Greater Lateral Femorotibial Cartilage Loss in Osteoarthritis Initiative Participants With Incident Total Knee Arthroplasty: A Prospective Cohort Study.
OBJECTIVE
To explore whether baseline to 12-month followup change in femorotibial cartilage thickness differs between subjects who received a total knee arthroplasty (TKA) between 24 and 60 months from those without TKA (non-TKA).


METHODS
In this prospective cohort study, 531 right knees from Osteoarthritis Initiative participants with definite radiographic knee osteoarthritis (Kellgren/Lawrence [K/L] grades 2-4) were studied. Segmentation was applied to coronal fast low-angle shot magnetic resonance images, to quantitatively determine cartilage thickness in 16 femorotibial subregions. Unadjusted P values (t-tests) and P values adjusted for age, baseline body mass index (BMI), K/L grade, and sex (generalized estimating equation models) were used to evaluate differences in longitudinal 1-year rates of cartilage thickness between TKAs and non-TKAs, with total knee arthroplasty status as fixed effect.


RESULTS
Of the 531 participants (mean ± SD ages 63 ± 9 years, BMI 30 ± 4.8 kg/m(2)), 40 received a femorotibial TKA within 4 years. At baseline, TKAs had thinner medial and lateral femorotibial cartilage (-15%; P < 0.001) than non-TKAs. Longitudinal cartilage thickness change was significantly greater in TKAs than in non-TKAs in the total femorotibial joint (area under the curve [AUC] 0.64), the lateral compartment (AUC 0.66), both tibiae (AUC ≥ 0.61), and the first 9 (of 16) ordered values of subregion change (AUC 0.64-0.69). Discrimination was stronger for TKAs that occurred at 24 and 36 months (n = 18) than for those at 48 and 60 months (n = 22).


CONCLUSIONS
Knees with incident TKA displayed smaller baseline cartilage thickness and greater lateral as well as location-independent ordered value femorotibial cartilage loss than non-TKAs. Discrimination of cartilage loss was greater for TKAs occurring within 2 years after the measurement than for those occurring later.
Paracelsus Medical University, Salzburg, Austria.
Wolfgang
W
Hitzl
Paracelsus Medical University, Salzburg, Austria, and Chondrometrics, Ainring, Germany.
Wolfgang
W
Wirth
Paracelsus Medical University, Salzburg, Austria, and Chondrometrics, Ainring, Germany.
Susanne
S
Maschek
Paracelsus Medical University, Salzburg, Austria, and Chondrometrics, Ainring, Germany.
Sebastian
S
Cotofana
University of California, San Francisco.
Michael
M
Nevitt
Novartis Pharma, Basel, Switzerland.
Markus R
MR
John
Merck KGaA, Darmstadt, Germany.
Christoph
C
Ladel
Paracelsus Medical University, Salzburg, Austria, and Chondrometrics, Ainring, Germany.
Felix
F
Eckstein
D000368:Aged; D019540:Area Under Curve; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology*; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology / Q000601:surgery*; D010147:Pain Measurement; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D016474:Weight-Bearing