Session Type: ACR Concurrent Abstract Session
Session Time: 4:30PM-6:00PM
Background/Purpose: Cartilage morphometry on magnetic resonance images (MRIs) is an important outcome measure for clinical trials among individuals with knee osteoarthritis (KOA). However, it remains unclear if investigators should measure both the affected (index) and less affected tibiofemoral compartments. If the less affected compartment shows little change over time then investigators may focus solely on the index compartment and reduce the burden involved with measuring both tibiofemoral compartments. Hence, we calculated the sensitivity to change of cartilage loss in the medial and lateral tibiofemoral compartments among knees selected to represent the full range of medial and lateral tibiofemoral KOA.
Methods: We selected 100 knees with baseline and 24-month MRIs stratified by medial joint space narrowing (mJSN, 25 knees in each mJSN grade, 90 knees lateral JSN = 0) and 100 knees stratified by lateral joint space narrowing (lJSN, 25 knees in each lJSN grade, 94 knees medial JSN = 0) from the Osteoarthritis Initiative (OAI). One reader (MZ) used a customized software to measure the tibiofemoral cartilage damage index (CDI) on both the medial and lateral compartments of all 200 knees. The tibiofemoral CDI, which is a parsimonious articular cartilage assessment that focuses on areas where cartilage defects often develop, is based on 36 informative locations within medial and lateral tibiofemoral compartments (Figure 1, yellow stars) and adjusted by height. We calculated the mean percent of CDI change (MC %, the mean two-year change of CDI divided by the mean baseline CDI) for medial, lateral, and total (medial + lateral) tibiofemoral.
Results : Four knees (2 in mJSN and 2 in lJSN) were excluded because of image quality. The MC % value of medial CDI in the medial disease cohort are 5 to 17 times greater than MC % value of lateral CDI (table 1). The MC % value of lateral CDI in the lateral disease cohort are 4 to 15 times greater than MC % of medial CDI (Table 1). Even among knees with advance-stage disease (JSN=3) there was 29% and 19% cartilage loss in the index tibiofemoral compartment (medial and lateral, respectively), which was 5 and 15 times the change in cartilage within the other compartment.
Conclusion: The majority of the cartilage loss happens in the index compartment of the knee. We believe investigators could focus on cartilage loss in the index compartment, which would reduce the burden of measuring articular cartilage loss. Furthermore, adults with advance-stage disease should not be excluded from trials based on a fear that they will not progress during a 2-year period.
To cite this abstract in AMA style:Zhang M, Price LL, Canavatchel AR, Driban JB, Yuan P, Lo GH, McAlindon TE. Cartilage Loss Primarily Occurs in the Most Affected Tibiofemoral Compartment with No Evidence of a Ceiling Effect Among Advanced-Stage Disease: A Two-Year Longitudinal Study of Data from the Osteoarthritis [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/cartilage-loss-primarily-occurs-in-the-most-affected-tibiofemoral-compartment-with-no-evidence-of-a-ceiling-effect-among-advanced-stage-disease-a-two-year-longitudinal-study-of-data-from-the-osteoart/. Accessed October 28, 2020.
« Back to 2016 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/cartilage-loss-primarily-occurs-in-the-most-affected-tibiofemoral-compartment-with-no-evidence-of-a-ceiling-effect-among-advanced-stage-disease-a-two-year-longitudinal-study-of-data-from-the-osteoart/