Relationship of meniscal damage, meniscal extrusion, malalignment, and joint laxity to subsequent cartilage loss in osteoarthritic knees.
OBJECTIVE
Progressive knee osteoarthritis (OA) is believed to result from local factors acting in a systemic environment. Previous studies have not examined these factors concomitantly or compared quantitative and qualitative cartilage loss outcomes. The aim of this study was to test whether meniscal damage, meniscal extrusion, malalignment, and laxity each predicted tibiofemoral cartilage loss after controlling for the other factors.


METHODS
Laxity and alignment were measured at baseline in individuals with knee OA. Magnetic resonance imaging included spin-echo coronal and sagittal imaging for meniscal scoring and axial and coronal spoiled gradient echo sequences with water excitation for cartilage quantification. Tibial and weight-bearing femoral condylar subchondral bone area and cartilage surface were segmented. Cartilage volume, denuded bone area, and cartilage thickness were quantified in each plate, with progression defined as cartilage loss >2 times the coefficient of variation for each plate. Qualitative outcome was assessed as worsening of the cartilage score. Logistic regression analysis with generalized estimating equations yielded odds ratios for each factor, adjusting for age, sex, body mass index, and the other factors.


RESULTS
We studied 251 knees in 153 persons. After full adjustment, medial meniscal damage predicted medial tibial cartilage volume loss and tibial and femoral denuded bone increase, while varus malalignment predicted medial tibial cartilage volume and thickness loss and tibial and femoral denuded bone increase. Lateral meniscal damage predicted every lateral outcome. Laxity and meniscal extrusion had inconsistent effects. After full adjustment, no factor except medial laxity predicted qualitative outcome.


CONCLUSIONS
Using quantitative cartilage loss assessment, local factors that independently predicted tibial and femoral loss included medial meniscal damage and varus malalignment (medially) and lateral meniscal damage (laterally). A measurement of quantitative outcome was more sensitive at revealing these relationships than a qualitative approach.
Division of Rheumatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA. L-Sharma@northwestern.edu
Leena
L
Sharma
Felix
F
Eckstein
Jing
J
Song
Ali
A
Guermazi
Pottumarthi
P
Prasad
Dipali
D
Kapoor
September
S
Cahue
Meredith
M
Marshall
Martin
M
Hudelmaier
Dorothy
D
Dunlop
D000368:Aged; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D008592:Menisci, Tibial / Q000503:physiopathology*; D008875:Middle Aged; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D011187:Posture / Q000502:physiology; D000070600:Tibial Meniscus Injuries