Natural course of knee osteoarthritis in middle-aged subjects with knee pain: 12-year follow-up using clinical and radiographic criteria.
OBJECTIVE
To explore the natural course of knee osteoarthritis (OA) in a middle-aged population with chronic knee pain.


METHODS
A population-based sample of 143 subjects (mean age 45 (range 35-54), 44% women) with knee pain (>3 months) at inclusion was studied. Weight-bearing posteroanterior tibiofemoral (TF) radiographs were obtained at baseline and 12 years later, and classified according to Kellgren/Lawrence (K/L). Patellofemoral (PF) OA was determined at 5- and 12-years' follow-up using a skyline view and a cut-off point of <5 mm joint space width. The ACR clinical criteria were used at baseline.


RESULTS
Seventy-six (53%) had no TF OA (K/L 0) at baseline, but 49 had clinical OA. Overall, 65/76 (86%) developed incident TF OA over 12 years (K/L >or=1): 44/49 (90%) of the subjects with clinical OA and 21/27 (78%) without clinical OA. Progression was found in 65/67 (97%) with TF OA at baseline. Of the 84 with no PF OA at the 5-year examination, 26 (31%) developed PF OA over 7 years.


CONCLUSIONS
A majority of the subjects with chronic knee pain developed knee OA over 12 years. It is concluded that knee pain is often the first sign of knee OA.
Thorstensson
C A
CA
Research and Development Centre, Spenshult, S-313 92 Oskarström, Sweden. carina.thorstensson@spenshult.se
Andersson
M L E
ML
Jönsson
H
H
Saxne
T
T
Petersson
I F
IF
D000328:Adult; D018771:Arthralgia / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D002908:Chronic Disease; D042241:Early Diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology; D011379:Prognosis; D011859:Radiography; D013548:Sweden / Q000453:epidemiology