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Association between radiographic features of knee osteoarthritis and pain: results from two cohort studies

BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b2844 (Published 21 August 2009) Cite this as: BMJ 2009;339:b2844

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Dear Sir

The Multicentre Osteoarthritis study (MOST) (BMJ 29.8.09 Vol.339.498)
helpfully focussed on the problem of knee pain and correlation with OA
radiologically, its limitations clearly described in the LA of the same
issue. In 1973/4 my colleagues and I, in planning a series of
physiotherapy trials for OA knees were concerned to establish reliable
criteria which included detailed assessment of the x-ray method. Kellgren
and Lawrence system (1957)1 of grading did not enable us to localize
degenerative changes in terms of compartments of the knee and gave
unacceptable inter and intra observer errors. We (Clarke GR et al 1975)2
developed a new system based upon separate grading for the joint
compartments achieved by comparing supine and erect anteroposterior films
and also 45 degrees with lateral views of the patellae (Hughston JC 1968)3
[though just weight bearing AP and Houston (Skyline) patella views should
work as well].

The Multicentre study (MOST) did not mention the type of plain x-rays
taken. It also appeared to focus solely on the tibio femoral compartments.

In addition any knee study attempting to correlate pain with
radiological findings ought to include a clinical assessment since soft
tissue rheumatism in the form of enthesitis for example, is particularly
common around knees and can easily be missed as the main cause of pain
whereas x-rays suggest that OA is the primary cause. Whilst clinical
examination and ultrasound, if necessary, may be the best way of finding
the extent of soft tissue rheumatism, MRI scans may also be helpful in
defining the cause of the pain. However, they show degenerative change in
such detail that it may sometimes be difficult to know, without the
clinical or other approaches, the cause of the pain. Since micro trauma
may precede soft tissue inflammation the MRI scan itself can show mixed
features. Thus the need for matching a symptom with the signs. In a
recent patient the MRI described OA in the patello femoral joint, but a
probable medial gastrocnemius head and/or adjacent capsular tear. In fact
the problem was resolved by treatment directed at the gastrocnaemius head
leaving the knee pain-free, despite the patello femoral OA. However, the
latter could soon have become a problem as well, if the soft tissue lesion
was not resolved.

Dr G R Clarke MB.,B.CHIR.,F.R.C.P.

Consultant Rheumatologist

Spire Hartswood Hospital,
Eagle Way,
Brentwood,
Essex CM13 3LE

1Kellgren J.H. and Lawrence J.S. (1957) “Radiological Assessment of
Osteoarthrosis”. Ann. rheum. Dis. 16, 494

2G. R. Clarke, L.A. Willis, W.W. Fish and P.J.R.Nichols (1975) “A
Radiological Assessment of Osteoarthrosis of the Knee: Experiments in
Observer Error” Rheumatol. and Rehab. 14.81

3 Hughston J.C. (1968) “Recurrent Subluxation of the Patella” J. Bone
Jt. Surg. 50A, 1003

Competing interests:
None declared

Competing interests: No competing interests

21 September 2009
G R Clarke
Consultant Rheumatologist
Spire Hartswood Hospital, Brentwood, Essex CM13 3LE