The natural history of cartilage defects in people with knee osteoarthritis.
OBJECTIVE
Cartilage defects are highly prevalent in subjects with knee osteoarthritis (OA). Although they are associated with increased cartilage loss and joint replacement, there is little data on the natural history of cartilage defects. The aim of this study was to examine the progression of cartilage defects over 2 years in people with knee OA and to identify factors associated with progression.


METHODS
One hundred and seventeen subjects with OA underwent magnetic resonance imaging of their dominant knee at baseline and follow-up. Cartilage defects were scored (0-4) at four sites. Bone size of the medial and lateral tibial plateau was determined. Height, weight, body mass index and physical activity were measured by standard protocols.


RESULTS
The mean cartilage defect score increased significantly over the 2-year study period in all tibiofemoral compartments (all P<0.001), except the lateral tibial compartment with age and tibial plateau bone area at baseline being predictors of progression. However, there was heterogeneity with 81% progressing at any site, 15% remaining stable and 4% decreasing.


CONCLUSIONS
Over 2 years, cartilage defects tend to progress in people with symptomatic OA, with only a small percentage decreasing in severity. Increasing age and increased bone area are risk factors for progression. Interventions aimed at preventing cartilage defects from occurring and reducing their severity may result in a reduction in the severity of OA, by reducing loss of articular cartilage and subsequent requirement for knee joint replacement.
Davies-Tuck
M L
ML
Department of Epidemiology and Preventive Medicine, Monash University, Central and Eastern Clinical School, Alfred Hospital, Melbourne, Vic 3004, Australia.
Wluka
A E
AE
Wang
Y
Y
Teichtahl
A J
AJ
Jones
G
G
Ding
C
C
Cicuttini
F M
FM
D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002357:Cartilage Diseases / Q000473:pathology*; D018450:Disease Progression; D015444:Exercise / Q000502:physiology; D005260:Female; D005269:Femur; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology*; D012307:Risk Factors; D012720:Severity of Illness Index; D013977:Tibia