Relationships amongst osteoarthritis biomarkers, dynamic knee joint load, and exercise: results from a randomized controlled pilot study

Table 1 Mean (SD) values for KAM and strength outcomes as well as for log-transformed, unadjusted biomarker levels and ratios of degradation to synthesis (sCPII) at baseline and follow-up for each group

	Baseline data (n = 17)		Follow-up data (n = 16)		Between-group changes
	Exercise	No exercise	Exercise	No exercise	Difference	p-value
Gait outcomes
Peak KAM (%BW*ht)	3.75 (0.91)	3.38 (0.78)	3.70 (0.91)	3.21 (0.95)	0.04 (-0.64, 0.72)	0.91
KAM impulse (%BWhtsec)	1.13 (0.40)	1.32 (0.41)	1.01 (0.35)	1.24 (0.55)	–0.05 (–0.23, 0.32)	0.72
Walking speed (m/s)	1.18 (0.23)	1.03 (0.17)	1.28 (0.18)	1.04 (0.16)	0.08 (–0.02, 0.18)	0.11
Strength outcomes
Knee extension torque (Nm/kg)	1.25 (0.34)	0.98 (0.25)	1.35 (0.39)	0.97 (0.23)	0.10 (–0.25, 0.06)	0.19
Knee flexion torque (Nm/kg)	1.06 (0.33)	0.82 (0.29)	1.12 (0.35)	0.70 (0.48)	0.18 (–0.41, 0.06)	0.12
Hip abduction torque (Nm/kg)	0.78 (0.19)	0.59 (0.26)	0.87 (0.28)	0.69 (0.13)	–0.02 (–0.14, 0.18)	0.77
Urinary markers
uCTX-II (log ng/mmol creatinine)	5.40 (0.81)	5.97 (0.57)	5.32 (0.93)	6.25 (0.68)	–0.33 (–0.71, 0.04)	0.11
uC2C (log μg/mmol creatinine)	2.45 (0.68)	2.46 (0.76)	2.57 (0.81)	2.71 (0.58)	–0.10 (–0.35, 0.16)	0.73
Serum markers
sHA (log U/L)	3.47 (0.93)	3.80 (0.96)	3.26 (1.13)	4.21 (0.86)	–0.79 (–1.67, 0.08)	0.10
sCOMP (log U/L)	2.20 (0.21)	2.26 (0.17)	2.11 (0.24)	2.36 (0.13)	–0.16 (–0.30,–0.02)	0.04
sCPII (log U/L)	6.56 (0.19)	6.44 (0.53)	6.50 (0.36)	6.71 (0.40)	–0.34 (–0.94, 0.24)	0.27
Ratios
uCTX-II:sCPII	–1.16 (0.74)	–0.46 (0.49)	–1.18 (0.97)	–0.46 (0.81)	0.01 (–0.63, 0.66)	0.97
uC2C:sCPII	–4.11 (0.69)	–3.98 (1.19)	–3.93 (0.98)	–4.01 (0.73)	0.22 (–0.59, 1.03)	0.61
sHA:sCPII	–3.09 (0.99)	–2.64 (0.87)	–3.24 (1.37)	–2.50 (0.77)	–0.45 (–1.43, 0.53)	0.39

Group comparisons (exercise – no exercise) denote the difference in mean change (95% CIs). Between-group mean differences for gait and strength data are unadjusted, while biomarker data for each log-transformed biomarker and ratio using linear regression modeling while adjusting for age and sex. Note that negative log-transformed values indicate that the absolute ratio was less than 1.0, with greater negative values indicating a smaller ratio of the degradation biomarker to the synthesis biomarker sCPII. Thus, improvements in the ratio of degradation to synthesis would be reflected in smaller negative values at follow-up.

ISSN: 1471-2474