Vitamin D levels, creatinine clerarance and their association with balance ability and muscle stregth in knee osteoarthritis

To examine the effect of serum active vitamin D (1,25 (OH) D) levels and creatinine clearance(CrCl) on balance ability and muscle strength in patients with knee osteoarthritis.35 women with radiographic knee osteoarthritis (OA) (Kellgren-Lawrence grade 2-3) with kneepain (61.03 ± 6.5 years) and 35 healthy women (60,97± 7,86 years) enrolled in this study. There wasno statistically significant difference between the groups about age, sex, length and body mass indexmeans (p > 0,05).Clinical balance tests performed were Berg balance scale (BBS), short physical performancebattery test (SPPBT) and tandem walking (5 meters). Balance ability was also measured bykinesthetic ability trainer 3000 (KAT) with static and dynamic protocols.Isokinetic strength measurements of both knee flexor/extensors (60º and 180º/sec angularvelocities) and both ankle dorsiflexor/plantar flexors (30º and 120º/sec angular velocities) wereassessed using the Cybex Norm isokinetic dynamometer.Serum 1,25 (OH) D levels and CrCl were determined in all study participants.Student's t test was used to determine the differences between two groups. P <0.05 wasconsidered significant statistically. Pearson correlation coefficient was applied for the relationshipsbetween different parameters. Balance disorders and clear knee- ankle weakness were determinedwhen OA group was compared to control group.Significant differences were found between the two groups BBS, SPPBT, tandem gait (5 meters),KAT static (respectively p : <0,001; 0,003; 0,001; 0,031). Knee osteoarthritis and control groupsbetween did not differ significantly about creatinine clearance (p=0,280). In OA group; active vitaminD levels, were significantly lower than the control group. (respectively values: 21,40±9,12 ve33,17±15,25) (p<0,001).In OA group, mean peak torque values of knee extensor and flexor for 60º and 180º/sec velocities,ankle dorsiflexor for 30º and 120º/sec velocities were significantly lower than the control group.Decline in balance ability and muscle strength is common in patients with knee osteoarthritis.Vitamin D deficiency may contribute to decrease in muscle strength seen in osteoarthritis orimmobilization as a consequence of knee osteoarthritis may lead to limited sun exposure and vitaminD deficiency. Vitamin D status should be cautiously investigated in patients with knee osteoarthritis.