Changes in bone marrow lesions in response to weight-loss in obese knee osteoarthritis patients: a prospective cohort study

Table 1 Baseline characteristics of all participants

Basic characteristics	N = 169
Female no. (%) ^*	136 (80 %)
Age (years) ^*	62.7 ± 6.3 (49.6-76.5)
Height (cm) ^*	166 ± 8 (148–191)
Weight (kg) ^*	102.3 ± 14.6 (76.0-145.0)
BMI (kg/m²) ^*	37.0 ± 4.5 (30.1-51.6)
C-reactive protein (mg/L) ^{1 §}	4.1 [2.2;7.3] (0.7-58.6)
Isometric maximal voluntary contraction
Quadriceps Muscle Strength (nm/kg) ^{1, 2 +}	1.1 [0.9;1.4] (0.1-2.8)
Hamstrings Muscle Strength (nm/kg) ^{1, 2 +}	0.5 [0.4;0.6] (0.0-1.1)
Radiographs
KL _{whole joint score} (0–4) ^{1, 3 *}	3.0 [2.0;3.0] (1.0 – 4.0)
KL _{medial tibiofemoral joint} (0–4) ^{1, 3 *}	2.0 [2.0;3.0] (0.0 – 4.0)
KL _{lateral tibiofemoral joint} (0–4) ^{1, 3 *}	2.0 [1.0;2.0] (0.0 – 4.0)
KL _{patellofemoral joint} (0–4) ^{1, 3 *}	2.0 [1.0;3.0] (0.0 – 4.0)
mJSW ^{1, 4 ^}	2.2 [0.00;3.8] (0.0 – 7.3)
MRI
Bone Marrow Lesions _{sum of size scores} ^{1, 5 *}	3.0 [1.0;5.0] (0.0-9.0)
Cartilage I _{combo score}(0–81) ^{1, 6 *}	15.0 [6.0;27.0] (0.0-61.0)
Osteophytes _{sum of scores} (0–36) ^{1 *}	13.0 [8.0;18.0] (1.0-35.0)
Menisci _{sum of extrusion scores} (0–12) ^{1 *}	7.0 [5.0;9.0] (0.0-12.0)
Menisci _{sum of morphology scores} (0–38) ^{1 *}	7.0 [6.0;8.0] (0.0-11.0)
Symptomatic assessment
KOOS _{Function in daily living (ADL)} ^*	60.4 ± 16.6 (11.8 – 98.5)
KOOS _Pain ^*	57.4 ± 15.9 (11.1 – 100)
Knee joint alignment axis ⁷
Varus (>0) / Valgus (<0) º	6.0 ± 4.8 (-8.6 – 23.7)

Plus-minus values are means ± SD and (min-max) unless otherwise stated.
¹ Presented as median, interquartile range [Q₁;Q₃] and (min – max).
² Measured isometric at 60 ° and normalized to body weight (nm/kg).
³ Scored using the Kellgren & Lawrence Grading system.
⁴ mJSW; minimum Joint Space Width (mm).
⁵ Sum of all BML size scores except those from patella.
⁶ For all analyzed areas we multiplied the “surface area”-score (0–3) with the “full thickness”-score (0–3), reaching results between 0 and 9 for each area, and then multiplied them into one “combo score” reaching a final score between 0 and 81.
⁷ From the static anatomical landmark calibration trials for each subject the knee joint mechanical axis alignment was calculated using a Plug-In-Gait model.
Number of participants included in analysis varied due to missing data for specific variables, as follows: ^* 169 patients; ⁺ 164 patients; ^{^} 152 patients; º 158 patients; ^§ 162 patients.

ISSN: 1471-2474