RESEARCH - Pain elsewhere worsens impact of knee pain

[Guest guest]

" Pain elsewhere " worsens impact of knee pain

Rheumawire

Jul 28, 2005

Janis

Keele, UK - Most older patients with knee pain also report pain at other

sites, and " pain elsewhere " worsens knee-related disability, Dr Croft

(Keele University, UK) and colleagues report in the August 2005 issue of

Arthritis & Rheumatism [1].

" The main implication is that it may be useful to classify older patients

who present with knee pain into those who have it as a solitary presentation

and those who present with it in the context of 'pain elsewhere'. Once other

possible underlying diagnoses have been ruled out, the clinician treating a

patient with 'knee pain plus pain elsewhere' [should] consider the

principles of general pain management (such as those used for fibromyalgia

or back pain), as well as purely local treatments to the knee, " Croft tells

rheumawire.

Is central pain sensitization a factor?

Croft and coauthors Drs Kelvin Jordan and Clare Jinks examined the effect of

" pain elsewhere " in addition to knee pain using a mail survey of people aged

50 or older registered with general medical practices in the UK.

Participants were asked to indicate, on a sketch of a figure, areas where

they had pain lasting more than one day in the previous month; they also

completed the Short Form 36 (SF36) health survey, the Hospital Anxiety and

Depression Scale, and the Western Ontario and McMaster University (WOMAC)

Osteoarthritis Index.

Surveys were mailed to 8995 potential participants, and 70% responded. The

data analysis was based on 5364 patients, of whom about one third reported

no pain. Of the remainder, 41% (n=2210) had knee pain with or without pain

elsewhere, and 23% (1245) had pain elsewhere.

The researchers found that 57% of responders with knee pain had pain in at

least two other joint areas. These subjects also reported worse physical

function and worse anxiety and depression and, as might be expected,

physical function declined as the number of pain sites rose.

" Knee pain and disability were less severe in those with knee pain alone

than in those with knee pain and pain elsewhere, even after adjusting for

age, sex, obesity, laterality of pain, and depression, " Croft reported.

Croft emphasizes, " This was an observational epidemiological study and not

an intervention study, and so suggestions about clinical interventions . . .

are very much given on the basis of . . . how current guidelines and reviews

fit with our results. As all researchers are fond of saying, more research

(namely intervention studies) is needed to prove whether separating people

into knee pain alone and knee pain plus in the clinic is a useful and

effective thing to do for patients and clinicians. "

The researchers found that most older people with knee pain also have pain

in other joints, and that the severity of knee pain and disability worsens

when the patient also has pain in other joints. They conclude that there

appears to be a link between the extent of pain experienced in the body and

the impact of pain in a particular area, such as the knee. " Our findings

contrast with the model of knee pain in older people that attributes the

effects of knee pain directly to the underlying pathology of osteoarthritis

(OA) in the joint, " the investigators write. They suggest that abnormal

central sensitization to pain might be a factor.

" There are certainly differences between those with knee pain alone and

those with knee plus other pain, but there are also differences between

those with knee pain plus [pain in] one or two [other spots] and those with

[pain in] three, four [or more spots], " Croft says. " As an epidemiologist, I

would encourage clinicians to think in terms of 'how much more pain has a

person got?' rather than construct different syndromes. However, I do think

that it might be useful in clinical practice with older people to separate

'knee pain on its own' from 'knee pain plus pain elsewhere'. " This might

encourage clinicians to think about pain management in general for the

latter group, without having to worry too much about defining the point at

which it becomes a " different syndrome. "

With regard to general issues of pain management, Croft stresses that his

was an epidemiological study and that, in the absence of an intervention

study, clinical advice rests on the authority of practice guidelines and

literature reviews. For the older patient with both knee and other pain,

Croft recommends:

Simple analgesia in which both local knee pain and pain elsewhere are

targeted

General exercise

Weight reduction

Good sleep hygiene

Treatment of anxiety and depression

Attention to the patient's general ideas and anxieties about pain

Providing self-help literature, advice, and information about groups

related to pain management to the patient.

Croft also points to the need for intervention studies, including research

to determine whether total knee replacement might reduce the frequency and

impact of pain elsewhere, as has been suggested by studies of hip

replacement [2].

Sources

1. Croft P, Jordan K, Jinks C. " Pain elsewhere " and the

impact of knee pain in older people. Arthritis Rheum 2005; 52:2350-2354.

2. Kosek E, Ordeberg G. Lack of pressure pain modulation by

heterotopic noxious conditioning stimulation in patients with painful

osteoarthritis before, but not following, surgical pain relief. Pain 2000;

8:69-78.

Not an MD

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org