Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose
The external knee adduction moment (KAM) during gait has been characterized as a surrogate for dynamic medial knee load and is believed to be a risk factor for medial knee OA disease progression. By incorporating both load magnitude and duration, KAM impulse may provide a cumulative measure of KAM sustained during each step of walking. A reduction in KAM may be accompanied by a deleterious increase in the external knee flexion moment (KFM). Few longitudinal studies have evaluated the association between KAM impulse and peak KFM and subsequent medial OA disease progression. We hypothesized that in persons with knee OA, greater baseline peak KAM, KAM impulse, and peak KFM during gait are each associated with baseline-to-2-year worsening of medial cartilage thickness loss.
Methods
Participants had knee OA (K/L grade equal or greater than 2 in at least 1 knee). Baseline knee kinematics and kinetics during gait were recorded using an 8-camera Digital Real-Time Eagle motion analysis system, and 6 AMTI force plates; inverse dynamics used to compute peak KAM, KAM impulse, and peak KFM. MRI scans of both knees were done at baseline and 2-year visits. Regions of interest (ROI) were the entire medial tibial and weightbearing femoral surfaces; tibial external, central, and posterior subregions and femoral external and central subregions. Disease progression in each ROI was analyzed as: 1) baseline-to-2-year cartilage thickness loss equal or greater than 5%, and 2) % cartilage loss from baseline to 2 years later. We used logistic and continuous outcome regression models with GEE, adjusting for gait speed, age, and gender, then further adjusting for radiographic disease severity.
Results
The study sample included 385 knees (203 persons): mean age 64.2 years (SD 9.9); BMI 28.4 kg/m2 (5.7); 156 (76.8%) women. In Table 1, peak KAM and KFM were not associated with cartilage thickness loss at least 5% in the fully adjusted models. In contrast, KAM impulse was associated with thickness loss at both medial surfaces and in all but the tibial posterior subregions. For the continuous outcomes, greater peak KAM and KAM impulse were each associated with greater mean 2-year % thickness loss at the medial tibial surface, particularly the external and central subregions, and at the weightbearing femoral surface, particularly the central subregion (Table 2).
Conclusion
Higher baseline KAM impulse was associated with 2-year medial tibiofemoral cartilage thickness loss using both definitions of progression. Peak KFM was not associated with cartilage loss. These findings support targeting KAM parameters, particularly KAM impulse, in an effort to delay disease progression.
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Table 1. Adjusted odds ratios (95% CI) for medial tibiofemoral cartilage thickness loss outcomes (n = 385 knees; 203 persons)
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Baseline predictor variable |
Covariables included in the adjusted models |
Cartilage thickness loss (defined as ³ 5%) at 2-year follow-up (n=385 knees)
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Medial tibial surface
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Medial central weightbearing femoral surface
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Whole (74/385) (19.2%) |
Central subregion (103/384) (26.8%) |
External subregion (93/378) (24.6%) |
Posterior subregion (74/385) (19.2%) |
Whole (103/384) (26.8%) |
Central subregion (124/380) (32.6%) |
External subregion (98/373) (26.3%) |
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Peak KAM (% body wt*ht)
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Gait speed, age, and gender |
1.49 (0.94, 2.36) |
1.40 (0.94, 2.08) |
1.43 (0.94, 2.18) |
1.25 (0.87, 1.78) |
1.77 (1.05, 2.99) |
1.77 (1.06, 2.95) |
1.50 (0.96, 2.35) |
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Gait speed, age, gender, and K/L grade |
1.28 (0.96, 1.71)
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1.26 (0.93, 1.69)
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1.29 (0.94, 1.77)
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1.16 (0.87, 1.54) |
1.50 (0.99, 2.27)
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1.56 (0.97, 2.52)
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1.32 (0.94, 1.85) |
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KAM impulse (s*% body wt*ht)
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Gait speed, age, and gender |
3.43 (1.58, 7.45) |
2.30 (1.21, 4.37) |
2.50 (1.25, 4.98) |
2.26 (1.07, 4.80) |
4.24 (2.14, 8.42)
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4.39 (2.08, 9.24)
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3.12 (1.54, 6.33)
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Gait speed, age, gender, and K/L grade |
2.29 (1.25, 4.17)
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1.81 (1.05, 3.12)
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1.99 (1.09, 3.61)
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1.85 (0.996, 3.42) |
3.05 (1.73, 5.39)
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3.51 (1.78, 6.95)
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2.40 (1.28, 4.49) |
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Peak KFM (% body wt*ht)
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Gait speed, age, and gender |
0.98 (0.67, 1.43) |
0.98 (0.71, 1.34) |
1.12 (0.84, 1.50) |
0.97 (0.69, 1.37) |
1.19 (0.87, 1.62) |
1.21 (0.90, 1.65)
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1.21 (0.89, 1.63)
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Gait speed, age, gender, and K/L grade |
1.00 (0.71, 1.41) |
1.00 (0.74, 1.35) |
1.15 (0.88, 1.51) |
0.99 (0.71, 1.36) |
1.25 (0.95, 1.66) |
1.26 (0.94, 1.67) |
1.28 (0.98, 1.68) |
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95% CI excluding 1 is significant |
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Table 2. Adjusted coefficients (95% CI) for medial tibiofemoral cartilage thickness loss outcomes (n = 385 knees; 203 persons)
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Baseline predictor variable |
Covariables included in the adjusted models |
% Cartilage thickness loss at 2-year follow-up (n=385 knees)
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Medial tibial surface
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Medial central weightbearing femoral surface
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Whole (n=385)
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Central subregion (n=384) |
External subregion (n=378)
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Post. subregion (n=385)
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Whole (n=384)
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Central subregion (n=380)
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External subregion (n=373)
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Peak KAM (% body wt*ht)
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Gait speed, age, and gender |
1.48 (0.08, 2.88) |
2.98 (0.19, 5.78) |
5.06 (0.77, 9.36) |
1.01 (-0.10, 2.13) |
3.28 (0.36, 6.19) |
5.19 (0.46, 9.93) |
-3.57 (-19.77, 12.62) |
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Gait speed, age, gender, and K/L grade |
1.22 (0.03, 2.41)
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2.41 (0.08, 4.74)
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4.29 (0.64, 7.95)
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0.83 (-0.14, 1.80) |
2.72 (0.24, 5.20)
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4.38 (0.31, 8.46)
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-3.97 (-19.30, 11.36) |
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KAM impulse (s*% body wt*ht)
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Gait speed, age, and gender |
3.67 (1.36, 5.99) |
6.95 (2.50, 11.40) |
12.09 (5.18, 18.99) |
2.28 (-0.02, 4.57) |
8.53 (4.47, 12.58)
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13.11 (5.80, 20.42)
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-13.36 (-61.38, 34.65)
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Gait speed, age, gender, and K/L grade |
3.22 (1.24, 5.20)
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5.92 (2.19, 9.65)
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10.77 (4.94, 16.60)
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1.94 (-0.08, 3.96) |
7.55 (4.26, 10.85)
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11.70 (5.52, 17.87)
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-14.09 (-60.85, 32.68) |
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Peak KFM (% body wt*ht)
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Gait speed, age, and gender |
0.15 (-0.79, 1.08) |
0.55 (-1.36, 2.45) |
0.73 (-2.44, 3.90) |
0.26 (-0.60, 1.12) |
0.61 (-1.14, 2.35) |
0.94 (-2.10, 3.99)
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-1.46 (-7.35, 4.42)
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Gait speed, age, gender, and K/L grade |
0.19 (-0.69, 1.06) |
0.66 (-1.10, 2.42) |
0.87 (-2.13, 3.87) |
0.29 (-0.54, 1.13) |
0.71 (-0.81, 2.23) |
1.06 (-1.63, 3.76) |
-1.35 (-7.48, 4.79) |
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95% CI excluding 0 is significant |
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Disclosure:
A. H. Chang,
None;
K. C. Moisio,
None;
F. Eckstein,
Chondrometrics GmBH,
3,
Merck Serono, Abbvie,
2;
J. S. Chmiel,
None;
O. Almagor,
None;
P. Prasad,
None;
K. W. Hayes,
None;
L. Belisle,
None;
Y. Zhang,
None;
J. Rayahin,
None;
L. Sharma,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/association-between-baseline-external-knee-adduction-and-flexion-moments-during-gait-and-medial-tibiofemoral-cartilage-thickness-loss-over-two-years-in-persons-with-knee-osteoarthritis-oa/