osteophytes and subchondral bone changes indicate that the degenerative process is advanced. Surgeons now realise that the disease process starts not in bone but in cartilage. Arthroscopy, MRI scanning and blood testing for molecular markers allow early assessment of cartilage condition and might eventually lead to much earlier diagnosis and intervention. Disease modifying anti-osteoarthritic drugs are in the early stages of development and, if effective, will revolutionize orthopaedic surgical practice. General practitioners must aim for earlier diagnosis. At the moment we refer those patients most suitable for (or most desperate for) joint replacement. If the condition could be managed medically and progression to end stage degeneration slowed or prevented then radical changes in secondary care services would follow.But for now, referral is most appropriate for the type of patient described below:

Who to refer for joint replacement

• Pain in the joint at rest despite good compliance with adequate medication
• Night pain despite good compliance with adequate medication
• Walking distance severely impaired by pain

Adequate analgesia is an important issue. In an audit of 100 consecutive patients referred to my hospital orthopaedic clinic with osteoarthritic joint pain, only 36 were taking any analgesia and less than half of those took it on a regular basis.

Spotting those at risk –early diagnosis in general practice

The triggers of osteoarthritis are complex. Primary generalized osteoarthritis of the type that produces hand pain and Heberden's nodes is clearly genetic and inherited in a Mendelian fashion. Patients with a family history of this condition should be counselled about joint protection, work choices, the avoidance of obesity and about maintaining good overall muscle tone and fitness. Localized large joint osteoarthritis is related to long-term joint stress or to previous cartilage disease. A nice way to visualize this is to consider firstly the effect of abnormal stress on normal cartilage and then, secondly, the damage caused by normal stress to abnormal cartilage. 

Osteoarthritis caused by abnormal stress acting on normal cartilage

Risk factors

• Obesity Previous trauma or meniscal surgery
• Hypermobility syndrome
• Paget's disease
• Aseptic necrosis of bone
• Childhood orthopaedic disease

Osteoarthritis caused by normal stress acting on abnormal cartilage

Risk factors

• Acromegaly
• Chronic gout
• Inflammatory arthritis
• Uncorrected hypothyroidism
• Pyrophosphate deposition disease

The triggers in the first group above are likely to be seen in the general practice setting and it's important to identify these patients and flag up their risk. Early intervention in high-risk patients will help them and advice on weight loss is a good example. This is an overlooked but fertile area for practice audit. Obesity is a huge problem! The Framingham study showed that a 5kg gain in weight increased the risk of knee osteoarthritis by forty percent. Fat patients are not appealing surgical or anesthetic candidates and all patients with osteoarthritis must strive for a reduction in body weight. Get a dietician involved if you can. Trauma too, is highly relevant. Meniscectomy leads to osteoarthritis within twenty years in seventy percent of patients and degeneration of the elbow joint follows fracture of the radial head as surely as night follows day. Patients in these categories need advice on lifestyle, body weight, and on how to protect their joints from further damage.

Childhood orthopaedic ailments such as Perthe's disease, congenital hip dislocation and slipped femoral epiphyses are also known to predispose to osteoarthritis in adult life.

Making the diagnosis – the clinical presentation of osteoarthritis

Pain is the cardinal feature in osteoarthritic joints and key questions relate to the presence of rest pain, night pain and pain on activity. The clinical features in many patients are clear-cut and although X-ray remains the gold standard, it is probably overused by GP's as it rarely alters the management. Apply the principles outlined below regardless of the X-ray result and most patients will benefit.

Different joints present in slightly different ways.

The degenerate hip

Watch your patient as they walk. Hip degeneration leads to a typical waddling gait with the affected leg held slightly externally rotated. The painful joint is held flexed, causing an apparent dip towards that side when walking – the so called trendelenburg gait or "adductor lurch."Hip osteoarthritis causes groin pain which will radiate down towards the knee or below if severe. Most patients with buttock pain have a problem in the lumbar spine but sometimes referred hip pain is felt in the ipsilateral upper buttock or low back and this can cause difficulty in diagnosis. In cases where there is real diagnostic difficulty then an injection of local anaesthetic into the hip under X-ray control helps to differentiate. Functionally the patient struggles with activities that involve hip flexion – tying shoelaces, putting on socks or getting into or out of a car. Examination reveals a loss of internal rotation, a loss of flexion and a loss of abduction in comparison with the non affected side. End stage disease also causes a loss of extension which can result in a fixed flexion deformity.

The degenerate knee

Again – watching gait can help make the diagnosis. The medial knee compartment is often worst affected and shows most loss of joint space on X-ray. In severe cases the typical "knock knee" or valgus drift develops. Osteophytes are often visible or palpable around the medial side of the joint and a small effusion may be present. Beware the "hot joint" - most osteoarthritic joints are cool to the touch and a joint with active signs of synovitis should make you review your diagnosis!Pain is felt around or within the knee and radiation down the leg is not common. Mechanical symptoms such as locking or giving way may occur and, in a degenerate knee, suggest the presence of loose bodies of ossified cartilage in the joint space.

Examination should reveal a cool joint with or without an effusion – often without. Both flexion and extension are impaired and loss of the latter can lead to a fixed flexion deformity that obliges the patient to stand or walk on a permanently flexed knee. Osteophytes may be palpable beneath the skin and there may be generalized tenderness – most marked on the medial aspect.

EARLY INTERVENTION STRATEGIES IN OSTEOARTHRITIS

Having identified the risk population and made an early diagnosis of osteoarthritis – what can a GP do in the practice setting?Current wisdom suggests the following step-wise approach.

Non-pharmacological management

Patient education and social support should form the bedrock of care in osteoarthritis. I find the leaflets produced by ARC – the Arthritis and Rheumatism Council – to be very user friendly. Dramatic benefit has been shown from this type of input and results improved if a spouse was actively involved in the package. Regular "telephone check ups" by a nurse practitioner reduced pain and improved function in two studies. Weight reduction is crucial but many general practitioners have become cynical about it. Don't be too pessimistic - a weight loss of 5kg is associated with a fifty-percent reduction in the risk of developing symptomatic knee OA. The days of forcing patients to achieve an unrealistically low target weight are behind us. Even a small weight loss will improve symptoms in most patients.

Persuading them to change their footwear is a simple but very effective intervention for patients with knee or hip degeneration. A good pair of cushion sole training shoes can make a huge difference to the symptoms – especially in the elderly.

Physiotherapy

Virtually all patients with osteoarthritis will benefit from seeing a physiotherapist and the earlier they are referred, the better. Physiotherapists frequently bemoan the fact that general practitioners don't send them patients with OA until it is too late for them to make useful interventions. Muscle tone and balance work, proprioceptive training, exercise regimes, stretches, taping, aerobic fitness and advice on joint protection are all valuable to the patient with early degenerative change in the joints. There has been some recent emphasis on foot biomechanics and orthotic insoles but I think this is overstated. Many patients wait months for expensive insoles only to discard them because they are too uncomfortable to wear.Some studies suggest a useful analgesic effect can be obtained by acupuncture but this has not yet gained a footing as a conventional treatment approach.

MEDICAL TREATMENTS

There are three strands to medical management of osteoarthritis – oral medication, topical applications and injection treatments. All fall comfortably into the remit of the average GP.

Oral medication

Allow your patient a trial of simple analgesia before considering the use of NSAID's. The latter are more toxic and with a few exceptions, significantly more expensive. Some patients' lives are transformed by anti-inflammatory medication but most do just as well on paracetamol or an opiate-paracetamol compound like coproxamol. Newer drugs such as Tramadol are vastly more costly and probably no more efficacious. Make sure your patient is taking their medication on a regular basis and in adequate dose before introducing changes.

Patients vary in their response to anti-inflammatory medication and it's often worth trying a few different NSAID's before abandoning this class of drug. Doctors and patients need to be cautious of the potential side effects from oral medication.

Topical applications

"Rubbing it better" has always been effective and cynics might claim that this is the only reason topical agents work. But good studies, including one meta-analysis, do indicate some role for topical anti-inflammatory gels and creams. The benefits are only moderate but some patients find them helpful. Another drug that works when applied topically is Capsaicin – an irritant extract of the pepper plant -although some patients are deterred by skin reactions.

Joint injections

Injecting steroid into osteoarthritic joints is either controversial or an essential part of day to day practice. It depends who you ask!In my experience rheumatologists use injections frequently and to apparent good effect. Surgeons seem much more wary. Many GP's would feel confident about injecting a knee joint but would steer clear of a hip, ankle or elbow. Steroids are relatively safe and moderately effective at reducing pain in osteoarthritic joints but there is the long term beneficial or harmful effects are unclear. The weight of evidence favors benefit and a few studies at a biochemical level show steroids protecting cartilage from further deterioration. Consensus suggests that no more than two or three steroid injections be given into a knee in the course of a year but many consultants would consider even that to be too often. In my view steroid injections are best reserved for those patients who are not (or not yet) suitable for surgery and for whom other remedies have failed to ease their pain. 

Patients suited to joint injection with steroid

Pain not controlled by other means and:

• Too young for surgery
• Too old for surgery
• Too medically unfit for surgery

Contraindications to joint injection:

• Allergic to local anaesthetic or to the steroid drug
• Local sepsis around the joint

• Warfarin therapy or haemophila are relative contraindications to injection because of the risk of causing bleeding within the joint.

Be very wary of introducing infection during joint injections. Always use a no touch aseptic technique, aspirate and examine the synovial fluid and avoid injections in patients with plaque psoriasis around the joint. The psoriais plaques are nearly always colonised by staphylococcus.

Recent work has focussed on the injection of hyaluronic acid into arthritic knees. Drugs such as synvisc one and hyalgan seem likely to play an increasingly important role in management. This type of injection is called viscosupplementation.

In summary

Osteoarthritis is a very common condition. Family doctors should try to identify it and intervene at an earlier stage than at present. An audit to flag those with predisposing factors and to tackle known risk factors is likely to be productive for most practices. New therapeutic approaches will come in time but a logical stepwise approach to care with early involvement of physiotherapists is the best we have for now. Many patients do eventually require surgery for pain relief but the road towards the knife can be made much easier by relatively simple interventions.

The Cameron Medical Website has a huge amount of content on issues related to joint pain, arthritis, back pain and other orthopaedic or joint problems. Most of it is written by Dr Cameron specially for this website. Click here to see what's available.  

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